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Sample records for active oxygen scavenging

  1. Reactive oxygen scavenging activity of matured whiskey and its active polyphenols.

    PubMed

    Koga, K; Taguchi, A; Koshimizu, S; Suwa, Y; Yamada, Y; Shirasaka, N; Yoshizumi, H

    2007-04-01

    The quality of whiskey is known to improve remarkably by its storage over many years. This process is commonly termed "maturing." In this process, polyphenols derived from lignin and tannin of the barrel have an important role in not only forming the matured flavor and taste but also contributing to the advance of clustering ethanol and water in whiskey. It is also likely that polyphenols generally possess reactive oxygen (RO) scavenging activity. The present study evaluated the RO scavenging activity (free-radical scavenging activity, H(2)O(2) reduction activity under peroxidase coculture, and H(2)O(2)scavenging activity) of 24 single malt whiskeys with a maturation age of 10 to 30 y produced in Japanese, Scotch (Islay), or Scotch (Speyside and Highland) regions. Single malt whiskey not only showed RO scavenging activity but there was also a positive correlation between this activity and the maturation age of whiskey exceeding the difference resulting from the manufacturing region. A nonvolatile fraction derived from the barrel was responsible for RO scavenging activity. In particular, the contents of ellagic and gallic acids and lyoniresinol, the main polyphenolic compounds in whiskey, increased with maturation age. For the free-radical scavenging activity per molecule, each compound was 1.68 to 3.14 times that of trolox (a water-soluble vitamin E). The activities of ellagic acid, gallic acid, and lyoniresinol in the whiskey (Yamazaki 18) were equivalent to that of 80.3, 31.2, and 11.1 ppm trolox, respectively. Accordingly, the total activity of these 3 compounds accounted for about 20% of the activity of the whiskey (630.7 ppm trolox). PMID:17995817

  2. Reactive oxygen species scavenging activity of Jixueteng evaluated by electron spin resonance (ESR) and photon emission.

    PubMed

    Toyama, Toshizo; Wada-Takahashi, Satoko; Takamichi, Maomi; Watanabe, Kiyoko; Yoshida, Ayaka; Yoshino, Fumihiko; Miyamoto, Chihiro; Maehata, Yojiro; Sugiyama, Shuta; Takahashi, Shun-Suke; Todoki, Kazuo; Lee, Masaichi-Chang-Il; Hamada, Nobushiro

    2014-12-01

    Jixueteng, the dried stem of Spatholobus suberectus Dunn (Leguminosae), is a traditional Chinese herbal medicine that is commonly classified as a herb that promotes blood circulation and can be used to treat blood stasis. The aim of this study was to examine the reactive oxygen species (ROS) scavenging activity of Jixueteng and other herbal medicines. The ROS scavenging activities of the water extracts of Jixueteng, Cnidium officinale and Salvia miltiorrhiza were examined using an electron spin resonance (ESR) technique and faint luminescence measurement. The ESR signal intensities of the superoxide anion (O2·) and hydroxyl radical (HO·) were reduced more by Jixueteng than the other herbal medicines we tested. High photon emission intensity to hydrogen peroxide (H202) and HO· was observed in Jixueteng using the XYZ chemiluminescence system that was used as faint luminescence measurement and analysis. The results of the present study revealed that the ROS scavenging activity of 8% Jixueteng was the strongest among the herbal medicines we tested. It has been reported that Jixueteng includes various polyphenols. In the ROS scavenging activity by Jixueteng, it is supposed that the antioxidant activity caused by these polyphenols would contribute greatly. In conclusion, a water extract component of Jixueteng had potent free radical scavenging activity and an antioxidative effect that inhibited the oxidative actions of O2·⁻, H2O2 and HO·. Therefore, Jixueteng represents a promising therapeutic drug for reactive oxygen-associated pathologies. PMID:25632478

  3. Scavenging activity of "beta catechin" on reactive oxygen species generated by photosensitization of riboflavin.

    PubMed

    Kumari, M V; Yoneda, T; Hiramatsu, M

    1996-05-01

    "beta CATECHIN", a preparation containing green tea extract, ascorbic acid, sunflower seed extract, dunaliella carotene and natural vitamin E, has been designed as a model "universal antioxidant" that offers protection via its scavenging action on a wide range of free radicals, both water-soluble and fat-soluble. Reactive oxygen species like singlet oxygen, hydroxyl and superoxide radicals, are often generated in biological systems during photosensitized oxidation reactions. We report on the simultaneous effect of "beta CATECHIN" on active oxygen species generated during the photosensitized oxidation of riboflavin using 2,2,6,6-tetramethyl-4-piperidone (TMPD) as a "spin-trapping" agent. The intensities of the resulting stable nitroxide radical adduct, 2,2,6,6-tetramethyl-4-piperidone-1-oxyl (TEMPONE), were detected by electron spin resonance (ESR) spectroscopy. Results show simultaneous, nonspecific and complete scavenging action of reactive oxygen species generated in our in vitro model system by "beta CATECHIN". It is therefore suggested that "beta CATECHIN" could offer protection against free radical insult and in preventing cancer and other diseases that are mediated by reactive oxygen species. PMID:8739038

  4. Singlet oxygen scavenging activity of tocopherol and plastochromanol in Arabidopsis thaliana: relevance to photooxidative stress.

    PubMed

    Rastogi, Anshu; Yadav, Deepak Kumar; Szymańska, Renata; Kruk, Jerzy; Sedlářová, Michaela; Pospíšil, Pavel

    2014-02-01

    In the present study, singlet oxygen (¹O₂) scavenging activity of tocopherol and plastochromanol was examined in tocopherol cyclase-deficient mutant (vte1) of Arabidopsis thaliana lacking both tocopherol and plastochromanol. It is demonstrated here that suppression of tocopherol and plastochromanol synthesis in chloroplasts isolated from vte1 Arabidopsis plants enhanced ¹O₂ formation under high light illumination as monitored by electron paramagnetic resonance spin-trapping spectroscopy. The exposure of vte1 Arabidopsis plants to high light resulted in the formation of secondary lipid peroxidation product malondialdehyde as determined by high-pressure liquid chromatography. Furthermore, it is shown here that the imaging of ultra-weak photon emission known to reflect oxidation of lipids was unambiguously higher in vte1 Arabidopsis plants. Our results indicate that tocopherol and plastochromanol act as efficient ¹O₂ scavengers and protect effectively lipids against photooxidative damage in Arabidopsis plants. PMID:23848570

  5. Oxygen scavenging with enzymes

    SciTech Connect

    Hitzman, D.O.

    1983-11-08

    An effective method of reducing the amount of oxygen present in an aqueous fluid is described, which protects materials otherwise susceptible to oxidative degradation in the presence of free (dissolved) oxygen. The method comprises reacting the oxygen with an alcohol selected from the group consisting of methanol, ethanol, propanol, and butanol, in the further presence of alcohol oxidase. An oxygen containing aqueous fluid is a fluid comprising water and free oxygen. The fluid containing free oxygen can be, for example, oil field fluids, recycle water, foodstuffs, etc. The method is applicable to oil field aqueous fluid systems in order to protect oil field equipment to avoid molecular degradation of polymeric viscosifiers used in floods, etc., and to treat foodstuffs. 17 claims.

  6. Study of oxygen scavenging PET-based films activated by water

    NASA Astrophysics Data System (ADS)

    Rossi, Gabriella; Scarfato, Paola; Incarnato, Loredana

    2016-05-01

    In this work an active barrier system consisting of a thin and transparent film based on polyethylene terephthalate (PET) was studied. Dynamic oxygen absorption measurements were performed at different values of relative humidity and temperature, pointing out that humidity is a key factor in activating the oxidation of the polymer sample. Moreover, the thermal and optical properties of the films were investigated and a good correlation was found between the crystallinity increase and the consequent transparency reduction occurring after the oxygen absorption.

  7. Prevention of asbestos-induced cell death in rat lung fibroblasts and alveolar macrophages by scavengers of active oxygen species

    SciTech Connect

    Shatos, M.A.; Doherty, J.M.; Marsh, J.P.; Mossman, B.T.

    1987-10-01

    The possible modulation of asbestos-related cell death using antioxidants in both target and effector cells of asbestosis was investigated. After exposure to crocidolite asbestos at a range of concentrations (2.5-25 ..mu..gcm/sup 2/ dish), the viability of a normal rat lung fibroblast line and freshly isolated alveolar macrophages (AM) was determined. In comparison to fibroblasts, AM were more resistant to the cytotoxic effects of asbestos. Cytotoxic concentrations of asbestos then were added to both cell types in combination with the antioxidants, superoxide dismutase (SOD), a scavenger of superoxide (O/sub 2//sup -./), and catalase, an enzyme scavenging H/sub 2/O/sub 2/. Dimethylthiourea (DMTU), a scavenger of the hydroxyl radical (OH/sup ./) and deferoxamine, an iron chelator, also were evaluated in similar studies. Results showed significant dosage-dependent reduction of asbestos-associated cell death with all agents. In contrast, asbestos-induced toxicity was not ameliorated after addition of chemically inactivated SOD and catalase or bovine serum albumin. Results above suggest asbestos-induced cell damage is mediated by active oxygen species. In this regard, the iron associated with the fiber andor its interaction with cell membranes might be critical in deriving a modified Haber-Weiss (Fenton-type) reaction resulting in production of OH/sup ./.

  8. [Effects of exogenous silicon on active oxygen scavenging systems in chloroplasts of cucumber (Cucumis sativus L.) seedlings under salt stress].

    PubMed

    Qian, Qiong-Qiu; Zai, Wen-San; Zhu, Zhu-Jun; Yu, Jing-Quan

    2006-02-01

    With K(2)SiO(4) (1.0 mmol/L) treatment, the effects of Si on the distribution of Na(+), K(+) to chloroplasts and antioxidant system of cucumber leaves under 50 mmol/L NaCl stress were studied. The results showed that there was a selective transport of K(+) into the chloroplasts so that Na(+) content of chloroplasts was lower under Si treatment (Table 1); H(2)O(2) and MDA contents in chloroplasts were significantly decreased (Fig.1), and the activities of SOD, APX, GR and DHAR were increased simultaneity (Fig.2), and AsA, GSH contents were also increased in chloroplasts of salt-stressed cucumber by additional Si treatment (Fig.3). It may be concluded that Si could decrease absorption of Na(+) and increase ability of active oxygen scavenging in chloroplasts, therefore the injury of chloroplast membrane under salinity stress in cucumber was alleviated. PMID:16477139

  9. Transcript levels of antioxidative genes and oxygen radical scavenging enzyme activities in chilled zucchini squash in response to superatmospheric oxygen

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The transcript levels of antioxidative genes including Mn-superoxide dismutase (Mn-SOD), Cu/Zn SOD, ascorbate peroxidise (APX), and catalase (CAT) do not vary significantly during storage at 5 °C with high oxygen treatment in freshly harvested zucchini squash (Cucurbita pepo L. cv. Elite). However, ...

  10. Evaluation of reactive oxygen species scavenging activities and DNA damage prevention effect of Pleioblastus kongosanensis f. aureostriatus leaf extract by chemiluminescence assay.

    PubMed

    Ni, Qinxue; Xu, Guangzhi; Gao, Qianxin; Yang, Dongdong; Zhang, Youzuo

    2013-11-01

    Reactive oxygen species scavenging effect of Pleioblastus kongosanensis f. aureostriatus leaf extract against O2(-), OH and H2O2 were investigated by chemiluminescence methods in vitro. Bamboo grass leaves were extracted with 70% ethanol solution and sequentially partitioned with solvents in an order of increasing polarity. Among fractions of different polarity, BuOH and EtOAc fractions showed powerful scavenging activities than others, and showed better scavenging ability on OH than that of O2(-)and H2O2, with IC50 of 0.55 μg/mL and 0.60 μg/mL, respectively. Both OH-induced DNA damage model by chemiluminescence assay and plasmid pUC18 double-strand break model by agarose gel electrophoresis showed that BuOH and EtOAc fractions had remarkable concentration-dependent prevention effect on the OH-induced damage of DNA attribute to their good scavenging effects on ROS. Results from the compositional analysis of different fractions indicate that the flavonoids in the Pleioblastus kongosanensis f. aureostriatus leaf may be responsible for its ROS scavenging activity and DNA damage prevention ability. PMID:24103782

  11. The scavenging of free radical and oxygen species activities and hydration capacity of collagen hydrolysates from walleye pollock ( Theragra chalcogramma) skin

    NASA Astrophysics Data System (ADS)

    Zhuang, Yongliang; Li, Bafang; Zhao, Xue

    2009-06-01

    Fish skin collagen hydrolysates (FSCH) were prepared from walleye pollock ( Theragra chalcogramma) using a mixture of enzymes, namely trypsin and flavourzyme. The degree of hydrolysis of the skin collagen was 27.3%. FSCH was mainly composed of low-molecular-weight peptides and the relative proportion of <1000Da fraction was 70.6%. Free radical and oxygen species scavenging activities of FSCH were investigated in four model systems, including diphenylpicrylhy-drazyl radical (DPPH), superoxide anion radical, hydroxyl radical and hydrogen peroxide model, and compared with that of a native antioxidant, reduced glutathione (GSH). FSCH was also evaluated by water-absorbing and water-holding capacity. The results showed that FSCH was able to scavenge free radical and oxygen species significantly and to enhance water-absorbing and water-holding capacity remarkably. Therefore, FSCH may have potential applications in the medicine and food industries.

  12. pH dependent catalytic activities of platinum nanoparticles with respect to the decomposition of hydrogen peroxide and scavenging of superoxide and singlet oxygen

    NASA Astrophysics Data System (ADS)

    Liu, Yi; Wu, Haohao; Li, Meng; Yin, Jun-Jie; Nie, Zhihong

    2014-09-01

    Recently, platinum (Pt) nanoparticles (NPs) have received increasing attention in the field of catalysis and medicine due to their excellent catalytic activity. To rationally design Pt NPs for these applications, it is crucial to understand the mechanisms underlying their catalytic and biological activities. This article describes a systematic study on the Pt NP-catalyzed decomposition of hydrogen peroxide (H2O2) and scavenging of superoxide (O2&z.rad;-) and singlet oxygen (1O2) over a physiologically relevant pH range of 1.12-10.96. We demonstrated that the catalytic activities of Pt NPs can be modulated by the pH value of the environment. Our results suggest that Pt NPs possess peroxidase-like activity of decomposing H2O2 into &z.rad;OH under acidic conditions, but catalase-like activity of producing H2O and O2 under neutral and alkaline conditions. In addition, Pt NPs exhibit significant superoxide dismutase-like activity of scavenging O2&z.rad;- under neutral conditions, but not under acidic conditions. The 1O2 scavenging ability of Pt NPs increases with the increase in the pH of the environment. The study will provide useful guidance for designing Pt NPs with desired catalytic and biological properties.Recently, platinum (Pt) nanoparticles (NPs) have received increasing attention in the field of catalysis and medicine due to their excellent catalytic activity. To rationally design Pt NPs for these applications, it is crucial to understand the mechanisms underlying their catalytic and biological activities. This article describes a systematic study on the Pt NP-catalyzed decomposition of hydrogen peroxide (H2O2) and scavenging of superoxide (O2&z.rad;-) and singlet oxygen (1O2) over a physiologically relevant pH range of 1.12-10.96. We demonstrated that the catalytic activities of Pt NPs can be modulated by the pH value of the environment. Our results suggest that Pt NPs possess peroxidase-like activity of decomposing H2O2 into &z.rad;OH under acidic conditions

  13. Effect of high oxygen atmosphere storage on quality, antioxidant enzymes, and DPPH-radical scavenging activity of Chinese bayberry fruit.

    PubMed

    Yang, Zhenfeng; Zheng, Yonghua; Cao, Shifeng

    2009-01-14

    The influence of high O(2) atmosphere on postharvest decay, quality, total phenolic, total anthocyanin contents, antioxidant enzymes activity, and antioxidant activity of Chinese bayberry fruit was investigated. Freshly harvested Chinese bayberry fruits were placed in jars and ventilated continuously with air or with 80 and 100% O(2) for up to 12 days. Samples were randomly selected initially and at 3-days interval during storage. The fruit exposed to high O(2) was resistant to decay, had high levels of total soluble solids, titratable acidity and ascorbic acid contents, and also reduced the increment of pH value. High O(2) treatment was less stressful as reflected by having the significantly lower malonaldehyde contents and higher catalase, ascorbic acid peroxidase, and peroxidase activities during storage. Both 80% and 100% O(2) treaments had also retained the bioactive contents and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity during storage. These results indicate that elevated O(2) levels may improve the ability of the antioxidative defense mechanism in Chinese bayberry and result in a better control of fruit decay. PMID:19093866

  14. Scavenging dissolved oxygen via acoustic droplet vaporization.

    PubMed

    Radhakrishnan, Kirthi; Holland, Christy K; Haworth, Kevin J

    2016-07-01

    Acoustic droplet vaporization (ADV) of perfluorocarbon emulsions has been explored for diagnostic and therapeutic applications. Previous studies have demonstrated that vaporization of a liquid droplet results in a gas microbubble with a diameter 5-6 times larger than the initial droplet diameter. The expansion factor can increase to a factor of 10 in gassy fluids as a result of air diffusing from the surrounding fluid into the microbubble. This study investigates the potential of this process to serve as an ultrasound-mediated gas scavenging technology. Perfluoropentane droplets diluted in phosphate-buffered saline (PBS) were insonified by a 2 MHz transducer at peak rarefactional pressures lower than and greater than the ADV pressure amplitude threshold in an in vitro flow phantom. The change in dissolved oxygen (DO) of the PBS before and after ADV was measured. A numerical model of gas scavenging, based on conservation of mass and equal partial pressures of gases at equilibrium, was developed. At insonation pressures exceeding the ADV threshold, the DO of air-saturated PBS decreased with increasing insonation pressures, dropping as low as 25% of air saturation within 20s. The decrease in DO of the PBS during ADV was dependent on the volumetric size distribution of the droplets and the fraction of droplets transitioned during ultrasound exposure. Numerically predicted changes in DO from the model agreed with the experimentally measured DO, indicating that concentration gradients can explain this phenomenon. Using computationally modified droplet size distributions that would be suitable for in vivo applications, the DO of the PBS was found to decrease with increasing concentrations. This study demonstrates that ADV can significantly decrease the DO in an aqueous fluid, which may have direct therapeutic applications and should be considered for ADV-based diagnostic or therapeutic applications. PMID:26964964

  15. A novel sulfite alternative scavenger and benefits for the use of traced oxygen scavengers

    SciTech Connect

    Batton, C.B.; Riede, R.F.

    1994-12-31

    Dissolved oxygen in boiler systems is known to cause corrosion. Mechanical deaeration removes the majority of the dissolved oxygen while oxygen scavengers remove the remaining trace level. Sodium sulfate is a commonly used scavenger, but has several use limitations, such as high solids contribution to boiler water and decomposition products that are corrosive gases which can cause downstream equipment problems. A novel sulfite replacement oxygen scavenger has been developed which addresses the limitations of sulfite. Identification and demonstrated performance of the new scavenger is presented using both research and field data. In addition to oxygen scavenger performance, the success of a boiler water treatment program is dependent upon the correct dosage added to the feedwater. Plant managers and operators often struggle with indirect or inaccurate methods to determine what is occurring within their system. An oxygen scavenger product containing a proprietary fluorescent tracer has been developed. This technology for boilers provides a breakthrough in measurement capability for monitoring the dynamics of a boiler system. These two oxygen scavenger developments represent the result of maintaining desirable performance characteristics and significantly improving current technology. Laboratory and field data supporting these results are presented.

  16. Substance P Inhibits Hyperosmotic Stress-Induced Apoptosis in Corneal Epithelial Cells through the Mechanism of Akt Activation and Reactive Oxygen Species Scavenging via the Neurokinin-1 Receptor

    PubMed Central

    Yang, Lingling; Sui, Wenjie; Li, Yunqiu; Qi, Xia; Wang, Yao; Zhou, Qingjun; Gao, Hua

    2016-01-01

    Hyperosmolarity has been recognized as an important pathological factor in dry eye leading to ocular discomfort and damage. As one of the major neuropeptides of corneal innervation, substance P (SP) has been shown to possess anti-apoptotic effects in various cells. The aim of this study was to determine the capacity and mechanism of SP against hyperosmotic stress-induced apoptosis in cultured corneal epithelial cells. The cells were exposed to hyperosmotic stress by the addition of high glucose in the presence or absence of SP. The results showed that SP inhibited hyperosmotic stress-induced apoptosis of mouse corneal epithelial cells. Moreover, SP promoted the recovery of phosphorylated Akt level, mitochondrial membrane potential, Ca2+ contents, intracellular reactive oxygen species (ROS) and glutathione levels that impaired by hyperosmotic stress. However, the antiapoptotic capacity of SP was partially suppressed by Akt inhibitor or glutathione depleting agent, while the neurokinin-1 (NK-1) receptor antagonist impaired Akt activation and ROS scavenging that promoted by SP addition. In conclusion, SP protects corneal epithelial cells from hyperosmotic stress-induced apoptosis through the mechanism of Akt activation and ROS scavenging via the NK-1 receptor. PMID:26901348

  17. Antioxidant Activity/Capacity Measurement. 3. Reactive Oxygen and Nitrogen Species (ROS/RNS) Scavenging Assays, Oxidative Stress Biomarkers, and Chromatographic/Chemometric Assays.

    PubMed

    Apak, Reşat; Özyürek, Mustafa; Güçlü, Kubilay; Çapanoğlu, Esra

    2016-02-10

    There are many studies in which the antioxidant potential of different foods have been analyzed. However, there are still conflicting results and lack of information as a result of unstandardized assay techniques and differences between the principles of the methods applied. The measurement of antioxidant activity, especially in the case of mixtures, multifunctional or complex multiphase systems, cannot be evaluated satisfactorily using a simple antioxidant test due to the many variables influencing the results. In the literature, there are many antioxidant assays that are used to measure the total antioxidant activity/capacity of food materials. In this review, reactive oxygen and nitrogen species (ROS/RNS) scavenging assays are evaluated with respect to their mechanism, advantages, disadvantages, and potential use in food systems. On the other hand, in vivo antioxidant activity (AOA) assays including oxidative stress biomarkers and cellular-based assays are covered within the scope of this review. Finally, chromatographic and chemometric assays are reviewed, focusing on their benefits especially with respect to their time saving, cost-effective, and sensitive nature. PMID:26689748

  18. Angiotensin converting enzyme inhibitors as oxygen free radical scavengers.

    PubMed

    Mira, M L; Silva, M M; Queiroz, M J; Manso, C F

    1993-01-01

    The authors have compared the ability of two non-SH-containing angiotensin converting enzyme (ACE) inhibitors (enalaprilat and lisinopril) with an -SH containing ACE inhibitor (captopril) to scavenge the hydroxyl radical (.OH). All three compounds were able to scavenge .OH radicals generated in free solution at approximately diffusion-controlled rates (10(10) M-1 s-1) as established by the deoxyribose assay in the presence of EDTA. The compounds also inhibited deoxyribose degradation in reaction mixtures which did not contain EDTA but not so effectively. This later findings also suggests that they have some degree of metal-binding capability. Chemiluminescence assays of oxidation of hypoxanthine by xanthine oxidase in the presence of luminol, confirm that the three ACE inhibitors are oxygen free radical scavengers. Our results indicate that the presence of a sulphydryl group in the chemical structure of ACE inhibitors is not relevant for their oxygen free radical scavenging ability. PMID:8244086

  19. Reactive oxygen species scavenger N-acetyl cysteine reduces methamphetamine-induced hyperthermia without affecting motor activity in mice

    PubMed Central

    Sanchez-Alavez, Manuel; Bortell, Nikki; Galmozzi, Andrea; Conti, Bruno; Marcondes, Maria Cecilia G

    2015-01-01

    Hyperthermia is a potentially lethal side effect of Methamphetamine (Meth) abuse, which involves the participation of peripheral thermogenic sites such as the Brown Adipose Tissue (BAT). In a previous study we found that the anti-oxidant N-acetyl cysteine (NAC) can prevent the high increase in temperature in a mouse model of Meth-hyperthermia. Here, we have further explored the ability of NAC to modulate Meth-induced hyperthermia in correlation with changes in BAT. We found that NAC treatment in controls causes hypothermia, and, when administered prior or upon the onset of Meth-induced hyperthermia, can ameliorate the temperature increase and preserve mitochondrial numbers and integrity, without affecting locomotor activity. This was different from Dantrolene, which decreased motor activity without affecting temperature. The effects of NAC were seen in spite of its inability to recover the decrease of mitochondrial superoxide induced in BAT by Meth. In addition, NAC did not prevent the Meth-induced decrease of BAT glutathione. Treatment with S-adenosyl-L-methionine, which improves glutathione activity, had an effect in ameliorating Meth-induced hyperthermia, but also modulated motor activity. This suggests a role for the remaining glutathione for controlling temperature. However, the mechanism by which NAC operates is independent of glutathione levels in BAT and specific to temperature. Our results show that, in spite of the absence of a clear mechanism of action, NAC is a pharmacological tool to examine the dissociation between Meth-induced hyperthermia and motor activity, and a drug of potential utility in treating the hyperthermia associated with Meth-abuse. PMID:26346736

  20. Modeling of the Temperature Effect on Oxygen Absorption by Iron-Based Oxygen Scavengers.

    PubMed

    Polyakov, Vladimir A; Miltz, Joseph

    2016-01-01

    A new engineering-oriented model for prediction of the effect of temperature on the kinetics of oxygen absorption by iron-based oxygen scavengers (IOSs) was developed. The model is based on the physicochemical mechanism of the O2 scavenging process by the active component of the IOS (iron powder). The conclusions of this study are: (1) the iron deposits formed on the iron particles are composed of 2 different layers: an inner layer of Fe3 O4 and an outer layer of FeOOH that vanishes with the depletion of oxygen. (2) The model considers the chemical processes in the heterogeneous closed system "Fe-H2 O-NaCl-O2 " and describes the kinetics of oxygen absorption by the powder, depending on the characteristics of the system. (3) The nonlinear ordinary differential equation (ODE) of the O2 absorption kinetics was derived and a simple approximate solution to this ODE was obtained theoretically that is similar to the empirical exponential formula published in the relevant literature. (4) The temperature dependence of the oxygen absorption rate is more complicated than that described by the Arrhenius equation. PMID:26650762

  1. Peroxynitrite scavenging activity of herb extracts.

    PubMed

    Choi, Hye Rhi; Choi, Jae Sue; Han, Yong Nam; Bae, Song Ja; Chung, Hae Young

    2002-06-01

    Peroxynitrite (ONOO(-)) is a cytotoxicant with strong oxidizing properties toward various cellular constituents, including sulphydryls, lipids, amino acids and nucleotides and can cause cell death, lipid peroxidation, carcinogenesis and aging. The aim of this study was to characterize ONOO(-) scavenging constituents from herbs. Twenty-eight herbs were screened for their ONOO(-) scavenging activities with the use of a fluorometric method. The potency of scavenging activity following the addition of authentic ONOO(-) was in the following order: witch hazel bark > rosemary > jasmine tea > sage > slippery elm > black walnut leaf > Queen Anne's lace > Linden flower. The extracts exhibited dose-dependent ONOO(-) scavenging activities. We found that witch hazel (Hamamelis virginiana L.) bark showed the strongest effect for scavenging ONOO(-) of the 28 herbs. Hamamelitannin, the major active component of witch hazel bark, was shown to have a strong ability to scavenge ONOO(-). It is suggested that hamamelitannin might be developed as an effective peroxynitrite scavenger for the prevention of ONOO(-) involved diseases. PMID:12112294

  2. The role of vasoactive intestinal peptide in scavenging singlet oxygen

    SciTech Connect

    Misra, B.R.; Misra, H.P. )

    1990-02-26

    The neuropeptide vasoactive intestinal peptide (VIP), a highly basic 28 amino acid peptide, has a widespread distribution in the body. The functional specificity of this peptide not only includes its potent vasodilatory activity, but also its role in protecting lungs against acute injury, in preventing T-lymphocyte proliferation and in modulating immune function. The purpose of this study was to examine the possible antioxidant properties of VIP. The authors found that VIP up to 50 {mu}g/ml had no inhibitory effect on its reduction of cytochrome C by xanthine and xanthine oxidase, indicating that the peptide does not have significant O{sub 2} scavenging ability. However, VIP was found to inhibit, in a dose-dependent manner, the {sup 1}O{sub 2} dependent 2, 2, 6, 6 tetramethyl piperidine oxide (TEMPO) formation. {sup 1}O{sub 2} was produced by rose benzal photosensitizing system and was detected as TEMP-{sup 1}O{sub 2} adduct (TEMPO) by electron paramagnetic resonance (EPR) spectroscopic technique. The formation of TEMPO signal was strongly inhibited by {beta}-carotene, histidine as well as azide, but not by superoxide dismutase (48 {mu}g/ml), catalase (20 {mu}g/ml) and mannitol (6mM), indicating that TEMPO signal was a TEMP-{sup 1}O{sub 2} adduct. These results indicate that VIP has potent antioxidant activity and may serve as a singlet O{sub 2} scavenger, thus it may modulate the oxidative tissue injury caused by this reactive oxygen species.

  3. Free Radical Scavenging Activity of Scoparia dulcis Extract.

    PubMed

    Babincová, M.; Sourivong, P.

    2001-01-01

    We studied the scavenging capabilities of an extract of Scoparia dulcis (a cosmopolitan weed widespread in Laos and Vietnam) for 1-diphenyl-2-picrylhydrazyl and measured hemoglobin-catalyzed linoleic acid peroxidation with an oxygen electrode. Our results demonstrated strong antioxidant activity corresponding to mitigation of the generation of hydroxyl radicals, a possible rationale for the observed therapeutic effects of this weed. PMID:12639412

  4. Scavenging of reactive oxygen species by silibinin dihemisuccinate.

    PubMed

    Mira, L; Silva, M; Manso, C F

    1994-08-17

    Silibinin dihemisuccinate (SDH) is a flavonoid of plant origin with hepatoprotective effects which have been partially attributed to its ability to scavenge oxygen free radicals. In the present paper the antioxidant properties of SDH were evaluated by studying the ability of this drug to react with relevant biological oxidants such as superoxide anion radical (O2-), hydrogen peroxide (H2O2), hydroxyl radical (HO.) and hypochlorous acid (HOCl). In addition, its effect on lipid peroxidation was investigated. SDH is not a good scavenger of O2- and no reaction with H2O2 was detected within the sensitivity limit of our assay. However, it reacts rapidly with HO. radicals in free solution at approximately diffusion-controlled rate (K = (1.0-1.2) x 10(10)/M/sec) and appears to be a weak iron ion chelator. SDH at concentrations in the micromolar range protected alpha 1-antiproteinase against inactivation by HOCl, showing that it is a potent scavenger of this oxidizing species. Luminol-dependent chemiluminescence induced by HOCl was also inhibited by SDH. The reaction of SDH with HOCl was monitored by the modification of the UV-visible spectrum of SDH. The studies on rat liver microsome lipid peroxidation induced by Fe(III)/ascorbate showed that SDH has an inhibitory effect, which is dependent on its concentration and the magnitude of lipid peroxidation. This work supports the reactive oxygen species scavenger action ascribed to SDH. PMID:8080448

  5. Pyrroloquinoline-quinone: a reactive oxygen species scavenger in bacteria.

    PubMed

    Misra, Hari S; Khairnar, Nivedita P; Barik, Atanu; Indira Priyadarsini, K; Mohan, Hari; Apte, Shree K

    2004-12-01

    Transgenic Escherichia coli expressing pyrroloquinoline-quinone (PQQ) synthase gene from Deinococcus radiodurans showed superior survival during Rose Bengal induced oxidative stress. Such cells showed significantly low levels of protein carbonylation as compared to non-transgenic control. In vitro, PQQ reacted with reactive oxygen species with rate constants comparable to other well known antioxidants, producing non-reactive molecular products. PQQ also protected plasmid DNA and proteins from the oxidative damage caused by gamma-irradiation in solution. The data suggest that radioprotective/oxidative stress protective ability of PQQ in bacteria may be consequent to scavenging of reactive oxygen species per se and induction of other free radical scavenging mechanism. PMID:15581610

  6. Oxygen Radical Scavenger Activity, EPR, NMR, Molecular Mechanics and Extended-Hückel Molecular Orbital Investigation of the Bis(Piroxicam)Copper(II) Complex.

    PubMed

    Cini, R; Pogni, R; Basosi, R; Donati, A; Rossi, C; Sabadini, L; Rollo, L; Lorenzini, S; Gelli, R; Marcolongo, R

    1995-01-01

    The oxygen radical scavenger activity (ORSA) of [Cu(II)(Pir)(2)] (HPir = Piroxicam = 4-hydroxy -2- methyl -N-2- pyridyl -2H- 1,2-benzothiazine -3- carboxamide 1,1-dioxide) was determined by chemiluminescence of samples obtained by mixing human neutrophils (from healthy subjects) and [Cu(II)(Pir)(2)(DMF)(2)] (DMF = N,N -dimethylformammide) in DMSO/GLY/PBS (2:1:2, v/v) solution (DMSO = dimethylsulfoxide, GLY = 1,2,3-propantriol, PBS = Dulbecco's buffer salt solution). The ratio of the residual radicals, for the HPir (1.02.10(-4)M) and [Cu(II)(Pir)(2)(DMF)(2)] (1.08.10(-5)M)/HPir (8.01.10-(-5)M) systems was higher than 12 (not stimulated) [excess of piroxicam was added (Cu/Pir molar ratio approximately 1:10) in order to have most of the metal complexed as bischelate]. In contrast, the ratio of residual radicals for the CuCl(2) (1.00.10(-5)M) and [Cu(II)(Pir)(2)(DMF)(2)] (1.08.10(-5)M)/Hpir (8.01.10(-5)M)system was 5. The [Cu(II)(Pir)(2)] compound is therefore a stronger radical scavenger than either HPir or CuCl(2). A molecular mechanics (MM) analysis of the gas phase structures of neutral HPir, its zwitterionic (HPir(+-)) and anionic (Pir(-)) forms, and some Cu(II)-piroxicam complexes based on X-ray structures allowed calculation of force constants. The most stable structure for HPir has a ZZZ conformation similar to that found in the Cu(II) (and Cd(II) complexes) in the solid state as well as in the gas phase. The structure is stabilized by a strong H bond which involves the N(amide)-H and O(enolic) groups. The MM simulation for the [Cu(II)(Pir)(2)(DMF)(2)] complex showed that two high repulsive intramolecular contacts exist between a pyridyl hydrogen atom of one Pir(-) molecule with the O donor of the other ligand. These interactions activate a transition toward a pseudo-tetrahedral geometry, in the case the apical ligands are removed. On refluxing a suspension of [Cu(II)(Pir)(2)(DMF)(2)] in acetone a brown microcystalline solid with the Cu(Pir)(2).0.5DMF

  7. Development of nitroxide radicals-containing polymer for scavenging reactive oxygen species from cigarette smoke

    NASA Astrophysics Data System (ADS)

    Yoshitomi, Toru; Kuramochi, Kazuhiro; Binh Vong, Long; Nagasaki, Yukio

    2014-06-01

    We developed a nitroxide radicals-containing polymer (NRP), which is composed of poly(4-methylstyrene) possessing nitroxide radicals as a side chain via amine linkage, to scavenge reactive oxygen species (ROS) from cigarette smoke. In this study, the NRP was coated onto cigarette filters and its ROS-scavenging activity from streaming cigarette smoke was evaluated. The intensity of electron spin resonance signals of the NRP in the filter decreased after exposure to cigarette smoke, indicating consumption of nitroxide radicals. To evaluate the ROS-scavenging activity of the NRP-coated filter, the amount of peroxy radicals in an extract of cigarette smoke was measured using UV-visible spectrophotometry and 1,1-diphenyl-2-picrylhydrazyl (DPPH). The absorbance of DPPH at 517 nm decreased with exposure to cigarette smoke. When NRP-coated filters were used, the decrease in the absorbance of DPPH was prevented. In contrast, both poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters, which have no nitroxide radical, did not show any effect, indicating that the nitroxide radicals in the NRP scavenge the ROS in cigarette smoke. As a result, the extract of cigarette smoke passed through the NRP-coated filter has a lower cellular toxicity than smoke passed through poly[4-(cyclohexylamino)methylstyrene]- and poly(acrylic acid)-coated filters. Accordingly, NRP is a promising material for ROS scavenging from cigarette smoke.

  8. The effects of oxygen scavenging on jet fuel thermal stability

    SciTech Connect

    Heneghan, S.P.; Williams, T.F.; Whitacre, S.; Ervin, J.S.

    1996-10-01

    Preliminary tests with a proposed oxygen scavenger (triphenyl-phosphine, TPP) have been done in closed static and flowing systems to study its effects on the oxidation and the deposit formation of jet fuel. TPP was found to significantly slow the oxidation of hexadecane or jet fuel at some temperatures/concentrations and increase the oxidation rate at other conditions. The additive helped decrease the formation of deposits at higher concentrations (200 mg/l) but not at lower concentrations. No evidence of phosphorous was observed in the deposits that were formed. Gas chomatography combined with mass spectrometry and atomic emission detection showed that TPP produced the expected oxidation product (triphenylphosphineoxide) and an unexpected triphenylphosphine-sulfide. The GC/AED allowed A quantitative analysis of the conversion efficiency of TPP to TPPO upon stressing in a closed system.

  9. Peroxyl radical scavenging activity of Ginkgo biloba extract EGb 761.

    PubMed

    Maitra, I; Marcocci, L; Droy-Lefaix, M T; Packer, L

    1995-05-26

    Antioxidant mechanisms have been proposed to underlie the beneficial pharmacological effects of EGb 761, an extract from Ginkgo biloba leaves used for treating peripheral vascular diseases and cerebrovascular insufficiency in the elderly. In vitro evidence has been reported that EGb 761 scavenges various reactive oxygen species, i.e. nitric oxide, and the superoxide, hydroxyl, and oxoferryl radicals. However, the ability of EGb 761 to scavenge peroxyl radicals (reactive species mainly involved in the propagation step of lipid peroxidation) has not been investigated. To characterize further the antioxidant action of EGb 761, we measured the protective effects of EGb 761 during: (1) the oxidation of B-phycoerythrin by peroxyl radicals generated in aqueous solution by 2,2'-azobis (2-amidinopropane) hydrochloride (AAPH); and (2) the reaction of luminol or cis-parinaric acid with peroxyl radicals generated from 2,2'-azobis (2,4-dimethylvaleronitrile) (AMVN) in liposomes or in human low density lipoprotein (LDL), respectively. To evaluate the peroxyl radical scavenging activity of EGb 761 in a more physiologically relevant model of damage to lipid-containing systems, we also analyzed the effect of the extract on the oxidation of human LDL exposed to the azo-initiators in terms of: (1) accumulation of cholesterol linoleate ester hydroperoxides, (2) depletion of alpha-tocopherol and beta-carotene, and (3) changes in intrinsic tryptophan fluorescence. EGb 761 afforded protection against oxidative damage in all the systems we analyzed; thus, it is an efficient scavenger of peroxyl radicals. This result extends the oxygen radical scavenging properties of the extract and supports the hypothesis of an antioxidant therapeutic action of EGb 761. PMID:7786306

  10. Radical scavenging activities of niacin-related compounds.

    PubMed

    Ogata, Shin; Takeuchi, Masayo; Teradaira, Shin; Yamamoto, Naokuni; Iwata, Keiko; Okumura, Katsuzumi; Taguchi, Hiroshi

    2002-03-01

    We investigated whether niacin-related compounds had radical-scavenging activity by electron spin resonance methods. Many compounds, but not trigonelline, had radical-scavenging activity against hydroxyl radicals. However, for the nitric oxide radical and 1,1-diphenyl-2-picrylhydrazyl radical, only nicotinic acid hydrazide and isonicotinic acid hydrazide had scavenging activities. These results suggest that the moiety of hydrazide might have an important role in scavenging abilities of various radicals. PMID:12005062

  11. Antioxidant and free radical scavenging activity of Spondias pinnata

    PubMed Central

    Hazra, Bibhabasu; Biswas, Santanu; Mandal, Nripendranath

    2008-01-01

    Background Many diseases are associated with oxidative stress caused by free radicals. Current research is directed towards finding naturally-occurring antioxidants of plant origin. The aim of the present study was to evaluate the in vitro antioxidant activities of Spondias pinnata stem bark extract. Methods A 70% methanol extract of Spondias pinnata stem bark was studied in vitro for total antioxidant activity, for scavenging of hydroxyl radicals, superoxide anions, nitric oxide, hydrogen peroxide, peroxynitrite, singlet oxygen and hypochlorous acid, and for iron chelating capacity, reducing power, and phenolic and flavonoid contents. Results The extract showed total antioxidant activity with a trolox equivalent antioxidant concentration (TEAC) value of 0.78 ± 0.02. The IC50 values for scavenging of free radicals were 112.18 ± 3.27 μg/ml, 13.46 ± 0.66 μg/ml and 24.48 ± 2.31 μg/ml for hydroxyl, superoxide and nitric oxide, respectively. The IC50 for hydrogen peroxide scavenging was 44.74 ± 25.61 mg/ml. For the peroxynitrite, singlet oxygen and hypochlorous acid scavenging activities the IC50 values were 716.32 ± 32.25 μg/ml, 58.07 ± 5.36 μg/ml and 127.99 ± 6.26 μg/ml, respectively. The extract was found to be a potent iron chelator with IC50 = 66.54 ± 0.84 μg/ml. The reducing power was increased with increasing amounts of extract. The plant extract (100 mg) yielded 91.47 ± 0.004 mg/ml gallic acid-equivalent phenolic content and 350.5 ± 0.004 mg/ml quercetin-equivalent flavonoid content. Conclusion The present study provides evidence that a 70% methanol extract of Spondias pinnata stem bark is a potential source of natural antioxidants. PMID:19068130

  12. Prussian Blue Nanoparticles as Multienzyme Mimetics and Reactive Oxygen Species Scavengers.

    PubMed

    Zhang, Wei; Hu, Sunling; Yin, Jun-Jie; He, Weiwei; Lu, Wei; Ma, Ming; Gu, Ning; Zhang, Yu

    2016-05-11

    The generation of reactive oxygen species (ROS) is an important mechanism of nanomaterial toxicity. We found that Prussian blue nanoparticles (PBNPs) can effectively scavenge ROS via multienzyme-like activity including peroxidase (POD), catalase (CAT), and superoxide dismutase (SOD) activity. Instead of producing hydroxyl radicals (•OH) through the Fenton reaction, PBNPs were shown to be POD mimetics that can inhibit •OH generation. We theorized for the first time that the multienzyme-like activities of PBNPs were likely caused by the abundant redox potentials of their different forms, making them efficient electron transporters. To study the ROS scavenging ability of PBNPs, a series of in vitro ROS-generating models was established using chemicals, UV irradiation, oxidized low-density lipoprotein, high glucose contents, and oxygen glucose deprivation and reperfusion. To demonstrate the ROS scavenging ability of PBNPs, an in vivo inflammation model was established using lipoproteins in Institute for Cancer Research (ICR) mice. The results indicated that PBNPs hold great potential for inhibiting or relieving injury induced by ROS in these pathological processes. PMID:26918394

  13. In vitro free radical scavenging activity of platinum nanoparticles

    NASA Astrophysics Data System (ADS)

    Watanabe, Aki; Kajita, Masashi; Kim, Juewon; Kanayama, Atsuhiro; Takahashi, Kyoko; Mashino, Tadahiko; Miyamoto, Yusei

    2009-11-01

    A polyacrylic acid (PAA)-protected platinum nanoparticle species (PAA-Pt) was prepared by alcohol reduction of hexachloroplatinate. The PAA-Pt nanoparticles were well dispersed and homogeneous in size with an average diameter of 2.0 ± 0.4 nm (n = 200). We used electron spin resonance to quantify the residual peroxyl radical (\\mathrm {AOO}^{\\bullet } ) generated from 2,2-azobis (2-aminopropane) dihydrochloride (AAPH) by thermal decomposition in the presence of O2 and a spectrophotometric method to quantify the residual 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. PAA-Pt scavenged these two radicals in a dose-dependent manner. Platinum was the functional component. PAA-Pt reduced the rate of oxygen consumption required for linoleic acid peroxidation initiated by \\mathrm {AOO}^{\\bullet } generated from AAPH, indicating inhibition of the propagation of linolate peroxidation. A thiobarbituric acid test also revealed dose-dependent inhibition of the linolate peroxidation by PAA-Pt. Fifty micromolar platinum, as PAA-Pt, completely quenched 250 µM DPPH radical for 5 min. Even when twice diluted in half, the PAA-Pt still quenched 100% of the 250 µM DPPH radical. The scavenging activity of PAA-Pt is durable. These observations suggest that PAA-Pt is an efficient scavenger of free radicals.

  14. Free Radical Scavenging and Antioxidant Activities of Silymarin Components

    PubMed Central

    Anthony, Kevin P.; Saleh, Mahmoud A.

    2013-01-01

    Silymarin is an over the counter food supplement that is sold as a liver enhancement and liver protection preparation. It is a major constituent of the seeds of Silybum marianum which is composed of a mixture of seven major components and several minor compounds. The seven major components: taxifolin, silychristin, silydianin, silybin A, silybin B, iso-silybin A and iso-silybin B were isolated and purified from the crude mixture of silymarin using preparative high performance liquid chromatography to determine which were the most effective for liver protection. Free radical scavenging, hydroxyl radical antioxidant capacity, oxygen radical antioxidant capacity, trolox-equivalent antioxidant capacity and total antioxidant capacity antioxidant activities were determined for each of the individual purified components as well as the crude silymarin mixture. Taxifolin was the most effective component for scavenging free radicals in the DPPH assay with an EC50 of 32 µM far more effective than all other components which showed EC50 ranging from 115 to 855 µM. Taxifolin was also found to be the most effective antioxidant in the oxygen radical antioxidant capacity (ORAC) assay with a trolox equivalent of 2.43 and the second most effective in the hydroxyl radical antioxidant capacity (HORAC) assay with a gallic acid equivalent of 0.57. Other antioxidants assays did not show significant differences between samples. PMID:26784472

  15. A novel biointerface that suppresses cell morphological changes by scavenging excess reactive oxygen species.

    PubMed

    Ikeda, Yutaka; Yoshinari, Tomoki; Nagasaki, Yukio

    2015-09-01

    During cell cultivation on conventional culture dishes, various events results in strong stresses that lead to the production of bioactive species such as reactive oxygen species (ROS) and nitric oxide. These reactive species cause variable damage to cells and stimulate cellular responses. Here, we report the design of a novel biocompatible surface that decreases stress by not only morphologically modifying the dish surface by using poly(ethylene glycol) tethered chains, but also actively scavenging oxidative stress by using our novel nitroxide radical-containing polymer. A block copolymer, poly(ethylene glycol)-b-poly[(2,2,6,6-tetramethylpiperidine-N-oxyl)aminomethylstyrene] (PEG-b-PMNT) was used to coat the surface of a dish. Differentiation of undifferentiated human leukemia (HL-60) cells was found to be suppressed on the polymer-coated dish. Notably, HL-60 cell cultivation caused apoptosis under high-density conditions, while spontaneous apoptosis was suppressed in cells plated on the PEG-b-PMNT-modified surface, because a healthy mitochondrial membrane potential was maintained. In contrast, low molecular weight antioxidants did not have apparent effects on the maintenance of mitochondria. We attribute this to the lack of cellular internalization of our immobilized polymer and selective scavenging of excessive ROS generated outside of cells. These results demonstrate the utility of our novel biocompatible material for actively scavenging ROS and thus maintaining cellular morphology. PMID:25691268

  16. Scavenging of reactive oxygen species as the mechanism of drug action.

    PubMed

    Robak, J; Marcinkiewicz, E

    1995-01-01

    Reactive oxygen species (ROS) are generated when oxygen is supplied in excess and/or its reduction is insufficient. The best explored ROS are superoxide anions, hydroxyl radicals and hydrogen peroxide. The first two are free radicals. ROS are harmful for the living cells and are implicated in a variety of pathological processes and diseases. Drugs used in the treatment of these states are either stimulators of endogenous defense mechanisms against ROS or inhibitors of ROS formation. Six groups of anti-ROS substances have been described in this paper. 1) Antioxidant substances used in substitutive therapy such as enzymes (e.g. superoxide dismutase), substances containing thiol groups and vitamins (A, E, P, C). 2) Chelating agents (e.g. desferoxamine), which lower the level of prooxidative transition metal ions. 3) Inhibitors of superoxide ions generation by stimulated cells or xanthine oxidase. Such mechanism of action was described for xanthine oxidase inhibitor-allopurinol. 4) Superoxide scavengers. Many known drugs were investigated for this activity, but the best documentation was presented for flavonoids. 5) Substances which eliminate hydrogen peroxide, mainly glutathione and its precursors. 6) Scavengers of hydroxyl radicals. Studies of the above activity were conducted mainly using an unspecific method--estimation of malondialdehyde generated during the action of hydroxyl radicals on lipids or on desoxyribose. Inhibition of malondialdehyde formation was described for many drugs of plant and synthetic origin. PMID:8688896

  17. Comparison of lignin derivatives as substrates for laccase-catalyzed scavenging of oxygen in coatings and films

    PubMed Central

    2014-01-01

    Background Lignin derivatives are phenylpropanoid biopolymers derived from pulping and biorefinery processes. The possibility to utilize lignin derivatives from different types of processes in advanced enzyme-catalyzed oxygen-scavenging systems intended for active packaging was explored. Laccase-catalyzed oxidation of alkali lignin (LA), hydrolytic lignin (LH), organosolv lignin (LO), and lignosulfonates (LS) was compared using oxygen-scavenging coatings and films in liquid and gas phase systems. Results When coatings containing lignin derivatives and laccase were immersed in a buffered aqueous solution, the oxygen-scavenging capability increased in the order LO < LH < LA < LS. Experiments with coatings containing laccase and LO, LH or LA incubated in oxygen-containing gas in air-tight chambers and at a relative humidity (RH) of 100% showed that paperboard coated with LO and laccase reduced the oxygen content from 1.0% to 0.4% during a four-day period, which was far better than the results obtained with LA or LH. LO-containing coatings incubated at 92% RH also displayed activity, with a decrease in oxygen from 1.0% to 0.7% during a four-day period. The oxygen scavenging was not related to the content of free phenolic hydroxyl groups, which increased in the order LO < LS < LH < LA. LO and LS were selected for further studies and films containing starch, clay, glycerol, laccase and LO or LS were characterized using gel permeation chromatograpy, dynamic mechanical analysis, and wet stability. Conclusions The investigation shows that different lignin derivatives exhibit widely different properties as a part of active coatings and films. Results indicate that LS and LO were most suitable for the application studied and differences between them were attributed to a higher degree of laccase-catalyzed cross-linking of LS than of LO. Inclusion in active-packaging systems offers a new way to utilize some types of lignin derivatives from biorefining

  18. Potent Radical-Scavenging Activities of Thiamin and Thiamin Diphosphate

    PubMed Central

    Okai, Yasuji; Higashi-Okai, Kiyoka; F. Sato, Eisuke; Konaka, Ryusei; Inoue, Masayasu

    2007-01-01

    Various radical-scavenging activities of thiamin and thiamin diphosphate (TDP) were found in some in vitro experiments. Thiamin and TDP caused considerable suppressive effects on superoxide generation in hypoxanthine and xanthine oxidase system which was measured by a sensitive chemiluminescence method using 2-methyl-6-[p-methylphenyl]-3,7-dihydroimidazo[1,2-alpha]pyrazin-3-one (MCLA), and their 50% inhibition (IC50) values were estimated to be 158 and 56 µM, respectively. They also showed the significant suppression against hydroperoxide generation derived from oxidized linoleic acid which was estimated by aluminum chloride method and their IC50 values were calculated to be 260 and 46 µM. They further prevented the oxygen radical generation in opsonized zymosan-stimulated human blood neutrophils which was shown by chemiluminescence method using luminol, and their IC50 values were calculated to be 169 and 38 µM. In contrast, they caused weak but significantly suppressive effects on the hydroxyl radical generation by Fenton reaction which was measured by electric spin resonance (ESR) method, their IC50 values were calculated to be 8.45 and 1.46 mM respectively. These results strongly suggest a possibility that thiamin and TDP play as radical scavengers in cell-free and cellular systems. PMID:18437212

  19. Effect of lanthanum ions (La3+) on the reactive oxygen species scavenging enzymes in wheat leaves.

    PubMed

    Zhang, Lijing; Zeng, Fuli; Xiao, Rong

    2003-03-01

    Physiological effects of lanthanum ions on the activities of the enzymes in the reactive oxygen species (ROS) scavenging system in leaves of wheat (Triticum aestivum L.) seedlings were studied. Wheat leaves treated in Hogland solution with 0.1 mM LaCl(3) for 48 h showed increased levels of superoxide dismutase (SOD), catalase (CAT), ascorbate-specific peroxidase (AsA-POD), and dehydroascorbate reductase (DHAR). However, a minor effect was observed on the levels of monodehydroascorbate reductase (MDAR) and glutathione reductase (GR), which regulate the release of energy required by the ROS scavenging system. The whole system was linked up by H(+) transmission. Our results indicated that the activities of the enzymes that function directly to remove ROS were elevated by La(3+) treatment, which is consistent with the observations that La(3+)-treated plants had increased tolerance to environmental stresses. The remaining levels of MDAR and GR suggested that these two enzymes might be regulated differently from that of the other four enzymes studied. PMID:12663948

  20. Reversible oxygen scavenging at room temperature using electrochemically reduced titanium oxide nanotubes

    NASA Astrophysics Data System (ADS)

    Close, Thomas; Tulsyan, Gaurav; Diaz, Carlos A.; Weinstein, Steven J.; Richter, Christiaan

    2015-05-01

    A material capable of rapid, reversible molecular oxygen uptake at room temperature is desirable for gas separation and sensing, for technologies that require oxygen storage and oxygen splitting such as fuel cells (solid-oxide fuel cells in particular) and for catalytic applications that require reduced oxygen species (such as removal of organic pollutants in water and oil-spill remediation). To date, however, the lowest reported temperature for a reversible oxygen uptake material is in the range of 200-300 °C, achieved in the transition metal oxides SrCoOx (ref. 1) and LuFe2O4+x (ref. 2) via thermal cycling. Here, we report rapid and reversible oxygen scavenging by TiO2-x nanotubes at room temperature. The uptake and release of oxygen is accomplished by an electrochemical rather than a standard thermal approach. We measure an oxygen uptake rate as high as 14 mmol O2 g-1 min-1, ˜2,400 times greater than commercial, irreversible oxygen scavengers. Such a fast oxygen uptake at a remarkably low temperature suggests a non-typical mechanistic pathway for the re-oxidation of TiO2-x. Modelling the diffusion of oxygen, we show that a likely pathway involves ‘exceptionally mobile’ interstitial oxygen produced by the oxygen adsorption and decomposition dynamics, recently observed on the surface of anatase.

  1. Scavenging of reactive oxygen and nitrogen species by the prodrug sulfasalazine and its metabolites 5-aminosalicylic acid and sulfapyridine.

    PubMed

    Couto, Diana; Ribeiro, Daniela; Freitas, Marisa; Gomes, Ana; Lima, José L F C; Fernandes, Eduarda

    2010-01-01

    Sulfasalazine is a prodrug composed by a molecule of 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP), linked by an azo bond, which has been shown to be effective in the therapy of inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease, as well as of rheumatic diseases, such as rheumatoid arthritis and ankylosing spondylitis. The precise mechanism of action of sulfasalazine and/or its metabolites has not been completely elucidated, though its antioxidant effects are well established and are probably due to its scavenging effects against reactive oxygen and nitrogen species (ROS and RNS), as well as metal chelating properties, in association to its inhibitory effects over neutrophil oxidative burst. The present work was focused on screening and comparing the potential scavenging activity for an array of ROS (O(2)(•-), H(2)O(2), (1)O(2), ROO(•) and HOCl) and RNS ((•)NO and ONOO(-)), mediated by sulfasalazine and its metabolites 5-ASA and SP, using validated in vitro screening systems. The results showed that both 5-ASA and sulfasalazine were able to scavenge all the tested ROS while SP was practically ineffective in all the assays. For HOCl, (1)O(2), and ROO(•), 5-ASA showed the best scavenging effects. A new and important finding of the present study was the strong scavenging effect of 5-ASA against (1)O(2). 5-ASA was shown to be a strong scavenger of (•)NO and ONOO(-). Sulfasalazine was also able to scavenge these RNS, although with a much lower potency than 5-ASA. SP was unable to scavenge (•)NO in the tested concentrations but was shown to scavenge ONOO(-), with a higher strength when the assay was performed in the presence of 25 mM bicarbonate, suggesting further scavenging of oxidizing carbonate radical. In conclusion, the ROS- and RNS-scavenging effects of sulfasalazine and its metabolites shown in this study may contribute to the anti-inflammatory effects mediated by sulfasalazine through the prevention of the

  2. Flavonoids function as antioxidants: By scavenging reactive oxygen species or by chelating iron?

    NASA Astrophysics Data System (ADS)

    Wuguo, Deng; Xingwang, Fang; Jilan, Wu

    1997-09-01

    Flavonoids have been reported to exhibit strong antioxidative activity. In the present work, a systematic mechanistic study has been performed on five flavonoids (baicalin, hesperidin, naringin, quercetin and rutin) selected according to their structural characteristics. The experimental results reveal that flavonoids function as antioxidant mainly by chelating iron ions and by scavenging peroxyl radicals whereas their OH radical scavenging effect is much less important.

  3. Oxygen-scavenging coatings and films based on lignosulfonates and laccase.

    PubMed

    Johansson, Kristin; Winestrand, Sandra; Johansson, Caisa; Järnström, Lars; Jönsson, Leif J

    2012-09-15

    Laccase and lignosulfonates were included in coating colors and embedded in latex-based or starch-based films and coatings on foil or board. After 6 days at 23 °C and 100% relative humidity, the oxygen content in airtight chambers decreased from 1.0% (synthetic gas consisting of 99% N(2) and 1% O(2)) to 0.3% in the presence of board coated with lignosulfonate and laccase, while the oxygen content remained unchanged in control experiments without enzyme. The water stability of lignosulfonate-containing latex-based coatings and starch-based films was improved after laccase-catalyzed oxidation of lignosulfonates, which indicates polymerization to products with lower solubility in water. Furthermore, the E' modulus of starch-based films increased with 30%, which indicates laccase-catalyzed polymerization of lignosulfonates resulting in increased stiffness of the film. The results suggest that laccases and lignosulfonates can be used as an oxygen-scavenging system in active packaging and that enzyme-catalyzed polymerization of lignosulfonates contributes to improved water stability and mechanical properties. PMID:22721759

  4. Scavenging of reactive oxygen species by a glycolipid fraction of Mycobacterium avium serovar 2.

    PubMed

    Scherer, T A; Lauredo, I T; Abraham, W M

    1997-01-01

    Previous experiments indicated that MIF-A3, a peptidoglycolipid extracted from Mycobacterium avium serovar 2 (Mycobacterium paratuberculosis 18), inhibits the killing of Candida albicans by activated bovine peripheral blood-derived macrophages and murine thioglycollate-elicited peritoneal macrophages in vitro. Subsequent in vitro data from our laboratory indicated that this reduction in killing may be related to the ability of MIF-A3 to scavenge reactive oxygen species (ROS). In this study we examined this hypothesis directly by determining if MIF-A3 reduced exogenous H2O2-induced candidacidal activity. When Candida albicans was incubated with H2O2 (4 mM) alone, colony-forming units/ml x 10(4) (CFU/ml) were 0.4 +/- 0.1 (mean +/- SE, n = 4) as compared to 11.3 +/- 2.0 CFU/ml in control (untreated) cultures (p < .05). The addition of catalase at concentrations > or = 6.8 U/ml, completely blocked the fungicidal effect of H2O2. However, reducing the amount of catalase from 6.8 U/ml to 3.4 U/ml resulted in a loss of scavenging activity, which was associated with a 50% increase in H2O2-mediated killing. Substituting MIF-A3 (400 micrograms/ml) for catalase, also reduced H2O2-induced fungicidal activity. In the absence of MIF-A3, H2O2 reduced Candida albicans to less than 10(3) CFU/ml. However, in the presence of MIF-A3 the CFU/ml of Candida albicans increased 7.5-fold. Based on concentration-response curves of H2O2 inhibition vs. increasing amounts of catalase we determined that the relative inhibitory capacity of the MIF-A3 (400 micrograms/ml) was approximately 1.0 U/ml "catalase equivalents." These findings provide direct evidence that MIF-A3 can scavenge H2O2, and reduce H2O2-induced killing of Candida albicans. PMID:8981049

  5. The use of oxygen scavengers to prevent the transient discolouration of ground beef packaged under controlled, oxygen-depleted atmospheres.

    PubMed

    Gill, C O; McGinnis, J C

    1995-01-01

    Rates of O(2) absorption from air were determined for a type of commercial O(2) scavenger that is formulated for rapid O(2) absorption at chiller temperatures. Rates of O(2) absorption from N(2) atmospheres containing 600 ppm O(2) were determined for trays that each contained 350 g of ground beef. Packs with controlled atmospheres of N(2) that contained ground beef and O(2) scavengers were prepared, to determine the conditions under which the scavengers could prevent the transient discolouration of the meat which arises from its reaction with the residual O(2) initially present in pack atmospheres. The rates of O(2) absorption by individual scavengers varied from the average by ±50%. The rate of O(2) absorption declined with decreasing oxygen concentration, from an average value per scavenger of about 12 ml h(-1) when O(2) concentrations were between 20 and 10%. At O(2) concentrations <1% (10,000 ppm) the rate of O(2) absorption was directly proportioned to the O(2) concentration so that the O(2) concentration in an atmosphere in a gas-impermeable pouch declined exponentially with time. The absorption of O(2) by ground beef was similarly dependent on the O(2) concentration. At 2 °C, the transient discolouration of beef in atmospheres initially containing about 50 ppm O(2) was prevented by the presence of 17.5 scavengers per l of atmosphere. At -15 °C, discolouration was prevented by 5 scavengers per l. The findings indicate that the O(2) concentration in pack atmospheres has to be reduced below 10 ppm within 30 min at 2 °C, or 2 h at -1.5 °C if ground beef is not to transiently discolour. It is unlikely that the required rates of O(2) absorption could be obtained economically with currently available, commercial O(2) scavengers. PMID:22060109

  6. Radical scavenging, antioxidant and cytotoxic activity of Brazilian Caatinga plants.

    PubMed

    David, Juceni P; Meira, Marilena; David, Jorge M; Brandão, Hugo N; Branco, Alexsandro; de Fátima Agra, M; Barbosa, M Regina V; de Queiroz, Luciano P; Giulietti, Ana M

    2007-04-01

    Extracts of 32 plants from the Brazilian northeastern semi-arid region called Caatinga were evaluated through DPPH radical scavenging assay, beta-carotene bleaching, and brine shrimp lethality tests (BST). Among the extracts studied Byrsonima cf. gardneriana, Mascagnia coriacea, Cordia globosa, Diodia apiculata and Hypenia salzmannii showed the highest activities in DPPH radical scavenging test. In the beta-carotene bleaching test the highest activities were observed for Passiflora cincinnata, Chamaecrista repens, B. cf. gardneriana, Rollinia leptopetala, Serjania glabrata, Diospyros gaultheriifolia, C. globosa, Mimosa ophtalmocentra, M. coriacea and Lippia cf. microphylla. In contrast, R. leptopetala, Zornia cf. brasiliensis and Leonotis nepetifolia were the most active species in the BST. PMID:17331673

  7. Free radicals and activated oxygen.

    PubMed

    Famaey, J P

    1982-01-01

    Superoxide anion (0(-2)), hydrogen peroxide (H2O2) and hydroxyl radical (OH.) are products of the biological reduction of 0(2). They are very reactive and poorly tolerated within living systems and enzymes that catalytically scavenge these products have been evolved as defense mechanisms. These include superoxide dismutases (SOD), catalase and peroxidases. Large amounts of O-2 are produced by different enzymatic and non enzymatic biological processes. Large amounts of activated oxygens are produced by phagocytosing cells such as macrophages and polymorphonuclear cells. This production is associated with the bactericidal actions of these cells but it also largely contributes to exacerbate and sustain the inflammation where these cells congregate. The arachidonic acid pathway triggered by the inflammatory stimuli is also a source for these oxidizing radicals. The production of activated oxygens has been associated with the normal aging process but also with various toxic reactions (e.g. the toxicity of the herbicide paraquat, of the ionizing radiations, of certain antibiotics such as streptonigrin, etc. . . .). O-2 induces the depolymerization of hyaluronic acid which lends viscosity and lubricating properties to synovial fluids. SOD possess antiinflammatory properties and a bovine SOD, orgotein, has now been largely investigated by intramuscular and intraarticular injections in the treatment of rheumatic diseases. Various antiinflammatory compounds (e.g. the salicylates) are able either to inhibit the production of these oxygen radicals or to scavenge them which seems of importance for their antiinflammatory properties. Singlet oxygen, another activated oxygen, might also play a role in the inflammatory process. PMID:6295769

  8. Novel chromone and xanthone derivatives: Synthesis and ROS/RNS scavenging activities.

    PubMed

    Proença, Carina; Albuquerque, Hélio M T; Ribeiro, Daniela; Freitas, Marisa; Santos, Clementina M M; Silva, Artur M S; Fernandes, Eduarda

    2016-06-10

    Chromones and xanthones are oxygen-containing heterocyclic compounds acknowledged by their antioxidant properties. In an effort to develop novel agents with improved activity, a series of compounds belonging to these chemical classes were prepared. Their syntheses involve the condensation of appropriate 2-methyl-4H-chromen-4-ones, obtained via Baker-Venkataraman rearrangement, with (E)-3-(3,4-dimethoxyphenyl)acrylaldehyde to provide the corresponding 2-[(1E,3E)-4-(3,4-dimethoxyphenyl)buta-1,3-dien-1-yl]-4H-chromen-4-ones. Subsequent electrocyclization and oxidation of these compounds led to the synthesis of 1-aryl-9H-xanthen-9-ones. After cleavage of the protecting groups, hydroxylated chromones and xanthones were assessed as scavenging agents against both reactive oxygen species (ROS) [superoxide radical (O2(•-)), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), singlet oxygen ((1)O2), and peroxyl radical (ROO(•))] and reactive nitrogen species (RNS) [nitric oxide ((•)NO) and peroxynitrite anion (ONOO(-))]. Generally, all the tested new hydroxylated chromones and xanthones exhibited scavenger effects dependent on the concentration, with IC50 values found in the micromolar range. Some of them were shown to have improved scavenging activity when compared with previously reported analogues, allowing the inference of preliminary conclusions on the structure-activity relationship. PMID:27031214

  9. Scoparone attenuates RANKL-induced osteoclastic differentiation through controlling reactive oxygen species production and scavenging

    SciTech Connect

    Lee, Sang-Hyun; Jang, Hae-Dong

    2015-02-15

    Scoparone, one of the bioactive components of Artemisia capillaris Thunb, has various biological properties including immunosuppressive, hepatoprotective, anti-allergic, anti-inflammatory, and antioxidant effects. This study aims at evaluating the anti-osteoporotic effect of scoparone and its underlying mechanism in vitro. Scoparone demonstrated potent cellular antioxidant capacity. It was also found that scoparone inhibited the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation and suppressed cathepsin K and tartrate-resistant acid phosphatase (TRAP) expression via c-jun N-terminal kinase (JNK)/extracellular signal-regulated kinase (ERK)/p38-mediated c-Fos–nuclear factor of activated T cells, cytoplasmic 1 (NFATc1) signaling pathway. During osteoclast differentiation, the production of general reactive oxygen species (ROS) and superoxide anions was dose-dependently attenuated by scoparone. In addition, scoparone diminished NADPH (nicotinamide adenine dinucleotide phosphate) oxidase 1 (Nox1) expression and activation via the tumor necrosis factor receptor-associated factor 6 (TRAF6)–cSrc–phosphatidylinositol 3-kinase (PI3k) signaling pathway and prevented the disruption of mitochondrial electron transport chain system. Furthermore, scoparone augmented the expression of superoxide dismutase 1 (SOD1) and catalase (CAT). The overall results indicate that the inhibitory effect of scoparone on RANKL-induced osteoclast differentiation is attributed to the suppressive effect on ROS and superoxide anion production by inhibiting Nox1 expression and activation and protecting the mitochondrial electron transport chain system and the scavenging effect of ROS resulting from elevated SOD1 and CAT expression. - Highlights: • Scoparone dose-dependently inhibited RANKL-induced osteoclast differentiation. • Scoparone diminished general ROS and superoxide anions in a dose-dependent manner. • Scoparone inhibited Nox1 expression and

  10. Electronic structure of some thymol derivatives correlated with the radical scavenging activity: theoretical study.

    PubMed

    Javan, Ashkan Jebelli; Javan, Marjan Jebeli

    2014-12-15

    Molecules acting as antioxidants capable of scavenging reactive oxygen species (ROS) are of upmost importance in the living cell. Thymol derivatives exhibit various antioxidant activities and potential health benefits. Exploration of structure-radical scavenging activity (SAR) was approached with a wide range of thymol derivatives. To accomplish this task, the DPPH experimental assay along with quantum-chemical calculations were also employed for these compounds. By comparing the structural properties of the derivatives of interest, their antioxidant activity was explained by the formation of an intramolecular hydrogen bond and the presence of unsaturated double bond (-CHCH substituent) in their radical spices. Moreover, the delocalization of odd electrons in these radicals has been investigated by natural bond orbital analysis and interpretation of spin density maps. Reactivity order of the compound towards the ROS: HO, HOO, and O2(-) was found to be as HO>HOO > O2(-). PMID:25038698

  11. Radical scavenging activity and cytotoxicity of ferulic acid.

    PubMed

    Ogiwara, Takako; Satoh, Kazue; Kadoma, Yoshinori; Murakami, Yukio; Unten, Senwa; Atsumi, Toshiko; Sakagami, Hiroshi; Fujisawa, Seiichiro

    2002-01-01

    Ferulic acid and eugenol were examined for their superoxide (O2-), hydroxyl radical (.OH) and nitric oxide (NO)-scavenging ability, using ESR spectroscopy with spin trap agents DMPO and carboxy-PTIO/NOC-7. Ferulic acid more efficiently scavenged .OH and NO than eugenol. The O2- scavenging activity of ferulic acid was comparable with that of eugenol. Ferulic acid significantly reduced the NO production by lipopolysaccharide (LPS)-stimulated mouse macrophage-like cells (Raw 264.7 cells) compared to eugenol. The cytotoxic activity of ferulic acid against Raw 264.7 cells was comparable with that against human submandibular gland carcinoma (HSG) cells and the cytotoxicity of ferulic acid was about 10-fold smaller than that of eugenol. The stoichiometric factor (n) (number of moles of peroxy radical trapped by moles of the relevant phenol) of ferulic acid and eugenol was investigated, using the induction period methods of the methyl methacrylate polymerization system. The n-value of ferulic acid (1.5) was higher than that of eugenol (1.0) and was similar to that of 2, 6-di-t-butyl-4-methylphenol (BHT). Ferulic acid as well as eugenol may produce a dimer during the induction period due to an n-value less than 2. These results suggested that ferulic acid may be useful for preventing cell damage perhaps caused by O2-, and in particular by .OH and NO, in living systems. PMID:12529986

  12. Effects of Titanium Layer Oxygen Scavenging on the High-k/InGaAs Interface.

    PubMed

    Winter, Roy; Shekhter, Pini; Tang, Kechao; Floreano, Luca; Verdini, Alberto; McIntyre, Paul C; Eizenberg, Moshe

    2016-07-01

    One of the main challenges in the path to incorporating InGaAs based metal-oxide-semiconductor structures in nanoelectronics is the passivation of high-k/InGaAs interfaces. Here, the oxygen scavenging effect of thin Ti layers on high-k/InGaAs gate stacks was studied. Electrical measurements and synchrotron X-ray photoelectron spectroscopy measurements, with in situ metal deposition, were used. Oxygen removal from the InGaAs native oxide surface layer remotely through interposed Al2O3 and HfO2 layers observed. Synchrotron X-ray photoelectron spectroscopy has revealed a decrease in the intensity of InOx features relative to In in InGaAs after Ti deposition. The signal ratio decreases further after annealing. In addition, Ti 2p spectra clearly show oxidation of the thin Ti layer in the ultrahigh vacuum XPS environment. Using capacitance-voltage and conductance-voltage measurements, Pt/Ti/Al2O3/InGaAs and Pt/Al2O3/InGaAs capacitors were characterized both before and after annealing. It was found that the remote oxygen scavenging from the oxide/semiconductor interface using a thin Ti layer can influence the density of interface traps in the high-k/InGaAs interface. PMID:27282201

  13. Effect of Heating on DPPH Radical Scavenging Activity of Meat Substitute

    PubMed Central

    Song, Hyeun Sung; Bae, Jun Kyu; Park, Inshik

    2013-01-01

    This study was conducted to evaluate the increase of DPPH radical scavenging activity of meat substitute by heating. The meat substitute showed higher DPPH radical scavenging activity than those of other foods rich in protein such as beef, pork, chicken, and soybean curd. The DPPH radical scavenging activity of meat substitute was dependent upon concentration, heating temperature and heating time of meat substitute. The DPPH radical scavenging activity of meat substitute was enhanced with increasing heating temperature and time. The increase of DPPH radical scavenging activity was only applied to meat substitute without showing any activation in other foods rich in protein such as beef, pork, chicken, and soybean curd. PMID:24471114

  14. Copper(II) as an efficient scavenger of singlet molecular oxygen.

    PubMed

    Joshi, P C

    1998-08-01

    Reactive oxygen species (ROS) are considered to play an important role in tissue injury that damages DNA, proteins, carbohydrates and lipids. Increased production of ROS and/or decreased efficiency of antioxidant defense system has been shown to contribute to a number of degenerative processes including cancer and AIDS. Among the various forms of ROS, singlet oxygen (1O2), which is generated predominantly in photosensitization reactions, is of particular physiologic significance because of its selectively long life in aqueous solution, its ability to cross the cell membrane barrier and high reactivity towards biomolecules. In the present study, the 1O2 scavenging potential of Cu(II) has been evaluated by (i) generating 1O2 by photosensitization of rose bengal (RB), (ii) establishing 1O2 quenching with recognized 1O2 scavengers like sodium azide, DABCO and (iii) examining the effect of Cu(II) in scavenging of 1O2. The results revealed that Cu(II) inhibited the rate of 1O2 production by 88%, 68%, 40%, 21% and 10% at a concentration of 10(-2) M, 5 x 10(-3) M, 10(-3) M; 5 x 10(-4) M, and 10(-4) M, respectively. Under similar experimental condition, sodium azide or DABCO at 10(-2) M inhibited the 1O2 production by 86% and 88%, respectively. Other 1O2 generating photosensitizer like hematoporphyrin, riboflavin and methylene blue also produced identical results with Cu(II) but Fe(II), Fe(III), Zn(II) or As(III) did not produce any quenching of 1O2. Presence of a copper binding peptide (Gly-Gly-His) in the reaction system reduced the 1O2 scavenging capacity of Cu(II) by 52-66% depending upon the UV dose. The 1O2 scavenging property of metal ion appears to have an advantage to reduce the oxidative damage of photodynamic reactions in order to prevent ROS-induced toxicity reactions. PMID:9854900

  15. Response to temperature stress of reactive oxygen species scavenging enzymes in the cross-tolerance of barley seed germination*

    PubMed Central

    Mei, Yu-qin; Song, Song-quan

    2010-01-01

    A number of studies have shown the existence of cross-tolerance in plants, but the physiological mechanism is poorly understood. In this study, we used the germination of barley seeds as a system to investigate the cross-tolerance of low-temperature pretreatment to high-temperature stress and the possible involvement of reactive oxygen species (ROS) scavenging enzymes in the cross-tolerance. After pretreatment at 0 °C for different periods of time, barley seeds were germinated at 35 °C, and the content of malondialdehyde (MDA) and the activities of ROS scavenging enzymes were measured by a spectrophotometer analysis. The results showed that barley seed germinated very poorly at 35 °C, and this inhibitive effect could be overcome by pretreatment at 0 °C. The MDA content varied, depending on the temperature at which seeds germinated, while barley seeds pretreated at 0 °C did not change the MDA content. Compared with seeds germinated directly at 35 °C, the seeds pretreated first at 0 °C and then germinated at 35 °C had markedly increased activities of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT), and glutathione reductase (GR). The SOD and APX activities of seeds germinated at 35 °C after 0 °C-pretreatment were even substantially higher than those at 25 °C, and GR activity was similar to that at 25 °C, at which the highest germination performance of barley seeds was achieved. These results indicate that low-temperature pretreatment can markedly increase the tolerance of barley seed to high temperature during germination, this being related to the increase in ROS scavenging enzyme activity. This may provide a new method for increasing seed germination under stress environments, and may be an excellent model system for the study of cross-tolerance. PMID:21121076

  16. Cytotoxic and radical scavenging activity of blended herbal extracts.

    PubMed

    Nemoto, Yukio; Satoh, Kazue; Toriizuka, Kazuo; Hirai, Yasuaki; Tobe, Takashi; Sakagami, Hiroshi; Nakashima, Hideki; Ida, Yoshiteru

    2002-01-01

    Chinese medicines have been applied to a variety of diseases producing various favorable effects, possibly due to the interactions between individual components. Establishment of an evaluation method for such interactions may facilitate the production of new natural medicines. We investigated here the interaction of the hot water extract of Aconiti Tuber (one of the most prominent Chinese medicines) and that of Scutellariae Radix, Coptidis Rhizoma, Glycyrrhizae Radix, Atractylodesi, Lanceae Rhizoma or Poria, by measuring the superoxide anion (O2-), hydroxyl radical (OH) and nitric oxide (NO) scavenging activity, using ESR spectroscopy. We found that a 1:1 mixture of the hot water extract of one herb and that of another herb (referred to as a combined formula) showed a higher radical scavenging activity and cytotoxic activity than the hot water extract of a 1:1 mixture of two herbs (referred to as a blended formula). Both formulae showed higher cytotoxic activity against human oral tumor cell lines than against normal cells. These data further confirm the medicinal usefulness of combinations of empirical Chinese medicines. PMID:12494872

  17. Isoflavonoid-Rich Flemingia macrophylla Extract Attenuates UVB-Induced Skin Damage by Scavenging Reactive Oxygen Species and Inhibiting MAP Kinase and MMP Expression

    PubMed Central

    Chiang, Hsiu-Mei; Chiu, Hua-Hsien; Liao, Sue-Tsai; Chen, Yen-Ting; Chang, Hsien-Chang; Wen, Kuo-Ching

    2013-01-01

    In this study, we investigated the antioxidant activity and anti-photoaging properties of an extract of Flemingia macrophylla, a plant rich in isoflavonoid content. Pretreatment of fibroblasts with Flemingia macrophylla extract (FME) inhibited elastase activity, promoted the protein expression of type I procollagen, and attenuated the phosphorylation of mitogen-activated protein (MAP) kinase and the protein expression of matrix-metalloproteinase- (MMP-) 1, 3, and 9. The IC50 values were 2.1 μg/mL for DPPH radical scavenging ability, 366.8 μg/mL for superoxide anion scavenging ability, 178.9 μg/mL for hydrogen peroxide scavenging ability, and 230.9 μg/mL for hydroxyl radical scavenging ability. Also, exposure of erythrocytes to various concentrations of FME (50–500 μg/mL) resulted in a dose- and time-dependent inhibition of AAPH-induced hemolysis. In human fibroblasts, FME at 10 μg/mL was shown to be a potent scavenger of UV-induced reactive oxygen species (ROS). The antioxidant and anti-photoaging properties of FME make it an ideal anti-intrinsic aging and anti-photoaging agent. PMID:23935672

  18. Isoflavonoid-Rich Flemingia macrophylla Extract Attenuates UVB-Induced Skin Damage by Scavenging Reactive Oxygen Species and Inhibiting MAP Kinase and MMP Expression.

    PubMed

    Chiang, Hsiu-Mei; Chiu, Hua-Hsien; Liao, Sue-Tsai; Chen, Yen-Ting; Chang, Hsien-Chang; Wen, Kuo-Ching

    2013-01-01

    In this study, we investigated the antioxidant activity and anti-photoaging properties of an extract of Flemingia macrophylla, a plant rich in isoflavonoid content. Pretreatment of fibroblasts with Flemingia macrophylla extract (FME) inhibited elastase activity, promoted the protein expression of type I procollagen, and attenuated the phosphorylation of mitogen-activated protein (MAP) kinase and the protein expression of matrix-metalloproteinase- (MMP-) 1, 3, and 9. The IC50 values were 2.1  μ g/mL for DPPH radical scavenging ability, 366.8  μ g/mL for superoxide anion scavenging ability, 178.9  μ g/mL for hydrogen peroxide scavenging ability, and 230.9  μ g/mL for hydroxyl radical scavenging ability. Also, exposure of erythrocytes to various concentrations of FME (50-500  μ g/mL) resulted in a dose- and time-dependent inhibition of AAPH-induced hemolysis. In human fibroblasts, FME at 10  μ g/mL was shown to be a potent scavenger of UV-induced reactive oxygen species (ROS). The antioxidant and anti-photoaging properties of FME make it an ideal anti-intrinsic aging and anti-photoaging agent. PMID:23935672

  19. Superoxide scavenging activity of pirfenidone-iron complex

    SciTech Connect

    Mitani, Yoshihiro; Sato, Keizo Muramoto, Yosuke; Karakawa, Tomohiro; Kitamado, Masataka; Iwanaga, Tatsuya; Nabeshima, Tetsuji; Maruyama, Kumiko; Nakagawa, Kazuko; Ishida, Kazuhiko; Sasamoto, Kazumi

    2008-07-18

    Pirfenidone (PFD) is focused on a new anti-fibrotic drug, which can minimize lung fibrosis etc. We evaluated the superoxide (O{sub 2}{sup {center_dot}}{sup -}) scavenging activities of PFD and the PFD-iron complex by electron spin resonance (ESR) spectroscopy, luminol-dependent chemiluminescence assay, and cytochrome c reduction assay. Firstly, we confirmed that the PFD-iron complex was formed by mixing iron chloride with threefold molar PFD, and the complex was stable in distillated water and ethanol. Secondary, the PFD-iron complex reduced the amount of O{sub 2}{sup {center_dot}}{sup -} produced by xanthine oxidase/hypoxanthine without inhibiting the enzyme activity. Thirdly, it also reduced the amount of O{sub 2}{sup {center_dot}}{sup -} released from phorbor ester-stimulated human neutrophils. PFD alone showed few such effects. These results suggest the possibility that the O{sub 2}{sup {center_dot}}{sup -} scavenging effect of the PFD-iron complex contributes to the anti-fibrotic action of PFD used for treating idiopathic pulmonary fibrosis.

  20. Enhanced reactive oxygen species scavenging by overproduction of superoxide dismutase and catalase delays postharvest physiological deterioration of cassava storage roots.

    PubMed

    Xu, Jia; Duan, Xiaoguang; Yang, Jun; Beeching, John R; Zhang, Peng

    2013-03-01

    Postharvest physiological deterioration (PPD) of cassava (Manihot esculenta) storage roots is the result of a rapid oxidative burst, which leads to discoloration of the vascular tissues due to the oxidation of phenolic compounds. In this study, coexpression of the reactive oxygen species (ROS)-scavenging enzymes copper/zinc superoxide dismutase (MeCu/ZnSOD) and catalase (MeCAT1) in transgenic cassava was used to explore the intrinsic relationship between ROS scavenging and PPD occurrence. Transgenic cassava plants integrated with the expression cassette p54::MeCu/ZnSOD-35S::MeCAT1 were confirmed by Southern-blot analysis. The expression of MeCu/ZnSOD and MeCAT1 was verified by quantitative reverse transcription-polymerase chain reaction and enzymatic activity analysis both in the leaves and storage roots. Under exposure to the ROS-generating reagent methyl viologen or to hydrogen peroxide (H2O2), the transgenic plants showed higher enzymatic activities of SOD and CAT than the wild-type plants. Levels of malondialdehyde, chlorophyll degradation, lipid peroxidation, and H2O2 accumulation were dramatically reduced in the transgenic lines compared with the wild type. After harvest, the storage roots of transgenic cassava lines show a delay in their PPD response of at least 10 d, accompanied by less mitochondrial oxidation and H2O2 accumulation, compared with those of the wild type. We hypothesize that this is due to the combined ectopic expression of Cu/ZnSOD and CAT leading to an improved synergistic ROS-scavenging capacity of the roots. Our study not only sheds light on the mechanism of the PPD process but also develops an effective approach for delaying the occurrence of PPD in cassava. PMID:23344905

  1. Baicalin Scavenged Reactive Oxygen Species and Protected Human Keratinocytes Against UVB-induced Cytotoxicity.

    PubMed

    Chang, Wen-Shin; Lin, En-Yuan; Hsu, Shih-Wei; Hu, Pei-Shin; Chuang, Chin-Liang; Liao, Cheng-Hsi; Fu, Chun-Kai; Su, Chung-Hao; Gong, Chi-Li; Hsiao, Chieh-Lun; Bau, DA-Tian; Tsai, Chia-Wen

    Ultraviolet B (UVB), with a wavelength of 280-320 nm, represents one of the most important environmental factors for skin disorders, including sunburn, hyperpigmentation, solar keratosis, solar elastosis and skin cancer. Therefore, protection against excessive UVA-induced damage is useful for prevention of sunburn and other human diseases. Baicalin, a major component of traditional Chinese medicine Scutellaria baicalensis, has been reported to possess antioxidant and cytostatic capacities. In this study, we examined whether baicalin is also capable of protecting human keratinocytes from UVB irradiation. The results showed that baicalin effectively scavenged reactive oxygen species (ROS) elevated within 4 h after UVB radiation and reversed the UVB-suppressed cell viability and UVB-induced apoptosis after 24 h. Our results demonstrated the utility of baicalin to complement the contributions of traditional Chinese medicine in UVB-induced damage to skin and suggested their potential application as pharmaceutical agents in long-term sun-shining injury prevention. PMID:27566079

  2. Singlet oxygen scavengers affect laser-dye impairment of endothelium-dependent responses of brain arterioles.

    PubMed

    Rosenblum, W I; Nelson, G H

    1996-04-01

    This study investigates the possible role of singlet oxygen in accounting for the inhibitory effect of laser-dye injury on endothelium-dependent dilations. The combination of helium-neon (HeNe) laser (20-s exposure) and intravascular Evans blue impairs endothelium-dependent dilation of mouse pial arterioles by acetylcholine (ACh), bradykinin (BK), and calcium ionophore A23187. Each has a different endothelium-derived mediator (EDRFACh, EDRFBK, EDRFionophore, respectively). In this study, diameters at a craniotomy site were monitored in vivo with an image splitter-television microscope. The laser-dye injury, as usual, abolished the responses 10 and 30 min after injury, with recovery, complete or partial, at 60 min. Dilations by sodium nitroprusside, an endothelium-independent dilator, were not affected by laser-dye. When the singlet oxygen scavengers L-histidine (10(-3) M) and L-tryptophan (10(-2) M) were added to the suffusate over the site, the responses to ACh at 10 and 30 min were relatively intact, the response to BK was partly protected at 10 min only, and the response to ionophore was still totally impaired at 10 and 30 min. Lysine, a nonscavenging amino acid, had no protective effects with any dilator. We postulate that a heat-induced injury initiates a chain of events resulting in prolonged singlet oxygen generation by the endothelial cell (not by the dye). We postulate further that destruction of EDRFACh by singlet oxygen is responsible for laser-dye inhibition of ACh and that generation of the radical must continue for > or = 30 min. On the other hand, the heat injury itself is probably responsible for the elimination of the response to ionophore. Heat plus singlet oxygen generated by heat-damaged tissue may initially impair the response to BK, but by 30 min only the effects of some other factor, presumably heat injury, account for the impaired response to BK. PMID:8967364

  3. Phytochemical investigation and evaluation of in vitro free radical scavenging activity of Tabernaemontana divaricata Linn.

    PubMed

    Jain, Sachin; Jain, Avijeet; Jain, Neetesh; Jain, D K; Balekar, Neelam

    2010-02-01

    We evaluate the in vitro free radical scavenging activity of the leaves of Tabernaemontana divaricata Linn. Petroleum ether, ethanol and aqueous extracts of T. divaricata were prepared with successive extraction in a soxhlet apparatus. Each extract was selected to study the free radical scavenging activity by superoxide scavenging assay method. It was found that the aqueous extract contained carbohydrates, glycosides, amino acids, flavonoids, tannins, alkaloids, and steroids, and the ethanolic extract contained glycosides, amino acids, flavonoids, tannins, alkaloids and steroids. The ethanolic extract of T. divaricata showed 58.7 +/- 0.62% inhibition in the superoxide scavenging model. The aqueous extract also showed almost similar activity (54.9 +/- 0.53% compared to the ethanolic extract), while petroleum ether extract showed poor inhibition of superoxide scavenging activity. All extracts showed the dose- and time-dependent inhibition of the superoxide scavenging activity. PMID:20140809

  4. Development of a fluorescent probe for measurement of peroxyl radical scavenging activity in biological samples.

    PubMed

    Güçlü, Kubilay; Kıbrıslıoğlu, Gülşah; Özyürek, Mustafa; Apak, Reşat

    2014-02-26

    In antioxidant activity testing, it has been argued that assays capable of measuring the inhibitive action against the biologically relevant peroxyl radicals (ROO(•)) from a controllable source are preferable in terms of simulating physiological conditions because ROO(•) is the predominant free radical found in lipid oxidation in foods and biological systems. A new fluorescent probe, p-aminobenzoic acid (PABA), was developed for selective measurement of peroxyl radical scavenging (PRS) activity of biological samples, in view of the fact that the existing PRS assays are quite laborious and require the application of strictly optimized conditions. The earlier probe, β-phycoerythrin, of a similar PRS assay of wide use, oxygen radical absorbance capacity (ORAC), varies from lot to lot of production, undergoes photobleaching, and interacts with polyphenols via non-specific protein binding, while the current probe, fluorescein, undergoes undesired fluorescence (FL) quenching and side reactions. The developed technique is based on the fluorescence decrease of the PABA probe (within an optimal time of 30 min) because of its oxidation by ROO(•), generated from the thermal dissociation of 2,2'-azobis(2-methylpropionamidine) dihydrochloride (AAPH). In the absence of the scavenger, ROO(•) reacted with the probe, generating non-fluorescent products, and caused a decrease in PABA fluorescence, whereas the ROO(•) scavenger resulted in a fluorescence increase because of the inhibition of the probe oxidation by ROO(•). Thus, the fluorescence increment of intact PABA is proportional to the ROO(•) scavenging activity of samples. The linear range of relative fluorescence intensity versus the PABA concentration was in the interval of 0.5-5.0 μM. Assay precision and accuracy were assessed by analyzing two spiked homogenates of liver and kidney at clinically relevant concentrations with 97-105% recovery and 2.3% interday reproducibility. The proposed method was

  5. A Noninvasive Technique for Monitoring Peroxidative and H2O2-Scavenging Activities during Interactions between Bacterial Plant Pathogens and Suspension Cells.

    PubMed Central

    Baker, C. J.; Harmon, G. L.; Glazener, J. A.; Orlandi, E. W.

    1995-01-01

    Stimulation of active oxygen metabolism occurs during the early stages of interactions involving bacteria and plant cell suspensions. Although many cellular processes are known to affect active oxygen metabolism in plants, it is not known which of these factors affect active oxygen levels during plant-bacteria interactions. Extracellular peroxidases have been shown to participate in both the production and utilization of active oxygen species such as H2O2 and superoxide. Catalase and other scavenging mechanisms also affect the overall level of active oxygen. In this study the luminol-dependent chemiluminescent reaction previously used to measure H2O2 levels in suspension cells was modified to allow the assay of both peroxidase and H2O2-scavenging activity. The early stages of the interactions between tobacco (Nicotiana tabacum) and Pseudomonas syringae pv syringae, as well as between soybean (Glycine max) and P. syringae pv glycinea, were investigated. This method of monitoring peroxidase and H2O2-scavenging activity proved to be rapid, sensitive, and nonintrusive, allowing the processing of multiple samples using intact cells or cell-free preparations. The results from the study demonstrate that the scavenging activities can be significant and must be considered when studying active oxygen production in biological interactions. PMID:12228480

  6. Inhibition of adriamycin cardiotoxicity by 5-fluorouracil: a potential free oxygen radical scavenger.

    PubMed

    Stathopoulos, G P; Malamos, N A; Dontas, I; Deliconstantinos, G; Perrea-Kotsareli, D; Karayannacos, P E

    1998-01-01

    Adriamycin (ADR), a broad spectrum anticancer agent, has a limit to total dose used, due to cumulative cardiotoxicity. This side effect has been tested in the present study in combined administration with 5-fluorouracil a cytotoxic drug that often is applied together with ADR in cancer treatment. The study was performed on Wistar rats, and the experiment consisted of weekly administration for 12 weeks of adriamycin alone, of 5-fluorouracil alone, a combination of both, and a control group (normal saline) in separate groups comprising 42 animals each. The histology of the cardiac muscle, large vessels and liver, biochemistry of serum cholesterol, triglycerides and HDL-C and oxygen free radical production were examined. It was found that addition of 5-FU to the ADR administration reduced significantly the cardiac lesions, delayed and reduced the increase of serum lipids, produced by ADR alone and oxygen free radical production was also reduced, indicating that 5-fluorouracil is acting as a scavenger of free radicals. PMID:9891497

  7. In vitro radical scavenging activity of two Columbian Magnoliaceae

    NASA Astrophysics Data System (ADS)

    Puertas M., Miguel A.; Mesa v., Ana M.; Sáez v., Jairo A.

    2005-08-01

    The recent interest in the conservation of the tropical forest is due, at least in part, to the potential economic and health benefits that can be exploited from several plants. This report shows the in vitro antioxidant activity of some fractions isolated from leaves of two Columbian Magnoliaceae, Talauma hernandezii G. Lozano-C and Dugandiodendron yarumalense Lozano. The activity was determined using the radical monocation 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS·+) and the stable free radical 2-2-diphenyl-1-picrylhydrazyl (DPPH·), as part of general biological screening of these plants. The antioxidant capacity obtained from fractions was similar to those of α-tocopherol, tert-butylated hydroxyanisole (BHA), and ascorbic acid. The most active scavenger extract was the fraction 7 (TAA = 48.6 mmol Trolox/kg extract and IC50 ≤ 0.01 kg extract/mmol DPPH); and the least active was the fraction 1 (TAA = 11.23 mmol Trolox/kg extract and IC50 = 0.21 kg extract/mmol DPPH) all of them isolated from D. yarumalense. These results suggest that these plants can be attractive as source of antioxidant compounds with the ability to reduce radicals like ATBS and DPPH.

  8. Scavenging capacity of marine carotenoids against reactive oxygen and nitrogen species in a membrane-mimicking system.

    PubMed

    Rodrigues, Eliseu; Mariutti, Lilian R B; Mercadante, Adriana Z

    2012-08-01

    Carotenoid intake has been associated with the decrease of the incidence of some chronic diseases by minimizing the in vivo oxidative damages induced by reactive oxygen (ROS) and nitrogen species (RNS). The carotenoids are well-known singlet oxygen quenchers; however, their capacity to scavenge other reactive species, such as peroxyl radical (ROO•, hydroxyl radical (HO•), hypochlorous acid (HOCl) and anion peroxynitrite (ONOO⁻), still needs to be more extensively studied, especially using membrane-mimicking systems, such as liposomes. Moreover, the identification of carotenoids possessing high antioxidant capacity can lead to new alternatives of drugs or nutritional supplements for prophylaxis or therapy of pathological conditions related to oxidative damages, such as cardiovascular diseases. The capacity to scavenge ROO•, HO•, HOCl and ONOO⁻ of seven carotenoids found in marine organisms was determined in liposomes based on the fluorescence loss of a fluorescent lipid (C₁₁-BODIPY⁵⁸¹/⁵⁹¹) due to its oxidation by these reactive species. The carotenoid-bearing hydroxyl groups were generally more potent ROS scavengers than the carotenes, whilst β-carotene was the most efficient ONOO⁻ scavenger. The role of astaxanthin as an antioxidant should be highlighted, since it was a more potent scavenger of ROO•, HOCl and ONOO⁻ than α-tocopherol. PMID:23015774

  9. Mechanisms of nitric oxide crosstalk with reactive oxygen species scavenging enzymes during abiotic stress tolerance in plants.

    PubMed

    Arora, Dhara; Jain, Prachi; Singh, Neha; Kaur, Harmeet; Bhatla, Satish C

    2016-01-01

    Nitric oxide (NO) acts in a concentration and redox-dependent manner to counteract oxidative stress either by directly acting as an antioxidant through scavenging reactive oxygen species (ROS), such as superoxide anions (O(2)(-)*), to form peroxynitrite (ONOO(-)) or by acting as a signaling molecule, thereby altering gene expression. NO can interact with different metal centres in proteins, such as heme-iron, zinc-sulfur clusters, iron-sulfur clusters, and copper, resulting in the formation of a stable metal-nitrosyl complex or production of varied biochemical signals, which ultimately leads to modification of protein structure/function. The thiols (ferrous iron-thiol complex and nitrosothiols) are also involved in the metabolism and mobilization of NO. Thiols bind to NO and transport it to the site of action whereas nitrosothiols release NO after intercellular diffusion and uptake into the target cells. S-nitrosoglutathione (GSNO) also has the ability to transnitrosylate proteins. It is an NO˙ reservoir and a long-distance signaling molecule. Tyrosine nitration of proteins has been suggested as a biomarker of nitrosative stress as it can lead to either activation or inhibition of target proteins. The exact molecular mechanism(s) by which exogenous and endogenously generated NO (or reactive nitrogen species) modulate the induction of various genes affecting redox homeostasis, are being extensively investigated currently by various research groups. Present review provides an in-depth analysis of the mechanisms by which NO interacts with and modulates the activity of various ROS scavenging enzymes, particularly accompanying ROS generation in plants in response to varied abiotic stress. PMID:26554526

  10. The activity of propolis in the scavenging of vitamin B2-photogenerated ROS.

    PubMed

    González, Mariela; Tereschuk, María L; Criado, Susana; Reynoso, Eugenia; Challier, Cecilia; Agüero, María Belén; Luna, Lorena; Ferrrari, Gabriela; Montaña, María P; García, Norman A

    2015-11-01

    Objectives The study was focused on the activity of propolis from Amaicha del Valle, Argentina (ProAV) as a promoter and scavenger of Riboflavin (Rf) - photogenerated reactive oxygen species (ROS). Methods Through a kinetic and mechanistic study, employing stationary and time-resolved photochemical and electrochemical techniques, the protecting activity of ProAV was investigated. Results In the absence of light and Rf, ProAV exerted a relatively efficient inhibitory effect on 1,1-diphenyl-2-picrylhydrazyl radicals and acts as a protector of artificially promoted linoleic acid oxidation. Under aerobic visible-light-irradiation conditions, in the presence of Rf as the only light-absorber species, a complex picture of competitive processes takes place, starting with the quenching of singlet and triplet electronically excited states of Rf by ProAV. The species O2(1 g), O2(•-), H2O2, and OH(•) are generated and interact with ProAV. Discussion ProAV behaves as an efficient ROS scavenger. It is scarcely photo-oxidized by interaction with the mentioned ROS. Quantitative results indicate that ProAV is even more resistant to photo-oxidation than the recognized antioxidant trolox. Two dihydroxychalcones, mostly present in the ProAV composition, are responsible for the protecting activity of the propolis. PMID:26207873

  11. A survey of operational characteristics, socioeconomic and health effects of scavenging activity in Lagos, Nigeria.

    PubMed

    Afon, Abel

    2012-07-01

    This study presents the social, economic, health and environmental implications of solid waste scavenging activity in Olusosun, one of the government's designated open waste dumpsites in Lagos, Nigeria. Using incidental or convenience sampling methods of questionnaire administration, 112 scavengers were sampled. It was established that scavenging on the site was only possible through registration with an associate on site. Recovering items from hills of waste involved physical energy and the use of manually-operated rudimentary equipment. Thus, 87% of the scavengers were males in their early twenties (minimum age = 19 years; maximum age = 35 years; mean = 26.7 years; SD = 4.2). The daily mean income from the exercise was Naira 480.80 (Naira 160 = $1.00). The most important method of arriving at the selling prices of the scavenged products was the use of scale measurement. Although the scavengers were aware that scavenging exposed them to both environmental and health hazards, they continued scavenging for economic and social reasons. The study concluded that because of the level of employment provided and the large number of people directly involved (1243 on this site alone), outright banning, even when the open dump is closed down, without rehabilitating the scavengers will constitute a social, economic and security threat to the community. Scavenging should, therefore, be integrated fully into the waste-management system and regulated. PMID:22605019

  12. Oxygen supply and nitric oxide scavenging by myoglobin contribute to exercise endurance and cardiac function.

    PubMed

    Merx, Marc W; Gödecke, Axel; Flögel, Ulrich; Schrader, Jürgen

    2005-06-01

    Recent studies of myoglobin (Mb) knockout (myo-/-) mice have extended our understanding of Mb's diverse functions and have demonstrated a complex array of compensatory mechanisms. The present study was aimed at detailed analysis of cardiac function and exercise endurance in myo-/- mice and at providing evidence for Mb's functional relevance. Myo-/- isolated working hearts display decreased contractility (dP/dtmax 3883+/-351 vs. 4618+/-268 mmHg/sec, myo-/- vs. WT, P<0.005). Due to a shift in sympathetic/parasympathetic tone, heart rate is reduced in conscious myo mice-/- (615+/-33 vs. 645+/-27 bpm, myo-/- vs. WT, P<0.001). Oxygen consumption (VO2) under resting conditions (3082+/-413 vs. 4452+/-552 ml x kg(-1) x h(-1), myo-/- vs. WT, P<0.001) and exercise endurance, as determined by spiroergometry, are decreased (466+/-113 vs. 585+/-153 m, myo-/- vs. WT, P<0.01). Conscious myo-/- mice evaluated by echocardiography display lowered cardiac output (0.64+/-0.06 vs. 0.75+/-0.09 ml x min(-1) x g(-1), myo-/- vs. WT, P<0.001), impaired systolic shortening (60+/-3.5 vs. 65+/-4%, myo-/- vs. WT, P<0.001) and fail to respond to beta1-stimulation. Strikingly, the latter cardiac effects of Mb deficiency can be partially attenuated by NOS inhibition. Loss of Mb results in a distinct phenotype, even under resting conditions, and the importance of oxygen supply and nitric oxide scavenging by Mb is clearly demonstrated at the conscious animal level. PMID:15817640

  13. Synthesis of dimeric phenol derivatives and determination of in vitro antioxidant and radical scavenging activities.

    PubMed

    Güllçin, Ilhami; Daştan, Arif

    2007-12-01

    In this study, di(2,6-dimethylphenol) (Di-DMP), di(2,6-diisopropylphenol) (Di-DIP, dipropofol) and di(2,6-di-t-butylphenol) (Di-DTP) were synthesized by the reaction of monomeric phenol derivatives with catalytic CuCl(OH). TMEDA and Na2S2O4. Their antioxidant capacity and radical scavenging activity were examined using different in vitro methodologies such as 1,1-diphenyl-2-picryl-hydrazyl (DPPH*) free radical scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, total antioxidant activity by ferric thiocyanate, total reducing power by potassium ferricyanide reduction method, superoxide anion radical scavenging, hydrogen peroxide scavenging and ferrous ions chelating activities. PMID:18237020

  14. Investigation of the free radical scavenging activity of Ginkgo biloba L. leaves.

    PubMed

    Ellnain-Wojtaszek, M; Kruczyński, Z; Kasprzak, J

    2003-02-01

    The free radical scavenging activity of methanolic, ethanolic and aqueous extracts from Ginkgo biloba leaves, has been determined by EPR (electron paramagnetic resonance) using the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging method. The investigation has also included selected constituents of G. biloba leaves, protocatechuic and p-coumaric acids, quercetin, rutin, isoginkgetin and (+)-catechin. PMID:12628386

  15. Antioxidant and free radical scavenging activities of some fruits.

    PubMed

    Prakash, Dhan; Upadhyay, Garima; Pushpangadan, P; Gupta, Charu

    2011-01-01

    Phenols, a major group of antioxidant phytochemicals, have profound importance due to their biological and free radical scavenging activities. To identify their potential sources extracts of some fruits and their different parts were studied for total phenolic contents (TPC), antioxidant (AOA) and free radical scavenging activities (FRSA). The amount of TPC varied from 10.5 (Carissa carandus, fruit peel) to 343.2 mg/g (Caesalpinia Mexicana, fruits) and AOA from 20.3% (Musa paradisiacal, fruits) to 96.7% (Caesalpinia Mexicana, fruits). Fruits of Caesalpinia Mexicana, Acacia auriculiformis, fruit pericarp green fibres of Cocus nucifera, and fruits of Emblica officinalis were found to have high TPC (73.1-343.2 mg/g) and high AOA (68.5-96.7%). Promising fruits were studied for their FRSA and reducing power (RP) measured by DPPH assay where the fruits of Caesalpinia mexicana, fruit pericarp fibres of Cocus nucifera, fruits of Emblica officinalis showed very low IC50 ranging from 0.009 to 0.016 mg/ml, EC50 from 0.39 to 0.70 mg/mg DPPH and reasonably high values (142.1-256.3) of anti radical power (ARP), indicating their strong FRSA and reducing power (RP) as evident by their low ASE/ml values (0.42-1.08). They also showed better inhibition of lipid peroxidation measured by using ferric thiocyanate assay and by using egg yolk compared to the reference standard quercetin. The ferrous and ferric ion chelating capacity of the promising fruits and their underutilized parts in terms of IC50 varied from 0.12 (Emblica officinalis, fruits) to 2.44 mg/ml (Mangifera indica, Seed kernel) and 0.22 (Caesalpinia Mexicana, fruits) to 2.59 mg/ml (Litchi chinensis, fruit peel) respectively. Fruit pulp, peel and seeds of Litchi chinensis with reasonable amount of phenols (48.3, 43.9, 50.1 mg/ml) showed low ARP (23.5, 38.3, 33.8) and ASE/ml (3.13, 2.18, 2.62) respectively in contrast to Aegle marmelos with comparatively lower phenols (35.1 mg/g) exhibited good ARP (57.4) and RP (1.67 ASE

  16. Changes in oxygen consumption induced by t-butyl hydroperoxide in perfused rat liver. Effect of free-radical scavengers.

    PubMed Central

    Videla, L A; Villena, M I; Donoso, G; Giulivi, C; Boveris, A

    1984-01-01

    The addition of t-butyl hydroperoxide to perfused rat liver elicited a biphasic effect on hepatic respiration. A rapid fall in liver oxygen consumption was initially observed, followed by a recovery phase leading to respiratory rates higher than the initial steady-state values of oxygen uptake. This overshoot in hepatic oxygen uptake was abolished by free-radical scavengers such as (+)-cyanidanol-3 or butylated hydroxyanisole at concentrations that did not alter mitochondrial respiration. (+)-Cyanidanol-3 was also able to facilitate the recovery of respiration, the diminution in the calculated rate of hydroperoxide utilization and the decrease in liver GSH content produced by two consecutive pulses of t-butyl hydroperoxide. It is suggested that the t-butyl hydroperoxide-induced overshoot in liver respiration is related to increased utilization of oxygen for lipid peroxidation as a consequence of free radicals produced in the scission of the hydroperoxide by cellular haemoproteins. PMID:6508746

  17. Study on the free radical scavenging activity of sea cucumber (Paracaudina chinens var.) gelatin hydrolysate

    NASA Astrophysics Data System (ADS)

    Zeng, Mingyong; Xiao, Feng; Zhao, Yuanhui; Liu, Zunying; Li, Bafang; Dong, Shiyuan

    2007-07-01

    Gelatin from the sea cucumber (Paracaudina chinens var.) was hydrolyzed by bromelain and the hydrolysate was found to have a high free radical scavenging activity. The hydrolysate was fractionated through an ultrafiltration membrane with 5 kDa molecular weight cutoff (MWCO). The portion (less than 5 kDa) was further separated by Sephadex G-25. The active peak was collected and assayed for free radical scavenging activity. The scavenging rates for superoxide anion radicals (O2·-) and hydroxyl radicals (·OH) of the fraction with the highest activity were 29.02% and 75.41%, respectively. A rabbit liver mitochondrial free radical damage model was adopted to study the free radical scavenging activity of the fraction. The results showed that the sea cucumber gelatin hydrolysate can prevent the damage of rabbit liver and mitochondria.

  18. Electron spin resonance measurement of radical scavenging activity of Aronia melanocarpa fruit juice

    PubMed Central

    Valcheva-Kuzmanova, Stefka; Blagović, Branka; Valić, Srećko

    2012-01-01

    Background: The fruits of Aronia melanocarpa (Michx.) Elliot contain large amounts of phenolic substances, mainly procyanidins, anthocyanins and other flavonoids, and phenolic acids. The ability of phenolic substances to act as antioxidants has been well established. Objective: In this study, we investigated the radical scavenging activity of A. melanocarpa fruit juice (AMFJ). Materials and Methods: The method used was electron spin resonance (ESR) spectroscopy. The galvinoxyl free radical was used as a scavenging object. AMFJ was added to the galvinoxyl free radical solution. The measure of the radical scavenging activity was the decrease of signal intensity. Results: AMFJ showed a potent antiradical activity causing a strong and rapid decrease of signal intensity as a function of time and juice concentration. This effect of AMFJ was probably due to the activity of its phenolic constituents. Conclusion: The ESR measurements in this study showed a pronounced radical scavenging effect of AMFJ, an important mechanism of its antioxidant activity. PMID:22701293

  19. New polyhydroxylated flavon-3-ols and 3-hydroxy-2-styrylchromones: synthesis and ROS/RNS scavenging activities.

    PubMed

    Sousa, Joana L C; Proença, Carina; Freitas, Marisa; Fernandes, Eduarda; Silva, Artur M S

    2016-08-25

    New polyhydroxylated flavon-3-ols and 3-hydroxy-2-styrylchromones were prepared and assessed as reactive oxygen species (ROS) and reactive nitrogen species (RNS) scavengers. The synthetic strategy involved the preparation of 2'-hydroxychalcones and 2'-hydroxycinnamylidenoacetophenones from base-catalyzed aldol reaction of appropriate 2'-hydroxyacetophenones and benzaldehydes/cinnamaldehydes, followed by an Algar-Flynn-Oyamada (AFO) reaction to give the polyalkoxy(flavon-3-ols and 3-hydroxy-2-styrylchromones). The last step of this synthetic route consisted in the cleavage of the protecting groups affording the expected polyhydroxylated derivatives. The present work consisted in the study of the in vitro scavenging activities of the synthetized compounds against the most physiologically relevant ROS [superoxide radical (O2(-)), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), singlet oxygen ((1)O2) and peroxyl radical (ROO)] and RNS [nitric oxide (NO) and peroxynitrite anion (ONOO(-))]. Generally, all the tested new polyhydroxylated flavon-3-ols and 3-hydroxy-2-styrylchromones exhibited scavenging effects dependent on the concentration, and with IC50 values found within the micromolar range. This work allowed the establishment of new structure-activity relationships and brought the knowledge about the selective choice of a structure depending on the targeted reactive species. PMID:27213247

  20. Studies on free radical scavenging activity in Chinese seaweeds part I. Screening results

    NASA Astrophysics Data System (ADS)

    Yan, Xiao-Jun; Fang, Guo-Ming; Lou, Qing-Xiang

    1999-09-01

    Antioxidants have attracted the attention of researchers due to their beneficial effects as free radical scavengers. Application of a stable free radical named 1, 1-diphenyl-2-picrylhydrazyl(DPPH) to screen the free radical scavenging activity in 27 species of Chinese seaweed showed that 15 of them had significant activity in at least one of the organic solvent extracts. The most interesting seaweed species were Gelidium amansii, Gloiosiphonia capillaris, Polysiphonia urceolata, Sargassum kjellmanianum, Desmarestia viridis, and Rhodomela teres.

  1. Smelling lavender and rosemary increases free radical scavenging activity and decreases cortisol level in saliva.

    PubMed

    Atsumi, Toshiko; Tonosaki, Keiichi

    2007-02-28

    Free radicals/reactive oxygen species are related to many biological phenomena such as inflammation, aging, and carcinogenesis. The body possesses various antioxidative systems (free radical scavenging activity, FRSA) for preventing oxidative stress, and saliva contains such activity. In the present study, we measured the total salivary FRSA induced after the smelling of lavender and rosemary essential oils that are widely used in aromatherapy. Various physiologically active substances in saliva such as cortisol, secretory IgA, and alpha-amylase activity were found to be correlated with aroma-induced FRSA. The subjects (22 healthy volunteers) sniffed aroma for 5 min, and each subject's saliva was collected immediately. FRSA was measured using 1,1-diphenyl-2-picrylhydrazyl. The FRSA values were increased by stimulation with low concentrations (1000 times dilution) of lavender or by high-concentrations (10 times dilution) of rosemary. In contrast, both lavender and rosemary stimulations decreased cortisol levels. A significant inverse correlation was observed between the FRSA values and the cortisol levels with each concentration of rosemary stimulation. No significant changes were noted in sIgA or alpha-amylase. These findings clarify that lavender and rosemary enhance FRSA and decrease the stress hormone, cortisol, which protects the body from oxidative stress. PMID:17291597

  2. Calcitriol-copper interaction leads to non enzymatic, reactive oxygen species mediated DNA breakage and modulation of cellular redox scavengers in hepatocellular carcinoma.

    PubMed

    Rizvi, Asim; Farhan, Mohd; Naseem, Imrana; Hadi, S M

    2016-09-01

    Calcitriol is the metabolically active form of Vitamin D and is known to kill cancer cells. Using the rat model of DEN induced hepatocellular carcinoma we show that there is a marked increase in cellular levels of copper in hepatocellular carcinoma and that calcitriol-copper interaction leads to reactive oxygen species mediated DNA breakage selectively in hepatocellular carcinoma cells. In vivo studies show that calcitriol selectively induces severe fluctuations in cellular enzymatic and non enzymatic scavengers of reactive oxygen species in the malignant tissue. Lipid peroxidation, a well established marker of oxidative stress, was found to increase, and substantial cellular DNA breakage was observed. We propose that calcitriol is a proxidant in the cellular milieu of hepatocellular carcinoma cells, and this copper mediated prooxidant action of calcitriol causes selective DNA breakage in malignant cells, while sparing normal (non malignant) cells. PMID:27343126

  3. Aging of whiskey increases 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity.

    PubMed

    Aoshima, Hitoshi; Tsunoue, Hideaki; Koda, Hirofumi; Kiso, Yoshinobu

    2004-08-11

    1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity of Japanese whiskey after various aging periods in oak barrels was measured to evaluate the antioxidative effects of whiskey. The activity of the whiskey increased with the aging period with high correlation. The activity of various types of whiskey was measured and shown to be correlated to the potentiation of the GABAA receptor response measured in a previous paper. However, the fragrant compounds in the whiskey which potentiated the GABAA receptor response had low DPPH radical scavenging activity, while phenol derivatives had high radical scavenging activity. The whiskey was extracted by pentane. The aqueous part showed the scavenging activity, whereas the pentane part did not. Thus, both the DPPH radical scavenging activity and the potentiation of the GABAA receptor response increased during whiskey aging in oak barrels, but were due to different components. The whiskey protected the H2O2-induced death of E. coli more than ethanol at the same concentration as that of the whiskey. The changes that occurred in the whiskey during aging may be the reason aged whiskies are so highly valued. PMID:15291502

  4. Production and Characterization of Active Transparent PET Films for Oxygen Sensitive Foods Packaging

    NASA Astrophysics Data System (ADS)

    Rosaria Galdi, Maria; Incarnato, Loredana

    2010-06-01

    The aim of this work is to investigate possible solutions to realize active, transparent PET film suitable for packaging oxygen sensitive foods. At this purpose, monolayer active PET films at different oxygen scavenger concentrations and multilayer active ones were produced by cast extrusion laboratory scale equipments. To assess their activity and to verify the efficacy of such solutions, O2 absorption analyses were carried out in continuous by an innovative oxygen meter.

  5. 2,2'-Azobis(isobutyronitrile)-derived alkylperoxyl radical scavenging activity assay of hydrophilic antioxidants by employing EPR spin trap method

    PubMed Central

    Kohri, Shunji; Fujii, Hirotada

    2013-01-01

    As interest in the study of antioxidant intake from foods and other agricultural products increases, methods for performing radical scavenging activity assays based on the electron paramagnetic resonance spectroscopic method, in which there is no interference from the sample color and turbidity, are required. In this study, we have developed a rapid and simple electron paramagnetic resonance based assay to evaluate the alkylperoxyl radical scavenging activity of several antioxidants. The alkylperoxyl radical species was generated by the photolysis of azo-radical initiator 2,2'-azobis(isobutyronitrile), in which the radical generation rate and period were controlled by the illumination light. The relative alkylperoxyl radical scavenging activity was obtained by a simple formula of competing reaction of antioxidant and spin trap toward the oxygen radical. The scavenging activities toward alkylperoxyl radical and alkoxy radical species were evaluated in six antioxidants. Although quercetin showed the highest activity toward both radicals, the order of the relative activities in the other antioxidants was different mutually between the alkylperoxyl radical and the alkoxyl radical. This alkylperoxyl radical scavenging activity assay based on electron paramagnetic resonance spectroscopy is useful for evaluation of colored and turbid food samples. PMID:24249966

  6. [In vitro anti-inflammatory and free radical scavenging activities of flavans from Ilex centrochinensis].

    PubMed

    Li, Lu-jun; Yu, Li-juan; Li, Yan-ci; Liu, Meng-yuan; Wu, Zheng-zhi

    2015-04-01

    This study was carried out to evaluate the anti-inflammatory and free radical scavenging activities of flavans from flex centrochinensis S. Y. Hu in vitro and their structure-activity relationship. LPS-stimulated RAW 264.7 macrophage was used as inflammatory model. MTT assay for cell availability, Griess reaction for nitric oxide (NO) production, the content of TNF-alpha, IL-1beta, IL-6 and PGE, were detected with ELISA kits; DPPH, superoxide anion and hydroxyl free radicals scavenging activities were also investigated. According to the result, all flavans tested exhibited anti-inflammatory effect in different levels. Among them, compounds 1, 3, 4 and 6 showed potent anti-inflammatory effect through the inhibition of NO, TNF-alpha, IL-lp and IL-6, of which 1 was the most effective inhibitor, however, 2 and 5 were relatively weak or inactive. The order of free radical scavenging activities was similar to that of anti-inflammatory activities. Therefore, these results suggest that 3, 4 and 6, especially of 1, were,in part responsible for the anti-inflammatory and free radical scavenging activity of Ilex centrochinensis. Hydroxyl group at 4'-position of B-ring plays an important role in the anti-inflammatory and free radical scavenging capacities. PMID:26281592

  7. Evaluation of Antioxidant, Free Radical Scavenging, and Antimicrobial Activity of Quercus incana Roxb.

    PubMed Central

    Sarwar, Rizwana; Farooq, Umar; Khan, Ajmal; Naz, Sadia; Khan, Sara; Khan, Afsar; Rauf, Abdur; Bahadar, Haji; Uddin, Reaz

    2015-01-01

    Considering the indigenous utilization of Quercus incana Roxb., the present study deals with the investigation of antioxidant, free radical scavenging activity, total phenolic content, and antimicrobial activity of Q. incana Roxb. In vitro antioxidant activity of the plant fractions were determined by 1,1-diphenyl-2-picrylhydrazyl and nitric oxide scavenging method. Total phenolic contents were determined by gallic acid equivalent and antimicrobial activities were determined by agar well diffusion method. It was observed that Q. incana Roxb. showed significant antibacterial activity against Gram-positive and Gram-negative bacteria. n-Butanol fraction showed maximum activity against Micrococcus leuteus with 19 mm zone of inhibition. n-Butanol fraction of Q. incana Roxb. showed immense antifungal activity against Aspergillus niger (32 mm ± 0.55) and A. flavus (28 mm ± 0.45). Similarly n-butanol fraction showed relatively good antioxidant activity with IC50 value of 55.4 ± 0.21 μg/mL. The NO scavenging activity of ethyl acetate fraction (IC50 = 23.21 ± 0.31 μg/mL) was fairly good compared to other fractions. The current study of Q. incana Roxb. suggests the presences of synergetic action of some biological active compounds that may be present in the leaves of medicinal plant. Further studies are needed to better characterize the important active constituents responsible for the antimicrobial, antioxidant and free radical scavenging activity. PMID:26635607

  8. Free radical scavenging activity of Cleome gynandra L. leaves on adjuvant induced arthritis in rats.

    PubMed

    Narendhirakannan, R T; Subramanian, S; Kandaswamy, M

    2005-08-01

    The generation of free radicals has been implicated in the causation of several diseases of known and unknown etiologies such as, rheumatoid arthritis, diabetes, cancer, etc., and compounds that can scavenge free radicals have great potential in ameliorating these disease processes. The present study was aimed to investigate the possible anti-oxidant potential of Cleome gynandra leaf extract at a dose of 150 mg/kg body weight for 30 days on adjuvant induced arthritis in experimental rats. Oral administration of C. gynandra leaf extract significantly increased the levels of lipid peroxides and activities of catalase, glutathione peroxidase and decreased the levels of reduced glutathione and superoxide dismutase activity in arthritis induced rats. The free radical scavenging activity of the plant was further evidenced by histological observations made on the limb tissue. The presence of biologically active ingredients and vital trace elements in the leaves readily account for free radical scavenging property of C. gynandra. PMID:16132687

  9. Nephroprotective and Nitric oxide Scavenging Activity of Tubers of Momordica tuberosa in Rats

    PubMed Central

    Pramod, Kumar; Devala, Rao G.; Lakshmayya; Ramachandra, Setty S.

    2011-01-01

    Hydroalcoholic extract (70% ethanol extract) of tubers of Momordica tuberosa Cogn. (Cucurbitaceae) was subjected to preliminary phytochemical screening by qualitative tests. Nitric oxide scavenging activity was performed by Griess reagent method. And nephroprotective activity was assessed in gentamicin, cisplatin and paracetamol induced renal damage in wistar rats (150-200 g) by standard methods. The protective property of 70% ethanol extract was assessed by measuring the levels of body weight, blood urea, serum creatinine, tissue glutathione and lipid peroxidation in administered doses. The extract exhibited free radical scavenging activity in dose dependant manner. And 100 µg/ml dose produced significantly higher scavenging activity than standard sodium metabisulphate at 25 µg/ml. Also, it significantly reduced the renal damage caused by cisplatin, gentamicin and paracetamol at a dose of 40 mg/kg. PMID:23408139

  10. Antioxidant activity and free radical scavenging capacity of phenolic extracts from Helicteres isora L. and Ceiba pentandra L.

    PubMed

    Loganayaki, Nataraj; Siddhuraju, Perumal; Manian, Sellamuthu

    2013-08-01

    In the present study, antioxidant activities of the phenolic extracts from H. isora fruits and C. pentandra seeds were investigated by employing established in vitro systems, which included reducing power, OH(●), DPPH(●), ABTS(●+), linoleic acid emulsion, metal chelation and antihemolytic activity. The extracts of C. pentandra contained relatively higher levels of total phenolics and flavonoids than those of H. isora. All the extracts showed dose dependent reducing power activity and moreover, they were well correlated with the total phenolic substances. A similar dose dependant trend has also been observed for hydroxyl radical scavenging activity and DPPH(●) radical scavenging activity. Further, addition of 250 μg of extracts to the reaction mixture produced 41.3-54.6% peroxidation inhibiting activity during 60 h of incubation. The potential of multiple antioxidant activity of samples can be further evidenced by inhibition of reactive oxygen mediated erythrocyte cell lysis and metal ion chelating activity. PMID:24425970

  11. Soyasaponins prevent H₂O₂-induced inhibition of gap junctional intercellular communication by scavenging reactive oxygen species in rat liver cells.

    PubMed

    Chen, Jiading; Sun, Suxia; Zha, Dingsheng; Wu, Jiguo; Mao, Limei; Deng, Hong; Chu, Xinwei; Luo, Haiji; Zha, Longying

    2014-01-01

    It appears to be more practical and effective to prevent carcinogenesis by targeting the tumor promotion stage. Gap junctional intercellular communication (GJIC) is strongly involved in carcinogenesis, especially the tumor promotion stage. Considerable interest has been focused on the chemoprevention activities of soyasaponin (SS), which are major phytochemicals found in soybeans and soy products. However, less is known about the preventive effects of SS (especially SS with different chemical structures) against tumor promoter-induced inhibition of GJIC. We investigated the protective effects of SS-A1, SS-A2, and SS-I against hydrogen peroxide (H2O2)-induced GJIC inhibition and reactive oxygen species (ROS) production in Buffalo rat liver (BRL) cells. The present results clearly show for the first time that SS-A1, SS-A2, and SS-I prevent the H2O2-induced GJIC inhibition by scavenging ROS in BRL cells in a dose-dependent manner at the concentration range of from 25 to 100 μg/mL. Soyasaponins attenuated the H2O2-induced ROS through potentiating the activities of superoxide dismutase and glutathione peroxidase. This may be an important mechanism by which SS protects against tumor promotion. In addition, various chemical structures of SS appear to exhibit different protective abilities against GJIC inhibition. This may partly attribute to their differences in ROS-scavenging activities. PMID:25268883

  12. Yields of single-strand breaks in double-stranded calf thymus DNA irradiated in aqueous solution in the presence of oxygen and scavengers

    SciTech Connect

    Udovicic, Lj.; Mark, F.; Bothe, E.

    1994-11-01

    Yields of radiation-induced single-strand breaks in double-stranded calf thymus DNA have been measured as a function of OH scavenger concentration in N{sub 2}O/O{sub 2}-saturated aqueous solution. The experimental data are well represented by a theoretical model based on non-homogeneous reaction kinetics, without the need to adjust any parameter. The good agreement between experimental and theoretical data is taken as evidence that, in the presence of oxygen, the main effect of added scavengers with respect to the formation of single-strand breaks in double-stranded DNA is OH radical scavenging. 30 refs., 3 figs., 1 tab.

  13. Effect of PDE5 inhibition combined with free oxygen radical scavenger therapy on erectile function in a diabetic animal model.

    PubMed

    De Young, L; Yu, D; Freeman, D; Brock, G B

    2003-10-01

    Phosphodiesterase (PDE) inhibitors represent an important advance in the treatment of erectile dysfunction (ED). In spite of widespread use and generally good efficacy, as a class they remain ineffective in 15-57% of men. Specific cohorts of patients with severe vascular or neurogenic basis to their ED, such as diabetic men or those who have undergone radical pelvic surgery, demonstrate lower response rates with PDE inhibition treatment. We believe that circulating levels of nitric oxide (NO) may be enhanced through delivery of adequate concentrations of free oxygen radical scavenger molecules such as vitamin E. Higher levels of NO, theoretically, should produce increased penile blood flow with the potential for a synergistic effect when combined with a PDE5 inhibitor. With this hypothesis in mind, 20 adult male Sprague-Dawley streptozotocin-induced (60 mg/kg i.p.) diabetic rats were divided into four therapeutic groups (n=5). Group I--control animals received peanut oil, group II--vitamin E 20 IU/day, group III--sildenafil 5 mg/kg/day and group IV--vitamin E 20 IU/day plus sildenafil 5 mg/kg/day, by oral gavage daily for 3 weeks. Erectile function was assessed as a rise in intracavernous pressure following cavernous nerve electrostimulation. Penile tissue was harvested to determine the changes in tissue morphology including neuronal nitric oxide synthase, smooth muscle alpha-actin and endothelial cell integrity. PDE5 protein content and activity were measured. Significant increases in intracavernous pressure were measured in the animals receiving combined vitamin E plus sildenafil treatment. Immunohistochemical staining showed increases of neuronal nitric oxide synthase, endothelial cell and smooth muscle cell staining. Western blot analysis did not show significant differences of PDE5 protein between the groups. However, higher PDE5 activity was measured in the sildenafil group and lower activity of PDE5 was recorded in the cohort receiving vitamin E with

  14. Screening of Malian medicinal plants for antifungal, larvicidal, molluscicidal, antioxidant and radical scavenging activities.

    PubMed

    Diallo, D; Marston, A; Terreaux, C; Touré, Y; Paulsen, B S; Hostettmann, K

    2001-08-01

    A total of 78 different extracts from 20 medicinal plants belonging to 14 plant families from Mali were tested for their antifungal, larvicidal, molluscicidal, antioxidant and radical scavenging activities. Dichloromethane, methanol, water and ethanol extracts were used. TLC autobiography for antifungal activity was run with Cladosporium cucumerinum and Candida albicans. Extracts were also tested on the larvae of the mosquitoes Aedes aegypti, Anopheles gambiae and Culex quinquefasciatus. Molluscicidal activities were established with the snails Biomphalaria glabrata, Biomphalaria pfeifferi and Bulinus truncatus. beta-Carotene and DPPH solutions sprayed on TLC plates were used for antioxidant and radical scavenging assays. Of the extracts investigated, 20% were antioxidant and radical scavengers, 19% fungicidal, 30% were larvicidal and 11% were molluscicidal. Three of the plant extracts, from Cussonia barteri (Araliaceae), Glinus oppositifolius (Aïzoaceae) and Lannea velutina (Anacardiaceae) gave positive responses in all four tests. PMID:11507731

  15. The effect of a Ta oxygen scavenger layer on HfO2-based resistive switching behavior: thermodynamic stability, electronic structure, and low-bias transport.

    PubMed

    Zhong, Xiaoliang; Rungger, Ivan; Zapol, Peter; Nakamura, Hisao; Asai, Yoshihiro; Heinonen, Olle

    2016-03-14

    Reversible resistive switching between high-resistance and low-resistance states in metal-oxide-metal heterostructures makes them very interesting for applications in random access memories. While recent experimental work has shown that inserting a metallic "oxygen scavenger layer" between the positive electrode and oxide improves device performance, the fundamental understanding of how the scavenger layer modifies the heterostructure properties is lacking. We use density functional theory to calculate thermodynamic properties and conductance of TiN/HfO2/TiN heterostructures with and without a Ta scavenger layer. First, we show that Ta insertion lowers the formation energy of low-resistance states. Second, while the Ta scavenger layer reduces the Schottky barrier height in the high-resistance state by modifying the interface charge at the oxide-electrode interface, the heterostructure maintains a high resistance ratio between high- and low-resistance states. Finally, we show that the low-bias conductance of device on-states becomes much less sensitive to the spatial distribution of oxygen removed from the HfO2 in the presence of the Ta layer. By providing a fundamental understanding of the observed improvements with scavenger layers, we open a path to engineer interfaces with oxygen scavenger layers to control and enhance device performance. In turn, this may enable the realization of a non-volatile low-power memory technology with concomitant reduction in energy consumption by consumer electronics and offering significant benefits to society. PMID:26902598

  16. 6-Methyl 3-chromonyl 2,4-thiazolidinedione/2,4-imidazolidinedione/2-thioxo-imidazolidine-4-one compounds: novel scavengers of reactive oxygen species.

    PubMed

    Berczyński, Paweł; Duchnik, Ewa; Kruk, Irena; Piechowska, Teresa; Aboul-Enein, Hassan Y; Bozdağ-Dündar, Oya; Ceylan-Unlusoy, Meltem

    2014-06-01

    The benefits of antioxidants on human health are usually ascribed to their potential ability to remove reactive oxygen species providing protection against oxidative stress. In this paper the free radicals scavenging activities of nine 6-methyl 3-chromonyl derivatives (CMs) were evaluated for the first time by the chemiluminescence, electron paramagnetic resonance, spin trapping and 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) methods. The total antioxidant capacity was also measured using a ferric-ferrozine reagent. Compounds having a hydrogen atom at the N3-position of the β-ring were effective in quenching CL resulted from the KO2 /18-crown-6-ether system (a source of superoxide anion radical, O2•¯) in a dose-dependent manner over the range of 0.05-1 mmol/L [IC50 ranged from 0.353 (0.04) to 0.668 (0.05) mmol/L]. The examined compounds exhibited a significant scavenging effect towards hydroxyl radicals (HO(•) HO(•)), produced by the Fenton reaction, and this ranged from 24.0% to 61.0%, at the concentration of 2.5 mmol/L. Furthermore, the compounds examined were also found to inhibit DPPH(•) and this ranged from 51.9% to 97.4% at the same concentration. In addition, the use of the total antioxidant capacity assay confirmed that CM compounds are able to act as reductants. According to the present study, CM compounds showed effective in vitro free radical scavenging activity and may be considered as potential therapeutics to control diseases of oxidative stress-related etiology. PMID:23843284

  17. Free radical scavenging reactions of sulfasalazine, 5-aminosalicylic acid and sulfapyridine: mechanistic aspects and antioxidant activity.

    PubMed

    Joshi, Ravi; Kumar, Sudheer; Unnikrishnan, M; Mukherjee, T

    2005-11-01

    Reactions of sulfasalazine (SAZ) and its metabolites, 5-aminosalicylic acid (5-ASA) and sulfapyridine (SP), with various oxidizing and reducing free radicals (hydroxyl, haloperoxyl, one-electron oxidizing, lipid peroxyl, glutathiyl, superoxide, tryptophanyl, etc.) have been studied to understand the mechanistic aspects of its action against free radicals produced during inflammation. Nanosecond pulse radiolysis technique coupled with transient spectrophotometry has been used for in situ generation of free radicals and to follow their reaction pathways. The transients produced in these reactions have been assigned and radical scavenging rate constants have been measured. In addition to scavenging of various primary and secondary free radicals by SAZ, 5-ASA and SP, 5-ASA has also been observed to efficiently scavenge radicals of biomolecules. 5-ASA has been found to be the active moiety of SAZ involved in the scavenging of oxidizing free radicals whereas reduction of SAZ produced molecular radical anion. The study suggests that free radical scavenging activity of 5-ASA may be a major path of pharmacological action of SAZ against inflammatory bowel diseases (IBD). PMID:16298742

  18. Analysis of scavengers' activities and recycling in some cities of Nigeria.

    PubMed

    Agunwamba, J C

    2003-07-01

    The state of solid waste recycling by scavengers in Onitsha, a heavily commercial city in Anambra State, and some other urban areas such as Nsukka, Enugu, and Port Harcourt was analyzed. Data were obtained through interviews of scavengers who deal with recyclables. Although the activities of scavengers are sub-optimal, they can have a great impact on Nigerian economy with respect to resource conservation, creation of job opportunities, and reduction of the magnitude of waste disposal problems. A cost analysis is presented to compare the different forms of recycling utilized by municipal solid waste management. It is shown that a well-planned recycling program with recycling and composting would result in 18.6% savings in waste management costs and 57.7% in landfill avoidance costs. However, if the compost materials are not recycled, the corresponding savings in cost become 8.6% and 28.6%, respectively. The option with the lowest cost involves encouraging individual households to separate at the source their recyclables, which are bought by scavengers. This results in 78.0% savings in waste management cost and 79.5% landfill avoidance cost. A low-cost approach aimed at the integration of scavenging activities into conventional solid waste management is presented. PMID:14703917

  19. Isolation of lactic acid bacteria exhibiting high scavenging activity for environmental hydrogen peroxide from fermented foods and its two scavenging enzymes for hydrogen peroxide.

    PubMed

    Watanabe, Akio; Kaneko, Chiaki; Hamada, Yasuhiro; Takeda, Kouji; Kimata, Shinya; Matsumoto, Takashi; Abe, Akira; Tanaka, Naoto; Okada, Sanae; Uchino, Masataka; Satoh, Junichi; Nakagawa, Junichi; Niimura, Youichi

    2016-01-01

    To obtain lactic acid bacteria that scavenge environmental hydrogen peroxide, we developed a specialized enrichment medium and successfully isolated Pediococcus pentosaceus Be1 strain from a fermented food. This strain showed vigorous environmental hydrogen peroxide scavenging activity over a wide range of hydrogen peroxide concentrations. High Mn-catalase and NADH peroxidase activities were found in the cell-free extract of the P. pentosaceus Be1 strain, and these two hydrogen peroxide scavenging enzymes were purified from the cell-free extract of the strain. Mn-catalase has been purified from several microorganisms by several researchers, and the NADH peroxidase was first purified from the original strain in this report. After cloning the genes of the Mn-catalase and the NADH peroxidase, the deduced amino acid sequences were compared with those of known related enzymes. PMID:27118075

  20. TIGAR contributes to ischemic tolerance induced by cerebral preconditioning through scavenging of reactive oxygen species and inhibition of apoptosis.

    PubMed

    Zhou, Jun-Hao; Zhang, Tong-Tong; Song, Dan-Dan; Xia, Yun-Fei; Qin, Zheng-Hong; Sheng, Rui

    2016-01-01

    Previous study showed that TIGAR (TP53-induced glycolysis and apoptosis regulator) protected ischemic brain injury via enhancing pentose phosphate pathway (PPP) flux and preserving mitochondria function. This study was aimed to study the role of TIGAR in cerebral preconditioning. The ischemic preconditioning (IPC) and isoflurane preconditioning (ISO) models were established in primary cultured cortical neurons and in mice. Both IPC and ISO increased TIGAR expression in cortical neurons. Preconditioning might upregulate TIGAR through SP1 transcription factor. Lentivirus mediated knockdown of TIGAR significantly abolished the ischemic tolerance induced by IPC and ISO. ISO also increased TIGAR in mouse cortex and hippocampus and alleviated subsequent brain ischemia-reperfusion injury, while the ischemic tolerance induced by ISO was eliminated with TIGAR knockdown in mouse brain. ISO increased the production of NADPH and glutathione (GSH), and scavenged reactive oxygen species (ROS), while TIGAR knockdown decreased GSH and NADPH production and increased the level of ROS. Supplementation of ROS scavenger NAC and PPP product NADPH effectively rescue the neuronal injury caused by TIGAR deficiency. Notably, TIGAR knockdown inhibited ISO-induced anti-apoptotic effects in cortical neurons. These results suggest that TIGAR participates in the cerebral preconditioning through reduction of ROS and subsequent cell apoptosis. PMID:27256465

  1. TIGAR contributes to ischemic tolerance induced by cerebral preconditioning through scavenging of reactive oxygen species and inhibition of apoptosis

    PubMed Central

    Zhou, Jun-Hao; Zhang, Tong-Tong; Song, Dan-Dan; Xia, Yun-Fei; Qin, Zheng-Hong; Sheng, Rui

    2016-01-01

    Previous study showed that TIGAR (TP53-induced glycolysis and apoptosis regulator) protected ischemic brain injury via enhancing pentose phosphate pathway (PPP) flux and preserving mitochondria function. This study was aimed to study the role of TIGAR in cerebral preconditioning. The ischemic preconditioning (IPC) and isoflurane preconditioning (ISO) models were established in primary cultured cortical neurons and in mice. Both IPC and ISO increased TIGAR expression in cortical neurons. Preconditioning might upregulate TIGAR through SP1 transcription factor. Lentivirus mediated knockdown of TIGAR significantly abolished the ischemic tolerance induced by IPC and ISO. ISO also increased TIGAR in mouse cortex and hippocampus and alleviated subsequent brain ischemia-reperfusion injury, while the ischemic tolerance induced by ISO was eliminated with TIGAR knockdown in mouse brain. ISO increased the production of NADPH and glutathione (GSH), and scavenged reactive oxygen species (ROS), while TIGAR knockdown decreased GSH and NADPH production and increased the level of ROS. Supplementation of ROS scavenger NAC and PPP product NADPH effectively rescue the neuronal injury caused by TIGAR deficiency. Notably, TIGAR knockdown inhibited ISO-induced anti-apoptotic effects in cortical neurons. These results suggest that TIGAR participates in the cerebral preconditioning through reduction of ROS and subsequent cell apoptosis. PMID:27256465

  2. Novel antioxidative nanotherapeutics in a rat periodontitis model: Reactive oxygen species scavenging by redox injectable gel suppresses alveolar bone resorption.

    PubMed

    Saita, Makiko; Kaneko, Junya; Sato, Takenori; Takahashi, Shun-suke; Wada-Takahashi, Satoko; Kawamata, Ryota; Sakurai, Takashi; Lee, Masaichi-Chang-il; Hamada, Nobushiro; Kimoto, Katsuhiko; Nagasaki, Yukio

    2016-01-01

    The excessive production of reactive oxygen species (ROS) has been implicated in a variety of disorders, but to date, ROS scavengers have not been widely used for local treatment of inflammation, because they are rapidly eliminated from the inflamed site. We have designed a novel redox injectable gel (RIG) that is formed at 37 °C after disintegration of nano-assembled flower micelles allowing nitroxide radicals to act locally as specific ROS scavengers for the treatment of periodontitis. In the present study, we have confirmed retention of the RIG in the periodontal region, along with its antioxidant-related anti-inflammatory effects, and we have subsequently evaluated the inhibitory effect of the RIG against Porphyromonas gingivalis (P. gingivalis)-induced alveolar bone loss attributed to ROS. Alveolar bone loss was estimated by morphometry, gingival blood flow was measured using laser Doppler flowmetry, and osteoclast differentiation was evaluated by tartrate-resistant acid phosphatase staining. The results show that the RIG can inhibit P. gingivalis-induced bone loss by antioxidant-related anti-inflammatory actions, and this suggests that the RIG is a promising novel therapeutic agent for the treatment of P. gingivalis-induced periodontitis. PMID:26559357

  3. Influence of coffee genotype on bioactive compounds and the in vitro capacity to scavenge reactive oxygen and nitrogen species.

    PubMed

    Rodrigues, Naira Poerner; Salva, Terezinha de Jesus Garcia; Bragagnolo, Neura

    2015-05-20

    The influence of green coffee genotype on the bioactive compounds and the in vitro antioxidant capacity against the principal reactive oxygen (ROO(•), H2O2, HO(•), and HOCl) and nitrogen (NO(•) and ONOO(-)) species of biological relevance was investigated. This is the first report on the capacity of green coffee to scavenge H2O2, HOCl, and NO(•). Variations in the contents of total chlorogenic acids (22.9-37.9 g/100 g), cinnamoyl-amino acid conjugates (0.03-1.12 g/100 g), trigonelline (3.1-6.7 g/100 g), and caffeine (3.9-11.8 g/100 g) were found. Hydrophilic extracts of Coffea canephora and Coffea kapakata were the most potent scavengers of ROO(•), H2O2, HO(•), NO(•), and ONOO(-) due to their chlorogenic acid contents, which were, on average, 30% higher than those found in Coffea arabica and Coffea racemosa. The results showed that genotype is a determinant characteristic in the bioactive compound contents and consequently in the antioxidant capacity of green coffee. PMID:25910038

  4. Edaravone (MCI-186) scavenges reactive oxygen species and ameliorates tissue damage in the murine spinal cord injury model.

    PubMed

    Aoyama, Takeshi; Hida, Kazutoshi; Kuroda, Satoshi; Seki, Toshitaka; Yano, Shunsuke; Shichinohe, Hideo; Iwasaki, Yoshinobu

    2008-12-01

    The present study evaluated the effect of the free radical scavenger edaravone on lesion volume and neurological dysfunction after spinal cord injury (SCI) in mice, and investigated its protective effects on superoxide generation. Female C57BL/6 mice were subjected to SCI using a pneumatic impact device and were treated with 3 mg/kg of edaravone or vehicle 30 minutes before the insult. Motor functions were quantitatively evaluated. Lesion volume was assessed by Dohrmann's two-cone method after one week. In situ detection of superoxide in the injured cord was carried out using the superoxide-sensitive dye dihydroethidium (DHE) staining technique. Pretreatment with edaravone significantly improved motor dysfunction and reduced the lesion volume to about 63% of the control (p < 0.05). Semi-quantitative measurements of red fluorescence emitted from DHE revealed that the superoxide concentration increased in the lesion periphery at 1 and 3 hours after the insult, and that pretreatment with edaravone significantly inhibited the increase of superoxide concentration in the lesion periphery at both time points (p < 0.0001). Double staining with DHE and monoclonal antibody against MAP2 showed that most cells positive for DHE were also positive for MAP2. These findings suggest that edaravone ameliorates tissue damage by scavenging reactive oxygen species, especially in the neurons, after SCI. PMID:19106491

  5. A soil actinobacterium scavenges atmospheric H2 using two membrane-associated, oxygen-dependent [NiFe] hydrogenases.

    PubMed

    Greening, Chris; Berney, Michael; Hards, Kiel; Cook, Gregory M; Conrad, Ralf

    2014-03-18

    In the Earth's lower atmosphere, H2 is maintained at trace concentrations (0.53 ppmv/0.40 nM) and rapidly turned over (lifetime ≤ 2.1 y(-1)). It is thought that soil microbes, likely actinomycetes, serve as the main global sink for tropospheric H2. However, no study has ever unambiguously proven that a hydrogenase can oxidize this trace gas. In this work, we demonstrate, by using genetic dissection and sensitive GC measurements, that the soil actinomycete Mycobacterium smegmatis mc(2)155 constitutively oxidizes subtropospheric concentrations of H2. We show that two membrane-associated, oxygen-dependent [NiFe] hydrogenases mediate this process. Hydrogenase-1 (Hyd1) (MSMEG_2262-2263) is well-adapted to rapidly oxidize H2 at a range of concentrations [Vmax(app) = 12 nmol⋅g⋅dw(-1)⋅min(-1); Km(app) = 180 nM; threshold = 130 pM in the Δhyd23 (Hyd1 only) strain], whereas Hyd2 (MSMEG_2719-2720) catalyzes a slower-acting, higher-affinity process [Vmax(app) = 2.5 nmol⋅g⋅dw(-1)⋅min(-1); Km(app) = 50 nM; threshold = 50 pM in the Δhyd13 (Hyd2 only) strain]. These observations strongly support previous studies that have linked group 5 [NiFe] hydrogenases (e.g., Hyd2) to the oxidation of tropospheric H2 in soil ecosystems. We further reveal that group 2a [NiFe] hydrogenases (e.g., Hyd1) can contribute to this process. Hydrogenase expression and activity increases in carbon-limited cells, suggesting that scavenging of trace H2 helps to sustain dormancy. Distinct physiological roles for Hyd1 and Hyd2 during the adaptation to this condition are proposed. Soil organisms harboring high-affinity hydrogenases may be especially competitive, given that they harness a highly dependable fuel source in otherwise unstable environments. PMID:24591586

  6. In vitro radical scavenging and cytotoxic activities of novel hybrid selenocarbamates.

    PubMed

    Romano, Beatriz; Plano, Daniel; Encío, Ignacio; Palop, Juan Antonio; Sanmartín, Carmen

    2015-04-15

    Novel selenocyanate and diselenide derivatives containing a carbamate moiety were synthesised and evaluated in vitro to determine their cytotoxic and radical scavenging properties. Cytotoxic activity was tested against a panel of human cell lines including CCRF-CEM (lymphoblastic leukaemia), HT-29 (colon carcinoma), HTB-54 (lung carcinoma), PC-3 (prostate carcinoma), MCF-7 (breast adenocarcinoma), 184B5 (non-malignant, mammary gland derived) and BEAS-2B (non-malignant, derived from bronchial epithelium). Most of the compounds displayed high antiproliferative activity with GI50 values below 10μM in MCF-7, CCRF-CEM and PC-3 cells. Radical scavenging properties of the new selenocompounds were confirmed testing their ability to scavenge DPPH and ABTS radicals. Based on the activity of selenium-based glutathione peroxidases (GPxs), compounds 1a, 2e and 2h were further screened for their capacity to reduce hydrogen peroxide under thiol presence. Results suggest that compound 1a mimics GPxs activity. Cytotoxic parameters, radical scavenging activity and ADME profile point to 1a as promising drug candidate. PMID:25792142

  7. Molecular mechanisms for the reaction between (˙)OH radicals and proline: insights on the role as reactive oxygen species scavenger in plant stress.

    PubMed

    Signorelli, Santiago; Coitiño, E Laura; Borsani, Omar; Monza, Jorge

    2014-01-01

    The accumulation of proline (Pro) and overproduction of reactive oxygen species (ROS) by plants exposed to stress is well-documented. In vitro assays show that enzyme inactivation by hydroxyl radicals ((•)OH) can be avoided in the presence of Pro, suggesting this amino acid might act as a (•)OH scavenger. Although production of hydroxyproline (Hyp) has been hypothesized in connection with such antioxidant activity, no evidence on the detailed mechanism of scavenging has been reported. To elucidate whether and how Hyp might be produced, we used density functional theory calculations coupled to a polarizable continuum model to explore 27 reaction channels including H-abstraction by (•)OH and (•)OH/H2O addition. The structure and energetics of stable species and transition states for each reaction channel were characterized at the PCM-(U)M06/6-31G(d,p) level in aqueous solution. Evidence is found for a main pathway in which Pro scavenges (•)OH by successive H-abstractions (ΔG(‡,298) = 4.1 and 7.5 kcal mol(-1)) to yield 3,4-Δ-Pro. A companion pathway with low barriers yielding Δ(1)-pyrroline-5-carboxylate (P5C) is also supported, linking with 5-Hyp through hydration. However, this connection remains unlikely in stressed plants because P5C would be efficiently recycled to Pro (contributing to its accumulation) by P5C reductase, hypothesis coined here as the "Pro-Pro cycle". PMID:24328335

  8. Singlet oxygen quenching and radical scavenging capacities of structurally-related flavonoids present in Zuccagnia punctata Cav.

    PubMed

    Vieyra, Faustino E Morán; Boggetti, Héctor J; Zampini, Iris C; Ordoñez, Roxana M; Isla, María I; Alvarez, Rosa M S; De Rosso, Veridiana; Mercadante, Adriana Z; Borsarelli, Claudio D

    2009-06-01

    The singlet oxygen (1O2) quenching and free radical (DPPH(*), ABTS(* +) and O2(* -)) scavenging ability of three structurally-related flavonoids (7-hydroxyflavanone HF, 2',4'-dihydroxychalcone DHC and 3,7-dihydroxyflavone DHF) present in the Argentinean native shrub Zuccagnia punctata Cav. were studied in solution by combining electrochemical and kinetic measurements, mass spectroscopy, end-point antioxidant assays and computational calculations. The results showed that the antioxidant properties of these flavonoids depend on several factors, such as their electron- and hydrogen atom donor capacity, the ionization degree of the more acidic group, solvatation effects and electrostatic interactions with the oxidant species. The theoretical calculations for both the gas and solution phases at the B3LYP level of theory for the Osanger reaction field model agreed with the experimental findings, thus supporting the characterization of the antioxidant mechanism of the Z. punctata flavonoids. PMID:19431060

  9. Interactions between carnosine and captopril on free radical scavenging activity and angiotensin-converting enzyme activity in vitro.

    PubMed

    Nakagawa, Kazuo; Ueno, Akemi; Nishikawa, Yukari

    2006-01-01

    Interactions between carnosine (beta-alanyl-L-histidine), being plentiful in skeletal muscles and neuronal tissues, and captopril, a widely used angiotensin-converting enzyme (ACE) inhibitor, were examined concerning free radical scavenging activity and ACE activity in vitro. Not only captopril, but also carnosine, at concentrations less than those ordinarily found in muscles and neuronal tissues, significantly scavenged 2,2'-azinobis (3-ethylbenzothiazoline-6-sulphonate) (ABTS) radical cations, and inhibited ACE activity. Cupric ions reversed the ABTS scavenging activity of carnosine and captopril, whereas cupric ions strengthened the inhibitory action of carnosine on ACE activity. In contrast, cupric ions antagonized the inhibition of ACE activity induced by ethylenediaminetetraacetic acid, indicating that the inhibitory effect of carnosine on ACE activity is not related to the chelating action of carnosine. On the other hand, carnosine and captopril synergistically enhanced the free radical scavenging activity, but not the inhibitory effect on the ACE activity. These data suggest that carnosine in its concurrent use with captopril could act as a beneficial free radical scavenger, with less danger of overdose, in the inhibition of ACE activity. PMID:16394648

  10. Free Radical Scavenging and Analgesic Activities of Cucumis sativus L. Fruit Extract

    PubMed Central

    Kumar, D; Kumar, S; Singh, J; Narender; Rashmi; Vashistha, BD; Singh, N

    2010-01-01

    The aqueous fruit extract of Cucumis sativus L. was screened for free radical scavenging and analgesic activities. The extract was subjected to in vitro antioxidant studies at 250 and 500 μg/ml and analgesic study at the doses 250 and 500 mg/kg, respectively. The free radical scavenging was compared with ascorbic acid, BHA (Butylated hydroxyl anisole), whereas, the analgesic effect was compared with Diclofenac sodium (50 mg/kg). The C. sativus fruit extract showed maximum antioxidant and analgesic effect at 500 μg/ml and 500 mg/kg, respectively. The presence of flavonoids and tannins in the extract as evidenced by preliminary phytochemical screening suggests that these compounds might be responsible for free radical scavenging and analgesic effects. PMID:21264095

  11. Nitric Oxide Measurement from Purified Enzymes and Estimation of Scavenging Activity by Gas Phase Chemiluminescence Method.

    PubMed

    Kumari, Aprajita; Gupta, Alok Kumar; Mishra, Sonal; Wany, Aakanksha; Gupta, Kapuganti Jagadis

    2016-01-01

    In plants, nitrate reductase (NR) is a key enzyme that produces nitric oxide (NO) using nitrite as a substrate. Lower plants such as algae are shown to have nitric oxide synthase enzyme and higher plants contain NOS activity but enzyme responsible for NO production in higher plants is subjected to debate. In plant nitric oxide research, it is very important to measure NO very precisely in order to determine its functional role. A significant amount of NO is being scavenged by various cell components. The net NO production depends in production minus scavenging. Here, we describe methods to measure NO from purified NR and inducible nitric oxide synthase from mouse (iNOS), we also describe a method of measure NO scavenging by tobacco cell suspensions and mitochondria from roots. PMID:27094408

  12. Direct sGC Activation Bypasses NO Scavenging Reactions of Intravascular Free Oxy-Hemoglobin and Limits Vasoconstriction

    PubMed Central

    Tabima, D. Marcela; Specht, Patricia A.C.; Tejero, Jesús; Champion, Hunter C.; Kim-Shapiro, Daniel B.; Baust, Jeff; Mik, Egbert G.; Hildesheim, Mariana; Stasch, Johannes-Peter; Becker, Eva-Maria; Truebel, Hubert

    2013-01-01

    Abstract Aims: Hemoglobin-based oxygen carriers (HBOC) provide a potential alternative to red blood cell (RBC) transfusion. Their clinical application has been limited by adverse effects, in large part thought to be mediated by the intravascular scavenging of the vasodilator nitric oxide (NO) by cell-free plasma oxy-hemoglobin. Free hemoglobin may also cause endothelial dysfunction and platelet activation in hemolytic diseases and after transfusion of aged stored RBCs. The new soluble guanylate cyclase (sGC) stimulator Bay 41-8543 and sGC activator Bay 60-2770 directly modulate sGC, independent of NO bioavailability, providing a potential therapeutic mechanism to bypass hemoglobin-mediated NO inactivation. Results: Infusions of human hemoglobin solutions and the HBOC Oxyglobin into rats produced a severe hypertensive response, even at low plasma heme concentrations approaching 10 μM. These reactions were only observed for ferrous oxy-hemoglobin and not analogs that do not rapidly scavenge NO. Infusions of L-NG-Nitroarginine methyl ester (L-NAME), a competitive NO synthase inhibitor, after hemoglobin infusion did not produce additive vasoconstriction, suggesting that vasoconstriction is related to scavenging of vascular NO. Open-chest hemodynamic studies confirmed that hypertension occurred secondary to direct effects on increasing vascular resistance, with limited negative cardiac inotropic effects. Intravascular hemoglobin reduced the vasodilatory potency of sodium nitroprusside (SNP) and sildenafil, but had no effect on vasodilatation by direct NO-independent activation of sGC by BAY 41-8543 and BAY 60-2770. Innovation and Conclusion: These data suggest that both sGC stimulators and sGC activators could be used to restore cyclic guanosine monophosphate-dependent vasodilation in conditions where cell-free plasma hemoglobin is sufficient to inhibit endogenous NO signaling. Antioxid. Redox Signal. 19, 2232–2243. PMID:23697678

  13. Phytochemical Analysis and Free Radical Scavenging Activity of Medicinal Plants Gnidia glauca and Dioscorea bulbifera

    PubMed Central

    Ghosh, Sougata; Derle, Abhishek; Ahire, Mehul; More, Piyush; Jagtap, Soham; Phadatare, Suvarna D.; Patil, Ajay B.; Jabgunde, Amit M.; Sharma, Geeta K.; Shinde, Vaishali S.; Pardesi, Karishma; Dhavale, Dilip D.; Chopade, Balu A.

    2013-01-01

    Gnidia glauca and Dioscorea bulbifera are traditional medicinal plants that can be considered as sources of natural antioxidants. Herein we report the phytochemical analysis and free radical scavenging activity of their sequential extracts. Phenolic and flavonoid content were determined. Scavenging activity was checked against pulse radiolysis generated ABTS•+ and OH radical, in addition to DPPH, superoxide and hydroxyl radicals by biochemical methods followed by principal component analysis. G. glauca leaf extracts were rich in phenolic and flavonoid content. Ethyl acetate extract of D. bulbifera bulbs and methanol extract of G. glauca stem exhibited excellent scavenging of pulse radiolysis generated ABTS•+ radical with a second order rate constant of 2.33×106 and 1.72×106, respectively. Similarly, methanol extract of G. glauca flower and ethyl acetate extract of D. bulbifera bulb with second order rate constants of 4.48×106 and 4.46×106 were found to be potent scavengers of pulse radiolysis generated OH radical. G. glauca leaf and stem showed excellent reducing activity and free radical scavenging activity. HPTLC fingerprinting, carried out in mobile phase, chloroform: toluene: ethanol (4: 4: 1, v/v) showed presence of florescent compound at 366 nm as well as UV active compound at 254 nm. GC-TOF-MS analysis revealed the predominance of diphenyl sulfone as major compound in G. glauca. Significant levels of n-hexadecanoic acid and octadecanoic acid were also present. Diosgenin (C27H42O3) and diosgenin (3á,25R) acetate were present as major phytoconstituents in the extracts of D. bulbifera. G. glauca and D. bulbifera contain significant amounts of phytochemicals with antioxidative properties that can be exploited as a potential source for herbal remedy for oxidative stress induced diseases. These results rationalize further investigation in the potential discovery of new natural bioactive principles from these two important medicinal plants. PMID:24367520

  14. In vitro activity of almond skin polyphenols for scavenging free radicals and inducing quinone reductase.

    PubMed

    Chen, C-Y Oliver; Blumberg, Jeffrey B

    2008-06-25

    Observational studies and clinical trials suggest nut intake, including almonds, is associated with an enhancement in antioxidant defense and a reduction in the risk of cancer and cardiovascular disease. Almond skins are rich in polyphenols (ASP) that may contribute to these putative benefits. To assess their potential mechanisms of action, we tested the in vitro effect of ASP extracted with methanol (M) or a gastrointestinal juice mimic (GI) alone or in combination with vitamins C (VC) or E (VE) (1-10 micromol/L) on scavenging free radicals and inducing quinone reductase (QR). Flavonoid profiles from ASP-M and -GI extracts were different from one another. ASP-GI was more potent in scavenging HOCl and ONOO (-) radicals than ASP-M. In contrast, ASP-M increased and ASP-GI decreased QR activity in Hepa1c1c7 cells. Adding VC or VE to ASP produced a combination- and dose-dependent action on radical scavenging and QR induction. In comparison to their independent actions, ASP-M plus VC were less potent in scavenging DPPH, HOCl, ONOO (-), and O 2 (-) (*). However, the interaction between ASP-GI plus VC promoted their radical scavenging activity. Combining ASP-M plus VC resulted in a synergistic interaction, inducing QR activity, but ASP-GI plus VC had an antagonistic effect. On the basis of their total phenolic content, the measures of total antioxidant activity of ASP-M and -GI were comparable. Thus, in vitro, ASP act as antioxidants and induce QR activity, but these actions are dependent upon their dose, method of extraction, and interaction with antioxidant vitamins. PMID:18512942

  15. Increased endogenous ascorbyl free radical formation with singlet oxygen scavengers in reperfusion injury: an EPR and functional recovery study in rat hearts.

    PubMed

    Lee, J W; Bobst, E V; Wang, Y G; Ashraf, M M; Bobst, A M

    2000-12-01

    The objective of this study was to investigate the effect of singlet oxygen ((1)O2) scavengers on functional recovery and ascorbyl free radical (AFR) formation in isolated ischemic rat hearts. Hearts were subjected to 40 min. of global ischemia followed by 30 min. of reperfusion. Hemodynamics were measured as heart rate (HR), coronary flow (CF), left ventricular developed pressure (LVDP) and contractility (dP/dt). Electron paramagnetic resonance (EPR) spectroscopy was used to measure AFR release in coronary perfusate during the first two min. of reperfusion as a function of ROS scavengers. Relative to ischemic controls the administration of the (1)O2 scavengers 2,2,6,6-tetramethyl-4-piperidone x HCl (4-oxo-TEMP), carnosine (beta-alanyl-L-histidine) or a combination of the two significantly improved functional recovery as measured by LVDP. While no AFR signal was detected in coronary perfusate collected during preischemic perfusion with and without (1)O2 scavengers, the AFR background signal due to ischemia was significantly increased with the (1)O2 and *O2- scavengers. No such increase was observed with the hydroxyl radical (*OH) scavenger mannitol. Besides the AFR increase with the (1)O2 and *O2- scavengers the functional recovery was only significantly improved with the (1)O2 scavengers. In contrast to previous AFR studies we found with endogenous AFR that an increased AFR formation is not necessarily only reflecting increased oxidative stress but can also report improved functional recovery. Combining the hemodynamic data with increased AFR formation in the presence of several different ROS scavengers gives supportive evidence for (1)O2 also being involved in reperfusion injury. PMID:11156483

  16. Radical scavenging and antioxidant activities of essential oil components--an experimental and computational investigation.

    PubMed

    Sharopov, Farukh S; Wink, Michael; Setzer, William N

    2015-01-01

    The antioxidant activities of eighteen different essential oil components have been determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay, the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical cation assay, and the ferric reducing antioxidant power (FRAP) assay. The phenolic compounds, carvacrol, thymol, and eugenol, showed the best antioxidant activities, while camphor, menthol, and menthone were the least active. The structural and electronic properties of the essential oil components were assessed using density functional theory (DFT) at the B3LYP/6-311++G** level. Correlations between calculated electronic properties and antioxidant activities were generally poor, but bond-dissociation energies (BDEs) seem to correlate with DPPH radical-scavenging activities, and the ferric reducing antioxidant power (FRAP) assay correlated with vertical ionization potentials calculated at the Hartree-Fock/6-311++G** level. PMID:25920239

  17. Non-targeted Metabolite Profiling and Scavenging Activity Unveil the Nutraceutical Potential of Psyllium (Plantago ovata Forsk).

    PubMed

    Patel, Manish K; Mishra, Avinash; Jha, Bhavanath

    2016-01-01

    Non-targeted metabolomics implies that psyllium (Plantago ovata) is a rich source of natural antioxidants, PUFAs (ω-3 and ω-6 fatty acids) and essential and sulfur-rich amino acids, as recommended by the FAO for human health. Psyllium contains phenolics and flavonoids that possess reducing capacity and reactive oxygen species (ROS) scavenging activities. In leaves, seeds, and husks, about 76, 78, 58% polyunsaturated, 21, 15, 20% saturated, and 3, 7, 22% monounsaturated fatty acids were found, respectively. A range of FAs (C12 to C24) was detected in psyllium and among different plant parts, a high content of the nutritive indicators ω-3 alpha-linolenic acid CPS (57%) and ω-6 linoleic acid CPS (18%) was detected in leaves. Similarly, total content of phenolics and the essential amino acid valine were also detected utmost in leaves followed by sulfur-rich amino acids and flavonoids. In total, 36 different metabolites were identified in psyllium, out of which 26 (13 each) metabolites were detected in leaves and seeds, whereas the remaining 10 were found in the husk. Most of the metabolites are natural antioxidants, phenolics, flavonoids, or alkaloids and can be used as nutrient supplements. Moreover, these metabolites have been reported to have several pharmaceutical applications, including anti-cancer activity. Natural plant ROS scavengers, saponins, were also detected. Based on metabolomic data, the probable presence of a flavonoid biosynthesis pathway was inferred, which provides useful insight for metabolic engineering in the future. Non-targeted metabolomics, antioxidants and scavenging activities reveal the nutraceutical potential of the plant and also suggest that psyllium leaves can be used as a green salad as a dietary supplement to daily food. PMID:27092153

  18. Non-targeted Metabolite Profiling and Scavenging Activity Unveil the Nutraceutical Potential of Psyllium (Plantago ovata Forsk)

    PubMed Central

    Patel, Manish K.; Mishra, Avinash; Jha, Bhavanath

    2016-01-01

    Non-targeted metabolomics implies that psyllium (Plantago ovata) is a rich source of natural antioxidants, PUFAs (ω-3 and ω-6 fatty acids) and essential and sulfur-rich amino acids, as recommended by the FAO for human health. Psyllium contains phenolics and flavonoids that possess reducing capacity and reactive oxygen species (ROS) scavenging activities. In leaves, seeds, and husks, about 76, 78, 58% polyunsaturated, 21, 15, 20% saturated, and 3, 7, 22% monounsaturated fatty acids were found, respectively. A range of FAs (C12 to C24) was detected in psyllium and among different plant parts, a high content of the nutritive indicators ω-3 alpha-linolenic acid (57%) and ω-6 linoleic acid (18%) was detected in leaves. Similarly, total content of phenolics and the essential amino acid valine were also detected utmost in leaves followed by sulfur-rich amino acids and flavonoids. In total, 36 different metabolites were identified in psyllium, out of which 26 (13 each) metabolites were detected in leaves and seeds, whereas the remaining 10 were found in the husk. Most of the metabolites are natural antioxidants, phenolics, flavonoids, or alkaloids and can be used as nutrient supplements. Moreover, these metabolites have been reported to have several pharmaceutical applications, including anti-cancer activity. Natural plant ROS scavengers, saponins, were also detected. Based on metabolomic data, the probable presence of a flavonoid biosynthesis pathway was inferred, which provides useful insight for metabolic engineering in the future. Non-targeted metabolomics, antioxidants and scavenging activities reveal the nutraceutical potential of the plant and also suggest that psyllium leaves can be used as a green salad as a dietary supplement to daily food. PMID:27092153

  19. Characterization of the superoxide anion radical scavenging activity by tetracycline antibiotics in aprotic media.

    PubMed

    Kładna, Aleksandra; Kruk, Irena; Michalska, Teresa; Berczyński, Paweł; Aboul-Enein, Hassan Y

    2011-01-01

    The tetracycline family antibiotics are widely used as human and veterinary treatments. The drugs are effective as antibiotics and also show antimicrobial and non-microbial action. However, the antioxidant properties of tetracyclines have not been characterized in aprotic media. To better understand their biological functions, the in vitro superoxide anion radical (O2•¯) scavenging activities of tetracycline, chlortetracycline, oxytetracycline, doxycycline and methacycline were characterized, along with a very efficient O2•¯ scavenger, tiron, in dimethyl sulphoxide (DMSO), using ultra-weak chemiluminescence (CL). We found that tetracycline, chlortetracycline and doxycycline efficiently inhibited CL from the O2•¯-generating system at concentration levels of 0.02-1.0 mmol/L. Methacycline and oxytetracycline were the O2•¯ scavengers at concentration levels of 0.01-0.1 mmol/L, whereas when their concentration was lowered the drugs were capable of generating O2•¯, leading to CL enhancement. For all the data obtained in this study, the scavenging activity for the compounds tested decreased in the following order: tetracycline > doxycycline > chlortetracycline > tiron methacycline > oxytetracycline. These results indicate that the tetracycline drugs directly alter O2•¯ redox chemistry in aprotic media. PMID:21413138

  20. Electrical Characteristics of Metal-Oxide-Semiconductor Capacitor with High-κ/Metal Gate Using Oxygen Scavenging Process.

    PubMed

    Lee, Junil; Kim, Jang Hyun; Kwon, Dae Woong; Park, Euyhwan; Park, Taehyung; Kim, Hyun Woo; Park, Byung-gook

    2016-05-01

    It has been widely accepted that the mismatch of lattice constants between HfO2 and Si generates interface traps at the HfO2-Si interface, which causes the degradation of device performances. For better interface quality, very thin SiO2 film (< 2 nm) has been inserted as an interlayer (IL) between HfO2 and Si despite of the increase of EOT. In order to obtain both the better interface quality and the reduction of EOT, we used Ti metal on HfO2/IL SiO2 stack as a scavenging layer to absorb oxygens in the SiO2 and various annealing conditions were applied to optimize the thickness of the SiO2. As a result, we can effectively shrink the EOT from 3.55 nm to 1.15 nm while maintaining the same physical thickness of gate stacks. Furthermore, the diffusion of oxygen was confirmed by high resolution transmission electron microscopy (HRTEM) and time-of-flight secondary ion mass Spectrometry (SIMS). PMID:27483842

  1. The Scientist Scavenger Hunt.

    ERIC Educational Resources Information Center

    Morphew, Valerie N.; Key, Kathleen

    1994-01-01

    Using a well-planned scavenger hunt, students' awareness of the significance of minorities and women in science is enhanced. Provides a sample scavenger hunt and resource list as well as activities for extension. (ZWH)

  2. Antimicrobial and free radical scavenging activities of five Palestinian medicinal plants.

    PubMed

    Qabaha, Khaled Ibraheem

    2013-01-01

    Extracts from five indigenous Palestinian medicinal plants including Rosmarinus officinalis, Pisidium guajava, Punica granatum peel, grape seeds and Teucrium polium were investigated for antimicrobial and free radical scavenging activities against eight microorganisms, using well diffusion method. The microorganisms included six bacterial isolates (i.e. Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginos, Klebsiella pneumonia, Bacillus subtilis and Micrococcus luteus) and two fungal isolates (i.e. Candida albicans and Aspergillus niger). A standard antioxidant assay was performed on the plant extracts to assess their capability in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH). Of the five tested plant extract, only Rosmarinus offcinalis extract contained significant antimicrobial activity against all eight microbial isolates including Pseudomonas aeruginosa. Extracts from other four plants exhibited a variable antimicrobial activity against all microorganisms, except Pseudomonas aeruginosa. Significant antioxidant activity was detected in all plant extracts. However, extracts from Pisidium guajava leaves contained significantly higher antioxidant activity compared to the other extracts tested. The antimicrobial and scavenging activities detected in this in vitro study in extracts from the five Palestinian medicinal plants suggest that further study is needed to identify active compounds to target diseases caused by a wide-spectrum pathogens. PMID:24146509

  3. Evaluation of Radical Scavenging Activity of Sempervivum tectorum and Corylus avellana Extracts with Different Phenolic Composition.

    PubMed

    Alberti, Ágnes; Riethmüller, Eszter; Béni, Szabolcs; Kéry, Ágnes

    2016-04-01

    Semnpervivum tectorum L. and Corylus avellana L. are traditional herbal remedies exhibiting antioxidant activity and representing diverse phenolic composition. The aim of this study was to reveal the contribution of certain compounds to total radical scavenging activity by studying S. tectorum and C. avellana extracts prepared with solvents of different selectivity for diverse classes of phenolics. Antioxidant activity of S. tectorum and C. avellana samples was determined in the ABTS and DPPH radical scavenging assays, and phenolic composition was evaluated by high-performance liquid chromatography/electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). Correlations between antioxidant activity and phenolic content of houseleek extracts have been revealed. Significant differences regarding antioxidant activity have been shown between S. tectorum 80% (v/v) methanol extract and its fractions. Additionally, synergism among the constituents present together in the whole extract was assumed. Significantly higher radical scavenging activity of hazel extracts has been attributed to the differences in phenolic composition compared with houseleek extracts. PMID:27396195

  4. Alkoxyl radical-scavenging activity of edaravone in patients with traumatic brain injury.

    PubMed

    Dohi, Kenji; Satoh, Kazue; Mihara, Yuko; Nakamura, Shunsuke; Miyake, Yasuhumi; Ohtaki, Hirokazu; Nakamachi, Tomoya; Yoshikawa, Toshikazu; Shioda, Seiji; Aruga, Tohru

    2006-11-01

    Lipid peroxidation is caused by reactive oxygen species (ROS) and is involved in traumatic brain injury (TBI). Consequently, a therapeutic strategy for TBI may be to control lipid peroxidation. The only drug approved to date for blocking lipid peroxidation is edaravone (MCI-186), a novel free-radical scavenger shown to exert neuroprotective effects in acute ischemic stroke. Although edaravone scavenges hydroxyl and nitric oxide radicals, its effect on alkoxyl radicals (OR-), which also contribute to lipid peroxidation, is unknown. To date, the study of free radicals in blood has been severely hampered by technical difficulties in their detection. We used an in vitro and ex vivo electron spin resonance (ESR) method employing 5,5-dimethyl-1-pyrroline-N-oxide as a spin trap to investigate whether edaravone can scavenge OR-. By mixing either methemoglobin or human blood with tert-butyl hydroperoxide, we found that this technique can detect OR- generated in vitro. We also found that generated OR- can be completely absorbed by administration of edaravone in vitro (400 microM). Analysis of jugular venous blood collected from 17 TBI patients immediately before and 20 minutes after the administration of edaravone (30 mg, i.v.) revealed higher OR- levels in the untreated patients blood than in normal control blood samples. However, treatment with edaravone suppressed these OR- levels by 24.6% (radical intensity = 71.1 +/- 5.2-53.6 +/- 5.2; p < 0.01). Thus, edaravone can scavenge OR- and significantly reduce levels of these radicals in TBI patients. The novel ex vivo ESR method described here provides a valuable clinical measure of oxidative stress. PMID:17115906

  5. Fluoranthene fumigation and exogenous scavenging of reactive oxygen intermediates (ROI) in evergreen Japanese red pine seedlings (Pinus densiflora Sieb. et. Zucc.).

    PubMed

    Oguntimehin, Ilemobayo; Sakugawa, Hiroshi

    2008-06-01

    Generation of reactive oxygen intermediates (ROI) such as O(2)(-), H(2)O(2), and *OH is known to be a major mechanism of damage in biological systems. This study investigated and compared effectiveness of scavenging ROI generated in fluoranthene (FLU) pre-fumigated Japanese red pine seedlings. Three kinds of eco-physiological assessments were used to express the impact of the different fumigants used inside the green house. Gas exchange measurements showed negative changes induced by 10 microM FLU on Japanese pine seedlings during a 10 d exposure period whilst no negative change was found during a 5 d exposure period. Moreover, during a 14 d FLU exposure incorporating ROI scavengers, results revealed that chlorophyll fluorescence, needle chemical contents and needle dry mass per unit area of the seedlings were affected. The negative effects of FLU on the conifer were dependent on both the dose and period of FLU fumigation. Peroxidase (PERO), superoxide dismutase (SOD) and mannitol (MANN) were all effective scavengers of ROI. MANN scavenged *OH, the most lethal of the ROI. For practicable use, MANN is more economical, and may be the best ROI scavenger among the three considered. It can be concluded that efficient scavenging of ROI in biological systems is important to mitigate the negative effects of FLU on Japanese red pine trees. PMID:18442844

  6. Polarographic assay based on hydrogen peroxide scavenging in determination of antioxidant activity of strong alcohol beverages.

    PubMed

    Gorjanović, Stanislava Z; Novaković, Miroslav M; Vukosavljević, Predrag V; Pastor, Ferenc T; Tesević, Vele V; Suznjević, Desanka Z

    2010-07-28

    Total antioxidant (AO) activity of strong alcohol beverages such as wine and plum brandies, whiskeys, herbal and sweet fruit liqueurs have been assessed using a polarographic assay based on hydrogen peroxide scavenging (HPS). Rank of order of total AO activity, expressed as percentage of decrease of anodic oxidation current of hydrogen peroxide, was found analogous with total phenolic content estimated by Folin-Ciocalteau (FC) assay and radical scavenging capacity against the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). Application of the assay for surveying of a quarter century long maturation of plum brandy in oak barrel was demonstrated. In addition, influence of different storage conditions on preservation of AO activity of some herbal liqueurs was surveyed. Wide area of application of this simple, fast, low cost and reliable assay in analysis and quality monitoring of various strong alcohol beverages was confirmed. PMID:20604507

  7. Evaluation of Abelmoschus moschatus extracts for antioxidant, free radical scavenging, antimicrobial and antiproliferative activities using in vitro assays

    PubMed Central

    2011-01-01

    Background Abelmoschus moschatus Medik. leaves and seeds are considered as valuable traditional medicine. The aromatic seeds of this plant are aphrodisiac, ophthalmic, cardio tonic, antispasmodic and used in the treatment of intestinal complaints and check queasiness. To give a scientific basis for traditional usage of this medicinal plant, the seed and leaf extracts were evaluated for their antioxidant, free radical scavenging, antimicrobial and antiproliferative activities. Methods In this study, antioxidant, antimicrobial and antiproliferative activities of A. moschatus extracts were evaluated in a series of in vitro assay involving free radicals, reactive oxygen species and their IC50 values were also determined. The antioxidant activities of the seed and leaf extracts of A. moschatus were determined by total antioxidant, DPPH, and ferrous reducing antioxidant property (FRAP) methods. In addition, the antiproliferative activity was also evaluated using colorectal adenocarcinoma and retinoblastoma human cancer cell lines. Moreover, six bacterial reference strains, two gram-positive (Bacillus subtilis and Staphylococcus aureus), four gram-negative (Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris and Salmonella enterica paratyphi) and one fungal strain (Candida albicans) were used to evaluate its antimicrobial activity. Results The results from this study showed that the antioxidant activities of A. moschatus as determined by the total phenol, flavonoids, total antioxidant and FRAP methods were higher in leaf than that of the seed extracts. On the other hand, the aqueous overnight seed extract (AMS-I) has shown significant radical scavenging activity as in 1, 1- Diphenyl-2-picrylhydrazyl (DPPH), hydrogen peroxide, hydroxyl radical, superoxide and lipid peroxidation as compared to other seed and leaf extracts. The AMS-I and AML-IV have shown activity against six and seven microorganisms respectively. Simulteneously, AMS-IV and AML-IV have demonstrated

  8. Effect of cinnamon water extract on monocyte-to-macrophage differentiation and scavenger receptor activity

    PubMed Central

    2014-01-01

    Background Water soluble cinnamon extract has been shown to increase insulin sensitivity and modulate macrophage activation, a desirable trait for the management of obesity or atherosclerosis. Our present study investigated whether cinnamon water extract (CWE) may influence the differentiation of monocytes into macrophages and the activity of macrophage scavenger receptors, commonly observed in atherosclerotic lesions. Methods We investigated the effect of CWE on the expression of various surface markers and the uptake of acetylated low density lipoprotein (LDL) in phorbol-12-myristate-13-acetate (PMA)-stimulated THP-1 cells. The protein levels of PMA or macrophage-colony stimulating factor (M-CSF)-stimulated type 1 macrophage scavenger receptor (SRA) were analyzed. Finally, the role of extracellar signal-related kinase (ERK) 1/2 in SRA synthesis and the effect of CWE on PMA-stimulated ERK1/2 were determined. Results CWE inhibited the differentiation of monocyte by decreasing the expression of CD11b, CD36 and SRA and the uptake of acetyl LDL. CWE suppressed the upregulation of SRA by M-CSF and modulated ERK1/2 activity, which was required for PMA-induced SRA synthesis. Conclusions Our results demonstrate that CWE was able to interfere with monocyte differentiation and macrophage scavenger activity, indicating its potential in preventing the development of atherosclerotic lesions. PMID:24602512

  9. Scavenging of reactive oxygen species and inhibition of the oxidation of low density lipoprotein by the aqueous extraction of Anoectochilus formosanus.

    PubMed

    Shih, Chun-Ching; Wu, Yueh-Wern; Lin, Wen-Chuan

    2003-01-01

    The ability of Anoectochilus formosanus extract (AFE) to react with relevant biological oxidants was evaluated in this study. In addition, its effect on oxidation of low density lipoprotein (LDL) was investigated in vitro and in vivo. AFE could scavenge reactive oxygen species, such as superoxide anion and hydroxyl radical. The study of human LDL oxidation showed that AFE delayed oxidation in a concentration-dependent manner. In vivo studies also showed that oral administration of AFE delayed the oxidation of LDL from hyperlipidemic hamsters. The ability of AFE to scavenge free radicals suggests that it may be a promising anti-atherogenic agent. PMID:12723752

  10. Radical scavenging activity and composition of raspberry (Rubus idaeus) leaves from different locations in Lithuania.

    PubMed

    Venskutonis, P R; Dvaranauskaite, A; Labokas, J

    2007-02-01

    Raspberry (Rubus idaeus) leaves, collected in different locations of Lithuania were extracted with ethanol and the extracts were tested for their antioxidant activity (AA) by using ABTS(.)(+) decolourisation and DPPH(.) scavenging methods. All extracts were active, with radical scavenging capacity at the used concentrations from 20.5 to 82.5% in DPPH(.) reaction system and from 8.0 to 42.7% in ABTS(.)(+) reaction. The total amount of phenolic compounds in the leaves varied from 4.8 to 12.0 mg of gallic acid equivalents (GAE) in 1 g of plant extract. Quercetin glucuronide, quercetin-3-O-glucoside and rutin were identified in the extracts. PMID:17215088

  11. Hydroxyl radical scavenging-based method for evaluation of TiO₂ photocatalytic activity.

    PubMed

    Mencigar, Danijela Pucko; Strlič, Matija; Štangar, Urška Lavrenčič; Korošec, Romana Cerc

    2013-01-01

    A novel hydroxyl radical scavenging method was developed to establish the photocatalytic activity of TiO₂ thin films. Transparent TiO₂ thin films were prepared on soda-lime glass substrates using the sol-gel method and characterized using X-ray diffraction. During photoirradiation in aqueous buffered solutions, activity of the films was followed using the substituted nitrobenzene N,N'-(5-nitro-1,3-phenylene)bisglutaramide as a hydroxyl radical scavenger and its hydroxylated products were quantified using HPLC. The yield of hydroxyl radicals was evaluated at various pH of the reaction media, and reflected the dependence of the rate of the hydroxylation reaction on the experimental conditions and on the different qualities of the TiO₂ thin films. The proposed method allows for direct assessment of hydroxyl radical production, it is straightforward and is proposed for routine use. PMID:24362997

  12. Relationship between structure, properties, and the radical scavenging activity of morin

    NASA Astrophysics Data System (ADS)

    Mendoza-Wilson, Ana María; Santacruz-Ortega, Hisila; Balandrán-Quintana, René R.

    2011-05-01

    The relationship between structure, kinetic, thermochemical and electronic properties of the morin flavonoid was researched in order to establish the molecular characteristics related to its maximum radical scavenging activity. The reaction of morin with the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH rad ) was carried out in ethanol, through the hydrogen-atom transfer (HAT) mechanism. Morin showed the highest radical scavenging activity under conditions of excess of free radical. It was found, by means of experimental and computational methods, that 3-OH, 2'-OH and 4'-OH are the main reactive sites, as well as that the 3-O-2'-O quinone is the first product of the reaction, tending to prevail in the enol form through a tautomerism effect, whose observed structural arrangement corresponds to the 3-O semiquinone.

  13. Isolation and structural determination of two novel phlorotannins from the brown alga Ecklonia kurome Okamura, and their radical scavenging activities.

    PubMed

    Yotsu-Yamashita, Mari; Kondo, Sawako; Segawa, Shinya; Lin, Yi-Chin; Toyohara, Haruhiko; Ito, Hisatomi; Konoki, Keiichi; Cho, Yuko; Uchida, Takafumi

    2013-01-01

    Two novel phlorotannins with a molecular weight of 974, temporarily named 974-A and 974-B, were isolated from the polyphenol powder prepared from the edible marine brown alga Ecklonia kurome Okamura, and their chemical structures were determined by spectroscopic method. The isolated yield of the total of 974-A and 974-B was approximately 4% (w/w) from the polyphenol powder. In 974-A, the carbon at the C2' position in the A ring of phlorofucofuroeckol-A forms a C-C bond with the carbon at the C2″ position of the C ring of triphloretol-B, while in 974-B, phlorofucofuroeckol-B and triphloretol-B form a C-C bond in the same manner as in 974-A. These structures were supported by high resolution-MS/MS data. To evaluate the antioxidant activities, the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay and intracellular radical scavenging assay, using 2',7'-dichlorofluorescin diacetate (DCFH-DA), were performed for 974-A, 974-B, and four known phlorotannins. The results of the DPPH assay showed that the IC(50) values of 974-A, 974-B, phlorofucofuroeckol-A, and dieckol were significantly smaller than those of phlorofucofuroeckol-B, phloroglucinol, α-tocopherol, and ascorbic acid. Furthermore, the DCFH-DA assay suggested that 974-A, 974-B, and dieckol reduce intracellular reactive oxygen species most strongly among the tested compounds. PMID:23334528

  14. Antioxidant activity and free radical-scavenging capacity of Gynura divaricata leaf extracts at different temperatures

    PubMed Central

    Wan, Chunpeng; Yu, Yanying; Zhou, Shouran; Liu, Wei; Tian, Shuge; Cao, Shuwen

    2011-01-01

    Background: Extraction temperature influences the total phenolic content (TPC), total flavonoid content (TFC) of medicinal plant extracts to a great extend. TPC and TFC are the principle activity constituents present in the plant. The effects of extraction temperature on TPC, TFC and free radical-scavenging capacity of Gynura divaricata leaf extracts are worth to study. Materials and Methods: Folin–Ciocalteu and aluminum chloride colorimetric assay were used to determine the TPC and TFC of Gynura divaricata leaf extracts at different temperatures. The antioxidant and free radical-scavenging activity were measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) and phosphomolybdenum methods. Results: TPC and TFC were significantly elevated with increasing extraction temperature (from 40°C to 100°C). However, TPC and TFC were not significantly different (P > 0.05) at the extraction temperatures 90°C and 100°C. Also, the extracts obtained at a higher temperature exhibited a significant free radical-scavenging activity compared with extraction at lower temperatures (P < 0.05). The TPCs (13.95-36.68 mg gallic acid equivalent/g dry material) were highly correlated with DPPH (R2 = 0.9229), ABTS (R2 = 0.9951) free radical-scavenging capacity, and total antioxidant activity (R2 = 0.9872) evaluated by phosphomolybdenum method. Conclusion: The TPC and TFC of G. divaricata leaf was significantly influenced by the extraction temperatures, which were the main antioxidant constituents present in the G. divaricata plant. PMID:21472078

  15. Screening and evaluation of antioxidant activity of some amido-carbonyl oxime derivatives and their radical scavenging activities.

    PubMed

    Ozen, Tevfik; Taş, Murat

    2009-10-01

    The antioxidant activity of some amido-carbonyl oximes containing a C=O and -NH-R adjacent to the oxime group, [Phenyl-C(=O)-C(=N-OH)-N(-H)-Phenyl(-R)] where R= H, 4-chloro, 4-methyl, 4-methoxy, 3,4-dichloro, 3,4-dimethyl, 3-chloro-4-dimethyl, 3-chloro-4-methoxy, naphthyl and an amido-carbonyl dioxime were investigated in vitro by ferric thiocyanate, total reducing power by potassium ferricyanide reduction, 1,1-diphenyl-2- picryl-hydrazyl (DPPH(.)) free radical scavenging, ferrous ions chelating, superoxide anion radical scavenging and hydrogen peroxide scavenging activity assays. The results indicated that the amido-carbonyl oximes have powerful antioxidant capacity. PMID:19772487

  16. Scavenging for the Past.

    ERIC Educational Resources Information Center

    McMahon, Sue; Strubbe, Mary

    1988-01-01

    Discusses the goals and planning of a scavenger hunt which was designed to increase enthusiasm in students and promote active learning. States that a scavenger hunt instills a sense of community pride in students and that the community cooperation fosters a positive relationship with the school. Provides a sample scavenger hunt checklist. (GEA)

  17. A quantitative structure-activity relationship model for radical scavenging activity of flavonoids.

    PubMed

    Om, A; Kim, J H

    2008-03-01

    A quantitative structure-activity relationship (QSAR) study has been carried out for a training set of 29 flavonoids to correlate and predict the 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity (RSA) values obtained from published data. Genetic algorithm and multiple linear regression were employed to select the descriptors and to generate the best prediction model that relates the structural features to the RSA activities using (1) three-dimensional (3D) Dragon (TALETE srl, Milan, Italy) descriptors and (2) semi-empirical descriptor calculations. The predictivity of the models was estimated by cross-validation with the leave-one-out method. The result showed that a significant improvement of the statistical indices was obtained by deleting outliers. Based on the data for the compounds used in this study, our results suggest a QSAR model of RSA that is based on the following descriptors: 3D-Morse, WHIM, and GETAWAY. Therefore, satisfactory relationships between RSA and the semi-empirical descriptors were found, demonstrating that the energy of the highest occupied molecular orbital, total energy, and energy of heat of formation contributed more significantly than all other descriptors. PMID:18361735

  18. Radical scavenging and anti-lipoperoxidative activities of Smallanthus sonchifolius leaf extracts.

    PubMed

    Valentová, Katerina; Sersen, Frantisek; Ulrichová, Jitka

    2005-07-13

    Radical scavenging and anti-lipoperoxidative effects of two organic fractions and two aqueous extracts from the leaves of a neglected Andean crop-yacon (Smallanthus sonchifolius Poepp. & Endl., Asteraceae) were determined using various in vitro models. The extracts' total phenolic content was 10.7-24.6%. They exhibited DPPH (IC50 16.14-33.39 microg/mL) and HO* scavenging activities (4.49-6.51 mg/mL). The extracts did not scavenge phenylglyoxylic ketyl radicals, but they retarded their formation. In the xanthine/xanthine oxidase superoxide radical generating system, the extracts' activities were 26.10-37.67 superoxide dismutase equivalents/mg. As one of the extracts displayed xanthine oxidase inhibitory activity, the effect of the extracts on a nonenzymatically generated superoxide was determined (IC50 7.36-21.01 microg/mL). The extracts inhibited t-butyl hydroperoxide-induced lipoperoxidation of microsomal and mitochondrial membranes (IC50 22.15-465.3 microg/mL). These results make yacon leaves a good candidate for use as a food supplement in the prevention of chronic diseases involving oxidative stress. PMID:15998117

  19. Preparation of Egg White Liquid Hydrolysate (ELH) and Its Radical-Scavenging Activity.

    PubMed

    Noh, Dong Ouk; Suh, Hyung Joo

    2015-09-01

    In the present study, an optimum protease was selected to hydrolyze the egg white liquid protein for the antioxidant peptides. Alcalase treatment yielded the highest amount of α-amino groups (15.27 mg/mL), while the control (no enzymatic hydrolysis) showed the lowest amount of α-amino groups (1.53 mg/mL). Alcalase also gave the highest degree of hydrolysis (DH) value (43.2%) and was more efficient for egg white liquid hydrolysis than the other enzymes. The Alcalase hydrolysate had the highest radical-scavenging activity (82.5%) at a concentration of 5.0 mg/mL. The conditions for enzymatic hydrolysis of egg white liquid with Alcalase were selected as substrate : water ratio of 2:1. Five percent Alacalse treatment did not show significant (P>0.05) increases of DH and α-amino nitrogen content after 24 h-hydrolysis. Thirty two hour-hydrolysis with 5% Alcalase is sufficient to make antioxidative egg white liquid hydrolysate from egg white liquid. DPPH and ABTS radical-scavenging activities were significantly (P<0.05) higher after enzymatic digestion. These results suggest that active peptides released from egg-white protein are effective radical-scavengers. Thus, this approach may be useful for the preparation of potent antioxidant products. PMID:26451355

  20. Polyphenolics profile, antioxidant and radical scavenging activity of leaves and stem of Raphanus sativus L.

    PubMed

    Beevi, Syed Sultan; Narasu, Mangamoori Lakshmi; Gowda, Bandi Boje

    2010-03-01

    Aerial parts (leaves and stem) of Raphanus sativus, which are usually discarded were found to possess potent antioxidant and radical scavenging activity, as measured by standard antioxidant assays. Methanolic and acetone extracts of R. sativus leaves had total polyphenolic content of 86.16 and 78.77 mg/g dry extract, which were comparable to the traditional rich sources such as green tea and black tea. HPLC identification of polyphenolics indicated the presence of catechin, protocatechuic acid, syringic acid, vanillic acid, ferulic acid, sinapic acid, o-coumaric acid, myricetin, and quercetin in leaves and stem. Among the different extraction solvents, methanolic extract of leaves and stem showed potent reductive capacity, significantly inhibited linoleic acid peroxidation and displayed metal chelating activity. Further, they scavenged free radicals effectively with IC50 (half maximal inhibitory concentration) of 31 and 42 microg/ml for DPPH radical, 23 and 52 microg/ml for superoxide radical, 67 and 197 microg/ml for hydrogen peroxide,and 56 and 62 microg/ml for nitric oxide, respectively. Leaves showed most potent antioxidant and radical scavenging activity as compared to stem, which may be accounted for the high polyphenolic content. Leaves and stem of R. sativus,often under-utilized part of this vegetable, thus possessed considerable amount of polyphenolics. Hence, it should be egarded as a potential source of natural antioxidants and could be effectively employed as an ingredient in health or in functional food. PMID:20072818

  1. Preparation of Egg White Liquid Hydrolysate (ELH) and Its Radical-Scavenging Activity

    PubMed Central

    Noh, Dong Ouk; Suh, Hyung Joo

    2015-01-01

    In the present study, an optimum protease was selected to hydrolyze the egg white liquid protein for the antioxidant peptides. Alcalase treatment yielded the highest amount of α-amino groups (15.27 mg/mL), while the control (no enzymatic hydrolysis) showed the lowest amount of α-amino groups (1.53 mg/mL). Alcalase also gave the highest degree of hydrolysis (DH) value (43.2%) and was more efficient for egg white liquid hydrolysis than the other enzymes. The Alcalase hydrolysate had the highest radical-scavenging activity (82.5%) at a concentration of 5.0 mg/mL. The conditions for enzymatic hydrolysis of egg white liquid with Alcalase were selected as substrate : water ratio of 2:1. Five percent Alacalse treatment did not show significant (P>0.05) increases of DH and α-amino nitrogen content after 24 h-hydrolysis. Thirty two hour-hydrolysis with 5% Alcalase is sufficient to make antioxidative egg white liquid hydrolysate from egg white liquid. DPPH and ABTS radical-scavenging activities were significantly (P<0.05) higher after enzymatic digestion. These results suggest that active peptides released from egg-white protein are effective radical-scavengers. Thus, this approach may be useful for the preparation of potent antioxidant products. PMID:26451355

  2. Free-Radical-Scavenging, Antityrosinase, and Cellular Melanogenesis Inhibitory Activities of Synthetic Isoflavones.

    PubMed

    Lu, Tzy-Ming; Ko, Horng-Huey; Ng, Lean-Teik; Hsieh, Yen-Pin

    2015-06-01

    In this study, we examined the potential of synthetic isoflavones for application in cosmeceuticals. Twenty-five isoflavones were synthesized and their capacities of free-radical-scavenging and mushroom tyrosinase inhibition, as well as their impact on cell viability of B16F10 murine melanoma cells and HaCaT human keratinocytes were evaluated. Isoflavones that showed significant mushroom tyrosinase inhibitory activities were further studied on reduction of cellular melanin formation and antityrosinase activities in B16F10 melanocytes in vitro. Among the isoflavones tested, 6-hydroxydaidzein (2) was the strongest scavenger of both ABTS(.+) and DPPH(.) radicals with SC50 values of 11.3 ± 0.3 and 9.4 ± 0.1 μM, respectively. Texasin (20) exhibited the most potent inhibition of mushroom tyrosinase (IC50 14.9 ± 4.5 μM), whereas retusin (17) showed the most efficient inhibition both of cellular melanin formation and antityrosinase activity in B16F10 melanocytes, respectively. In summary, both retusin (17) and texasin (20) exhibited potent free-radical-scavenging capacities as well as efficient inhibition of cellular melanogenesis, suggesting that they are valuable hit compounds with potential for advanced cosmeceutical development. PMID:26080742

  3. Production and Scavenging of Reactive Oxygen Species and Redox Signaling during Leaf and Flower Senescence: Similar But Different.

    PubMed

    Rogers, Hilary; Munné-Bosch, Sergi

    2016-07-01

    Reactive oxygen species (ROS) play a key role in the regulation of many developmental processes, including senescence, and in plant responses to biotic and abiotic stresses. Several mechanisms of ROS generation and scavenging are similar, but others differ between senescing leaves and petals, despite these organs sharing a common evolutionary origin. Photosynthesis-derived ROS, nutrient remobilization, and reversibility of senescence are necessarily distinct features of the progression of senescence in the two organs. Furthermore, recent studies have revealed specific redox signaling processes that act in concert with phytohormones and transcription factors to regulate senescence-associated genes in leaves and petals. Here, we review some of the recent advances in our understanding of the mechanisms underpinning the production and elimination of ROS in these two organs. We focus on unveiling common and differential aspects of redox signaling in leaf and petal senescence, with the aim of linking physiological, biochemical, and molecular processes. We conclude that the spatiotemporal impact of ROS in senescing tissues differs between leaves and flowers, mainly due to the specific functionalities of these organs. PMID:27208233

  4. Mitochondrial reactive oxygen species are scavenged by Cockayne syndrome B protein in human fibroblasts without nuclear DNA damage

    PubMed Central

    Cleaver, James E.; Brennan-Minnella, Angela M.; Swanson, Raymond A.; Fong, Ka-wing; Chen, Junjie; Chou, Kai-ming; Chen, Yih-wen; Revet, Ingrid; Bezrookove, Vladimir

    2014-01-01

    Cockayne syndrome (CS) is a human DNA repair-deficient disease that involves transcription coupled repair (TCR), in which three gene products, Cockayne syndrome A (CSA), Cockayne syndrome B (CSB), and ultraviolet stimulated scaffold protein A (UVSSA) cooperate in relieving RNA polymerase II arrest at damaged sites to permit repair of the template strand. Mutation of any of these three genes results in cells with increased sensitivity to UV light and defective TCR. Mutations in CSA or CSB are associated with severe neurological disease but mutations in UVSSA are for the most part only associated with increased photosensitivity. This difference raises questions about the relevance of TCR to neurological disease in CS. We find that CSB-mutated cells, but not UVSSA-deficient cells, have increased levels of intramitochondrial reactive oxygen species (ROS), especially when mitochondrial complex I is inhibited by rotenone. Increased ROS would result in oxidative damage to mitochondrial proteins, lipids, and DNA. CSB appears to behave as an electron scavenger in the mitochondria whose absence leads to increased oxidative stress. Mitochondrial ROS, however, did not cause detectable nuclear DNA damage even when base excision repair was blocked by an inhibitor of polyADP ribose polymerase. Neurodegeneration in Cockayne syndrome may therefore be associated with ROS-induced damage in the mitochondria, independent of nuclear TCR. An implication of our present results is that mitochondrial dysfunction involving ROS has a major impact on CS-B pathology, whereas nuclear TCR may have a minimal role. PMID:25136123

  5. Mitochondrial reactive oxygen species are scavenged by Cockayne syndrome B protein in human fibroblasts without nuclear DNA damage.

    PubMed

    Cleaver, James E; Brennan-Minnella, Angela M; Swanson, Raymond A; Fong, Ka-wing; Chen, Junjie; Chou, Kai-ming; Chen, Yih-wen; Revet, Ingrid; Bezrookove, Vladimir

    2014-09-16

    Cockayne syndrome (CS) is a human DNA repair-deficient disease that involves transcription coupled repair (TCR), in which three gene products, Cockayne syndrome A (CSA), Cockayne syndrome B (CSB), and ultraviolet stimulated scaffold protein A (UVSSA) cooperate in relieving RNA polymerase II arrest at damaged sites to permit repair of the template strand. Mutation of any of these three genes results in cells with increased sensitivity to UV light and defective TCR. Mutations in CSA or CSB are associated with severe neurological disease but mutations in UVSSA are for the most part only associated with increased photosensitivity. This difference raises questions about the relevance of TCR to neurological disease in CS. We find that CSB-mutated cells, but not UVSSA-deficient cells, have increased levels of intramitochondrial reactive oxygen species (ROS), especially when mitochondrial complex I is inhibited by rotenone. Increased ROS would result in oxidative damage to mitochondrial proteins, lipids, and DNA. CSB appears to behave as an electron scavenger in the mitochondria whose absence leads to increased oxidative stress. Mitochondrial ROS, however, did not cause detectable nuclear DNA damage even when base excision repair was blocked by an inhibitor of polyADP ribose polymerase. Neurodegeneration in Cockayne syndrome may therefore be associated with ROS-induced damage in the mitochondria, independent of nuclear TCR. An implication of our present results is that mitochondrial dysfunction involving ROS has a major impact on CS-B pathology, whereas nuclear TCR may have a minimal role. PMID:25136123

  6. Production and Scavenging of Reactive Oxygen Species and Redox Signaling during Leaf and Flower Senescence: Similar But Different1[OPEN

    PubMed Central

    2016-01-01

    Reactive oxygen species (ROS) play a key role in the regulation of many developmental processes, including senescence, and in plant responses to biotic and abiotic stresses. Several mechanisms of ROS generation and scavenging are similar, but others differ between senescing leaves and petals, despite these organs sharing a common evolutionary origin. Photosynthesis-derived ROS, nutrient remobilization, and reversibility of senescence are necessarily distinct features of the progression of senescence in the two organs. Furthermore, recent studies have revealed specific redox signaling processes that act in concert with phytohormones and transcription factors to regulate senescence-associated genes in leaves and petals. Here, we review some of the recent advances in our understanding of the mechanisms underpinning the production and elimination of ROS in these two organs. We focus on unveiling common and differential aspects of redox signaling in leaf and petal senescence, with the aim of linking physiological, biochemical, and molecular processes. We conclude that the spatiotemporal impact of ROS in senescing tissues differs between leaves and flowers, mainly due to the specific functionalities of these organs. PMID:27208233

  7. Free radical scavenging activity and lipoxygenase inhibition of Mahonia aquifolium extract and isoquinoline alkaloids

    PubMed Central

    Rackova, Lucia; Oblozinsky, Marek; Kostalova, Daniela; Kettmann, Viktor; Bezakova, Lydia

    2007-01-01

    Roots and stem-bark of Mahonia aquifolium (Oregon grape) (Berberidaceae) are effectively used in the treatment of skin inflammatory conditions. In the present study, the effect of Mahonia aquifolium crude extract and its two representative alkaloid fractions containing protoberberine and bisbenzylisoquinoline (BBIQ) alkaloids on activity of 12-lipoxygenase (12-LOX), was studied. The reactivity with 1,1-diphenyl-2-picryl-hydrazyl (DPPH), a free stable radical, was evaluated to elucidate the rate of possible lipid-derived radical scavenging in the mechanism of the enzyme inhibition. The results indicate that although the direct radical scavenging mechanism cannot be ruled out in the lipoxygenase inhibition by Mahonia aquifolium and its constituents, other mechanisms based on specific interaction between enzyme and alkaloids could play the critical role in the lipoxygenase inhibition rather than non-specific reactivity with free radicals. PMID:17634120

  8. Superoxide dismutase of Streptococcus suis serotype 2 plays a role in anti-autophagic response by scavenging reactive oxygen species in infected macrophages.

    PubMed

    Fang, Lihua; Shen, Hongxia; Tang, Yulong; Fang, Weihuan

    2015-04-17

    Streptococcus suis serotype 2 (SS2) causes septic shock and meningitis. However, its pathogenesis is still not well-understood. We have recently shown that superoxide dismutase sodA of SS2 is a virulence factor probably by increasing resistance to oxidative stresses. Reactive oxygen species (ROS) are products of the respiratory burst of phagocytic cells and have been shown to activate autophagy. We wanted to know if and how SS2 explores its sodA to interfere with cell autophagic responses. A sodA deletion mutant (Δsod) was compared with its parent and complemented strain in autophagic response in the murine macrophage cell line RAW264.7. We found that the Δsod mutant induced significant autophagic responses in infected cells, shown as increased LC3 lipidation (LC3-II) and EGFP-LC3 punctae, than those infected by its parent or complemented strain at 1 or 2h post-infection. Co-localization of the autophagosomal EGFP-LC3 vesicles with lysosomes was seen in cells infected with Δsod mutant and its parent strain, indicating that SS2 infection induced complete autophagic responses. Reduced autophagic responses of cells infected with the wild-type strain might be related to decreased ROS by the scavenging effect of its sodA, as shown by increased superoxide anion or ROS level in cells infected with the Δsod mutant and in the cell free xanthine oxidase-hypoxanthine ROS-generating system, as compared with its parent or complemented strain. Taken together, SS2 makes use of its sodA for survival not only by scavenging ROS but also by alleviating the host autophagic responses due to ROS stimulation. PMID:25726301

  9. Determination of Radical Scavenging Activity and Total Phenols of Wine and Spices: A Randomized Study.

    PubMed

    Lugemwa, Fulgentius Nelson; Snyder, Amanda L; Shaikh, Koonj

    2013-01-01

    Thirty eight bottles of red wine (Carbanet Sauvignon) were randomly selected based on vintage, region, price, and age (number of months in a barrel). The total phenolic content of each wine was determined using Folin-Ciocalteau assay. The radical scavenging activity was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. Apart from a few bottles that exhibited above average radical scavenging activity and phenolic content, there was no good correlation of those two quantities with region, price or vintage. The average phenolic amount was 2874 mg/L. The lowest phenolic content was found to be 1648 mg/L for an eight dollar wine. Wine with the highest amount of phenol of 4495 mg/L was a 2007, nine dollar bottle from South America. High amount of phenols did not translate into high radical scavenging activity. Barrel-aging did not increase the amount of phenols or the radical scavenging activity of wine. In order to discover new and potent sources of antioxidants from plants, the following spices were studied: ginger, cilantro, cumin, anise, linden, eucalyptus, marjoram, oregano, sage, thyme and rosemary. Whole spices were crushed and extracted for 96 h at room temperature using a combination of ethyl acetate, ethyl alcohol and water in the ratio of 4.5:4.5:1 (v/v/v). The radical scavenging activity of extracts was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. The total phenolic content of each spice was also determined using the Folin-Ciocalteau assay. Eucalyptus was found to be the most potent antioxidant with an LC50 of 324.1 mg of phenol/L, followed by marjoram with an LC50 of 407.5 mg of phenol/L, and rosemary with an LC50 of 414.0 mg/L. The least potent antioxidants were ginger and cilantro with LC50 of 7604 mg/L of phenol and 7876 mg of phenol/L, respectively. PMID:26784340

  10. Determination of Radical Scavenging Activity and Total Phenols of Wine and Spices: A Randomized Study

    PubMed Central

    Lugemwa, Fulgentius Nelson; Snyder, Amanda L.; Shaikh, Koonj

    2013-01-01

    Thirty eight bottles of red wine (Carbanet Sauvignon) were randomly selected based on vintage, region, price, and age (number of months in a barrel). The total phenolic content of each wine was determined using Folin-Ciocalteau assay. The radical scavenging activity was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. Apart from a few bottles that exhibited above average radical scavenging activity and phenolic content, there was no good correlation of those two quantities with region, price or vintage. The average phenolic amount was 2874 mg/L. The lowest phenolic content was found to be 1648 mg/L for an eight dollar wine. Wine with the highest amount of phenol of 4495 mg/L was a 2007, nine dollar bottle from South America. High amount of phenols did not translate into high radical scavenging activity. Barrel-aging did not increase the amount of phenols or the radical scavenging activity of wine. In order to discover new and potent sources of antioxidants from plants, the following spices were studied: ginger, cilantro, cumin, anise, linden, eucalyptus, marjoram, oregano, sage, thyme and rosemary. Whole spices were crushed and extracted for 96 h at room temperature using a combination of ethyl acetate, ethyl alcohol and water in the ratio of 4.5:4.5:1 (v/v/v). The radical scavenging activity of extracts was evaluated using 2,2-diphenyl-1-picryhydrazyl (DPPH) assay. The total phenolic content of each spice was also determined using the Folin-Ciocalteau assay. Eucalyptus was found to be the most potent antioxidant with an LC50 of 324.1 mg of phenol/L, followed by marjoram with an LC50 of 407.5 mg of phenol/L, and rosemary with an LC50 of 414.0 mg/L. The least potent antioxidants were ginger and cilantro with LC50 of 7604 mg/L of phenol and 7876 mg of phenol/L, respectively. PMID:26784340

  11. DPPH free radical scavenging activity and phenotypic difference in hepatoprotective plant (Silybum marianum L.).

    PubMed

    Ahmad, Nisar; Fazal, Hina; Abbasi, Bilal Haider; Anwar, Shazma; Basir, Abdul

    2013-06-01

    Silybum marianum L. is medicinally important for its active principle component silymarin. Silymarin regenerates damaged hepatic tissues. On the basis of such regenerative properties, the radical scavenging activity (1,1-diphenyl-2-picrylhydrazyl (DPPH)) of different tissues and the phenotypic difference of the hepatoprotective species, S. marianum L. were evaluated. There was less phenotypic difference in purple and white varieties of S. marianum. Assay of the antioxidant potential of different parts of the plant revealed that significantly higher activity (78.2%) was observed in seeds of the purple flowering plant than seeds of white flowering plant (49%) after different time intervals. Young leaves collected from white flowering plant exhibit 64.8% activity, which is higher than the purple flowering plant (55.1%). Significantly, same activity was observed in mature leaves of white (52%) and purple flowering plants (50%). The main stem collected from both the varieties exhibits similar activity from 50 to 52%. A 67.2% activity was recorded for mature roots of white flowering plant followed by roots of the purple variety (65%). The present study revealed that seeds and roots of both the varieties scavenge and detoxify more DPPH free radicals than other plant parts and can be used as a source of natural antioxidants and food additives. PMID:22362017

  12. Effects of Different Drying Methods and Storage Time on Free Radical Scavenging Activity and Total Phenolic Content of Cosmos caudatus

    PubMed Central

    Mediani, Ahmed; Abas, Faridah; Tan, Chin Ping; Khatib, Alfi

    2014-01-01

    The present study was conducted to determine the effect of air (AD), oven (OD) and freeze drying (FD) on the free radical scavenging activity and total phenolic content (TPC) of Cosmos caudatus and the effect of storage time by the comparison with a fresh sample (FS). Among the three drying methods that were used, AD resulted in the highest free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH) (IC50 = 0.0223 mg/mL) and total phenolic content (27.4 g GAE/100 g), whereas OD produced the lowest scavenging activity and TPC value. After three months of storage, the dried samples showed a high and consistent free radical scavenging activity when compared to stored fresh material. The drying methods could preserve the quality of C. caudatus during storage and the stability of its bioactive components can be maintained. PMID:26784876

  13. LC/PDA/ESI-MS Profiling and Radical Scavenging Activity of Anthocyanins in Various Berries.

    PubMed

    Nakajima, Jun-Ichiro; Tanaka, Ippei; Seo, Shujiro; Yamazaki, Mami; Saito, Kazuki

    2004-01-01

    Anthocyanin extracts of two blueberries, Vaccinium myrtillus (bilberry) and Vaccinium ashei (rabbiteye blueberry), and of three other berries, Ribes nigrum (black currant), Aronia melanocarpa (chokeberry), and Sambucus nigra (elderberry), were analyzed by high-performance liquid chromatography coupled with photodiode array detection and electrospray ionization - mass spectrometry (LC/PDA/ESI-MS). Both bilberry and rabbiteye blueberry contained 15 identical anthocyanins with different distribution patterns. Black currant, chokeberry, and elderberry contained 6, 4, and 4 kinds of anthocyanins, respectively. The radical scavenging activities of these berry extracts were analyzed by using 2,2-diphenyl-1-picrylhydrazyl (DPPH). All these extracts showed potent antiradical activities. PMID:15577184

  14. Hydrogen Peroxide Scavenging Activity of Novel Coumarins Synthesized Using Different Approaches

    PubMed Central

    Al-Amiery, Ahmed A.; Al-Majedy, Yasameen K.; Kadhum, Abdul Amir H.; Mohamad, Abu Bakar

    2015-01-01

    New derivatives of 7-hydroxy-4-methylcoumarin were synthesized using a chemical method and a microwave-assisted method to compare the feasibility, reaction times, and yields of the product. The newly synthesized coumarins were characterized by different spectroscopic techniques (FT-IR and NMR) and micro-elemental analysis (CHNS). In vitro antioxidant activities of these compounds were evaluated against hydrogen peroxide and were compared with standard natural antioxidant, vitamin C. Our results reveal that these compounds exhibit excellent radical scavenging activities. PMID:26147722

  15. Effects of gamma irradiation on total polyphenols, radical scavenging activities and decolourization of Nelumbo nucifera extracts

    NASA Astrophysics Data System (ADS)

    Jeong, Il Yun; Lee, Hyo Jung; Park, Yong Dae; Jin, Chang Hyun; Choi, Dae Seong; Byun, Myung Woo

    2009-07-01

    The ethanolic leaf extract of Nelumbo nucifera (NC) was exposed to γ-irradiation, and its antioxidant activities, total polyphenols and colour characteristics were studied to discern its potential ability as a food or cosmetic materials. The results demonstrated that the radical scavenging activities and total polyphenols of the γ-irradiated leaf extract of NC were not observed to be significantly different. However, γ-irradiation significantly increased the Hunter colour L*-value at doses of 20 and 50 kGy, while the Hunter colour b*-values were decreased under the same conditions.

  16. Variable protection by OH scavengers against radiation-induced inactivation of isolated transcriptionally active chromatin: the influence of secondary radicals

    SciTech Connect

    Herskind, C.; Westergaard, O.

    1988-04-01

    Isolated r-chromatin, the chromatin form of the extrachromosomal gene coding for the rRNA precursor in Tetrahymena, has been used to study radiation-induced inactivation in vitro in the presence of the OH radical scavengers, t-butanol, formate ions, and methanol. Induction of biologically important DNA lesions was detected by the effect on transcription by endogenous RNA polymerases associated with the isolated r-chromatin. The OH scavengers were found to give strong protection in the presence of oxygen as anticipated from previous results obtained with this system. By contrast, only a modest protection was observed under 100% N/sub 2/ or 100% N/sub 2/O, and the level of protection was different for each scavenger. The data suggest that secondary radicals may inactivate r-chromatin under anoxia. In the presence of oxygen, the secondary radicals react with O/sub 2/ to form organic peroxy radicals (or O/sub 2/-) which seem to be less reactive. Since the protective effect of the OH scavengers varies with the gassing conditions, the dose modifying effects of O/sub 2/ and N/sub 2/O relative to N/sub 2/ depend on the identity and concentration of OH scavenger. The implications for radiation-chemical studies on DNA and living cells are discussed.

  17. On the antioxidant properties of kynurenic acid: free radical scavenging activity and inhibition of oxidative stress.

    PubMed

    Lugo-Huitrón, R; Blanco-Ayala, T; Ugalde-Muñiz, P; Carrillo-Mora, P; Pedraza-Chaverrí, J; Silva-Adaya, D; Maldonado, P D; Torres, I; Pinzón, E; Ortiz-Islas, E; López, T; García, E; Pineda, B; Torres-Ramos, M; Santamaría, A; La Cruz, V Pérez-De

    2011-01-01

    Kynurenic acid (KYNA) is an endogenous metabolite of the kynurenine pathway for tryptophan degradation and an antagonist of both N-methyl-D-aspartate (NMDA) and alpha-7 nicotinic acetylcholine (α7nACh) receptors. KYNA has also been shown to scavenge hydroxyl radicals (OH) under controlled conditions of free radical production. In this work we evaluated the ability of KYNA to scavenge superoxide anion (O(2)(-)) and peroxynitrite (ONOO(-)). The scavenging ability of KYNA (expressed as IC(50) values) was as follows: OH=O(2)(-)>ONOO(-). In parallel, the antiperoxidative and scavenging capacities of KYNA (0-150 μM) were tested in cerebellum and forebrain homogenates exposed to 5 μM FeSO(4) and 2.5 mM 3-nitropropionic acid (3-NPA). Both FeSO(4) and 3-NPA increased lipid peroxidation (LP) and ROS formation in a significant manner in these preparations, whereas KYNA significantly reduced these markers. Reactive oxygen species (ROS) formation were determined in the presence of FeSO(4) and/or KYNA (0-100 μM), both at intra and extracellular levels. An increase in ROS formation was induced by FeSO(4) in forebrain and cerebellum in a time-dependent manner, and KYNA reduced this effect in a concentration-dependent manner. To further know whether the effect of KYNA on oxidative stress is independent of NMDA and nicotinic receptors, we also tested KYNA (0-100 μM) in a biological preparation free of these receptors - defolliculated Xenopus laevis oocytes - incubated with FeSO(4) for 1 h. A 3-fold increase in LP and a 2-fold increase in ROS formation were seen after exposure to FeSO(4), whereas KYNA attenuated these effects in a concentration-dependent manner. In addition, the in vivo formation of OH evoked by an acute infusion of FeSO(4) (100 μM) in the rat striatum was estimated by microdialysis and challenged by a topic infusion of KYNA (1 μM). FeSO(4) increased the striatal OH production, while KYNA mitigated this effect. Altogether, these data strongly suggest that KYNA

  18. Assessment of haemolytic, cytotoxic and free radical scavenging activities of an underutilized fruit, Baccaurea ramiflora Lour. (Roxb.) Muell. Arg.

    PubMed

    Saha, Manas Ranjan; Dey, Priyankar; Chaudhuri, Tapas Kumar; Goyal, Arvind Kr; Sarker, Dilip De; Sen, Arnab

    2016-02-01

    Baccaurea ramiflora Lour. (Roxb.) Muell. Arg. is an underutilized juicy fruit bearing plant found in sub-Himalayan area, South China, Indo-Burma region, etc. The fruit is considered to be nutritive, and in this study, we evaluated its antioxidant, haemolytic and cytotoxic properties. The juice was examined for the quenching activity of hydroxyl radical, nitric oxide, singlet oxygen, peroxynitrite, total antioxidant activity (TAA), erythrocyte membrane stabilizing activity (EMSA) along with quantification of phenolic and flavonoid contents and also tested for its potential activity as iron chelator, inhibitor of lipid peroxidation and total reducing power. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were also performed to correlate antioxidant capacities with the phenolic and flavonoid content. Haemolytic activity on murine erythrocyte and MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) cytotoxic test was performed on murine splenocytes, thymocytes, hepatocytes and peritoneal exudates macrophage to examine the cytotoxic effect of its juice. The result exhibited its potent free radical scavenging activity. In case of TAA, DPPH (2, 2-diphenyl-1-picrylhydrazyl), EMSA and lipid peroxidation, the fruit juice was found to have significant (P < 0.001) antioxidant capacity, which is evident from low IC50 (half maximal inhibitory concentration) value. Results obtained from haemolytic inhibition assay and MTT cytotoxic test confirms that the juice does not contain any cytotoxic effect and the fruit is safe for consumption. Fourier transform infrared (FTIR) spectra analysis exhibited high possibility of presence of flavonoid compounds in the juice. PMID:26934779

  19. Scavenging of reactive oxygen species in apoplastic and symplastic areas of rolled leaves in Ctenanthe setosa under drought stress.

    PubMed

    Saruhan, Neslihan; Terzi, Rabiye; Sağlam, Aykut; Kadioğlu, Asim

    2010-09-01

    The correspondence among apoplastic and symplastic antioxidant status, stomatal conductance and water potential was investigated during leaf rolling in Ctenanthe setosa (Rosc.) Eichler (Marantaceae) under drought stress. Apoplastic and symplastic extractions of leaf and petiole were performed at different visual leaf rolling scores from 1 to 4 (1 is unrolled, 4 is tightly rolled and the others are intermediate form). In the leaf symplast, the highest changes were found in catalase (CAT) and guaiacol peroxidase (GPX) activities when compared to score 1 during leaf rolling. No significant change was observed in superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities in the symplast of leaf during the rolling. The same phenomenon was also present in the symplast of petiole except APX activity. In the leaf apoplast, the highest increase occurred in APX and GPX activities, whilst a slight increase in CAT and SOD activities. In the apoplast of petiole, the highest increment was found only in GPX activity, while there were small increases in SOD, APX and CAT activities. Hydrogen peroxide content increased up to score 3 in the apoplast and symplast of leaf and petiole but then slightly decreased. Also, superoxide production increased in the leaf and petiole apoplast but its quantity in the apoplast was much more than that of the symplast. On the other hand, NAD(P)H oxidase activity increased in the leaf but no change was observed in the petiole. In conclusion, as a result of water deficit during leaf rolling antioxidant enzymes are induced to scavenging of ROS produced in symplast and apoplast. PMID:20724275

  20. Effects of MCI-186 upon neutrophil-derived active oxygens.

    PubMed

    Sumitomo, K; Shishido, N; Aizawa, H; Hasebe, N; Kikuchi, K; Nakamura, M

    2007-01-01

    Reactions of 3-methyl-1-phenyl-2-pyrazoline-5-one (MCI-186) with hypochlorous acid and superoxide were analysed by spectrophotometry and mass spectrometry. The results were applied to the neutrophil system to evaluate the scavenging activity of neutrophil-derived active oxygen species by MCI-186. MCI-186 reacted rapidly with hypochlorous acid (1 x 10(6) M(-1)s(-1)) to form a chlorinated intermediate, followed by a slow conversion to a new spectrum. MCI-186 consumed 3 moles of hypochlorous acid and did not react with superoxide. The newly synthesized fluorescence probes, 2-[6-(4'-amino)-phenoxy-3H-xanthen-3-on-9-yl]benzoic acid (APF) and 2-[6-(4'-hydroxy)phenoxy-3H-anthen-3-on-9-yl]benzoic acid (HPF) successfully detected neutrophil-derived active oxygens (Setsukinai K, Urano Y, Kakinuma K, Majima HJ, Nagano T. Development of novel fluorescence probes that can reliably detect reactive oxygen species and distinguish specific species. J Biol Chem 2003; 278: 3170-3175). The rate constants for the reaction of hypochlorous acid with MCI-186 and fluorescence probes was in the order of MCI-186 > APF > HPF. Fluorescence due to the oxidation of APF and HPF was observed with the stimulated neutrophils. The result that the intensity from APF oxidation was higher than that from HPF oxidation is compatible with reports that APF selectively reacts with hypochlorous acid. Fluorescence due to oxidation of both APF and HPF decreased when the reactions were carried out in the presence of a fluorescence probe and MCI-186 in a dose-dependent manner. These results indicate that MCI-186 effectively scavenges neutrophil-derived hypochlorous acid and other active oxygens. PMID:17705989

  1. Active oxygen doctors the evidence

    NASA Astrophysics Data System (ADS)

    Castelló, Ana; Francès, Francesc; Corella, Dolores; Verdú, Fernando

    2009-02-01

    Investigation at the scene of a crime begins with the search for clues. In the case of bloodstains, the most frequently used reagents are luminol and reduced phenolphthalein (or phenolphthalin that is also known as the Kastle-Meyer colour test). The limitations of these reagents have been studied and are well known. Household cleaning products have evolved with the times, and new products with active oxygen are currently widely used, as they are considered to be highly efficient at removing all kinds of stains on a wide range of surfaces. In this study, we investigated the possible effects of these new cleaning products on latent bloodstains that may be left at a scene of a crime. To do so, various fabrics were stained with blood and then washed using cleaning agents containing active oxygen. The results of reduced phenolphthalein, luminol and human haemoglobin tests on the washed fabrics were negative. The conclusion is that these new products alter blood to such an extent that it can no longer be detected by currently accepted methods employed in criminal investigations. This inability to locate bloodstains means that highly important evidence (e.g. a DNA profile) may be lost. Consequently, it is important that investigators are aware of this problem so as to compensate for it.

  2. Beneficial effect of the oxygen free radical scavenger amifostine (WR-2721) on spinal cord ischemia/reperfusion injury in rabbits

    PubMed Central

    Chronidou, Fany; Apostolakis, Efstratios; Papapostolou, Ioannis; Grintzalis, Konstantinos; Georgiou, Christos D; Koletsis, Efstratios N; Karanikolas, Menelaos; Papathanasopoulos, Panagiotis; Dougenis, Dimitrios

    2009-01-01

    Background Paraplegia is the most devastating complication of thoracic or thoraco-abdominal aortic surgery. During these operations, an ischemia-reperfusion process is inevitable and the produced radical oxygen species cause severe oxidative stress for the spinal cord. In this study we examined the influence of Amifostine, a triphosphate free oxygen scavenger, on oxidative stress of spinal cord ischemia-reperfusion in rabbits. Methods Eighteen male, New Zealand white rabbits were anesthetized and spinal cord ischemia was induced by temporary occlusion of the descending thoracic aorta by a coronary artery balloon catheter, advanced through the femoral artery. The animals were randomly divided in 3 groups. Group I functioned as control. In group II the descending aorta was occluded for 30 minutes and then reperfused for 75 min. In group III, 500 mg Amifostine was infused into the distal aorta during the second half-time of ischemia period. At the end of reperfusion all animals were sacrificed and spinal cord specimens were examined for superoxide radicals by an ultra sensitive fluorescent assay. Results Superoxide radical levels ranged, in group I between 1.52 and 1.76 (1.64 ± 0.10), in group II between 1.96 and 2.50 (2.10 ± 0.23), and in group III (amifostine) between 1.21 and 1.60 (1.40 ± 0.19) (p = 0.00), showing a decrease of 43% in the Group of Amifostine. A lipid peroxidation marker measurement ranged, in group I between 0.278 and 0.305 (0.296 ± 0.013), in group II between 0.427 and 0.497 (0.463 ± 0.025), and in group III (amifostine) between 0.343 and 0.357 (0.350 ± 0.007) (p < 0.00), showing a decrease of 38% after Amifostine administration. Conclusion By direct and indirect methods of measuring the oxidative stress of spinal cord after ischemia/reperfusion, it is suggested that intra-aortic Amifostine infusion during spinal cord ischemia phase, significantly attenuated the spinal cord oxidative injury in rabbits. PMID:19758462

  3. An organoselenium drug with antioxidant activity and free radical scavenging capacity in vitro.

    PubMed

    Ibrahim, Mohammad; Hassan, Waseem; Deobald, Anna Maria; Braga, Antonio Luis; Rocha, Joao B T

    2012-12-01

    Organoselenum compounds have been reported to have a wide range of pharmacological properties. Amine-based diselenide, (Z)-N-(4-methylbenzylidene)-1-(2-((2-(1-((E)-4-methyl benzylideneamino)ethyl)phenyl)diselanyl)phenyl)ethanamine ethyl)phenyl) diselanyl) phenyl) ethylimino) methyl)phenol (compound A), and diphenyl diselenide (PhSe)2 were screened for in vitro antioxidant activity. Compound A and (PhSe)2 were tested against sodium nitroprusside (SNP)- and Fe(II)-induced thiobarbituric acid-reactive species (TBARS) in rat brain homogenates. The radical scavenging activity was measured by 1,1-diphenyl-2-picrylhydrazyl assay. Both compounds A and (PhSe)2 decreased Fe(II)- and SNP-stimulated TBARS production in rat brain homogenates. Compound A exhibited the strongest antioxidant activity in the radical scavenging assay, although (PhSe)2, the simplest of the diaryl diselenide, presented no activity. In conclusion, the results of the present investigation indicated that compound A and (PhSe)2 had preventive effects against SNP- and Fe(II)-induced oxidative stress in rat brain homogenates. The amine group in the organic moiety dramatically changed the potency of amine-based diselenide. PMID:22562597

  4. Effect of gamma irradiation on the antimicrobial and free radical scavenging activities of Glycyrrhiza glabra root

    NASA Astrophysics Data System (ADS)

    Fatima Khattak, Khanzadi; James Simpson, Thomas

    2010-04-01

    The efficacy of gamma irradiation as a method of decontamination for food and herbal materials is well established. In the present study, Glycyrrhiza glabra roots were irradiated at doses 5, 10, 15, 20 and 25 kGy in a cobalt-60 irradiator. The irradiated and un-irradiated control samples were evaluated for phenolic contents, antimicrobial activities and DPPH scavenging properties. The result of the present study showed that radiation treatment up to 20 kGy does not affect the antifungal and antibacterial activity of the plant. While sample irradiated at 25 kGy does showed changes in the antibacterial activity against some selected pathogens. No significant differences in the phenolic contents were observed for control and samples irradiated at 5, 10 and 15 kGy radiation doses. However, phenolic contents increased in samples treated with 20 and 25 kGy doses. The DPPH scavenging activity significantly ( p<0.05) increased in all irradiated samples of the plant.

  5. Theoretical insights on the antioxidant activity of edaravone free radical scavengers derivatives

    NASA Astrophysics Data System (ADS)

    Cerón-Carrasco, José P.; Roy, Hélène M.; Cerezo, Javier; Jacquemin, Denis; Laurent, Adèle D.

    2014-04-01

    The prediction of antioxidant properties is not straightforward due to the complexity of the in vivo systems. Here, we use theoretical descriptors, including the potential of ionization, the electrodonating power and the spin density distribution, to characterize the antioxidant capacity of edaravone (EDV) derivatives. Our computations reveal the relationship between these parameters and their potential bioactivity as free radical scavengers. We conclude that more efficient antioxidants could be synthesized by tuning the R1 and R2 positions of the EDV structure, rather than modifying the R3 group. Such modifications might improve the antioxidant activity in neutral and deprotonated forms.

  6. The effect of Ta ``oxygen scavenger layer'' on HfO2-based resistive switching behavior: termodynamic stability, electronic structure, and low-bias transport

    NASA Astrophysics Data System (ADS)

    Zhong, Xiaoliang; Rungger, Ivan; Zapol, Peter; Nakamura, Hisao; Asai, Yoshihiro; Heinonen, Olle

    Metal-oxide-metal heterostructures are promising candidates for next-generation random access memories, which exhibit reversible resistive switching between high- and low-conductance states. Recent experimental work showed that inserting a metallic `oxygen scavenger layer' between TiN electrode and HfO2 significantly improves device switching performance. We show, using atomistic modeling within the GGA +U scheme of Density Functional Theory, that a Ta oxygen scavenger layer significantly enhances the thermodynamic stability of depleting oxygen from the oxide. Furthermore, the presence of a Ta layer reduces the dependence of the Schottky barrier heights on the location of the oxygen removed from the oxide matrix. Finally, the Schottky barrier height has a very small effect on the on-state low-bias conductance; this is more sensitive to the location of the depleted oxygen. We gratefully acknowledge the computing resources provided on Blues, a high-performance computing cluster operated by the Laboratory Computing Resource Center at Argonne National Laboratory. Work at Argonne was supported by U. S. DOE, Office of Science under Contract No. DE-AC02-06CH11357.

  7. An Arabidopsis Zinc Finger Protein Increases Abiotic Stress Tolerance by Regulating Sodium and Potassium Homeostasis, Reactive Oxygen Species Scavenging and Osmotic Potential.

    PubMed

    Zang, Dandan; Li, Hongyan; Xu, Hongyun; Zhang, Wenhui; Zhang, Yiming; Shi, Xinxin; Wang, Yucheng

    2016-01-01

    Plant zinc finger proteins (ZFPs) comprise a large protein family and they are mainly involved in abiotic stress tolerance. Although Arabidopsis RING/FYVE/PHD ZFP At5g62460 (AtRZFP) is found to bind to zinc, whether it is involved in abiotic stress tolerance is still unknown. In the present study, we characterized the roles of AtRZFP in response to abiotic stresses. The expression of AtRZFP was induced significantly by salt and osmotic stress. AtRZFP positively mediates tolerance to salt and osmotic stress. Additionally, compared with wild-type Arabidopsis plants, plants overexpressing AtRZFP showed reduced reactive oxygen species (ROSs) accumulation, enhanced superoxide dismutase and peroxidase activity, increased soluble sugars and proline contents, reduced K(+) loss, decreased Na(+) accumulation, stomatal aperture and the water loss rate. Conversely, AtRZFP knockout plants displayed the opposite physiological changes when exposed to salt or osmotic stress conditions. These data suggested that AtRZFP enhances salt and osmotic tolerance through a series of physiological processes, including enhanced ROSs scavenging, maintaining Na(+) and K(+) homeostasis, controlling the stomatal aperture to reduce the water loss rate, and accumulating soluble sugars and proline to adjust the osmotic potential. PMID:27605931

  8. Biomimetic nanomaterials: Development of protein coated nanoceria as a potential antioxidative nano-agent for the effective scavenging of reactive oxygen species in vitro and in zebrafish model.

    PubMed

    Bhushan, Bharat; Nandhagopal, Soundharapandiyan; Rajesh Kannan, Rajaretinam; Gopinath, P

    2016-10-01

    Reactive oxygen species (ROS) induced oxidative stress is one of the major factors responsible for initiation of several intracellular toxic events that leads to cell death. Antioxidant enzymes defence system of the body is responsible for maintaining the oxidative balance and cellular homeostasis. Several diseases are promoted by the excessive oxidative stress caused by the impaired antioxidant defence system that leads to oxidant/antioxidant imbalance in the body. In order to restore or precise the aberrant antioxidant system, a large number of catalytic nanoparticles has been screened so far. Exceptional antioxidative activity of nanoceria made it as a potential antioxidative nano-agent for the effective scavenging of toxic ROS. In this work albumin coated nanoceria (ANC) was synthesized and further characterised by various physicochemical techniques. The antioxidant and superoxide dismutase (SOD) assay confirm that the albumin coating do not alter the antioxidant potential of ANC. The biocompatibility and protective efficacy of ANC against oxidative stress was investigated both in vitro and in vivo in human lung epithelial (L-132) cells and zebrafish embryos, respectively. The inductively coupled plasma mass spectrometry (ICP-MS), transmission electron microscopy (TEM) and field emission scanning electron microscope (FE-SEM) analysis corroborates the uptake of ANC by the cells. Furthermore, the semi-quantitative gene expression studies confirmed that the ANC successfully defend the cells against oxidative stress by preserving the antioxidant system of the cells. Thus, the current work open up a new avenue for the development of improved antioxidant nano-drug therapies. PMID:27388966

  9. An Arabidopsis Zinc Finger Protein Increases Abiotic Stress Tolerance by Regulating Sodium and Potassium Homeostasis, Reactive Oxygen Species Scavenging and Osmotic Potential

    PubMed Central

    Zang, Dandan; Li, Hongyan; Xu, Hongyun; Zhang, Wenhui; Zhang, Yiming; Shi, Xinxin; Wang, Yucheng

    2016-01-01

    Plant zinc finger proteins (ZFPs) comprise a large protein family and they are mainly involved in abiotic stress tolerance. Although Arabidopsis RING/FYVE/PHD ZFP At5g62460 (AtRZFP) is found to bind to zinc, whether it is involved in abiotic stress tolerance is still unknown. In the present study, we characterized the roles of AtRZFP in response to abiotic stresses. The expression of AtRZFP was induced significantly by salt and osmotic stress. AtRZFP positively mediates tolerance to salt and osmotic stress. Additionally, compared with wild-type Arabidopsis plants, plants overexpressing AtRZFP showed reduced reactive oxygen species (ROSs) accumulation, enhanced superoxide dismutase and peroxidase activity, increased soluble sugars and proline contents, reduced K+ loss, decreased Na+ accumulation, stomatal aperture and the water loss rate. Conversely, AtRZFP knockout plants displayed the opposite physiological changes when exposed to salt or osmotic stress conditions. These data suggested that AtRZFP enhances salt and osmotic tolerance through a series of physiological processes, including enhanced ROSs scavenging, maintaining Na+ and K+ homeostasis, controlling the stomatal aperture to reduce the water loss rate, and accumulating soluble sugars and proline to adjust the osmotic potential. PMID:27605931

  10. Synthesis, Characterization, Antimicrobial Screening and Free-Radical Scavenging Activity of Some Novel Substituted Pyrazoles.

    PubMed

    Hamada, Nagwa Mohamed Mahrous; Abdo, Nadia Yousef Megally

    2015-01-01

    The present work deals with the synthesis of acetoxysulfonamide pyrazole derivatives, substituted 4,5-dihydropyrazole-1-carbothioamide and 4,5-dihydropyrazole-1-isonicotinoyl derivatives starting from substituted vanillin chalcones. Acetoxysulfonamide pyrazole derivatives were prepared from the reaction of chalcones with p-sulfamylphenylhydrazine followed by treatment with acetic anhydride. At the same time 4,5-dihydropyrazole-1-carbothioamide and 4,5-dihydropyrazole-1-isonicotinoyl derivatives were prepared from the reaction of chalcones with either thiosemicarbazide or isonicotinic acid hydrazide, respectively. The synthesized compounds were structurally characterized on the basis of IR, 1H-NMR, 13C-NMR spectral data and microanalyses. All of the newly isolated compounds were tested for their antimicrobial activities. The antimicrobial screening using the agar well-diffusion method revealed that the chloro derivatives are the most active ones. Moreover, the antioxidant and anti-inflammatory activity of these chloro derivatives are also studied using the DPPH radical scavenging and NO radical scavenging methods, respectively. PMID:26060913

  11. Indoline Amide Glucosides from Portulaca oleracea: Isolation, Structure, and DPPH Radical Scavenging Activity.

    PubMed

    Jiao, Ze-Zhao; Yue, Su; Sun, Hong-Xiang; Jin, Tian-Yun; Wang, Hai-Na; Zhu, Rong-Xiu; Xiang, Lan

    2015-11-25

    A polyamide column chromatography method using an aqueous ammonia mobile phase was developed for large-scale accumulation of water-soluble indoline amide glucosides from a medicinal plant, Portulaca oleracea. Ten new [oleraceins H, I, K, L, N, O, P, Q, R, S (1-10)] and four known [oleraceins A-D (11-14)] indoline amide glucosides were further purified and structurally characterized by various chromatographic and spectroscopic methods. The DPPH radical scavenging activities of oleraceins K (5) and L (6), with EC50 values of 15.30 and 16.13 μM, respectively, were twice that of a natural antioxidant, vitamin C; the EC50 values of the 12 other indoline amides, which ranged from 29.05 to 43.52 μM, were similar to that of vitamin C. Structure-activity relationships indicated that the DPPH radical scavenging activities of these indoline amides correlate with the numbers and positions of the phenolic hydroxy groups. PMID:26562741

  12. Monoamine oxidase B and free radical scavenging activities of natural flavonoids in Melastoma candidum D. Don.

    PubMed

    Lee, M H; Lin, R D; Shen, L Y; Yang, L L; Yen, K Y; Hou, W C

    2001-11-01

    Monoamine oxidase type B (MAO-B) activity and free radicals are elevated in certain neurological diseases. Four natural flavonoids, quercitrin, isoquercitrin, rutin, and quercetin, were isolated for the first time from the leaves of Melastoma candidum D. Don. They exhibited an inhibitory effect on MAO-B. These potent flavonoids were purified using bioassay-guided fractionation and were separated by Diaion, Sephadex LH-20, and MCI CHP20P columns. The IC(50) values of the four potent flavonoids, quercitrin, isoquercitrin, rutin, and quercetin on monoamine oxidase were 19.06, 11.64, 3.89, and 10.89 microM and enzyme kinetics analysis revealed apparent inhibition constants (K(i)) of 21.01, 2.72, 1.83, and 7.95 microM, respectively, on the substrate, benzylamine. The four potent compounds also exhibited hydroxyl radical scavenging activity as determined using a spin trapping electron spin resonance method. This suggests that the four flavonoids from M. candidum possess both MAO-B inhibitory and free radical scavenging activities. These important properties may be used for preventing some neurodegenerative diseases in the future. PMID:11714358

  13. The evaluation of nitric oxide scavenging activity of certain Indian medicinal plants in vitro: a preliminary study.

    PubMed

    Jagetia, Ganesh Chandra; Baliga, Manjeshwar Shrinath

    2004-01-01

    The plant extracts of 17 commonly used Indian medicinal plants were examined for their possible regulatory effect on nitric oxide (NO) levels using sodium nitroprusside as an NO donor in vitro. Most of the plant extracts tested demonstrated direct scavenging of NO and exhibited significant activity. The potency of scavenging activity was in the following order: Alstonia scholaris > Cynodon dactylon > Morinda citrifolia > Tylophora indica > Tectona grandis > Aegle marmelos (leaf) > Momordica charantia > Phyllanthus niruri > Ocimum sanctum > Tinospora cordifolia (hexane extract) = Coleus ambonicus > Vitex negundo (alcoholic) > T. cordifolia (dichloromethane extract) > T. cordifolia (methanol extract) > Ipomoea digitata > V. negundo (aqueous) > Boerhaavia diffusa > Eugenia jambolana (seed) > T. cordifolia (aqueous extract) > V. negundo (dichloromethane/methanol extract) > Gingko biloba > Picrorrhiza kurroa > A. marmelos (fruit) > Santalum album > E. jambolana (leaf). All the extracts evaluated exhibited a dose-dependent NO scavenging activity. The A. scholaris bark showed its greatest NO scavenging effect of 81.86% at 250 microg/mL, as compared with G. biloba, where 54.9% scavenging was observed at a similar concentration. The present results suggest that these medicinal plants might be potent and novel therapeutic agents for scavenging of NO and the regulation of pathological conditions caused by excessive generation of NO and its oxidation product, peroxynitrite. PMID:15383230

  14. Phenylpropanoid Glycoside Analogues: Enzymatic Synthesis, Antioxidant Activity and Theoretical Study of Their Free Radical Scavenger Mechanism

    PubMed Central

    López-Munguía, Agustín; Hernández-Romero, Yanet; Pedraza-Chaverri, José; Miranda-Molina, Alfonso; Regla, Ignacio; Martínez, Ana; Castillo, Edmundo

    2011-01-01

    Phenylpropanoid glycosides (PPGs) are natural compounds present in several medicinal plants that have high antioxidant power and diverse biological activities. Because of their low content in plants (less than 5% w/w), several chemical synthetic routes to produce PPGs have been developed, but their synthesis is a time consuming process and the achieved yields are often low. In this study, an alternative and efficient two-step biosynthetic route to obtain natural PPG analogues is reported for the first time. Two galactosides were initially synthesized from vanillyl alcohol and homovanillyl alcohol by a transgalactosylation reaction catalyzed by Kluyveromyces lactis β-galactosidase in saturated lactose solutions with a 30%–35% yield. To synthesize PPGs, the galactoconjugates were esterified with saturated and unsaturated hydroxycinnamic acid derivatives using Candida antarctica Lipase B (CaL-B) as a biocatalyst with 40%–60% yields. The scavenging ability of the phenolic raw materials, intermediates and PPGs was evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH•) method. It was found that the biosynthesized PPGs had higher scavenging abilities when compared to ascorbic acid, the reference compound, while their antioxidant activities were found similar to that of natural PPGs. Moreover, density functional theory (DFT) calculations were used to determine that the PPGs antioxidant mechanism proceeds through a sequential proton loss single electron transfer (SPLET). The enzymatic process reported in this study is an efficient and versatile route to obtain PPGs from different phenylpropanoid acids, sugars and phenolic alcohols. PMID:21674039

  15. Simultaneous quantification and peroxynitrite-scavenging activities of flavonoids in Polygonum aviculare L. herb.

    PubMed

    Nugroho, Agung; Kim, Eon Ji; Choi, Jae Sue; Park, Hee-Juhn

    2014-02-01

    The plant Polygonum aviculare L. (Polygonaceae) is an annual herbaceous plant which is known to be beneficial for treating gastroduodenal ulcer, hypertension, diarrhea, hemorrhage, and hemorrhoids. Ten phenolic compounds, including nine flavonoids (myricetin, quercetin, kaempferol, myricitrin, desmanthin-1, isoquercitrin, quercitrin, avicularin, juglanin), and gallic acid were used for simultaneous HPLC quantification and peroxynitrite-scavenging assay. Simultaneous quantification of these substances were performed on five extracts (EtOH-, MeOH-, 70% MeOH-, 30% MeOH-, and H2O extracts) as well as on the three fractions (Et2O-, EtOAc-, and BuOH fractions), under the condition of a Capcell Pak C18 column (5μm, 250mm×4.6mm i.d.) and a gradient elution of 0.05% trifluoroacetic acid (TFA) and MeOHCH3CN (60:40). Of the three fractions, the EtOAc fraction displayed the highest content of flavonoids (sum, 208.9mg/g) with the strongest peroxynitrite-scavenging activity (IC50, 2.68μg/mL). The activities of the eight compounds (myricitrin, isoquercitrin, avicularin, quercitrin, myricetin, desmanthin-1, quercetin, and kaempferol) were comparable to that of the positive control (l-penicillamine; IC50: 1.03μg/mL). These results suggest that folkloric medicinal uses of P. aviculare are mainly attributed to flavonoids, such as particularly highly contained myricetin, myricitrin, and desmanthin-1. PMID:24270289

  16. Is alpha-lipoic acid a scavenger of reactive oxygen species in vivo? Evidence for its initiation of stress signaling pathways that promote endogenous antioxidant capacity.

    PubMed

    Petersen Shay, Kate; Moreau, Régis F; Smith, Eric J; Hagen, Tory M

    2008-06-01

    The chemical reduction and oxidation (redox) properties of alpha-lipoic acid (LA) suggest that it may have potent antioxidant potential. A significant number of studies now show that LA and its reduced form, dihydrolipoic acid (DHLA), directly scavenge reactive oxygen species (ROS) and reactive nitrogen species (RNS) species and protect cells against a host of insults where oxidative stress is part of the underlying etiology. However, owing to its limited and transient accumulation in tissues following oral intake, the efficacy of nonprotein-bound LA to function as a physiological antioxidant has been questioned. Herein, we review the evidence that the micronutrient functions of LA may be more as an effector of important cellular stress response pathways that ultimately influence endogenous cellular antioxidant levels and reduce proinflammatory mechanisms. This would promote a sustained improvement in cellular resistance to pathologies where oxidative stress is involved, which would not be forthcoming if LA solely acted as a transient ROS scavenger. PMID:18409172

  17. Direct observation of both contact and remote oxygen scavenging of GeO{sub 2} in a metal-oxide-semiconductor stack

    SciTech Connect

    Fadida, S. Shekhter, P.; Eizenberg, M.; Cvetko, D.; Floreano, L.; Verdini, A.; Kymissis, I.

    2014-10-28

    In the path to incorporating Ge based metal-oxide-semiconductor into modern nano-electronics, one of the main issues is the oxide-semiconductor interface quality. Here, the reactivity of Ti on Ge stacks and the scavenging effect of Ti were studied using synchrotron X-ray photoelectron spectroscopy measurements, with an in-situ metal deposition and high resolution transmission electron microscopy imaging. Oxygen removal from the Ge surface was observed both in direct contact as well as remotely through an Al{sub 2}O{sub 3} layer. The scavenging effect was studied in situ at room temperature and after annealing. We find that the reactivity of Ti can be utilized for improved scaling of Ge based devices.

  18. Flavanoid-rich fraction from Sageretia theezans leaves scavenges reactive oxygen radical species and increases the resistance of low-density lipoprotein to oxidation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To explore their bioactive fractions, S. theezans leaves were extracted 2 with 60% acetone and then fractionated sequentially with hexane, ethyl acetate, and water. ROS (HOCl, ONOO-, and O2 deg -) scavenging activity, ORAC value and total phenolic content of each fraction were investigated. The ethy...

  19. Free radical scavenging activity of novel thiazolidine-2,4-dione derivatives.

    PubMed

    Berczyński, Paweł; Kruk, Irena; Piechowska, Teresa; Ceylan-Unlusoy, Meltem; Bozdağ-Dündar, Oya; Aboul-Enein, Hassan Y

    2013-01-01

    Free radical activity towards superoxide anion radical (O2•¯), hydroxyl radical (HO(•)) and 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) of a series of novel thiazolidine-2,4-dione derivatives (TSs) was examined using chemiluminescence, electron paramagnetic resonance (EPR) and EPR spin trapping techniques. 5,5-Dimethyl-1-pyrroline-N-oxide (DMPO) was applied as the spin trap. Superoxide radical was produced in the potassium superoxide/18-crown-6 ether dissolved in dimethyl sulfoxide. Hydroxyl radical was generated in the Fenton reaction (Fe(II) + H2O2. It was found that TSs showed a slight scavenging effect (15-38% reduction at 2.5 mmol/L concentration) of the DPPH radical and a high scavenging effect of O2•¯ (41-88%). The tested compounds showed inhibition of HO(•)-dependent DMPO-OH spin adduct formation (the amplitude of EPR signal decrease ranged from 20 to 76% at 2.5 mmol/L concentration. Our findings present new group compounds of relatively high reactivity towards free radicals. PMID:23225772

  20. Free radical scavenging, antidiarrheal and anthelmintic activity of Pistia stratiotes L. extracts and its phytochemical analysis.

    PubMed

    Bin Karim, Mohammed Faisal; Imam, Hasan; Sarker, Md Moklesur-Rahman; Uddin, Nizam; Hasan, Nahid; Paul, Nirmala; Haque, Tahmina

    2015-05-01

    In this phyto-pharmacological screening of Pistia stratiotes L leaf and root extracts each separately in two different solvents demonstrated its potential medicinal value. Apparent antioxidant value is demonstrated by DPPH, Nitric oxide scavenging and Ferric ion reducing method. Additionally, total flavonoid and phenolic compounds were measured. The leaf methanolic extract scavenged both nitric oxide (NO) and DPPH radical with a dose dependent manner. But the pet ether fraction of root was found to have highest efficacy in Fe(3±) reducing power assay. Flavonoid was found to contain highest in the pet ether fraction of root (411.35mg/g) in terms of quercetin equivalent, similarly highest amount (34.96mg/g) of total phenolic compounds (assayed as gallic acid equivalents) were found to contain in the same fraction. The methanolic fractions appeared less cytotoxic compared to pet ether extracts. The plant extracts caused a dose dependent decrease in faecal droppings in both castor oil and magnesium sulphate induced diarrhea, where as leaf extracts in each solvent appeared most effective. Also, the plant extracts showed anthelmintic activity in earthworm by inducing paralysis and death in a dose dependent manner. At highest doses (50 mg/ml) all fractions were almost effective as the positive control piperazine citrate (10 mg/ml). Thus, besides this cytotoxic effect it's traditional claim for therapeutic use can never be overlooked. PMID:26004725

  1. Nutrient composition, phenolic content and free radical scavenging activity of some uncommon vegetables of Pakistan.

    PubMed

    Khattak, Khanzadi Fatima

    2011-07-01

    Vegetables play a vital role in the prevention of human disease and in the improvement of general health as these contain vitamins, amino acids, fiber, antioxidants and minerals. In the present study, some less familiar vegetables of Pakistan namely chickpea (leaves), chungah (shoots), drumstick tree (inflorescences), radish (fruit pods), mountain ebony (flower buds), mustard (leaves), purslane (leaves) and white goosefoot (leaves and shoots) were evaluated for proximate composition, mineral content, phenolic content and free radical scavenging activity. The protein, fat, fiber, carbohydrate and ash contents of the selected vegetables were in the range of 2.9 to 6.6%, 0.2 to 2.5%, 2.4 to 8.6%, 9.7 to 20.1% and 1.0 to 2.3%, respectively. The concentration of vitamin C ranged between 32.6 to 120.1 mg/100 g. The phosphorus, calcium, iron, zinc, manganese, magnesium and copper were 190 to 3400, 103 to 987, 19 to 93, 12 to 47, 9 to 121, 299 to 1635 and non detectable level to 42 mg/kg, respectively. The amount of total phenolic content varied from 55.3 to 221.0 mg/g in the dry methanolic extracts of the studied plants. The EC(50) values were below 1400 μg/ml, indicating that all the studied vegetables have good scavenging effect on DPPH radical. PMID:21715260

  2. Antioxidant and radical-scavenging activities of Slovak honeys - An electron paramagnetic resonance study.

    PubMed

    Zalibera, Michal; Staško, Andrej; Šlebodová, Anna; Jančovičová, Viera; Čermáková, Tatiana; Brezová, Vlasta

    2008-09-15

    The antioxidant properties of 15 honey samples from different floral sources and various Slovak regions were investigated by means of electron paramagnetic resonance spectroscopy. Cation radical of ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) diammonium salt), DPPH (1,1-diphenyl-2-picrylhydrazyl) and hydroxyl radicals generated by the photochemical decomposition of hydrogen peroxide were used as oxidants. The antioxidant activities found with ABTS(+), expressed as trolox equivalent antioxidant capacity (TEAC), ranged from 0.15 to 1.14mmolkg(-1), and those determined with DPPH, from 0.04 to 0.32mmolkg(-1). TEAC values correlated well with results found by elimination of DPPH, and both values revealed a linear relationship with the concentration of phenolics obtained with the Folin-Ciocalteu phenol test (expressed as gallic acid equivalents, GAE). The colour coordinates (CIE L(∗)a(∗)b(∗)), as well as reflectance spectra determined for original honeys using a white background, demonstrated that the colour difference (ΔE(∗)) and coordinate b(∗) interrelate with TEAC values. The radical-scavenging capacities (RSC) of the honey samples determined in the experiments with photochemically decomposed hydrogen peroxide, generating reactive OH radicals in the presence of spin trapping agent, differ from those found with ABTS(+) and DPPH. Here, probably, the reactive OH radicals, having higher redox potential, are scavenged by a variety of compounds not effective with ABTS(+) and DPPH (e.g., saccharides, proteins). PMID:26049247

  3. Targeted acylation for all the hydroxyls of (+)-catechin and evaluation of their individual contribution to radical scavenging activity.

    PubMed

    Hong, Shan; Liu, Songbai

    2016-04-15

    The reactivity profile of all the hydroxyl groups in (+)-catechin towards acylation and their respective contribution to radical scavenging activity were systematically explored in this work. Selective acylation of the hydroxyls on different rings was carried out employing either a basic or acidic activation strategy. Monoacylation of B ring was achieved effectively with the aid of dimethyltin dichloride. Monoacylation of A ring was accomplished by sequential protection and deprotection of B and C rings. Based on specific acylation of all the individual hydroxyls of (+)-catechins, the structure radical scavenging activity relationship of each hydroxyl of (+)-catechin was established. It was demonstrated that the vicinal phenolic hydroxyls on B ring played the most important role in the ABTS radical scavenging activity and those on A and C rings made a much smaller contribution. This study has laid solid groundwork for further modification of the catechins and improvement of their properties. PMID:26616969

  4. Change in chemical constituents and free radical-scavenging activity during Pear (Pyrus pyrifolia) cultivar fruit development.

    PubMed

    Cho, Jeong-Yong; Lee, Sang-Hyun; Kim, Eun Hee; Yun, Hae Rim; Jeong, Hang Yeon; Lee, Yu Geon; Kim, Wol-Soo; Moon, Jae-Hak

    2015-01-01

    Changes in chemical constituent contents and DPPH radical-scavenging activity in fruits of pear (Pyrus pyrifolia) cultivars during the development were investigated. The fruits of seven cultivars (cv. Niitaka, Chuhwangbae, Wonhwang, Hwangkeumbae, Hwasan, Manpungbae, and Imamuraaki) were collected at 15-day intervals after day 20 of florescence. Vitamins (ascorbic acid and α-tocopherol), arbutin, chlorogenic acid, malaxinic acid, total caffeic acid, total flavonoids, and total phenolics were the highest in immature pear fruit on day 20 after florescence among samples at different growth stages. All of these compounds decreased gradually in the fruit during the development. Immature pear fruit on day 35 or 50 after florescence exhibited higher free radical-scavenging activity than that at other times, although activities were slightly different among cultivars. The chemical constituent contents and free radical-scavenging activity were largely different among immature fruits of the pear cultivars, but small differences were observed when they matured. PMID:25348501

  5. Effects of hydroxyl radical scavengers KCN and CO on ultraviolet light-induced activation of crude soluble guanylate cyclase

    SciTech Connect

    Karlsson, J.O.; Axelsson, K.L.; Andersson, R.G.

    1985-01-01

    The crude soluble guanylate cyclase (GC) from bovine mesenteric artery was stimulated by ultraviolet (UV) light (366 nm). Addition of free radical scavengers, dimethylsulfoxide or superoxide dismutase and/or catalase to the GC assay did not abolish the stimulatory effect of UV light. On the contrary, the UV light-induced activation was enhanced in the presence of these scavengers. KCN (1 mM) did not affect the UV light-induced activation, while 0.1 mM of CO potentiated the activation. These results may indicate that UV light is operating through a direct interaction with the ferrous form of the GC-heme.

  6. Neuronal apoptosis in rats is accompanied by rapid impairment of cellular respiration and is prevented by scavengers of reactive oxygen species.

    PubMed

    Atlante, A; Gagliardi, S; Marra, E; Calissano, P

    1998-04-10

    Apoptosis of cerebellar granule cells induced by potassium withdrawal is accompanied by a very rapid decrease in both cell and mitochondrial respiration supported by glucose and succinate, respectively. The respiratory control ratio, which is an index of oxidative phosphorylation and therefore reflects the ability of mitochondria to produce ATP, is reduced by 50% within the first 2 h after the beginning of apoptosis, insulin-like growth factor I (IGF-I), actinomicin D or cycloheximide, previously reported to inhibit apoptosis, fully prevent the impairment of cellular respiration while scavengers of reactive oxygen species partially inhibit apoptosis and restore cellular respiration. PMID:9605472

  7. Possibility of cellulose-based electro-active paper energy scavenging transducer.

    PubMed

    Abas, Zafar; Kim, Heung Soo; Zhai, Lindong; Kim, Jaehwan; Kim, Joo Hyung

    2014-10-01

    In this paper, a cellulose-based Electro-Active Paper (EAPap) energy scavenging transducer is presented. Cellulose is proven as a smart material, and exhibits piezoelectric effect. Specimens were prepared by coating gold electrodes on both sides of cellulose film. The fabricated specimens were tested by a base excited aluminum cantilever beam at resonant frequency. Different tests were performed with single and multiple parallel connected electrodes coated on the cellulose film. A maximum of 131 mV output voltage was measured, when three electrodes were connected in parallel. It was observed that voltage output increases significantly with the area of electrodes. From these results, it can be concluded that the piezoelectricity of cellulose-based EAPap can be used in energy transduction application. PMID:25942809

  8. Fingerprints, Pharmaceutical and Radical Scavenging Activity Evaluation of an Alzheimer-Targeted Herbal Preparation

    PubMed Central

    Dabaghian, Farid; Khademian, Sedigheh; Azadi, Amir; Zarshenas, Mohammad

    2016-01-01

    Background: As the most common form of dementia, Alzheimer disease is characterized by progressive loss of memory and deterioration of cognitive functions. It is predicted that about 75.63 million people would suffer from dementia by 2030. Apart from conventional remedies, the application of herbal medicines is on the rise. There are numerous natural medicaments reported in the traditional manuscript of Persian medicine. Accordingly, in the present study, the intended remedy was selected and an appropriate pharmacognostical and pharmaceutical evaluations were performed. Methods: By searching through the traditional pharmaceutical manuscripts such as Qarabadeen-e-Salehi, Qarabadeen-e-Azam, Qarabadeen-e-Ghaderi and Canon of Medicine, a simple but proven compound remedy (frankincense and black pepper) was selected. A floating tablet was designed and formulated from those herbal components. Related pharmaceutical assessments such as weight variation, hardness, friability, and disintegration tests as well as pharmacognostical evaluations such as microscopic characterization, TLC, GC/MS, FT/IR fingerprints, and radical scavenging activity assessment (DPPH) were performed. Results: The resulting formulation, as a floating tablet, included 60% of frankincense gum and 15% of black pepper along with appropriate pharmaceutical ingredients (weight variation: 0.219±0.004 g, hardness: 6.50±0.67, friability: 0.45%, disintegration time >30 min). Microscopic characterization demonstrated stone cells, calcium oxalate crystals, sclereids of endocarp and pitted cells of mesocarp of pepper fruits as well as oil drops of frankincense gum. TLC fingerprinting showed classes of secondary metabolites related to both components. GC/MS analysis revealed Acetyl acetate and trans-Caryophyllene as the main constituent. Moderate radical scavenging activity (IC50 >100 µg/ml) was calculated for the methanol extract of tablets. Conclusion: Carrying out and validating a GC method for

  9. An efficient method for high-purity anthocyanin isomers isolation from wild blueberries and their radical scavenging activity.

    PubMed

    Chorfa, Nasima; Savard, Sylvain; Belkacemi, Khaled

    2016-04-15

    An efficient process for the purification of anthocyanin monomeric isomers from wild blueberries of Lake Saint-Jean region (Quebec, Canada) was developed and easy scalable at industrial purpose. The blueberries were soaked in acidified ethanol, filtered, and the filtrate was cleaned by solid phase extraction using silica gel C-18 and DSC-SCX cation-exchange resin. Anthocyanin-enriched elutes (87 wt.%) were successfully fractionated by preparative liquid chromatography. The major anthocyanins mono-galactoside, -glucoside and -arabinoside isomers of delphinidin, cyanidin, petunidin, peonidin and malvidin were isolated with a purity up to 100% according to their LC-MS and (1)H NMR spectra. The oxygen radical absorbance capacity (ORAC) of the obtained pure anthocyanins was evaluated. Delphinidin-3-galactoside has the highest capacity (13.062 ± 2.729 μmol TE/μmol), and malvidin-3-glucoside the lowest (0.851 ± 0.032 μmol TE/μmol). A mechanistic pathway preview is suggested for the anthocyanins scavenging free radical activity by hydrogen transfer. PMID:26675861

  10. Sulphur antioxidants inhibit oxidative stress induced retinal ganglion cell death by scavenging reactive oxygen species but influence nuclear factor (erythroid-derived 2)-like 2 signalling pathway differently.

    PubMed

    Majid, Aman Shah Abdul; Yin, Zheng Qin; Ji, Dan

    2013-01-01

    This study aimed to show if two different sulphur containing drugs sulbutiamine and acetylcysteine (NAC) could attenuate the effects of two different insults being serum deprivation and glutamate/buthionine sulfoximine (GB)-induced death to transformed retinal ganglion cell line (RGC-5) in culture. Cells were exposed to either 5 mM of GB for 24 h or serum deprivation for 48 h with inclusion of either NAC or sulbutiamine. Cell viability, microscopic evidence for apoptosis, caspase 3 activity, reactive oxygen species (ROS), glutathione (GSH), catalase and gluthathione-S-transferase (GST) were determined. The effects of NAC and sulbutiamine on the oxidative stress related transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf-2) levels and its dependent phase II enzyme haemeoxygenase-1 (HO-1) were carried out using Western blot and quantitative-polymerase chain reaction (PCR). NAC and sulbutiamine dose-dependently attenuated serum deprivation-induced cell death. However NAC but not sulbutiamine attenuated GB-induced cell death. NAC and sulbutiamine both independently stimulated the GSH and GST production but scavenged different types of ROS with different efficacy. Moreover only sulbutiamine stimulated catalase and significantly increased Nrf-2 and HO-1 levels. In addition, the pan caspase inhibitor, benzoylcarbonyl-Val-Ala-Asp-fluoromethyl ketone (z-VAD-fmk) attenuated the negative effect of serum deprivation while the necroptosis inhibitor (necrostatin-1) counteracted solely an insult of GB. The neuroprotective actions of NAC and sulbutiamine in GB or serum-deprivation insult are therefore different. PMID:23811559

  11. 1,1-Diphenyl-2-picrylhydrazyl radical and superoxide anion scavenging activity of Rhizophora mangle (L.) bark

    PubMed Central

    Sánchez, Janet Calero; García, Roberto Faure; Cors, Ma. Teresa Mitjavila

    2010-01-01

    Background: Rhizophora mangle (L.) produce a variety of substances that possesses pharmacological actions. Although it shown antioxidant properties in some assays, there is no available information about its effect on some free radical species. So the objective of the present research is to evaluate the DPPH radical and superoxide anion scavenging properties of R. mangle extract and its polyphenol fraction. Methods: Rhizophora mangle (L.) bark aqueous extract and its major constituent, polyphenols fraction, were investigated for their antioxidant activities employing 2 in vitro assay systems: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and superoxide anion radicals scavenging. Results: IC50 for DPPH radical-scavenging activity was 6.7 µg tannins/mL for extract and 7.6 µg tannins/mL for polyphenolic fraction. The extract showed better activity than its fraction (P < 0.05) in the DPPH radicals reducing power. Polyphenolic fraction exhibited better superoxide anion scavenging ability (IC50 = 21.6 µg tannins/mL) than the extract (IC50 = 31.9 µg tannins/mL). Antioxidant activities of both samples increased with the rise of tannins concentration. The comparison of regression lines showed significant differences (P < 0.05) between extract and its polyphenolic fraction in both assays, indicating that extract was more effective in DPPH radical scavenging than its fraction at tannin concentrations below the crossing point of both lines, while that fraction was more effective than extract inhibiting the superoxide anions generation. Conclusions: R. mangle aqueous extract showed a potent antioxidant activity, achieved by the scavenging ability observed against DPPH radicals and superoxide anions. Regarding its polyphenolic composition, the antioxidant effects observed in this study are due, most probably, to the presence of polyphenolic compounds. PMID:21589751

  12. Anti-inflammatory, gastroprotective, free-radical-scavenging, and antimicrobial activities of hawthorn berries ethanol extract.

    PubMed

    Tadić, Vanja M; Dobrić, Silva; Marković, Goran M; Dordević, Sofija M; Arsić, Ivana A; Menković, Nebojsa R; Stević, Tanja

    2008-09-10

    Hawthorn [Crataegus monogyna Jacq. and Crataegus oxyacantha L.; sin. Crataegus laevigata (Poiret) DC., Rosaceae] leaves, flowers, and berries are used in traditional medicine in the treatment of chronic heart failure, high blood pressure, arrhythmia, and various digestive ailments, as well as geriatric and antiarteriosclerosis remedies. According to European Pharmacopoeia 6.0, hawthorn berries consist of the dried false fruits of these two species or their mixture. The present study was carried out to test free-radical-scavenging, anti-inflammatory, gastroprotective, and antimicrobial activities of hawthorn berries ethanol extract. Phenolic compounds represented 3.54%, expressed as gallic acid equivalents. Determination of total flavonoid aglycones content yielded 0.18%. The percentage of hyperoside, as the main flavonol component, was 0.14%. With respect to procyanidins content, the obtained value was 0.44%. DPPH radical-scavenging capacity of the extract was concentration-dependent, with EC50 value of 52.04 microg/mL (calculation based on the total phenolic compounds content in the extract). Oral administration of investigated extract caused dose-dependent anti-inflammatory effect in a model of carrageenan-induced rat paw edema. The obtained anti-inflammatory effect was 20.8, 23.0, and 36.3% for the extract doses of 50, 100, and 200 mg/kg, respectively. In comparison to indomethacin, given in a dose producing 50% reduction of rat paw edema, the extract given in the highest tested dose (200 mg/kg) showed 72.4% of its activity. Gastroprotective activity of the extract was investigated using an ethanol-induced acute stress ulcer in rats with ranitidine as a reference drug. Hawthorn extract produced dose-dependent gastroprotective activity (3.8 +/- 2.1, 1.9 +/- 1.7, and 0.7 +/- 0.5 for doses of 50, 100, and 200 mg/kg, respectively), with the efficacy comparable to that of the reference drug. Antimicrobial testing of the extract revealed its moderate bactericidal

  13. Contribution of flavonoids to the overall radical scavenging activity of olive (Olea europaea L.) leaf polar extracts.

    PubMed

    Goulas, Vlassios; Papoti, Vassiliki T; Exarchou, Vassiliki; Tsimidou, Maria Z; Gerothanassis, Ioannis P

    2010-03-24

    The contribution of flavonoids to the overall radical scavenging activity of olive leaf polar extracts, known to be good sources of oleuropein related compounds, was examined. Off line and on line HPLC-DPPH(*) assays were employed, whereas flavonoid content was estimated colorimetrically. Individual flavonoid composition was first assessed by RP-HPLC coupled with diode array and fluorescence detectors and verified by LC-MS detection system. Olive leaf was found a robust source of flavonoids regardless sampling parameters (olive cultivar, leaf age or sampling date). Total flavonoids accounted for the 13-27% of the total radical scavenging activity assessed using the on line protocol. Luteolin 7-O-glucoside was one of the dominant scavengers (8-25%). Taking into consideration frequency of appearance the contribution of luteolin (3-13%) was considered important, too. Our findings support that olive leaf, except for oleuropein and related compounds, is also a stable source of bioactive flavonoids. PMID:20166722

  14. Analgesic and free radical scavenging activities of hydromethanolic extract of Crateva adansonii stem bark

    PubMed Central

    Udeh, Nkeiruka E.; Onoja, Samuel O.

    2015-01-01

    Background: Crateva adansonii is a moderately sized deciduous tree found throughout the tropics especially along the river banks. This study was aimed at the evaluation of the analgesic and antioxidant activities of the methanolic extract of C. adansonii stem-bark. Methods: The analgesic activity of Crateva extract was investigated using both chemical and thermal models of nociception in rodents while the antioxidant activity was evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) photometric model. Results: The extract produced a minute concentration-dependent increase in free radical scavenging activities. The extract (100, 200, and 400 mg/kg) caused a significant (P < 0.05) dose-dependent reduction in the number of writhing in treated rats when compared to the negative control. The extract at 100, 200, 400 mg/kg, and pentazocine (3 mg/kg) increased the pain reaction time in the treated rats by 58.05%, 66.67%, 94.76%, and 79.40%, respectively, when compared to the negative control. Conclusion: The C. adansonii stem bark possesses analgesic activity against peripheral and central mediated pain sensation and also antioxidant properties. This study justifies the ethnomedical use of C. adansonii in pain treatment. PMID:26401412

  15. Free Radical Scavenging and Cellular Antioxidant Properties of Astaxanthin.

    PubMed

    Dose, Janina; Matsugo, Seiichi; Yokokawa, Haruka; Koshida, Yutaro; Okazaki, Shigetoshi; Seidel, Ulrike; Eggersdorfer, Manfred; Rimbach, Gerald; Esatbeyoglu, Tuba

    2016-01-01

    Astaxanthin is a coloring agent which is used as a feed additive in aquaculture nutrition. Recently, potential health benefits of astaxanthin have been discussed which may be partly related to its free radical scavenging and antioxidant properties. Our electron spin resonance (ESR) and spin trapping data suggest that synthetic astaxanthin is a potent free radical scavenger in terms of diphenylpicryl-hydrazyl (DPPH) and galvinoxyl free radicals. Furthermore, astaxanthin dose-dependently quenched singlet oxygen as determined by photon counting. In addition to free radical scavenging and singlet oxygen quenching properties, astaxanthin induced the antioxidant enzyme paroxoanase-1, enhanced glutathione concentrations and prevented lipid peroxidation in cultured hepatocytes. Present results suggest that, beyond its coloring properties, synthetic astaxanthin exhibits free radical scavenging, singlet oxygen quenching, and antioxidant activities which could probably positively affect animal and human health. PMID:26784174

  16. Free Radical Scavenging and Cellular Antioxidant Properties of Astaxanthin

    PubMed Central

    Dose, Janina; Matsugo, Seiichi; Yokokawa, Haruka; Koshida, Yutaro; Okazaki, Shigetoshi; Seidel, Ulrike; Eggersdorfer, Manfred; Rimbach, Gerald; Esatbeyoglu, Tuba

    2016-01-01

    Astaxanthin is a coloring agent which is used as a feed additive in aquaculture nutrition. Recently, potential health benefits of astaxanthin have been discussed which may be partly related to its free radical scavenging and antioxidant properties. Our electron spin resonance (ESR) and spin trapping data suggest that synthetic astaxanthin is a potent free radical scavenger in terms of diphenylpicryl-hydrazyl (DPPH) and galvinoxyl free radicals. Furthermore, astaxanthin dose-dependently quenched singlet oxygen as determined by photon counting. In addition to free radical scavenging and singlet oxygen quenching properties, astaxanthin induced the antioxidant enzyme paroxoanase-1, enhanced glutathione concentrations and prevented lipid peroxidation in cultured hepatocytes. Present results suggest that, beyond its coloring properties, synthetic astaxanthin exhibits free radical scavenging, singlet oxygen quenching, and antioxidant activities which could probably positively affect animal and human health. PMID:26784174

  17. Antioxidant effects of the sarsaparilla via scavenging of reactive oxygen species and induction of antioxidant enzymes in human dermal fibroblasts.

    PubMed

    Park, Gunhyuk; Kim, Tae-mi; Kim, Jeong Hee; Oh, Myung Sook

    2014-07-01

    Ultraviolet (UV) radiation from sunlight causes distinct changes in collagenous skin tissues as a result of the breakdown of collagen, a major component of the extracellular matrix. UV irradiation downregulates reactive oxygen species (ROS)-elimination pathways, thereby promoting the production of ROS, which are implicated in skin aging. Smilax glabra Roxb (sarsaparilla) has been used in folk medicine because of its many effects. However, no study on the protective effects of sarsaparilla root (SR) on human dermal fibroblasts has been reported previously. Here, we investigated the protective effect of SR against oxidative stress in dermal fibroblasts. SR significantly inhibited oxidative damage and skin-aging factor via mitogen-activated protein kinase signaling pathways. Also, SR decreased Ca(2+) and ROS, mitochondrial membrane potential, dysfunction, and increased glutathione, NAD(P)H dehydrogenase and heme oxygenase-1. These results demonstrate that SR can protect dermal fibroblasts against UVB-induced skin aging via antioxidant effects. PMID:25022355

  18. In Vitro Antimicrobial Bioassays, DPPH Radical Scavenging Activity, and FTIR Spectroscopy Analysis of Heliotropium bacciferum.

    PubMed

    Ahmad, Sohail; AbdEl-Salam, Naser M; Ullah, Riaz

    2016-01-01

    The present study deals with the antimicrobial, antioxidant, and functional group analysis of Heliotropium bacciferum extracts. Disc diffusion susceptibility method was followed for antimicrobial assessment. Noteworthy antimicrobial activities were recorded by various plant extracts against antibiotic resistant microorganisms. Plant flower extracts antioxidant activity was investigated against 2, 2-diphenyl-1-picryl hydrazyl radical by ultraviolet spectrophotometer (517 nm). Plant extracts displayed noteworthy radical scavenging activities at all concentrations (25-225 μg/mL). Notable activities were recorded by crude, chloroform and ethyl acetate extracts up to 88.27% at 225 μg/mL concentration. Compounds functional groups were examined by Fourier transform infrared spectroscopic studies. Alkanes, alkenes, alkyl halides, amines, carboxylic acids, amides, esters, alcohols, phenols, nitrocompounds, and aromatic compounds were identified by FTIR analysis. Thin layer chromatography bioautography was carried out for all plant extracts. Different bands were separated by various solvent systems. The results of the current study justify the use of Heliotropium bacciferum in traditional remedial herbal medicines. PMID:27597961

  19. Formulation of microspheres containing Crataegus monogyna Jacq. extract with free radical scavenging activity.

    PubMed

    Lucconi, Giulia; Chlapanidas, Theodora; Martino, Emanuela; Gaggeri, Raffaella; Perteghella, Sara; Rossi, Daniela; Faragò, Silvio; Vigo, Daniele; Faustini, Massimo; Collina, Simona; Torre, Maria Luisa

    2014-02-01

    Extracts of Crataegus monogyna Jacq. (hawthorn) show an interesting free radical scavenging (FRS) effect, related to their flavonoids content. Unfortunately, their oral administration is affected by their low bioavailability. The aim of this work is to obtain a multiparticulate drug delivery system for hawthorn extracts for oral administration. The extracts from flowering tops (FL) or fruits (FR) of hawthorn were obtained with maceration, using ethanol as an extraction solvent, and their antioxidant activity was evaluated. FL extract showed the highest FRS activity (EC50 3.72 ± 1.21 µg/ml), so it was selected to prepare microparticulate systems by a spray-drying technique, which were characterized by granulometric analysis, scanning electron microscopy-energy dispersive X-ray spectroscopy, confocal fluorescence microscopy and hyperoside content. Antioxidant activity was evaluated before and after gastrointestinal transit in vitro simulation. Results indicate that the microparticulate systems maintained the antioxidant activity of hawthorn also after gastrointestinal transit in vitro simulation, exhibiting properties suitable for oral administration. PMID:23301945

  20. In Vitro Antimicrobial Bioassays, DPPH Radical Scavenging Activity, and FTIR Spectroscopy Analysis of Heliotropium bacciferum

    PubMed Central

    2016-01-01

    The present study deals with the antimicrobial, antioxidant, and functional group analysis of Heliotropium bacciferum extracts. Disc diffusion susceptibility method was followed for antimicrobial assessment. Noteworthy antimicrobial activities were recorded by various plant extracts against antibiotic resistant microorganisms. Plant flower extracts antioxidant activity was investigated against 2, 2-diphenyl-1-picryl hydrazyl radical by ultraviolet spectrophotometer (517 nm). Plant extracts displayed noteworthy radical scavenging activities at all concentrations (25–225 μg/mL). Notable activities were recorded by crude, chloroform and ethyl acetate extracts up to 88.27% at 225 μg/mL concentration. Compounds functional groups were examined by Fourier transform infrared spectroscopic studies. Alkanes, alkenes, alkyl halides, amines, carboxylic acids, amides, esters, alcohols, phenols, nitrocompounds, and aromatic compounds were identified by FTIR analysis. Thin layer chromatography bioautography was carried out for all plant extracts. Different bands were separated by various solvent systems. The results of the current study justify the use of Heliotropium bacciferum in traditional remedial herbal medicines. PMID:27597961

  1. Scavenging iron: a novel mechanism of plant immunity activation by microbial siderophores.

    PubMed

    Aznar, Aude; Chen, Nicolas W G; Rigault, Martine; Riache, Nassima; Joseph, Delphine; Desmaële, Didier; Mouille, Grégory; Boutet, Stéphanie; Soubigou-Taconnat, Ludivine; Renou, Jean-Pierre; Thomine, Sébastien; Expert, Dominique; Dellagi, Alia

    2014-04-01

    Siderophores are specific ferric iron chelators synthesized by virtually all microorganisms in response to iron deficiency. We have previously shown that they promote infection by the phytopathogenic enterobacteria Dickeya dadantii and Erwinia amylovora. Siderophores also have the ability to activate plant immunity. We have used complete Arabidopsis transcriptome microarrays to investigate the global transcriptional modifications in roots and leaves of Arabidopsis (Arabidopsis thaliana) plants after leaf treatment with the siderophore deferrioxamine (DFO). Physiological relevance of these transcriptional modifications was validated experimentally. Immunity and heavy-metal homeostasis were the major processes affected by DFO. These two physiological responses could be activated by a synthetic iron chelator ethylenediamine-di(o-hydroxyphenylacetic) acid, indicating that siderophores eliciting activities rely on their strong iron-chelating capacity. DFO was able to protect Arabidopsis against the pathogenic bacterium Pseudomonas syringae pv tomato DC3000. Siderophore treatment caused local modifications of iron distribution in leaf cells visible by ferrocyanide and diaminobenzidine-H₂O₂ staining. Metal quantifications showed that DFO causes a transient iron and zinc uptake at the root level, which is presumably mediated by the metal transporter iron regulated transporter1 (IRT1). Defense gene expression and callose deposition in response to DFO were compromised in an irt1 mutant. Consistently, plant susceptibility to D. dadantii was increased in the irt1 mutant. Our work shows that iron scavenging is a unique mechanism of immunity activation in plants. It highlights the strong relationship between heavy-metal homeostasis and immunity. PMID:24501001

  2. Scavenging Iron: A Novel Mechanism of Plant Immunity Activation by Microbial Siderophores1[C][W

    PubMed Central

    Aznar, Aude; Chen, Nicolas W.G.; Rigault, Martine; Riache, Nassima; Joseph, Delphine; Desmaële, Didier; Mouille, Grégory; Boutet, Stéphanie; Soubigou-Taconnat, Ludivine; Renou, Jean-Pierre; Thomine, Sébastien; Expert, Dominique; Dellagi, Alia

    2014-01-01

    Siderophores are specific ferric iron chelators synthesized by virtually all microorganisms in response to iron deficiency. We have previously shown that they promote infection by the phytopathogenic enterobacteria Dickeya dadantii and Erwinia amylovora. Siderophores also have the ability to activate plant immunity. We have used complete Arabidopsis transcriptome microarrays to investigate the global transcriptional modifications in roots and leaves of Arabidopsis (Arabidopsis thaliana) plants after leaf treatment with the siderophore deferrioxamine (DFO). Physiological relevance of these transcriptional modifications was validated experimentally. Immunity and heavy-metal homeostasis were the major processes affected by DFO. These two physiological responses could be activated by a synthetic iron chelator ethylenediamine-di(o-hydroxyphenylacetic) acid, indicating that siderophores eliciting activities rely on their strong iron-chelating capacity. DFO was able to protect Arabidopsis against the pathogenic bacterium Pseudomonas syringae pv tomato DC3000. Siderophore treatment caused local modifications of iron distribution in leaf cells visible by ferrocyanide and diaminobenzidine-H2O2 staining. Metal quantifications showed that DFO causes a transient iron and zinc uptake at the root level, which is presumably mediated by the metal transporter iron regulated transporter1 (IRT1). Defense gene expression and callose deposition in response to DFO were compromised in an irt1 mutant. Consistently, plant susceptibility to D. dadantii was increased in the irt1 mutant. Our work shows that iron scavenging is a unique mechanism of immunity activation in plants. It highlights the strong relationship between heavy-metal homeostasis and immunity. PMID:24501001

  3. Adaptive Neuro-Fuzzy Inference System Applied QSAR with Quantum Chemical Descriptors for Predicting Radical Scavenging Activities of Carotenoids.

    PubMed

    Jhin, Changho; Hwang, Keum Taek

    2015-01-01

    One of the physiological characteristics of carotenoids is their radical scavenging activity. In this study, the relationship between radical scavenging activities and quantum chemical descriptors of carotenoids was determined. Adaptive neuro-fuzzy inference system (ANFIS) applied quantitative structure-activity relationship models (QSAR) were also developed for predicting and comparing radical scavenging activities of carotenoids. Semi-empirical PM6 and PM7 quantum chemical calculations were done by MOPAC. Ionisation energies of neutral and monovalent cationic carotenoids and the product of chemical potentials of neutral and monovalent cationic carotenoids were significantly correlated with the radical scavenging activities, and consequently these descriptors were used as independent variables for the QSAR study. The ANFIS applied QSAR models were developed with two triangular-shaped input membership functions made for each of the independent variables and optimised by a backpropagation method. High prediction efficiencies were achieved by the ANFIS applied QSAR. The R-square values of the developed QSAR models with the variables calculated by PM6 and PM7 methods were 0.921 and 0.902, respectively. The results of this study demonstrated reliabilities of the selected quantum chemical descriptors and the significance of QSAR models. PMID:26474167

  4. Adaptive Neuro-Fuzzy Inference System Applied QSAR with Quantum Chemical Descriptors for Predicting Radical Scavenging Activities of Carotenoids

    PubMed Central

    Jhin, Changho; Hwang, Keum Taek

    2015-01-01

    One of the physiological characteristics of carotenoids is their radical scavenging activity. In this study, the relationship between radical scavenging activities and quantum chemical descriptors of carotenoids was determined. Adaptive neuro-fuzzy inference system (ANFIS) applied quantitative structure-activity relationship models (QSAR) were also developed for predicting and comparing radical scavenging activities of carotenoids. Semi-empirical PM6 and PM7 quantum chemical calculations were done by MOPAC. Ionisation energies of neutral and monovalent cationic carotenoids and the product of chemical potentials of neutral and monovalent cationic carotenoids were significantly correlated with the radical scavenging activities, and consequently these descriptors were used as independent variables for the QSAR study. The ANFIS applied QSAR models were developed with two triangular-shaped input membership functions made for each of the independent variables and optimised by a backpropagation method. High prediction efficiencies were achieved by the ANFIS applied QSAR. The R-square values of the developed QSAR models with the variables calculated by PM6 and PM7 methods were 0.921 and 0.902, respectively. The results of this study demonstrated reliabilities of the selected quantum chemical descriptors and the significance of QSAR models. PMID:26474167

  5. Radical Scavenging Activities of Tannin Extracted from Amaranth (Amaranthus caudatus L.).

    PubMed

    Jo, Hyeon-Ju; Chung, Kang-Hyun; Yoon, Jin A; Lee, Kwon-Jai; Song, Byeong Chun; An, Jeung Hee

    2015-06-01

    This study investigates the bioactivity of tannin from amaranth (Amaranthus caudatus L.) extracts. The antioxidant activities of the extracts from amaranth leaves, flowers, and seeds were evaluated. Tannin from leaves of amaranth has been evaluated for superoxide scavenging activity by using DPPH and ABTS(+) analysis, reducing power, protective effect against H2O2-induced oxidative damage in L-132 and BNL-CL2 cells, and inhibition of superoxide radical effects on HL-60 cells. At a concentration of 100 μg/ml, tannin showed protective effects and restored cell survival to 69.2% and 41.8% for L-132 and BNL-CL2 cells, respectively. Furthermore, at the same concentration, tannin inhibited 41% of the activity of the superoxide radical on HL-60 cells and 43.4% of the increase in nitric oxide levels in RAW 264.7 cells. The expression levels of the antioxidant-associated protein SOD-1 were significantly increased in a concentration-dependent manner in RAW 264.7 cells treated with tannin from amaranth leaves. These results suggest that tannin from the leaves of Amaranthus caudatus L. is a promising source of antioxidant component that can be used as a food preservative or nutraceutical. PMID:25639718

  6. Structural characterization, α-glucosidase inhibitory and DPPH scavenging activities of polysaccharides from guava.

    PubMed

    Zhang, Ziling; Kong, Fansheng; Ni, Hui; Mo, Zhixian; Wan, Jian-Bo; Hua, Dehong; Yan, Chunyan

    2016-06-25

    To explore the chemicals responsible for the health benefits of guava, water-soluble polysaccharides were extracted including GP90 and P90. They exhibited excellent α-glucosidase inhibition activity with an EC50 of 2.27μg/mL and 0.18mg/mL. This suggests that their activities were 1379- and 17-fold higher than the positive control. The DPPH scavenging activities of GP90 was even higher than Vc at some concentrations. Upon further isolation, a novel polysaccharide termed GB90-1B was obtained. Monosaccharide analysis, methylation analysis, and NMR were used to analyze the structural characterization of GB90-1B. Structural analysis revealed that its backbone consisted of (1→5)-linked-α-l-arabinose, (1→2,3,5)-linked-α-l-arabinose and (1→3)-linked-α-l-arabinose. Branch linkages included (1→6)-linked-α-d-glucose, (1→)-linked-α-d-glucose and (1→)-linked-α-l-arabinose. The structure of the repeating unit of GP90-1B was predicted. PMID:27083799

  7. An exploratory study on the peroxyl-radical-scavenging activity of 2,6-dimethyl-5-hepten-2-ol and its heterocyclic analogues

    NASA Astrophysics Data System (ADS)

    Stobiecka, Agnieszka; Sikora, Magdalena; Bonikowski, Radosław; Kula, Józef

    2016-03-01

    The structural properties and radical scavenging activity of 2,6-dimethyl-5-hepten-2-ol (1) and its new heterocyclic analogues, i.e. 2-methyl-4-(5-methylfuran-2-yl)-butan-2-ol (2) and 2-methyl-4-(5-methylthiophen-2-yl)-butan-2-ol (3) and have been studied by using the experimental and theoretical methods for the first time. Activity of title compounds against the peroxyl radical was determined by using standard fluorimetric test, i.e. the Oxygen Radical Absorbance Capacity assay (ORACFL). Furthermore, the electron-donating ability of odorants has been evaluated by using colorimetric ABTS assay. According to the experimental results obtained from the ORACFL test 2,6-dimethyl-5-hepten-2-ol was characterized by the highest activity in comparison with the novel counterparts. Nevertheless, all investigated compounds exhibited pronounced anti-peroxyl radical activity comparable to that exerted by the one of the most prominent antioxidant among the monoterpene alcohols, i.e. by linalool. On the other hand, the title compounds exerted relatively low capacity to quench the radical cation of ABTS. Theoretical calculations based on the Density Functional Theory (DFT) method with the hybrid functional B3LYP were carried out in order to investigate selected structural and electronic properties including the geometrical parameters as well as the energy of frontier molecular orbitals of parent molecules and the resulting radicals. Furthermore, the possible mechanism of peroxyl-radical-scavenging has been determined by using the thermodynamic descriptors such as the bond dissociation enthalpies (BDEs) and ionization potentials (IPs). These theoretical data pointed out the relevance of HAT mechanism in the peroxyl-radical-scavenging exhibited by 2,6-dimethyl-5-hepten-2-ol and its new heterocyclic analogues in polar and non-polar medium.

  8. Synthesis, crystal structure, ABTS radical-scavenging activity, antimicrobial and docking studies of some novel quinoline derivatives

    NASA Astrophysics Data System (ADS)

    Tabassum, Sumaiya; Suresha Kumara, T. H.; Jasinski, Jerry P.; Millikan, Sean P.; Yathirajan, H. S.; Sujan Ganapathy, P. S.; Sowmya, H. B. V.; More, Sunil S.; Nagendrappa, Gopalpur; Kaur, Manpreet; Jose, Gilish

    2014-07-01

    In this study, a series of nine novel 2-chloroquinolin-3-yl ester derivatives have been synthesized via a two-step protocol from 2-chloroquinoline-3-carbaldehyde. The structures of all these compounds were confirmed by spectral data. The single crystal X-ray structure of two derivatives, (2-chloroquinolin-3-yl)methyl acetate [6a] and (2-chloro-6-methylquinolin-3-yl)methyl acetate [6e] have also been determined. The synthesized compounds were further evaluated for their ABTS radical-scavenging activity and antimicrobial activities. Amongst all the tested compounds, 6a exhibited maximum scavenging activity with ABTS. Concerning antibacterial and antifungal activities, compound (2-chloro-6-methoxyquinolin-3-yl)methyl 2,4-dichlorobenzoate [6i] was found to be the most active in the series against B. subtilis, S. aureus, E. coli, K. pneumonia, C. albicans and A. niger species. The structure-antimicrobial activity relationship of these derivatives were studied using Autodock.

  9. Screening of radical scavenging activity and polyphenol content of Bulgarian plant species

    PubMed Central

    Nikolova, Milena

    2011-01-01

    Background: Discovery of new plant species with antioxidant properties is a priority of many research teams. Most of the species included in this study are unstudied for antioxidant properties, but they are taxonomically related to reference plants with well-documented antioxidant activity. Materials and Methods: Free radical scavenging activity of plant extracts was evaluated using a 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. An aluminum chloride colorimetric method was used for flavonoid determination. The amount of phenolic compounds in the extracts was estimated by using the Folin–Ciocalteu reagent. Results: As a result of screening, it was found that the significant antioxidant properties possess several unstudied until now plant species (Veronica bellidioides L., V. kellereri Deg. et Urm, V. vindobonensis (M. Fisher) M. Fisher, V. beccabunga L., V. rhodopaea L., V. austriaca (Velen.) Degen., Clinopodium vulgare L., Stachysrecta L., Clematis vitalba L., and Xeranthemum annum L.). The antioxidant potential of the new species is comparable to that of reference medicinal plants. Conclusions: The existing data presented here provide new information for antioxidant potential of plant species that have not been traditionally used as medicinal plants. PMID:22224049

  10. Anti-genotoxic and free-radical scavenging activities of extracts from (Tunisian) Myrtus communis.

    PubMed

    Hayder, N; Abdelwahed, A; Kilani, S; Ammar, R Ben; Mahmoud, A; Ghedira, K; Chekir-Ghedira, L

    2004-11-14

    The effect of extracts from leaves of Myrtus communis on the SOS reponse induced by Aflatoxin B1 (AFB1) and Nifuroxazide was investigated in a bacterial assay system, i.e. the SOS chromotest with Escherichia coli PQ37. Aqueous extract, the total flavonoids oligomer fraction (TOF), hexane, chloroform, ethyl acetate and methanol extracts and essential oil obtained from M. communis significantly decreased the SOS response induced by AFB1 (10 microg/assay) and Nifuroxazide (20 microg/assay). Ethyl acetate and methanol extracts showed the strongest inhibition of the induction of the SOS response by the indirectly genotoxic AFB1. The methanol and aqueous extracts exhibited the highest level of protection towards the SOS-induced response by the directly genotoxic Nifuroxazide. In addition to anti-genotoxic activity, the aqueous extract, the TOF, and the ethyl acetate and methanol extracts showed an important free-radical scavenging activity towards the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical. These results suggest the future utilization of these extracts as additives in chemoprevention studies. PMID:15474415

  11. Physicochemical characterisation and radical-scavenging activity of Cucurbitaceae seed oils.

    PubMed

    Jorge, Neuza; da Silva, Ana Carolina; Malacrida, Cassia Roberta

    2015-01-01

    Oils extracted from Cucurbitaceae seeds were characterised for their fatty acid and tocopherol compositions. In addition, some physicochemical characteristics, total phenolic contents and the radical-scavenging activities were determined. Oil content amounted to 23.9% and 27.1% in melon and watermelon seeds, respectively. Physicochemical characteristics were similar to those of other edible oils and the oils showed significant antioxidant activities. Fatty acid composition showed total unsaturated fatty acid content of 85.2-83.5%, with linoleic acid being the dominant fatty acid (62.4-72.5%), followed by oleic acid (10.8-22.7%) and palmitic acid (9.2-9.8%). The oils, especially watermelon seed oil, showed high total tocopherol and phenolic contents. The γ-tocopherol was the predominant tocopherol in both oils representing 90.9 and 95.6% of the total tocopherols in melon and watermelon seed oils, respectively. The potential utilisation of melon and watermelon seed oils as a raw material for food, chemical and pharmaceutical industries appears to be favourable. PMID:25697079

  12. Synthesis, crystal structure, superoxide scavenging activity, anticancer and docking studies of novel adamantyl nitroxide derivatives

    NASA Astrophysics Data System (ADS)

    Zhu, Xiao-he; Sun, Jin; Wang, Shan; Bu, Wei; Yao, Min-na; Gao, Kai; Song, Ying; Zhao, Jin-yi; Lu, Cheng-tao; Zhang, En-hu; Yang, Zhi-fu; Wen, Ai-dong

    2016-03-01

    A novel adamantyl nitroxide derivatives has been synthesized and characterized by IR, ESI-MS and elemental analysis. Quantum chemical calculations have also been performed to calculate the molecular geometry using density functional theory (B3LYP) with the 6-31G (d,p) basis set. The calculated results showed that the optimized geometry can well reproduce the crystal structure. The antioxidant and antiproliferative activity were evaluated by superoxide (NBT) and MTT assay. The adamantyl nitroxide derivatives exhibited stronger scavenging ability towards O2· - radicals when compared to Vitamin C, and demonstrated a remarked anticancer activity against all the tested cell lines, especially Bel-7404 cells with IC50 of 43.3 μM, compared to the positive control Sorafenib (IC50 = 92.0 μM). The results of molecular docking within EGFR using AutoDock confirmed that the titled compound favorably fitted into the ATP binding site of EGFR and would be a potential anticancer agent.

  13. Nutrient scavenging activity and antagonistic factors of non-photobiont lichen-associated bacteria: a review.

    PubMed

    Sigurbjörnsdóttir, M Auður; Andrésson, Ólafur S; Vilhelmsson, Oddur

    2016-04-01

    Lichens are defined as the specific symbiotic structure comprising a fungus and a green alga and/or cyanobacterium. Up until recently, non-photobiont endothallic bacteria, while known to be present in large numbers, have generally been dismissed as functionally irrelevant cohabitants of the lichen thallus, or even environmental contaminants. Recent analyses of lichen metagenomes and innovative co-culture experiments have uncovered a functionally complex community that appears to contribute to a healthy lichen thallus in several ways. Lichen-associated bacteriomes are typically dominated by several lineages of Proteobacteria, some of which may be specific for lichen species. Recent work has implicated members of these lineages in several important ecophysiological roles. These include nutrient scavenging, including mobilization of iron and phosphate, nitrogen fixation, cellulase, xylanase and amylase activities, and oxidation of recalcitrant compounds, e.g. aromatics and aliphatics. Production of volatile organic compounds, conferring antibacterial and antifungal activity, has also been demonstrated for several lichen-associated isolates. In the present paper we review the nature of non-phototrophic endolichenic bacteria associated with lichens, and give insight into the current state of knowledge on their importance the lichen symbiotic association. PMID:26931608

  14. Development of active polyvinyl alcohol/β-cyclodextrin composites to scavenge undesirable food components.

    PubMed

    López-de-Dicastillo, Carol; Jordá, María; Catalá, Ramón; Gavara, Rafael; Hernández-Muñoz, Pilar

    2011-10-26

    Active food packaging systems based on the incorporation of agents into polymeric package walls are being designed to purposely release or retain compounds to maintain or even increase food quality. The objective of this work was to develop polyvinyl alcohol (PVOH)/β-cyclodextrin (βCD) composite films that can be applied to reduce undesirable component content such as cholesterol in foods through active retention of the compounds in the package walls during storage. Cyclodextrins were added to PVOH in a proportion of 1:1 and cross-linked with glyoxal under acidic media to reduce its water-soluble character. Three different cross-linking procedures were used: cross-linking of the polymer/polysaccharide mixture in solution and film casting, PVOH. βCD*; cross-linking of the polymer, addition of βCD, and casting of the mixture, PVOH*.CD; and casting of a PVOH film, addition of a βCD/glyoxal solution onto the film, and cross-linking during drying, PVOH.CD*. Characterization studies showed that the PVOH*.CD and PVOH.CD* films provided the best physical characteristics with the lowest release values and the highest barrier properties. As a potential application, materials were tested as potential cholesterol-scavenging films. There was a significant reduction in the cholesterol concentration in milk samples when they were exposed to the materials developed. PMID:21905652

  15. Flavour characterisation and free radical scavenging activity of coriander (Coriandrum sativum L.) foliage.

    PubMed

    Priyadarshi, Siddharth; Khanum, Hafeeza; Ravi, Ramasamy; Borse, Babasaheb Baskarrao; Naidu, Madeneni Madhava

    2016-03-01

    The primary objective was to characterize Indian Coriandrum sativum L. foliage (Vulgare alef and Microcarpum DC varieties) and its radical scavenging activity. Foliage of Vulgare alef and Microcarpum DC contained ascorbic acid (1.16 ± 0.35 and 1.22 ± 0.54 mg/g), total carotenoids (1.49 ± 0.38 and 3.08 ± 1.2 mg/g), chlorophyll 'a' (8.23 ± 2.4 and 12.18 ± 2.9 mg/g), chlorophyll 'b' (2.74 ± 0.8 and 4.39 ± 1.3 mg/g) and total chlorophyll (10.97 ± 2.6 and 16.57 ± 3.2 mg/g). The polyphenol content was 26.75 ± 1.85 and 30.00 ± 2.64 mg/g in Vulgare alef and Microcarpum DC, respectively. Ethanol extracts (200 ppm) of alef and Microcarpum DC showed higher radical scavenging activity of 42.05 ± 2.42 % and 62.79 ± 1.36 % when compared with 95 % butylated hydroxyanisole. The principal component analysis results indicated that e-nose can distinguish the volatiles effectively. Quantitative descriptive sensory analysis showed that Microcarpum DC variety is superior to Vulgare alef variety. Nearly 90 % of the flavour compounds present were identified by GC-MS in both varieties. The principal component identified in both the varieties were decanal (7.645 and 7.74 %), decanol < n- > (25.12 and 39.35 %), undecanal (1.20 and 1.75 %), dodecanal (7.07 and 2.61 %), tridecen-1-al < 2E > (6.67 and 1.21 %), dodecen-1-ol < 2E- > (16.68 and 8.05 %), 13-tetradecenal (9.53 and 8.60 %), tetradecanal (5.61 and 4.35 %) and 1-octadecanol (1.25 and 3.67 %). PMID:27570292

  16. Age-dependent basal level and induction capacity of copper-zinc and manganese superoxide dismutase and other scavenging enzyme activities in leukocytes from young and elderly adults.

    PubMed Central

    Niwa, Y.; Iizawa, O.; Ishimoto, K.; Akamatsu, H.; Kanoh, T.

    1993-01-01

    Several enzymes, including superoxide dismutase (SOD), catalase, glutathione peroxidase, and D-glucose-6-phosphate dehydrogenase are capable of scavenging reactive oxygen species in in vivo. We assessed both basal levels and the capacity of these enzyme activities to be induced in human leukocytes in response to a variety of agents. Basal activity of copper-zinc SOD, and manganese SOD showed little variation with age. In contrast, the basal activity of the three H2O2 scavenging enzymes, catalase, glutathione peroxidase, and D-glucose-6-phosphate dehydrogenase, was significantly higher in younger adults than in elderly individuals. Both manganese SOD and copper, zinc SOD activities were significantly induced by paraquat, interleukin-1, tumor necrosis factor, adriamycin, and bleomycin in lymphocytes and neutrophils from asymptomatic non-aged adults, whereas neither activity was induced in aged individuals. In contrast, glutathione peroxidase activity was significantly induced in both groups of subjects, whereas catalase and D-glucose-6-phosphate dehydrogenase were only slightly induced in either. Enzyme induction with paraquat, adriamycin, or bleomycin was inhibitable by neutralizing antibody to interleukin-1 and tumor necrosis factor, suggesting that the inductions observed with these three drugs are due to the distal mediators, interleukin-1 or tumor necrosis factor released from the cells. Finally, as observed in the regulation of genes in eukaryotes (Storz et al: Bacterial defenses against oxidative stress. Trends Genetics 1990, 6:363-368, ref. 1) O2- and H2O2 seem to differ in the rate of change with age in both basal levels and inducibility under oxygen stress. PMID:8317554

  17. Radical Scavenging Activity of the Essential Oil of Silver Fir (Abies alba)

    PubMed Central

    Yang, Seun-Ah; Jeon, Sang-Kyung; Lee, Eun-Jung; Im, Nam-Kyung; Jhee, Kwang-Hwan; Lee, Sam-Pin; Lee, In-Seon

    2009-01-01

    The essential oil of silver fir (Abies alba) is known to help respiratory system and have easing and soothing effect for muscle. In the present study, we investigated the chemical composition, cytotoxicity and its biological activities of silver fir (Abies alba) essential oil. The composition of the oil was analyzed by GC-MS and bornyl acetate (30.31%), camphene (19.81%), 3-carene (13.85%), tricyclene (12.90%), dl-limonene (7.50%), α-pinene (2.87%), caryophyllene (2.18%), β-phellandrene (2.13%), borneol (1.74%), bicyclo[2.2.1]hept-2-ene,2,3-dimethyl (1.64%) and α-terpinene (1.24%) were the major components in the oil. The results tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay indicated that the oil showed no cytotoxic effect, at concentrations of 1 and 5%, for as long as 24 and 3 h, respectively. The antiradical capacity was evaluated by measuring the scavenging activity of the essential oil on the 2,20-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis 3-ethyl benzothiazoline-6-sulfonic acid (ABTS) radicals. The oil was able to reduce the both radicals dose-dependently, and the concentration required for 50% reduction (RC50) against DPPH radicals (2.7 ± 0.63%) was lower than ABTS radicals (8.5 ± 0.27%). The antibacterial activity of the oil was also evaluated using disc diffusion method against Staphylococcus aureus, Streptococcus mutans, Listeria monocytogenes, Acinetobacter baumannii, Escherichia coli, and Vibrio parahaemolyticcus. The oil exhibited no antibacterial activity against all the bacterial strains tested except S. aureus of mild activity. PMID:19430614

  18. Radical Scavenging Activity of the Essential Oil of Silver Fir (Abies alba).

    PubMed

    Yang, Seun-Ah; Jeon, Sang-Kyung; Lee, Eun-Jung; Im, Nam-Kyung; Jhee, Kwang-Hwan; Lee, Sam-Pin; Lee, In-Seon

    2009-05-01

    The essential oil of silver fir (Abies alba) is known to help respiratory system and have easing and soothing effect for muscle. In the present study, we investigated the chemical composition, cytotoxicity and its biological activities of silver fir (Abies alba) essential oil. The composition of the oil was analyzed by GC-MS and bornyl acetate (30.31%), camphene (19.81%), 3-carene (13.85%), tricyclene (12.90%), dl-limonene (7.50%), alpha-pinene (2.87%), caryophyllene (2.18%), beta-phellandrene (2.13%), borneol (1.74%), bicyclo[2.2.1]hept-2-ene,2,3-dimethyl (1.64%) and alpha-terpinene (1.24%) were the major components in the oil. The results tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay indicated that the oil showed no cytotoxic effect, at concentrations of 1 and 5%, for as long as 24 and 3 h, respectively. The antiradical capacity was evaluated by measuring the scavenging activity of the essential oil on the 2,20-diphenylpicrylhydrazyl (DPPH) and 2,2'-azino-bis 3-ethyl benzothiazoline-6-sulfonic acid (ABTS) radicals. The oil was able to reduce the both radicals dose-dependently, and the concentration required for 50% reduction (RC(50)) against DPPH radicals (2.7 +/- 0.63%) was lower than ABTS radicals (8.5 +/- 0.27%). The antibacterial activity of the oil was also evaluated using disc diffusion method against Staphylococcus aureus, Streptococcus mutans, Listeria monocytogenes, Acinetobacter baumannii, Escherichia coli, and Vibrio parahaemolyticcus. The oil exhibited no antibacterial activity against all the bacterial strains tested except S. aureus of mild activity. PMID:19430614

  19. Free radical scavenging activity, total phenolic content, total antioxidant status, and total oxidant status of endemic Thermopsis turcica

    PubMed Central

    Aksoy, Laçine; Kolay, Erdi; Ağılönü, Yasin; Aslan, Zeyneb; Kargıoğlu, Mustafa

    2013-01-01

    Thermopsis turcica, endemic to Turkey, is in danger of extinction. Studies on this species are very few due to the fact that it was only discovered in 1983 and grows in a small circumscribed area in Turkey. In this study, free radical scavenging activity, total phenolic content, total oxidant status (TOS), and total antioxidant status (TAS) of methanol (TTM) and acetone (TTA) extracts of T. turcica were measured spectroscopically. Free radical scavenging activity was determined according to the elimination of DPPH radicals and total phenol content was determined by the Folin–Ciocalteu reaction. Total oxidant status (TOS) and total antioxidant status (TAS) were measured with commercially available kits. Methanol and acetone extracts of T. turcica were found to have a specific radical scavenging effect. This effect was found to be related to the total phenolic content of the extracts. Since the TTA had a higher phenolic content than the methanol extract, it had a stronger radical scavenging effect. In addition, the total antioxidant capacity of the methanol extract was observed to be higher than that of its acetone counterpart. As a result, due to its antioxidative properties, T. turcica is thought to be a natural source of antioxidants. PMID:23961240

  20. Determination of DPPH free radical scavenging activity: application of artificial neural networks.

    PubMed

    Musa, Khalid Hamid; Abdullah, Aminah; Al-Haiqi, Ahmed

    2016-03-01

    A new computational approach for the determination of 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity (DPPH-RSA) in food is reported, based on the concept of machine learning. Trolox standard was mix with DPPH at different concentrations to produce different colors from purple to yellow. Artificial neural network (ANN) was trained on a typical set of images of the DPPH radical reacting with different levels of Trolox. This allowed the neural network to classify future images of any sample into the correct class of RSA level. The ANN was then able to determine the DPPH-RSA of cinnamon, clove, mung bean, red bean, red rice, brown rice, black rice and tea extract and the results were compared with data obtained using a spectrophotometer. The application of ANN correlated well to the spectrophotometric classical procedure and thus do not require the use of spectrophotometer, and it could be used to obtain semi-quantitative results of DPPH-RSA. PMID:26471610

  1. Metabolic Profiles and Free Radical Scavenging Activity of Cordyceps bassiana Fruiting Bodies According to Developmental Stage

    PubMed Central

    Hyun, Sun-Hee; Lee, Seok-Young; Sung, Gi-Ho; Kim, Seong Hwan; Choi, Hyung-Kyoon

    2013-01-01

    The metabolic profiles of Cordyceps bassiana according to fruiting body developmental stage were investigated using gas chromatography-mass spectrometry. We were able to detect 62 metabolites, including 48 metabolites from 70% methanol extracts and 14 metabolites from 100% n-hexane extracts. These metabolites were classified as alcohols, amino acids, organic acids, phosphoric acids, purine nucleosides and bases, sugars, saturated fatty acids, unsaturated fatty acids, or fatty amides. Significant changes in metabolite levels were found according to developmental stage. Relative levels of amino acids, purine nucleosides, and sugars were higher in development stage 3 than in the other stages. Among the amino acids, valine, isoleucine, lysine, histidine, glutamine, and aspartic acid, which are associated with ABC transporters and aminoacyl-tRNA biosynthesis, also showed higher levels in stage 3 samples. The free radical scavenging activities, which were significantly higher in stage 3 than in the other stages, showed a positive correlation with purine nucleoside metabolites such as adenosine, guanosine, and inosine. These results not only show metabolic profiles, but also suggest the metabolic pathways associated with fruiting body development stages in cultivated C. bassiana. PMID:24058459

  2. Micronization of Taxifolin by Supercritical Antisolvent Process and Evaluation of Radical Scavenging Activity

    PubMed Central

    Zu, Shuchong; Yang, Lei; Huang, Jinming; Ma, Chunhui; Wang, Wenjie; Zhao, Chunjian; Zu, Yuangang

    2012-01-01

    The aim of this study was to prepare micronized taxifolin powder using the supercritical antisolvent precipitation process to improve the dissolution rate of taxifolin. Ethanol was used as solvent and carbon dioxide was used as an antisolvent. The effects of process parameters, such as temperature (35–65 °C), pressure (10–25 MPa), solution flow rate (3–6 mL/min) and concentration of the liquid solution (5–20 mg/mL) on the precipitate crystals were investigated. With a lower temperature, a stronger pressure and a lower concentration of the liquid solution, the size of crystals decreased. The precipitation temperature, pressure and concentration of taxifolin solution had a significant effect. However, the solution flow rate had a negligible effect. It was concluded that the physicochemical properties and dissolution rate of crystalline taxifolin could be improved by physical modification such as particle size reduction using the supercritical antisolvent (SAS) process. Further, the SAS process was a powerful methodology for improving the physicochemical properties and radical scavenging activity of taxifolin. PMID:22942740

  3. Class A scavenger receptor activation inhibits endoplasmic reticulum stress-induced autophagy in macrophage.

    PubMed

    Huang, Hanpeng; Li, Xiaoyu; Zhuang, Yan; Li, Nan; Zhu, Xudong; Hu, Jin; Ben, Jingjing; Yang, Qing; Bai, Hui; Chen, Qi

    2014-05-01

    Macrophage death in advanced atherosclerosis promotes plaque necrosis and destabilization. Involvement of autophagy in bulk degradation of cellular components has been recognized recently as an important mechanism for cell survival under endoplasmic reticulum (ER) stress. We previously found that the engagement of class A scavenger receptor (SR-A) triggered JNK-dependent apoptosis in ER-stressed macrophages. However, pro-apoptotic mechanisms mediated by SR-A are not fully understood. Therefore, we sought to see if SR-A mediated apoptosis was associated with autophagy in macrophages. Here, we showed that fucoidan inhibited microtubule-associated protein light chain 3-phospholipid conjugates (LC3-II) formation as well as the number of autophagosomes under ER stress. The inhibition of LC3-II formation was paralleled by the activation of the mTOR pathway, and the inhibition of mTOR allowed LC3-II induction in macrophages treated with thapsigargin plus fucoidan. Furthermore, apoptosis induced by fucoidan was prevented under ER stress by the mTOR inhibitor. We propose that fucoidan, a SR-A agonist, may contribute to macrophage apoptosis during ER stress by inhibiting autophagy. PMID:25013404

  4. A novel method to measure both the reductive and the radical scavenging activity in a linoleic acid model system.

    PubMed

    Lindenmeier, Michael; Burkon, Alexander; Somoza, Veronika

    2007-12-01

    The aim of this study was to develop a combined method for measuring the total antioxidant activity, the reductive and the radical scavenging activity. Linoleic acid was used as the substrate for an iron-initiated lipid peroxidation to measure the total antioxidant activity. In addition, methyl esters of linoleic acid hydroperoxides were used as substrates to measure the reductive antioxidant activity. The radical scavenging antioxidant activity was calculated by subtracting the reductive antioxidative activity from the total antioxidative activity. As representative examples, the antioxidants alpha-tocopherol, ascorbic acid, trans-resveratrol and L-glutathione as well as commonly used food additives such as 2(3)-tert-butyl-4-hydroxyanisole (BHA) and 2,6-bis(1,1-dimethylethyl)-4-methylphenol (BHT) were analyzed. The results for the novel antioxidation test showed that alpha-tocopherol, BHA and BHT are primarily acting as radical scavengers, whereas ascorbic acid and L-glutathione show a strong reductive capacity. As linoleic acid as well as its hydroperoxides both are present in foods and in the organism, the test presented here can be considered representative of radical reactions occurring in food matrixes and in vivo. Further experiments are required to document the comprehensive applicability in foods and in vivo. PMID:17680718

  5. Different Reactive Oxygen Species Scavenging Properties of Flavonoids Determine Their Abilities to Extend the Shelf Life of Tomato1[OPEN

    PubMed Central

    Zhang, Yang; De Stefano, Rosalba; Robine, Marie; Butelli, Eugenio; Bulling, Katharina; Hill, Lionel; Rejzek, Martin; Martin, Cathie; Schoonbeek, Henk-jan

    2015-01-01

    The shelf life of tomato (Solanum lycopersicum) fruit is determined by the processes of overripening and susceptibility to pathogens. Postharvest shelf life is one of the most important traits for commercially grown tomatoes. We compared the shelf life of tomato fruit that accumulate different flavonoids and found that delayed overripening is associated with increased total antioxidant capacity caused by the accumulation of flavonoids in the fruit. However, reduced susceptibility to Botrytis cinerea, a major postharvest fungal pathogen of tomato, is conferred by specific flavonoids only. We demonstrate an association between flavonoid structure, selective scavenging ability for different free radicals, and reduced susceptibility to B. cinerea. Our study provides mechanistic insight into how flavonoids influence the shelf life, information that could be used to improve the shelf life of tomato and, potentially, other soft fruit. PMID:26082399

  6. Ethylene Response Factor TERF1, Regulated by ETHYLENE-INSENSITIVE3-like Factors, Functions in Reactive Oxygen Species (ROS) Scavenging in Tobacco (Nicotiana tabacum L.).

    PubMed

    Zhang, Hongbo; Li, Ang; Zhang, Zhijin; Huang, Zejun; Lu, Pingli; Zhang, Dingyu; Liu, Xinmin; Zhang, Zhong-Feng; Huang, Rongfeng

    2016-01-01

    The phytohormone ethylene plays a crucial role in the production and accumulation of reactive oxygen species (ROS) in plants under stress conditions. Ethylene response factors (ERFs) are important ethylene-signaling regulators functioning in plant defense responses against biotic and abiotic stresses. However, the roles of ERFs during plant adapting to ROS stress have not yet been well documented. Our studies previously reported that a tomato ERF transcription factor TERF1 functions in the regulation of plant ethylene responses and stress tolerance. Here, we report our findings regarding the roles of TERF1 in ROS scavenging. In this study, we revealed that the transcription of TERF1 is regulated by upstream EIN3-like (EIN3, ethylene-insensitive 3) regulators LeEIL3 and LeEIL4 in tomato (Solanum lycopersicum), and is also inducible by exogenous applied ROS-generating reagents. Ectopic expression of TERF1 in tobacco promoted the expression of genes involved in oxidative stress responses, including carbonic anhydrase functioning in hypersensitive defense, catalase and glutathione peroxidase catalyzing oxidative reactions, and GDP-D-mannose pyrophosphorylase functioning in ascorbic acid biosynthesis, reduced the ROS content induced by ethylene treatment, and enhanced stress tolerance of tobacco seedlings to hydrogen peroxide (H2O2). Cumulatively, these findings suggest that TERF1 is an ethylene inducible factor regulating ROS scavenging during stress responses. PMID:27435661

  7. Ethylene Response Factor TERF1, Regulated by ETHYLENE-INSENSITIVE3-like Factors, Functions in Reactive Oxygen Species (ROS) Scavenging in Tobacco (Nicotiana tabacum L.)

    PubMed Central

    Zhang, Hongbo; Li, Ang; Zhang, Zhijin; Huang, Zejun; Lu, Pingli; Zhang, Dingyu; Liu, Xinmin; Zhang, Zhong-Feng; Huang, Rongfeng

    2016-01-01

    The phytohormone ethylene plays a crucial role in the production and accumulation of reactive oxygen species (ROS) in plants under stress conditions. Ethylene response factors (ERFs) are important ethylene-signaling regulators functioning in plant defense responses against biotic and abiotic stresses. However, the roles of ERFs during plant adapting to ROS stress have not yet been well documented. Our studies previously reported that a tomato ERF transcription factor TERF1 functions in the regulation of plant ethylene responses and stress tolerance. Here, we report our findings regarding the roles of TERF1 in ROS scavenging. In this study, we revealed that the transcription of TERF1 is regulated by upstream EIN3-like (EIN3, ethylene-insensitive 3) regulators LeEIL3 and LeEIL4 in tomato (Solanum lycopersicum), and is also inducible by exogenous applied ROS-generating reagents. Ectopic expression of TERF1 in tobacco promoted the expression of genes involved in oxidative stress responses, including carbonic anhydrase functioning in hypersensitive defense, catalase and glutathione peroxidase catalyzing oxidative reactions, and GDP-D-mannose pyrophosphorylase functioning in ascorbic acid biosynthesis, reduced the ROS content induced by ethylene treatment, and enhanced stress tolerance of tobacco seedlings to hydrogen peroxide (H2O2). Cumulatively, these findings suggest that TERF1 is an ethylene inducible factor regulating ROS scavenging during stress responses. PMID:27435661

  8. Increased tolerance to salt stress in OPDA-deficient rice ALLENE OXIDE CYCLASE mutants is linked to an increased ROS-scavenging activity

    PubMed Central

    Hazman, Mohamed; Hause, Bettina; Eiche, Elisabeth; Nick, Peter; Riemann, Michael

    2015-01-01

    Salinity stress represents a global constraint for rice, the most important staple food worldwide. Therefore the role of the central stress signal jasmonate for the salt response was analysed in rice comparing the responses to salt stress for two jasmonic acid (JA) biosynthesis rice mutants (cpm2 and hebiba) impaired in the function of ALLENE OXIDE CYCLASE (AOC) and their wild type. The aoc mutants were less sensitive to salt stress. Interestingly, both mutants accumulated smaller amounts of Na+ ions in their leaves, and showed better scavenging of reactive oxygen species (ROS) under salt stress. Leaves of the wild type and JA mutants accumulated similar levels of abscisic acid (ABA) under stress conditions, and the levels of JA and its amino acid conjugate, JA–isoleucine (JA-Ile), showed only subtle alterations in the wild type. In contrast, the wild type responded to salt stress by strong induction of the JA precursor 12-oxophytodienoic acid (OPDA), which was not observed in the mutants. Transcript levels of representative salinity-induced genes were induced less in the JA mutants. The absence of 12-OPDA in the mutants correlated not only with a generally increased ROS-scavenging activity, but also with the higher activity of specific enzymes in the antioxidative pathway, such as glutathione S-transferase, and fewer symptoms of damage as, for example, indicated by lower levels of malondialdehyde. The data are interpreted in a model where the absence of OPDA enhanced the antioxidative power in mutant leaves. PMID:25873666

  9. Radical scavenging activities of Rio Red grapefruits and Sour orange fruit extracts in different in vitro model systems.

    PubMed

    Jayaprakasha, G K; Girennavar, Basavaraj; Patil, Bhimanagouda S

    2008-07-01

    Antioxidant fractions from two different citrus species such as Rio Red (Citrus paradise Macf.) and Sour orange (Citrus aurantium L.) were extracted with five different polar solvents using Soxhlet type extractor. The total phenolic content of the extracts was determined by Folin-Ciocalteu method. Ethyl acetate extract of Rio Red and Sour orange was found to contain maximum phenolics. The dried fractions were screened for their antioxidant activity potential using in vitro model systems such as 1,1-diphenyl-2-picryl hydrazyl (DPPH), phosphomolybdenum method and nitroblue tetrazolium (NBT) reduction at different concentrations. The methanol:water (80:20) fraction of Rio Red showed the highest radical scavenging activity 42.5%, 77.8% and 92.1% at 250, 500 and 1000 ppm, respectively, while methanol:water (80:20) fraction of Sour orange showed the lowest radical scavenging activity at all the tested concentrations. All citrus fractions showed good antioxidant capacity by the formation of phosphomolybdenum complex at 200 ppm. In addition, superoxide radical scavenging activity was assayed using non-enzymatic (NADH/phenaxine methosulfate) superoxide generating system. All the extracts showed variable superoxide radical scavenging activity. Moreover, methanol:water (80:20) extract of Rio Red and methanol extract of Sour orange exhibited marked reducing power in potassium ferricyanide reduction method. The data obtained using above in vitro models clearly establish the antioxidant potential of citrus fruit extracts. However, comprehensive studies need to be conducted to ascertain the in vivo bioavailability, safety and efficacy of such extracts in experimental animals. To the best of our knowledge, this is the first report on antioxidant activity of different polar extracts from Rio Red and Sour oranges. PMID:17935981

  10. Assessment of the Polyphenolic Content, Free Radical Scavenging, Anti-inflammatory, and Antimicrobial Activities of Acetone and Aqueous Extracts of Lippia javanica (Burm.F.) Spreng

    PubMed Central

    Asowata-Ayodele, Abiola M.; Otunola, Gloria A.; Afolayan, Anthony J.

    2016-01-01

    polyphenolic content and biological activities of the spice plant, Lippia javanica from South Africa was evaluatedSignificantly high polyphenolic content and free radical scavenging activities were observed for both extractsModerate antimicrobial action, concentration-dependent inhibition of protein denaturation and membrane haemolysis were also observed. Abbreviations used: AA: ascorbic acid, ABTS: 2,2’azino-bis (3-ethylbenthiazoline-6-sulfonic acid), BHT: Butylated hydroxytoluene, DPPH: 1,1-Diphenyl-2-picryl-hydrazyl, NBT: 2,2’-di-pnitrophenyl-5,5’-diphenyl-(3,3’-dimethoxy-4,4’-diphenylene)- ditetrazolium chloride, PMS: Potassium metabisulfite, ROS: Reactive oxygen species, TBA: Thiobarbituric acid, TCA: Trichloroacetic acid. PMID:27563225

  11. Prediction of Radical Scavenging Activities of Anthocyanins Applying Adaptive Neuro-Fuzzy Inference System (ANFIS) with Quantum Chemical Descriptors

    PubMed Central

    Jhin, Changho; Hwang, Keum Taek

    2014-01-01

    Radical scavenging activity of anthocyanins is well known, but only a few studies have been conducted by quantum chemical approach. The adaptive neuro-fuzzy inference system (ANFIS) is an effective technique for solving problems with uncertainty. The purpose of this study was to construct and evaluate quantitative structure-activity relationship (QSAR) models for predicting radical scavenging activities of anthocyanins with good prediction efficiency. ANFIS-applied QSAR models were developed by using quantum chemical descriptors of anthocyanins calculated by semi-empirical PM6 and PM7 methods. Electron affinity (A) and electronegativity (χ) of flavylium cation, and ionization potential (I) of quinoidal base were significantly correlated with radical scavenging activities of anthocyanins. These descriptors were used as independent variables for QSAR models. ANFIS models with two triangular-shaped input fuzzy functions for each independent variable were constructed and optimized by 100 learning epochs. The constructed models using descriptors calculated by both PM6 and PM7 had good prediction efficiency with Q-square of 0.82 and 0.86, respectively. PMID:25153627

  12. Prediction of radical scavenging activities of anthocyanins applying adaptive neuro-fuzzy inference system (ANFIS) with quantum chemical descriptors.

    PubMed

    Jhin, Changho; Hwang, Keum Taek

    2014-01-01

    Radical scavenging activity of anthocyanins is well known, but only a few studies have been conducted by quantum chemical approach. The adaptive neuro-fuzzy inference system (ANFIS) is an effective technique for solving problems with uncertainty. The purpose of this study was to construct and evaluate quantitative structure-activity relationship (QSAR) models for predicting radical scavenging activities of anthocyanins with good prediction efficiency. ANFIS-applied QSAR models were developed by using quantum chemical descriptors of anthocyanins calculated by semi-empirical PM6 and PM7 methods. Electron affinity (A) and electronegativity (χ) of flavylium cation, and ionization potential (I) of quinoidal base were significantly correlated with radical scavenging activities of anthocyanins. These descriptors were used as independent variables for QSAR models. ANFIS models with two triangular-shaped input fuzzy functions for each independent variable were constructed and optimized by 100 learning epochs. The constructed models using descriptors calculated by both PM6 and PM7 had good prediction efficiency with Q-square of 0.82 and 0.86, respectively. PMID:25153627

  13. Effect of gamma irradiation on the microbial load, nutrient composition and free radical scavenging activity of Nelumbo nucifera rhizome

    NASA Astrophysics Data System (ADS)

    Khattak, Khanzadi Fatima; Simpson, Thomas James; Ihasnullah

    2009-03-01

    The assurance of microbial quality is necessary to make plant materials suitable for human consumption and commercialization. The aim of the present study was to evaluate the possibility to apply the gamma radiation treatment on the rhizome samples of Nelumbo nucifera for microbial decontamination. The radiation processing was carried out at dose levels of 1, 2, 4 and 6 kGy. The irradiated and control samples were analyzed for microbial load, organoleptic acceptance, extraction yield, proximate composition, phenolic contents and DPPH scavenging activity. The results indicated that gamma radiation treatment significantly reduced microbial load and increased the storability of the irradiated samples. The treated samples were also acceptable sensorically. The extraction yield and phenolic contents increased with the increase of radiation dose. Gamma radiation also enhanced the DPPH scavenging activity.

  14. Phytochemical screening and free radical scavenging activity of Citrullus colocynthis seeds extracts

    PubMed Central

    Benariba, Nabila; Djaziri, Rabeh; Bellakhdar, Wafaa; Belkacem, Nacera; Kadiata, Marcel; Malaisse, Willy J.; Sener, Abdullah

    2013-01-01

    Objective To study the phytochemical screening of different extracts from Citrullus colocynthis (C. colocynthis ) seeds extracts and to assess their antioxidant activity on the DPPH free radical scavenging. Methods Phytochemical screening, total content of polyphenols and flavonoids of C. colocynthis seeds extracts, including a crude aqueous extract (E1), a defatted aqueous extract (E2), a hydromethanolic extract (HM), an ethyl acetate extract (EA) and a n-butanol extract (n-B) was carried out according to the standard methods and to assess their corresponding effect on the antioxidant activity of this plant. Results None of these extracts contained detectable amount of alkaloid, quinone, antraquinone, or reducing sugar. Catechic tannins and flavonoids were abundant in E1, HM and EA, whilst terpenoids were abundantly present in E1 and n-B but only weekly in HM. Coumarins were found in E2, EA and n-B. Polyphenols, expressed as gallic acid equivalent, amounted, per 100 g plant matter, to 329, 1002 and 150 mg in EA, HM an E1 respectively. Flavonoids, expressed as catechin equivalent, amounted, per 100 g plant matter to 620, 241 and 94 mg in EA, HM and E1 respectively. Comparable values were found in n-B and E1, with lower values in E2. Quercetin, myricetin and gallic acid were found in the EA and HM extracts by thin layer chromatography, The antioxidative effect of these extracts yielded, when tested at a concentration of 2 000 µg/mL in a 1,1-diphenyl-2-picrylhydrazyl assay, a reducing percentage of 88.8% with EA, 74.5% with HM and 66.2% with E1, and corresponding IC50 of 350, 580 and 500 µg/mL as compared to 1.1 µg/mL for ascorbic acid. Conclusions These qualitative and quantitative analytical data document the presence in C. colocynthis extracts of such chemical compounds as flavonoids responsible for the antioxidant activity, as well as other biological activities of this plant. PMID:23570014

  15. Curcumin Blocks Naproxen-Induced Gastric Antral Ulcerations through Inhibition of Lipid Peroxidation and Activation of Enzymatic Scavengers in Rats.

    PubMed

    Kim, Jeong-Hwan; Jin, Soojung; Kwon, Hyun Ju; Kim, Byung Woo

    2016-08-28

    Curcumin is a polyphenol derived from the plant Curcuma longa, which is used for the treatment of diseases associated with oxidative stress and inflammation. The present study was undertaken to determine the protective effect of curcumin against naproxen-induced gastric antral ulcerations in rats. Different doses (10, 50, and 100 mg/kg) of curcumin or vehicle (curcumin, 0 mg/kg) were pretreated for 3 days by oral gavage, and then gastric mucosal lesions were caused by 80 mg/kg naproxen applied for 3 days. Curcumin significantly inhibited the naproxen-induced gastric antral ulcer area and lipid peroxidation in a dose-dependent manner. In addition, curcumin markedly increased activities of radical scavenging enzymes, such as superoxide dismutase (SOD), catalase, and glutathione peroxidase in a dose-dependent manner. Specifically, 100 mg/kg curcumin completely protected the gastric mucosa against the loss in the enzyme, resulting in a drastic increase of activities of radical scavenging enzymes up to more than the level of untreated normal rats. Histological examination obviously showed that curcumin prevents naproxen-induced gastric antral ulceration as a result of direct protection of the gastric mucosa. These results suggest that curcumin blocks naproxen-induced gastric antral ulcerations through prevention of lipid peroxidation and activation of radical scavenging enzymes, and it may offer a potential remedy of gastric antral ulcerations. PMID:27197667

  16. HPLC-Analysis of Polyphenolic Compounds in Gardenia jasminoides and Determination of Antioxidant Activity by Using Free Radical Scavenging Assays

    PubMed Central

    Uddin, Riaz; Saha, Moni Rani; Subhan, Nusrat; Hossain, Hemayet; Jahan, Ismet Ara; Akter, Raushanara; Alam, Ashraful

    2014-01-01

    Purpose: Gardenia jasminoides is a traditional medicinal plant rich in anti-inflammatory flavonoids and phenolic compounds and used for the treatment of inflammatory diseases and pain. In this present study, antioxidant potential of Gardenia jasminoides leaves extract was evaluated by using various antioxidant assays. Methods: Various antioxidant assays such as 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, reducing power and total antioxidant capacity expressed as equivalent to ascorbic acid were employed. Moreover, phenolic compounds were detected by high-performance liquid chromatography (HPLC) coupled with diode-array detection. Results: The methanol extract showed significant free radical scavenging activities in DPPH radical scavenging antioxidant assays compared to the reference antioxidant ascorbic acid. Total antioxidant activity was increased in a dose dependent manner. The extract also showed strong reducing power. The total phenolic content was determined as 190.97 mg/g of gallic acid equivalent. HPLC coupled with diode-array detection was used to identify and quantify the phenolic compounds in the extracts. Gallic acid, (+)-catechin, rutin hydrate and quercetin have been identified in the plant extracts. Among the phenolic compounds, catechin and rutin hydrate are present predominantly in the extract. The accuracy and precision of the presented method were corroborated by low intra- and inter-day variations in quantitative results in leaves extract. Conclusion: These results suggest that phenolic compounds and flavonoids might contribute to high antioxidant activities of Gardenia jasminoides leaves. PMID:24754012

  17. Extracts and constituents of Rubus chingii with 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity.

    PubMed

    Ding, Hsiou-Yu

    2011-01-01

    The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity of the fruits of Rubus chingii was studied in vitro. Ethanolic extract, ethyl acetate and n-butanol fractions from dried R. chingii fruits revealed strong DPPH free radical scavenging activity with IC(50) values of 17.9, 3.4 and 4.0 μg/mL, respectively. The ethyl acetate and n-butanol fractions were further purified by a combination of silica gel chromatography, Lobar RP-8 chromatography, and high-pressure liquid chromatography (HPLC). Nine compounds were isolated, where methyl (3-hydroxy-2-oxo-2,3-dihydroindol-3-yl)-acetate (2), vanillic acid (5), kaempferol (7), and tiliroside (9) showed stronger DPPH free radical scavenging activity than that of ascorbic acid (131.8 μM) with IC(50) values of 45.2, 34.9, 78.5, and 13.7 μM, respectively. In addition, rubusine (1) is a new compound discovered in the present study and methyl (3-hydroxy-2-oxo-2,3-dihydroindol-3-yl)-acetate (2), methyl dioxindole-3-acetate (3), and 2-oxo-1,2-dihydroquinoline-4-carboxylic acid (4) were isolated from the fruits for the first time. PMID:21747716

  18. Optimization of hydroxyl radical scavenging activity of exo-polysaccharides from Inonotus obliquus in submerged fermentation using response surface methodology.

    PubMed

    Chen, Hui; Xu, Xiangqun; Zhu, Yang

    2010-04-01

    The objectives of this study were to investigate the effect of fermentation medium on the hydroxyl radical scavenging activity of exo-polysaccharides from Inonotus obliquus by response surface methodology. A two-level fractional factorial design was used to evaluate the effect of different components of medium. Corn flour, peptone, and KH2PO4 were important factors significantly affecting hydroxyl radical scavenging activity. These selected variables were subsequently optimized using path of steepest ascent (descent), a central composite design, and response surface analysis. The optimal medium composition was (% w/v): corn flour 5.30, peptone 0.32, KH2PO4 0.26, MgSO4 0.02, and CaCl2 0.01. Under the optimal condition, the hydroxyl radical scavenging rate (49.4%) was much higher than that using either basal fermentation medium (10.2%) and single variable optimization of fermentation medium (35.5%). The main monosaccharides components of the RSM optimized polysaccharides are rhamnose, arabinose, xylose, mannose, glucose and galactose with molar proportion at 1.45%, 3.63%, 2.17%, 15.94%, 50.00%, and 26.81%. PMID:20467262

  19. Effects of Extraction and Processing Methods on Antioxidant Compound Contents and Radical Scavenging Activities of Laver (Porphyra tenera)

    PubMed Central

    Hwang, Eun-Sun; Thi, Nhuan Do

    2014-01-01

    Laver is one of the most consumed edible red algae seaweeds in the genus Porphyra. Laver is primarily prepared in the form of dried, roasted, and seasoned products. We investigated the total polyphenol and flavonoid contents of laver products, and evaluated the in vitro antioxidant properties of solvent extracts from commercially processed laver products. Significant differences in the concentration of phenolic compounds were found among differently processed laver. The total phenolic content for laver extracts ranged from 10.81 mg gallic acid equivalent (GAE)/g extract to 32.14 mg GAE/g extract, depending on extraction solvent and temperature. Laver extracts contained very few flavonoids (0.55 mg catechin equivalent/g extracts to 1.75 mg catechin equivalent/g extracts). 2,2-Diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS), hydroxyl radical, and superoxide anion scavenging assays were used to determine the radical scavenging capacities of laver extracts. These assays revealed that the processing method and extraction condition affected the antioxidant potentials of laver. Antioxidant activity of dried laver, roasted laver, and seasoned laver increased in a concentration-dependent manner (100~1,000 μg/mL). The radical scavenging activities of 37°C and 100°C water extracts were lower than that of a 37°C 70% ethanol extract. The highest radical scavenging capacity was observed in the 37°C 70% ethanol extracts of dried laver, roasted laver, and seasoned laver. Overall, these results support that notion that laver contains bioactive compounds, such as polyphenols and flavonoids, which may have a positive effect on health. PMID:24772408

  20. Chemical composition and radical scavenging activity of essential oil and methanolic extract of Eremostachys azerbaijanica Rech.f. from Iran.

    PubMed

    Asnaashari, Solmaz; Afshar, Fariba Heshmati; Ebrahimi, Atefeh; Moghadam, Sedigheh Bamdad; Delazar, Abbas

    2016-01-01

    In the present study, the chemical composition of the essential oil and methanol (MeOH) extract of aerials of E. azerbaijanica were identified. Furthermore, the free radical scavenging properties of the volatile oil as well as the MeOH extract of the plant were assessed. The essential oil of the air-dried aerial parts was obtained by hydro-distillation using a Clevenger-type apparatus. The oil was then analyzed by gas chromatography-mass spectrometry and gas chromatography with flame ionization detector. Soxhlet extraction was performed on the aerial parts using n-hexane, dichloromethane and MeOH. The MeOH extract was then subjected to solid-phase extraction using a C18 Sep-Pak cartridge. Isolation and structural elucidation of the pure components was accomplished by high-performance liquid chromatography and spectroscopic methods (UV, (1)H-NMR). The free radical scavenging properties were determined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. A total of 59 components representing 95.9% of the oil constituents were identified which were primarily characterized as terpenoids or aliphatic skeletons. The major components of the oil were hexahydrofarnesyl acetone (27.1%), 2-methyl-6-propyl-dodecane (16.4%) and tricosane (9.3%). One flavonoid (luteolin-7-O-rutinoside) and one phenylethanoid (verbascoside) were also isolated and identified from the MeOH extract. The results of DPPH assays showed that the essential oil of E. azerbaijanica possessed weak free radical scavenging activity whereas the MeOH extract and its pure constituents showed significant scavenging activities in comparison with positive controls. PMID:27168750

  1. Chemical composition and radical scavenging activity of essential oil and methanolic extract of Eremostachys azerbaijanica Rech.f. from Iran

    PubMed Central

    Asnaashari, Solmaz; Afshar, Fariba Heshmati; Ebrahimi, Atefeh; Moghadam, Sedigheh Bamdad; Delazar, Abbas

    2016-01-01

    In the present study, the chemical composition of the essential oil and methanol (MeOH) extract of aerials of E. azerbaijanica were identified. Furthermore, the free radical scavenging properties of the volatile oil as well as the MeOH extract of the plant were assessed. The essential oil of the air-dried aerial parts was obtained by hydro-distillation using a Clevenger-type apparatus. The oil was then analyzed by gas chromatography–mass spectrometry and gas chromatography with flame ionization detector. Soxhlet extraction was performed on the aerial parts using n-hexane, dichloromethane and MeOH. The MeOH extract was then subjected to solid-phase extraction using a C18 Sep-Pak cartridge. Isolation and structural elucidation of the pure components was accomplished by high-performance liquid chromatography and spectroscopic methods (UV, 1H-NMR). The free radical scavenging properties were determined by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay. A total of 59 components representing 95.9% of the oil constituents were identified which were primarily characterized as terpenoids or aliphatic skeletons. The major components of the oil were hexahydrofarnesyl acetone (27.1%), 2-methyl-6-propyl-dodecane (16.4%) and tricosane (9.3%). One flavonoid (luteolin-7-O-rutinoside) and one phenylethanoid (verbascoside) were also isolated and identified from the MeOH extract. The results of DPPH assays showed that the essential oil of E. azerbaijanica possessed weak free radical scavenging activity whereas the MeOH extract and its pure constituents showed significant scavenging activities in comparison with positive controls. PMID:27168750

  2. Effect of Cu(2+)-complexation on the scavenging ability of chrysin towards photogenerated singlet molecular oxygen (O2((1)Δg)). Possible biological implications.

    PubMed

    Muñoz, Vanesa A; Ferrari, Gabriela V; Montaña, M Paulina; Miskoski, Sandra; García, Norman A

    2016-09-01

    Visible-light irradiation of aqueous-ethanolic solutions of Riboflavin (Rf) in the individual presence of the flavone chrysin (Chr) and its complex with Cu(2+) ([Chr2Cu]; 2:1 L:M) generates singlet molecular oxygen O2((1)Δg), that concomitantly interact with both flavone derivatives. Overall (kt) and reactive (kr) rate constants in the order of 10(7)M(-1)s(-1) were determined for the process. Metal chelation greatly enhances the scavenging ability of [Chr2Cu] towards O2((1)Δg) through a mechanism dominated, in >80%, by the physical component. In this way, practically all O2((1)Δg) is deactivated by the complex without significant loss of the quencher. The isolated flavone quenches O2((1)Δg) in a prevailing reactive fashion. The very low value exhibited by [Chr2Cu] for the kr/kt ratio constitutes a positive quality for antioxidative protectors in biological media, where elevated local concentration and high reactivity of significant molecules make them initial targets for O2((1)Δg) aggression. Finally, two interesting properties in the field of free radicals scavenging by [Chr2Cu] must be mentioned. In first place metal chelation itself, in the obvious sense of free metal ion withdrawal from the oxidizable medium, prevents the initiation of a free radical-mediated oxidation processes through mechanisms of Fenton or lipid peroxidation. In addition, the incorporation of Cu adds to [Chr2Cu] the ability of a free radical scavenger, already described for similar Cu-chelate compounds. This collection of beneficial properties positions the complex as a remarkably promising bioprotector towards ROS-mediated oxidation. A quantification of the efficiency on the initial anti-oxidative effect exerted by Chr and [Chr2Cu] towards tryptophan was carried out. The amino acid is an archetypal molecular model, commonly employed to monitor oxidative degradation of proteinaceous media. It was efficiently photoprotected against O2((1)Δg)-mediated photooxidation by [Chr2Cu]. PMID

  3. Determination of Free Radical Scavenging, Antioxidative DNA Damage Activities and Phytochemical Components of Active Fractions from Lansium domesticum Corr. Fruit

    PubMed Central

    Klungsupya, Prapaipat; Suthepakul, Nava; Muangman, Thanchanok; Rerk-Am, Ubon; Thongdon-A, Jeerayu

    2015-01-01

    Lansium domesticum Corr. or “long-kong” is one of the most popular fruits in Thailand. Its peel (skin, SK) and seeds (SD) become waste unless recycled or applied for use. This study was undertaken to determine the bioactivity and phytochemical components of L. domesticum (LD) skin and seed extracts. Following various extraction and fractionation procedures, 12 fractions were obtained. All fractions were tested for antioxidant capacity against O2−• and OH•. It was found that the peel of L. domesticum fruits exhibited higher O2−• and OH• scavenging activity than seeds. High potential antioxidant activity was found in two fractions of 50% ethanol extract of peel followed by ethyl acetate (EA) fractionation (LDSK50-EA) and its aqueous phase (LDSK50-H2O). Therefore, these two active fractions were selected for further studies on their antioxidative activity against DNA damage by hydrogen peroxide (H2O2) in human TK6 cells using comet assay. The comet results revealed DNA-protective activity of both LDSK50-EA and LDSK50-H2O fractions when TK6 human lymphoblast cells were pre-treated at 25, 50, 100, and 200 μg/mL for 24 h prior to H2O2 exposure. The phytochemical analysis illustrated the presence of phenolic substances, mainly scopoletin, rutin, and chlorogenic acid, in these two active fractions. This study generates new information on the biological activity of L. domesticum. It will promote and strengthen the utilization of L. domesticum by-products. PMID:26287238

  4. Preliminary studies on the activities of spin traps as scavengers of free radicals

    SciTech Connect

    Ogunbiyi, P.O.; Washington, I. )

    1991-03-15

    The spin trapping agents, N-t-Butyl-a-phenyl-nitrone (PBN) and 5,5-Dimethyl-1-pyroline-N-oxide (DMPO) have been used to investigate the primary free radicals involved in various tissue injuries. Also, PBN and DMPO can provide some protection against free radical-induced lung injuries. However, their therapeutic potentials as free radical scavengers remained unexamined. In this study, the effects of PBN and DMPO on guinea pig lung microsomal lipid peroxidation were investigated using thiobarbituric acid-reactive substance assay. Superoxide anions (O{sup 2}{minus}) were generated in an enzymatic and a non-enzymatic system. PBN and DMPO each, significantly inhibited NADPH-stimulated lipid peroxidation irrespective of the presence of Fe{sup 3+}. Cytochrome c reduction by the enzymatic and nitro blue tetrazolium reduction by the non-enzymatic O{sup 2}{minus} generating systems were both inhibited by PBN and DMPO as well as superoxide dismutase and dimethyl sulfoxide when compared with the controls. The spin traps exhibited lower potencies in these systems than the reference compounds, SOD and DMSO, which are well established as O{sup 2}{minus} and hydroxyl radical scavengers respectively. Results demonstrate the free radical scavenging properties of PBN and DMPO. This is an indication of their possible usefulness as antioxidants.

  5. Optimized enzymatic colorimetric assay for determination of hydrogen peroxide (H2O2) scavenging activity of plant extracts

    PubMed Central

    Fernando, Chamira Dilanka; Soysa, Preethi

    2015-01-01

    The classical method to determine hydrogen peroxide (H2O2) scavenging activity of plant extracts is evaluated by measuring the disappearance of H2O2 at a wavelength of 230 nm. Since this method suffers from the interference of phenolics having strong absorption in the UV region, a simple and rapid colorimetric assay was developed where plant extracts are introduced to H2O2, phenol and 4-aminoantipyrine reaction system in the presence of horseradish peroxidase (HRP). This reaction yields a quinoneimine chromogen which can be measured at 504 nm. Decrease in the colour intensity reflects the H2O2 scavenged by the plant material. • Optimum conditions determined for this assay were 30 min reaction time, 37 °C, pH 7, enzyme concentration of 1 U/ml and H2O2 concentration of 0.7 mM. The limit of detection (LOD) and limit of quantitation (LOQ) were 136 μM and 411 μM, respectively. • Half maximal effective concentration required to scavenge 50% of H2O2 in the system (EC50 value) calculated for several plant extracts and standard antioxidants resulted in coefficient of variance (CV%) of the EC50 values less than 3.0% and correlation coefficient values (R2) > 0.95 for all dose response curves obtained. • This method is convenient and very precise which is suitable for the rapid quantification of H2O2 scavenging ability of standard antioxidants and natural antioxidants present in plant extracts. PMID:26285798

  6. Cytotoxic, radical scavenging and antimicrobial activities of sesquiterpenoids from the Tahitian liverwort Mastigophora diclados (Brid.) Nees (Mastigophoraceae).

    PubMed

    Komala, Ismiarni; Ito, Takuya; Nagashima, Fumihiro; Yagi, Yasuyuki; Asakawa, Yoshinori

    2010-10-01

    A drimane, (+)-drimenol (1), five known herbertanes, (-)-alpha-herbertenol (2), (-)-herbertenediol (3), mastigophorene A (4), (-)-mastigophorene C (5) and (-)-mastigophorene D (6), a pimarane, (-)-ent-pimara-8(14),15-dien-19-oic acid (7), and two eudesmanolides, (-)-diplophyllolide A (8) and (-)-diplophyllin (9) were isolated from the Tahitian Mastigophora diclados (Brid.) Nees. Herbertane sesquiterpenes (2, 3, 5 and 6) showed cytotoxicity against HL-60 and KB cell lines, radical scavenging activity and antimicrobial activity against Bacillus subtilis. (-)-Diplophyllolide A (8) also exhibited cytotoxicity against HL-60 and KB cell lines. PMID:20458547

  7. Basic investigations on the performance of a normoxic polymer gel with tetrakis-hydroxy-methyl-phosphonium chloride as an oxygen scavenger: Reproducibility, accuracy, stability, and dose rate dependence

    SciTech Connect

    Bayreder, Christian; Georg, Dietmar; Moser, Ewald; Berg, Andreas

    2006-07-15

    Magnetic resonance (MR)-based polymer gel dosimetry using normoxic polymer gels, represents a new dosimetric method specially suited for high-resolution three-dimensional dosimetric problems. The aim of this study was to investigate the dose response with regard to stability, accuracy, reproducibility, and the dose rate dependence. Tetrakis-hydroxy-methyl-phosphonium chloride (THPC) is used as an oxygen scavenger, and methacrylic acid as a monomer. Accuracy, reproducibility, and dose resolution were determined for MR protocols at low spatial resolution (typical for clinical scanners), medium, and microimaging-resolution protocols at three different dose levels. The dose-response stability and preirradiation-induced variations in R2, related to the time interval between preparation and irradiation of the polymer gel, were investigated. Also postirradiation stability of the polymer gel was considered. These experiments were performed using a {sup 60}Co beam (E=1.2 MV) in a water phantom. Moreover, we investigated the dose rate dependence in the low, medium, and saturation dose region of the normoxic polymer gel using a linear accelerator at photon energy of 25 MV. MR scanning was performed on a 3 T whole body scanner (MEDSPEC 30/80, BRUKER BIOSPIN, Ettlingen, Germany) using several coils and different gradient systems adapted to the acquired spatial resolution investigated. For T2-parameter selective imaging and determination of the relaxation rate R2=1/T2, a multiple spin echo sequence with 20 equidistant echoes was used. With regard to preirradiation induced variations R2 increases significantly with the increasing time interval between the polymer gel preparation and irradiation. Only a slight increase in R2 can be observed for varying the postirradiation-time solely. The dose reproducibility at voxel volumes of about 1.4x1.4x2 mm{sup 3} is better than 2%. The accuracy strongly depends on the calibration curve. THPC represents a very effective oxygen scavenger in

  8. Radical scavenging and cytochrome P450 3A4 inhibitory activity of bergaptol and geranylcoumarin from grapefruit.

    PubMed

    Girennavar, Basavaraj; Jayaprakasha, G K; Jadegoud, Y; Nagana Gowda, G A; Patil, Bhimanagouda S

    2007-06-01

    Grapefruit juice has been shown to increase the oral bioavailability of several clinically important drugs by inhibiting first pass metabolism. Several compounds in grapefruit juice have shown different biological activities. Unique among them are furocoumarins with potent inhibitory activity against cytochrome P450 enzymes. In the present study, two bioactive compounds were isolated from grapefruit juice and grapefruit peel oil. The purity of the isolated compounds has been analyzed by HPLC. Structures of the compounds were elucidated by extensive NMR and mass spectral studies and identified as bergaptol and geranylcoumarin. The isolated compounds were tested for their radical scavenging activity using 2,2'-azobis (3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazil (DPPH) methods at different concentrations. Bergaptol showed very good radical scavenging activity at all the tested concentrations. Furthermore, these compounds were evaluated for their inhibitory activity against CYP3A4 enzyme. Bergaptol and geranylcoumarin were found to be potent inhibitors of debenzylation activity of CYP3A4 enzyme with an IC(50) value of 24.92 and 42.93 microM, respectively. PMID:17400460

  9. Bacterial Fucose-Rich Polysaccharide Stabilizes MAPK-Mediated Nrf2/Keap1 Signaling by Directly Scavenging Reactive Oxygen Species during Hydrogen Peroxide-Induced Apoptosis of Human Lung Fibroblast Cells

    PubMed Central

    Roy Chowdhury, Sougata; Sinha, Tridib Kumar; Sen, Ramkrishna; Basak, Ratan Kumar; Adhikari, Basudam; Bhattacharyya, Arindam

    2014-01-01

    Continuous free radical assault upsets cellular homeostasis and dysregulates associated signaling pathways to promote stress-induced cell death. In spite of the continuous development and implementation of effective therapeutic strategies, limitations in treatments for stress-induced toxicities remain. The purpose of the present study was to determine the potential therapeutic efficacy of bacterial fucose polysaccharides against hydrogen peroxide (H2O2)-induced stress in human lung fibroblast (WI38) cells and to understand the associated molecular mechanisms. In two different fermentation processes, Bacillus megaterium RB-05 biosynthesized two non-identical fucose polysaccharides; of these, the polysaccharide having a high-fucose content (∼42%) conferred the maximum free radical scavenging efficiency in vitro. Structural characterizations of the purified polysaccharides were performed using HPLC, GC-MS, and 1H/13C/2D-COSY NMR. H2O2 (300 µM) insult to WI38 cells showed anti-proliferative effects by inducing intracellular reactive oxygen species (ROS) and by disrupting mitochondrial membrane permeability, followed by apoptosis. The polysaccharide (250 µg/mL) attenuated the cell death process by directly scavenging intracellular ROS rather than activating endogenous antioxidant enzymes. This process encompasses inhibition of caspase-9/3/7, a decrease in the ratio of Bax/Bcl2, relocalization of translocated Bax and cytochrome c, upregulation of anti-apoptotic members of the Bcl2 family and a decrease in the phosphorylation of MAPKs (mitogen activated protein kinases). Furthermore, cellular homeostasis was re-established via stabilization of MAPK-mediated Nrf2/Keap1 signaling and transcription of downstream cytoprotective genes. This molecular study uniquely introduces a fucose-rich bacterial polysaccharide as a potential inhibitor of H2O2-induced stress and toxicities. PMID:25412177

  10. Bacterial fucose-rich polysaccharide stabilizes MAPK-mediated Nrf2/Keap1 signaling by directly scavenging reactive oxygen species during hydrogen peroxide-induced apoptosis of human lung fibroblast cells.

    PubMed

    Roy Chowdhury, Sougata; Sengupta, Suman; Biswas, Subir; Sinha, Tridib Kumar; Sen, Ramkrishna; Basak, Ratan Kumar; Adhikari, Basudam; Bhattacharyya, Arindam

    2014-01-01

    Continuous free radical assault upsets cellular homeostasis and dysregulates associated signaling pathways to promote stress-induced cell death. In spite of the continuous development and implementation of effective therapeutic strategies, limitations in treatments for stress-induced toxicities remain. The purpose of the present study was to determine the potential therapeutic efficacy of bacterial fucose polysaccharides against hydrogen peroxide (H2O2)-induced stress in human lung fibroblast (WI38) cells and to understand the associated molecular mechanisms. In two different fermentation processes, Bacillus megaterium RB-05 biosynthesized two non-identical fucose polysaccharides; of these, the polysaccharide having a high-fucose content (∼ 42%) conferred the maximum free radical scavenging efficiency in vitro. Structural characterizations of the purified polysaccharides were performed using HPLC, GC-MS, and (1)H/(13)C/2D-COSY NMR. H2O2 (300 µM) insult to WI38 cells showed anti-proliferative effects by inducing intracellular reactive oxygen species (ROS) and by disrupting mitochondrial membrane permeability, followed by apoptosis. The polysaccharide (250 µg/mL) attenuated the cell death process by directly scavenging intracellular ROS rather than activating endogenous antioxidant enzymes. This process encompasses inhibition of caspase-9/3/7, a decrease in the ratio of Bax/Bcl2, relocalization of translocated Bax and cytochrome c, upregulation of anti-apoptotic members of the Bcl2 family and a decrease in the phosphorylation of MAPKs (mitogen activated protein kinases). Furthermore, cellular homeostasis was re-established via stabilization of MAPK-mediated Nrf2/Keap1 signaling and transcription of downstream cytoprotective genes. This molecular study uniquely introduces a fucose-rich bacterial polysaccharide as a potential inhibitor of H2O2-induced stress and toxicities. PMID:25412177

  11. A STRESS-RESPONSIVE NAC1-Regulated Protein Phosphatase Gene Rice Protein Phosphatase18 Modulates Drought and Oxidative Stress Tolerance through Abscisic Acid-Independent Reactive Oxygen Species Scavenging in Rice1[W][OPEN

    PubMed Central

    You, Jun; Zong, Wei; Hu, Honghong; Li, Xianghua; Xiao, Jinghua; Xiong, Lizhong

    2014-01-01

    Plants respond to abiotic stresses through a complexity of signaling pathways, and the dephosphorylation mediated by protein phosphatase (PP) is an important event in this process. We identified a rice (Oryza sativa) PP2C gene, OsPP18, as a STRESS-RESPONSIVE NAC1 (SNAC1)-regulated downstream gene. The ospp18 mutant was more sensitive than wild-type plants to drought stress at both the seedling and panicle development stages. Rice plants with OsPP18 suppressed through artificial microRNA were also hypersensitive to drought stress. Microarray analysis of the mutant revealed that genes encoding reactive oxygen species (ROS) scavenging enzymes were down-regulated in the ospp18 mutant, and the mutant exhibited reduced activities of ROS scavenging enzymes and increased sensitivity to oxidative stresses. Overexpression of OsPP18 in rice led to enhanced osmotic and oxidative stress tolerance. The expression of OsPP18 was induced by drought stress but not induced by abscisic acid (ABA). Although OsPP18 is a typical PP2C with enzymatic activity, it did not interact with SNF1-RELATED PROTEIN KINASE2 protein kinases, which function in ABA signaling. Meanwhile, the expression of ABA-responsive genes was not affected in the ospp18 mutant, and the ABA sensitivities of the ospp18 mutant and OsPP18-overexpressing plants were also not altered. Together, these findings suggest that OsPP18 is a unique PP2C gene that is regulated by SNAC1 and confers drought and oxidative stress tolerance by regulating ROS homeostasis through ABA-independent pathways. PMID:25318938

  12. Assessment of Free Radical Scavenging Activity of Dimethylglycine Sodium Salt and Its Role in Providing Protection against Lipopolysaccharide-Induced Oxidative Stress in Mice.

    PubMed

    Bai, Kaiwen; Xu, Wen; Zhang, Jingfei; Kou, Tao; Niu, Yu; Wan, Xiaoli; Zhang, Lili; Wang, Chao; Wang, Tian

    2016-01-01

    In the present study, the free radical scavenging activities (against 1,1-diphenyl-2-pierylhydrazy (DPPH), 2,2'-Azinobis-(3-ethylbenzthiazoline-6- sulphonate) (ABTS+), Hydrogen peroxide (H2O2)) of dimethylglycine sodium salt (DMG-Na) were measured and compared with those of Trolox (6-hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid), a commonly used antioxidant. The radical scavenging activities of DMG-Na were found to be the highest at 40 mg/ml. In Experiment 2, gastric intubation in mice with 12 mg DMG-Na/0.3 ml sterile saline solution significantly increased (P < 0.05) the body weight (BW) (28 d), organ proportion (liver and spleen), and antioxidant capacity in serum and the liver (Superoxide dismutase (SOD), Hydrogen peroxidase (CAT), Glutathione peroxidase (GPx), and Total antioxidant capacity (T-AOC)), and significantly decreased (P < 0.05) the activities of serum Glutamic-pyruvic transaminase (ALT) and Glutamic oxalacetic transaminase (AST) and Methane Dicarboxylic Aldehyde (MDA) contents in the serum and liver. Specifically, the effect of 12 mg DMG-Na/0.3 ml sterile saline solution, which showed the highest antioxidant capacity, was further studied using a mice model. In Experiment 3, the mice CL (CON+ lipopolysaccharide (LPS)) group showed a significant decrease (P < 0.05) in the serum ALT and AST content; hepatic mitochondrial antioxidant capacity (Manganese Superoxide dismutase (MnSOD), Glutathione reductase (GR), GPx, Glutathione (GSH)); MDA and Protein carbonyl (PC) content; Reactive oxygen species (ROS) level, Mitochondrial membrane potential (MMP) level, and expression of liver antioxidant genes (Nuclear factor erythroid 2-related factor 2 (Nrf2), Heme oxygenase 1 (HO-1), Manganese superoxide dismutase (MnSOD), Glutathione peroxidase 1 (Gpx1), Sirtuin 1 (Sirt1)) relative to the mice CS (CON+ sterile saline) group. The DL (DMG+LPS) group showed a significant decrease (P < 0.05) in serum ALT and AST content, ROS level, and expression of liver

  13. Assessment of Free Radical Scavenging Activity of Dimethylglycine Sodium Salt and Its Role in Providing Protection against Lipopolysaccharide-Induced Oxidative Stress in Mice

    PubMed Central

    Zhang, Jingfei; Kou, Tao; Niu, Yu; Wan, Xiaoli; Zhang, Lili; Wang, Chao; Wang, Tian

    2016-01-01

    In the present study, the free radical scavenging activities (against 1,1-diphenyl-2-pierylhydrazy (DPPH), 2,2'-Azinobis-(3-ethylbenzthiazoline-6- sulphonate) (ABTS+), Hydrogen peroxide (H2O2)) of dimethylglycine sodium salt (DMG-Na) were measured and compared with those of Trolox (6-hydroxy-2, 5, 7, 8-tetramethylchroman-2-carboxylic acid), a commonly used antioxidant. The radical scavenging activities of DMG-Na were found to be the highest at 40 mg/ml. In Experiment 2, gastric intubation in mice with 12 mg DMG-Na/0.3 ml sterile saline solution significantly increased (P < 0.05) the body weight (BW) (28 d), organ proportion (liver and spleen), and antioxidant capacity in serum and the liver (Superoxide dismutase (SOD), Hydrogen peroxidase (CAT), Glutathione peroxidase (GPx), and Total antioxidant capacity (T-AOC)), and significantly decreased (P < 0.05) the activities of serum Glutamic-pyruvic transaminase (ALT) and Glutamic oxalacetic transaminase (AST) and Methane Dicarboxylic Aldehyde (MDA) contents in the serum and liver. Specifically, the effect of 12 mg DMG-Na/0.3 ml sterile saline solution, which showed the highest antioxidant capacity, was further studied using a mice model. In Experiment 3, the mice CL (CON+ lipopolysaccharide (LPS)) group showed a significant decrease (P < 0.05) in the serum ALT and AST content; hepatic mitochondrial antioxidant capacity (Manganese Superoxide dismutase (MnSOD), Glutathione reductase (GR), GPx, Glutathione (GSH)); MDA and Protein carbonyl (PC) content; Reactive oxygen species (ROS) level, Mitochondrial membrane potential (MMP) level, and expression of liver antioxidant genes (Nuclear factor erythroid 2-related factor 2 (Nrf2), Heme oxygenase 1 (HO-1), Manganese superoxide dismutase (MnSOD), Glutathione peroxidase 1 (Gpx1), Sirtuin 1 (Sirt1)) relative to the mice CS (CON+ sterile saline) group. The DL (DMG+LPS) group showed a significant decrease (P < 0.05) in serum ALT and AST content, ROS level, and expression of liver

  14. Hydrogen scavengers

    SciTech Connect

    Carroll, David W.; Salazar, Kenneth V.; Trkula, Mitchell; Sandoval, Cynthia W.

    2002-01-01

    There has been invented a codeposition process for fabricating hydrogen scavengers. First, a .pi.-bonded allylic organometallic complex is prepared by reacting an allylic transition metal halide with an organic ligand complexed with an alkali metal; and then, in a second step, a vapor of the .pi.-bonded allylic organometallic complex is combined with the vapor of an acetylenic compound, irradiated with UV light, and codeposited on a substrate.

  15. Enhanced DPPH radical scavenging activity and DNA protection effect of litchi pericarp extract by Aspergillus awamori bioconversion

    PubMed Central

    2012-01-01

    Background Litchi (Litchi chinensis Sonn.) pericarp is a major byproduct which contains a significant amount of polyphenol. This study was designed to biotransformation litchi pericarp extract (LPE) by Aspergillus awamori to produce more bioactive compounds with stronger antioxidant activities. Results The study exhibited that the 2,2-diphenyl-1-picrylhydrazyl radical scavenging activities significantly (p < 0.05) increased from 15.53% to 18.23% in the water-extracted fraction and from 25.41% to 36.82% in the ethyl acetate-extracted fraction. Application of DNA cleavage assay further demonstrated the enhanced protection effect of the fermented phenolics on DNA damage. It is also noted that the water-extracted fraction of the fermented LPE possessed a much stronger capacity than the ethyl acetate-extracted fraction to prevent from damage of supercoiled DNA. Interestingly, it was found that some new compounds such as catechin and quercetin appeared after of A. awamori fermentation of LPE, which could account for the enhanced antioxidant activity. Conclusion The DPPH radical scavenging activity and DNA protection effect of LPE were increased by Aspergillus awamori bioconversion while some compounds responsible for the enhanced antioxidant activity were identified. This study provided an effective way of utilizing fruit pericarp as a readily accessible source of the natural antioxidants in food industry and, thus, extended the application area such as fruit by-products. PMID:23016522

  16. Evidence for the Therapeutic Efficacy of Either Mild Hypothermia or Oxygen Radical Scavengers after Repetitive Mild Traumatic Brain Injury

    PubMed Central

    Miyauchi, Takashi; Wei, Enoch P.

    2014-01-01

    Abstract Repetitive brain injury, particularly that occurring with sporting-related injuries, has recently garnered increased attention in both the clinical and public settings. In the laboratory, we have demonstrated the adverse axonal and vascular consequences of repetitive brain injury and have demonstrated that moderate hypothermia and/or FK506 exerted protective effects after repetitive mild traumatic brain injury (mTBI) when administered within a specific time frame, suggesting a range of therapeutic modalities to prevent a dramatic exacerbation. In this communication, we revisit the utility of targeted therapeutic intervention to seek the minimal level of hypothermia needed to achieve protection while probing the role of oxygen radicals and their therapeutic targeting. Male Sprague-Dawley rats were subjected to repetitive mTBI by impact acceleration injury. Mild hypothermia (35°C, group 2), superoxide dismutase (group 3), and Tempol (group 4) were employed as therapeutic interventions administered 1 h after the repetitive mTBI. To assess vascular function, cerebral vascular reactivity to acetylcholine was evaluated 3 and 4 h after the repetitive mTBI, whereas to detect the burden of axonal damage, amyloid precursor protein (APP) density in the medullospinal junction was measured. Whereas complete impairment of vascular reactivity was observed in group 1 (without intervention), significant preservation of vascular reactivity was found in the other groups. Similarly, whereas remarkable increase in the APP-positive axon was observed in group 1, there were no significant increases in the other groups. Collectively, these findings indicate that even mild hypothermia or the blunting free radical damage, even when performed in a delayed period, is protective in repetitive mTBI. PMID:24341607

  17. Endothelial dysfunction enhances vasoconstriction due to scavenging of nitric oxide by a hemoglobin-based oxygen carrier

    PubMed Central

    Yu, Binglan; Shahid, Mohd; Egorina, Elena M.; Sovershaev, Mikhail A.; Raher, Michael J.; Lei, Chong; Wu, Mei X.; Bloch, Kenneth D.; Zapol, Warren M.

    2010-01-01

    Background At present, there is no safe and effective hemoglobin-based oxygen carrier (HBOC) to substitute for red blood cell transfusion. It is uncertain whether a deficiency of endothelial nitric oxide bioavailability (endothelial dysfunction) prevents or augments the HBOC-induced vasoconstriction. Methods Hemodynamic effects of infusion of PolyHeme (1.08 g hemoglobin/kg, Northfield Laboratories, Evanston, IL) or murine tetrameric hemoglobin (0.48 g hemoglobin/kg) were determined in awake healthy lambs, awake mice and anesthetized mice. In vitro, a cumulative dose-tension response was obtained by sequential addition of PolyHeme or tetrameric hemoglobin to phenylephrine-precontracted murine aortic rings. Results Infusion of PolyHeme did not cause systemic hypertension in awake lambs, but produced acute systemic and pulmonary vasoconstriction. Infusion of PolyHeme did not cause systemic hypertension in healthy wild-type mice, but induced severe systemic vasoconstriction in mice with endothelial dysfunction (either db/db mice or high-fat fed wild-type mice for 4–6 weeks). The db/db mice were more sensitive to systemic vasoconstriction than wild-type mice after the infusion of either tetrameric hemoglobin or PolyHeme. Murine aortic ring studies confirmed that db/db mice have an impaired response to an endothelial-dependent vasodilator and an enhanced vasoconstrictor response to a HBOC. Conclusions Reduction of low molecular weight hemoglobin concentrations to less than 1% is insufficient to abrogate the vasoconstrictor effects of HBOC infusion in healthy awake sheep or in mice with reduced vascular nitric oxide levels associated with endothelial dysfunction. These findings suggest that testing HBOCs in animals with endothelial dysfunction can provide a more sensitive indication of their potential vasoconstrictor effects. PMID:20179495

  18. Inhibitory activities of soluble and bound millet seed phenolics on free radicals and reactive oxygen species.

    PubMed

    Chandrasekara, Anoma; Shahidi, Fereidoon

    2011-01-12

    Oxidative stress, caused by reactive oxygen species (ROS), is responsible for modulating several pathological conditions and aging. Soluble and bound phenolic extracts of commonly consumed millets, namely, kodo, finger (Ravi), finger (local), foxtail, proso, little, and pearl, were investigated for their phenolic content and inhibition of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and ROS, namely, hydroxyl radical, peroxyl radical, hydrogen peroxide (H(2)O(2)), hypochlorous acid (HOCl), and singlet oxygen ((1)O(2)). Inhibition of DPPH and hydroxyl radicals was detrmined using electron paramagnetic resonance (EPR) spectroscopy. The peroxyl radical inhibitory activity was measured using the oxygen radical absorbance capacity (ORAC) assay. The scavenging of H(2)O(2), HOCl, and (1)O(2) was evaluated using colorimetric methods. The results were expressed as micromoles of ferulic acid equivalents (FAE) per gram of grain on a dry weight basis. In addition, major hydroxycinnamic acids were identified and quantified using high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry (MS). All millet varieties displayed effective radical and ROS inhibition activities, which generally positively correlated with phenolic contents, except for hydroxyl radical. HPLC analysis revealed the presence of ferulic and p-coumaric acids as major hydroxycinnamic acids in phenolic extract and responsible for the observed effects. Bound extracts of millet contributed 38-99% to ROS scavenging, depending on the variety and the test system employed. Hence, bound phenolics must be included in the evaluation of the antioxidant activity of millets and other cereals. PMID:21133411

  19. Simultaneous quantification and validation of caffeoylquinic acids and flavonoids in Hemistepta lyrata and peroxynitrite-scavenging activity.

    PubMed

    Nugroho, Agung; Lim, Sang-Cheol; Byeon, Jeong Su; Choi, Jae Sue; Park, Hee-Juhn

    2013-03-25

    Traditionally, Hemistepta lyrata is consumed as a mountainous vegetable or a medicinal herb to treat inflammation, fever, hemorrhage, and hemorrhoids. In order to provide the scientific evidence of traditional uses of this plant, we identified and quantified thirteen active substances (caffeic acid, chlorogenic acid, and 3,5-di-O-caffeoylquinic acid as caffeoylquinic acids; apigenin, isorhoifolin, acacetin, linarin, diosmetin, diosmin, pectolinarigenin, and pectolinarin as flavones or their glycosides; kaempferol 3-O-rutinoside and rutin as flavonol glycosides) from H. lyrata and evaluated their peroxynitrite-scavenging activity. The chromatographic separation was performed on a Capcell Pak C18 column (5μm, 250mm×4.6mm i.d.) with a gradient elution of 0.05% TFA (trifluoroacetic acid) and 0.05% TFA in MeOH-CH(3)CN (60:40). Validation of HPLC methods on the linearity, LOD, LOQ, intra-day and inter-day variabilities, recovery, and repeatability proved that this method is selective, sensitive, precise, accurate, and reproducible. In peroxynitrite-scavenging assay, caffeic acid derivatives (chlorogenic acid, caffeic acid, and 3,5-di-O-caffeoylquinic acid) exhibited relatively lower IC(50) values than other substances tested. And HPLC simultaneous quantification showed that the 70% MeOH extract and the BuOH fraction contain a higher quantity of caffeic acid derivatives (17.82 and 30.09mg/g, consecutively). Therefore, caffeic acid derivatives could be the main contributors to the peroxynitrite-scavenging activity of H. lyrata than other phenolic substances. PMID:23333682

  20. Antimicrobial, free radical scavenging activities and catalytic oxidation of benzyl alcohol by nano-silver synthesized from the leaf extract of Aristolochia indica L.: a promenade towards sustainability

    NASA Astrophysics Data System (ADS)

    Shanmugam, C.; Sivasubramanian, G.; Parthasarathi, Bera; Baskaran, K.; Balachander, R.; Parameswaran, V. R.

    2015-07-01

    Silver nanoparticles (Ag-NPs) were synthesized from aqueous silver nitrate through a simple route using the leaf extract of Aristolochia indica L. (LAIL) which acted as a reducing as well as capping agent. X-ray diffraction confirmed that the synthesized silver particles have a face centred cubic structure. EDS predicted the presence of elemental silver. The SEM images showed the synthesis of spherically mono-dispersed particles, with nano dimensions accounted by the TEM images. Infra-red spectrum adopted to the different organic functionalities present at the surface of the particles. TGA indicated an overall 11 % weight loss up to 1000 °C, suggesting desorption of biomolecules from the surface. X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of metallic silver nanoparticles. The prepared material was utilized as catalyst in the oxidation of benzyl alcohol with molecular oxygen as the oxidant in methanol, under ambient conditions of temperature and pressure. Also Ag-NPs showed good to moderate anti-microbial activity employing the Agar disc diffusion method against various strains using Ciprofloxacin and Fluconazole as standard. Free radical scavenging activity of the nanoparticles were observed by modified 1,1-diphynyl-2-picrylhydrazyl, DPPH and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS in vitro assays. The work presented here demonstrates the adaptability of the synthesized Ag-NPs in participating as a disinfectant agent, free radical scavenger and an effective oxidation catalyst. The basic premise of attaining sustainability through the green synthesis of smart multifaceted materials has been consciously addressed.

  1. Enhancing cytokinin synthesis by overexpressing ipt alleviated drought inhibition of root growth through activating ROS-scavenging systems in Agrostis stolonifera

    PubMed Central

    Xu, Yi; Burgess, Patrick; Zhang, Xunzhong; Huang, Bingru

    2016-01-01

    Drought stress limits root growth and inhibits cytokinin (CK) production. Increases in CK production through overexpression of isopentenyltransferase (ipt) alleviate drought damages to promote root growth. The objective of this study was to investigate whether CK-regulated root growth was involved in the alteration of reactive oxygen species (ROS) production and ROS scavenging capacity under drought stress. Wild-type (WT) creeping bentgrass (Agrostis stolonifera L. ‘Penncross’) and a transgenic line (S41) overexpressing ipt ligated to a senescence-activated promoter (SAG12) were exposed to drought stress for 21 d in growth chambers. SAG12-ipt transgenic S41 developed a more extensive root system under drought stress compared to the WT. Root physiological analysis (electrolyte leakage and lipid peroxidation) showed that S41 roots exhibited less cellular damage compared to the WT under drought stress. Roots of SAG12-ipt transgenic S41 had significantly higher endogenous CK content than the WT roots under drought stress. ROS (hydrogen peroxide and superoxide) content was significantly lower and content of total and free ascorbate was significantly higher in S41 roots compared to the WT roots under drought stress. Enzymatic assays and transcript abundance analysis showed that superoxide dismutase, catalase, peroxidase, and dehydroascorbate reductase were significantly higher in S41 roots compared to the WT roots under drought stress. S41 roots also maintained significantly higher alternative respiration rates compared to the WT under drought stress. The improved root growth of transgenic creeping bentgrass may be facilitated by CK-enhanced ROS scavenging through antioxidant accumulation and activation of antioxidant enzymes, as well as higher alternative respiration rates when soil water is limited. PMID:26889010

  2. Antimicrobial, free radical scavenging activities and catalytic oxidation of benzyl alcohol by nano-silver synthesized from the leaf extract of Aristolochia indica L.: a promenade towards sustainability

    NASA Astrophysics Data System (ADS)

    Shanmugam, C.; Sivasubramanian, G.; Parthasarathi, Bera; Baskaran, K.; Balachander, R.; Parameswaran, V. R.

    2016-06-01

    Silver nanoparticles (Ag-NPs) were synthesized from aqueous silver nitrate through a simple route using the leaf extract of Aristolochia indica L. (LAIL) which acted as a reducing as well as capping agent. X-ray diffraction confirmed that the synthesized silver particles have a face centred cubic structure. EDS predicted the presence of elemental silver. The SEM images showed the synthesis of spherically mono-dispersed particles, with nano dimensions accounted by the TEM images. Infra-red spectrum adopted to the different organic functionalities present at the surface of the particles. TGA indicated an overall 11 % weight loss up to 1000 °C, suggesting desorption of biomolecules from the surface. X-ray photoelectron spectroscopy (XPS) analysis revealed the presence of metallic silver nanoparticles. The prepared material was utilized as catalyst in the oxidation of benzyl alcohol with molecular oxygen as the oxidant in methanol, under ambient conditions of temperature and pressure. Also Ag-NPs showed good to moderate anti-microbial activity employing the Agar disc diffusion method against various strains using Ciprofloxacin and Fluconazole as standard. Free radical scavenging activity of the nanoparticles were observed by modified 1,1-diphynyl-2-picrylhydrazyl, DPPH and 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid), ABTS in vitro assays. The work presented here demonstrates the adaptability of the synthesized Ag-NPs in participating as a disinfectant agent, free radical scavenger and an effective oxidation catalyst. The basic premise of attaining sustainability through the green synthesis of smart multifaceted materials has been consciously addressed.

  3. Enhancing cytokinin synthesis by overexpressing ipt alleviated drought inhibition of root growth through activating ROS-scavenging systems in Agrostis stolonifera.

    PubMed

    Xu, Yi; Burgess, Patrick; Zhang, Xunzhong; Huang, Bingru

    2016-03-01

    Drought stress limits root growth and inhibits cytokinin (CK) production. Increases in CK production through overexpression of isopentenyltransferase (ipt) alleviate drought damages to promote root growth. The objective of this study was to investigate whether CK-regulated root growth was involved in the alteration of reactive oxygen species (ROS) production and ROS scavenging capacity under drought stress. Wild-type (WT) creeping bentgrass (Agrostis stolonifera L. 'Penncross') and a transgenic line (S41) overexpressing ipt ligated to a senescence-activated promoter (SAG12) were exposed to drought stress for 21 d in growth chambers. SAG12-ipt transgenic S41 developed a more extensive root system under drought stress compared to the WT. Root physiological analysis (electrolyte leakage and lipid peroxidation) showed that S41 roots exhibited less cellular damage compared to the WT under drought stress. Roots of SAG12-ipt transgenic S41 had significantly higher endogenous CK content than the WT roots under drought stress. ROS (hydrogen peroxide and superoxide) content was significantly lower and content of total and free ascorbate was significantly higher in S41 roots compared to the WT roots under drought stress. Enzymatic assays and transcript abundance analysis showed that superoxide dismutase, catalase, peroxidase, and dehydroascorbate reductase were significantly higher in S41 roots compared to the WT roots under drought stress. S41 roots also maintained significantly higher alternative respiration rates compared to the WT under drought stress. The improved root growth of transgenic creeping bentgrass may be facilitated by CK-enhanced ROS scavenging through antioxidant accumulation and activation of antioxidant enzymes, as well as higher alternative respiration rates when soil water is limited. PMID:26889010

  4. Activated Human Mast Cells Induce LOX-1-Specific Scavenger Receptor Expression in Human Monocyte-Derived Macrophages

    PubMed Central

    Alanne-Kinnunen, Mervi; Lappalainen, Jani; Öörni, Katariina; Kovanen, Petri T.

    2014-01-01

    Objective Activated mast cells in atherosclerotic lesions degranulate and release bioactive compounds capable of regulating atherogenesis. Here we examined the ability of activated human primary mast cells to regulate the expression of the major scavenger receptors in cultured human primary monocyte-derived macrophages (HMDMs). Results Components released by immunologically activated human primary mast cells induced a transient expression of lectin-like oxidized LDL receptor (LOX-1) mRNA in HMDMs, while the expression of two other scavenger receptors, MSR1 and CD36, remained unaffected. The LOX-1-inducing secretory components were identified as histamine, tumor necrosis factor alpha (TNF-α), and transforming growth factor beta (TGF-β1), which exhibited a synergistic effect on LOX-1 mRNA expression. Histamine induced a transient expression of LOX-1 protein. Mast cell –induced increase in LOX-1 expression was not associated with increased uptake of oxidized LDL by the macrophages. Conclusions Mast cell-derived histamine, TNF-α, and TGF-β1 act in concert to induce a transient increase in LOX-1 expression in human primary monocyte-derived macrophages. The LOX-1-inducing activity potentially endows mast cells a hitherto unrecognized role in the regulation of innate immune reactions in atherogenesis. PMID:25250731

  5. A comparative evaluation of mutagenic, antimutagenic, radical scavenging and antibacterial activities of essential oils of Pituranthos chloranthus (Coss. et Dur.).

    PubMed

    Neffati, Aicha; Limem, Ilef; Kilani, Soumaya; Bouhlel, Ines; Skandrani, Ines; Bhouri, Wissem; Ben Sghaier, Mohamed; Boubaker, Jihed; Ledauphin, Jerome; Barillier, Daniel; Ghedira, Leila Chekir; Ghedira, Kamel

    2009-01-01

    The Salmonella typhimurium/microsome assay is a widely used bacterial genotoxicity assay to test potential carcinogens. The aim of this work was to evaluate the mutagenic and antimutagenic activities with and without the addition of an extrinsic metabolic activation system of essential oils obtained from an aerial part of Pituranthos chloranthus harvested from different stations in Tunisia. The oils showed no mutagenicity when tested with S. typhimurium strains TA98, TA100, and TA1535. On the other hand, we showed that these essential oils reduced significantly Benzo [a] pyrene (B[a] P) and sodium-azide-induced mutagenicity. The scavenging capacity of these essential oils was also estimated by evaluating the inhibition of DPPH radical. Essential oils harvested at Medenine and Gabes in November were more effective in scavenging activity. The essential oils were tested for their antimicrobial properties against five different bacteria, and were found to be weakly active, with MIC and MBC values in the range 0.6-4 and 2.2-5 mg/mL, respectively. PMID:19793030

  6. A study on the activities of a few free radicals scavenging enzymes present in five roadside plants.

    PubMed

    Mandal, M; Mukherji, S

    2001-10-01

    The road side plants are continuously exposed to the high levels of oxides of nitrogen and sulphur dioxide, emitted from automobile. Resistance to automobile exhaust pollution was studied with Nerium indicum Mill, Boerhaavia diffusa L., Amaranthus spinosus L., Cephalandra indica Naud., and Tabernaemontana divaricata L., growing on the edges of Delhi Road, National Highway 2 (NH 2) near Dankuni, West Bengal. By analysing the activities of a few enzymes like superoxide dismutase, catalase, ascorbate peroxidase, glutathione reductase and phenolic peroxidase, it appears that among the five plants examined,Amaranthus and Cephalandra are equipped with a very good scavenging system to combat effects of air pollution. PMID:12018603

  7. Detoxication of sulfur half-mustards by nucleophilic scavengers: robust activity of thiopurines.

    PubMed

    Liu, Jinyun; Powell, K Leslie; Thames, Howard D; MacLeod, Michael C

    2010-03-15

    Sulfur mustard (bis-(2-chloroethyl)sulfide) has been used in chemical warfare since World War I and is well known as an acutely toxic vesicant. It has been implicated as a carcinogen after chronic low-level exposure and is known to form interstrand cross-links in DNA. Sulfur and nitrogen mustards are currently of interest as potential chemical threat agents for terrorists because of ease of synthesis. Sulfur mustard and monofunctional analogues (half-mustards, 2-[chloroethyl] alkyl sulfides) react as electrophiles, damaging cellular macromolecules, and thus are potentially subject to scavenging by nucleophilic agents. We have determined rate constants for the reaction of four purine derivatives that contain nucleophilic thiol moieties with several sulfur-half-mustards. Three of these compounds, 2,6-dithiopurine, 2,6-dithiouric acid, and 9-methyl-6-mercaptopurine, exhibit facile reaction with the electrophilic mustard compounds. At near neutral pH, these thiopurines are much better nucleophilic scavengers of mustard electrophiles than other low molecular weight thiols such as N-acetyl cysteine and glutathione. Progress curves calculated by numerical integration techniques indicate that equimolar concentrations of thiopurine provide significant reductions in the overall exposure to the episulfonium ions, which are the major reactive, electrophiles produced when sulfur mustards are dissolved in aqueous solution. PMID:20050632

  8. Can Soaked-in Scavengers Protect Metalloprotein Active Sites from Reduction During Data Collection?

    SciTech Connect

    Macedo, S.; Pechlaner, M; Schmid, W; Weik, M; Sato, K; Dennison, C; Djinovic-Carugo, K

    2009-01-01

    One of the first events taking place when a crystal of a metalloprotein is exposed to X-ray radiation is photoreduction of the metal centres. The oxidation state of a metal cannot always be determined from routine X-ray diffraction experiments alone, but it may have a crucial impact on the metal's environment and on the analysis of the structural data when considering the functional mechanism of a metalloenzyme. Here, UV-Vis microspectrophotometry is used to test the efficacy of selected scavengers in reducing the undesirable photoreduction of the iron and copper centres in myoglobin and azurin, respectively, and X-ray crystallography to assess their capacity of mitigating global and specific radiation damage effects. UV-Vis absorption spectra of native crystals, as well as those soaked in 18 different radioprotectants, show dramatic metal reduction occurring in the first 60 s of irradiation with an X-ray beam from a third-generation synchrotron source. Among the tested radioprotectants only potassium hexacyanoferrate(III) seems to be capable of partially mitigating the rate of metal photoreduction at the concentrations used, but not to a sufficient extent that would allow a complete data set to be recorded from a fully oxidized crystal. On the other hand, analysis of the X-ray crystallographic data confirms ascorbate as an efficient protecting agent against radiation damage, other than metal centre reduction, and suggests further testing of HEPES and 2,3-dichloro-1,4-naphtoquinone as potential scavengers.

  9. Antioxidant and free radical scavenging activities of some medicinal plants from the Lamiaceae.

    PubMed

    Matkowski, Adam; Piotrowska, Magdalena

    2006-07-01

    Antioxidative effects of methanolic extracts from six wild European Lamiaceae species have been studied with the use of three in vitro assays. The ability of scavenging free radicals was measured by DPPH reduction spectrophotometric assay. The reducing potential towards transition metals was tested by phosphomolybdenum method and the inhibition of lipid oxidation was tested by Fe/ascorbate system with photometric TBARS detection. All studied herbs exposed strong antioxidant capability, but the results were different for each species depending on the applied test. In DPPH scavenging the order from strongest to the weakest was: Leonurus cardiaca, Lamium album, Marrubium vulgare, Stachys officinalis, Lamium purpureum, Galeopsis speciosa. With phosphomolybdenum method the extract of S. officinalis was the strongest in both 40 degrees Celsius and 90 degrees Celsius but other species acted differently in both temperatures. In lipid peroxidation assay, the maximum inhibition of 78% was reached by S. officinalis and M. vulgare, whereas for both Lamium sp. and L. cardiaca slightly exceeded 70% and for G. speciosa reached 65%. The observed differences indicate the complexity of involved mechanisms and support the necessity of combining several assays in studying the antioxidant potential of medicinal plants. PMID:16713687

  10. Chemical composition, anti-inflammatory, molluscicidal and free-radical scavenging activities of the leaves of Ficus radicans 'Variegata' (Moraceae).

    PubMed

    Naressi, Maria Augusta; Ribeiro, Marcos Alessandro dos Santos; Bersani-Amado, Ciomar Aparecida; Zamuner, Maria Lucilia M; Costa, Willian Ferreira da; Tanaka, Clara M Abe; Sarragiotto, Maria Helena

    2012-01-01

    The methanol crude extract of the leaves of Ficus radicans Roxb. 'Variegata' (Moraceae) and the n-hexane, ethyl acetate and aqueous methanol fractions resulting from its fractionation were evaluated for their anti-inflammatory, molluscicidal and free-radical scavenging activities. The crude extract and fractions exhibited significant inhibition of inflammation in both croton oil (CO)-induced ear oedema in mice (p<0.001) and carrageenan-induced rat paw oedema models (p<0.01). The molluscicidal assay against Biomphalaria glabrata showed a weak activity for the n-hexane fraction (DL(50)= 400 µg mL(-1)). A moderated 1,1-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging activity was observed for the ethyl acetate fraction (IC(50)= 66.2 µg mL(-1)). Fractionation of the extracts through chromatographic methods afforded the coumarins 7-methoxycoumarin, 7-hydroxy-6-methoxycoumarin and methoxy-3,4-dihydrocoumarin, the steroids β-sitosterol and β-sitosterol 3-O-β-glucopyranoside, as well as a cinnamic acid derivative and a flavonoid identified as trans-4-methoxy-2-β-D-glucopyranosyloxy cinnamic acid and quercetin 3-O-β-D-xylopyranosyl-(1 → 2)-α-L-rhamnopyranoside, respectively. The compounds were identified on the basis of their NMR spectral data and comparison with those previously reported in the literature. PMID:21424983

  11. Biochar activated by oxygen plasma for supercapacitors

    NASA Astrophysics Data System (ADS)

    Gupta, Rakesh Kumar; Dubey, Mukul; Kharel, Parashu; Gu, Zhengrong; Fan, Qi Hua

    2015-01-01

    Biochar, also known as black carbon, is a byproduct of biomass pyrolysis. As a low-cost, environmental-friendly material, biochar has the potential to replace more expensive synthesized carbon nanomaterials (e.g. carbon nanotubes) for use in future supercapacitors. To achieve high capacitance, biochar requires proper activation. A conventional approach involves mixing biochar with a strong base and baking at a high temperature. However, this process is time consuming and energy inefficient (requiring temperatures >900 °C). This work demonstrates a low-temperature (<150 °C) plasma treatment that efficiently activates a yellow pine biochar. Particularly, the effects of oxygen plasma on the biochar microstructure and supercapacitor characteristics are studied. Significant enhancement of the capacitance is achieved: 171.4 F g-1 for a 5-min oxygen plasma activation, in comparison to 99.5 F g-1 for a conventional chemical activation and 60.4 F g-1 for untreated biochar. This enhancement of the charge storage capacity is attributed to the creation of a broad distribution in pore size and a larger surface area. The plasma activation mechanisms in terms of the evolution of the biochar surface and microstructure are further discussed.

  12. The Corynebacterium glutamicum mycothiol peroxidase is a reactive oxygen species-scavenging enzyme that shows promiscuity in thiol redox control.

    PubMed

    Pedre, Brandán; Van Molle, Inge; Villadangos, Almudena F; Wahni, Khadija; Vertommen, Didier; Turell, Lucía; Erdogan, Huriye; Mateos, Luis M; Messens, Joris

    2015-06-01

    Cysteine glutathione peroxidases (CysGPxs) control oxidative stress levels by reducing hydroperoxides at the expense of cysteine thiol (-SH) oxidation, and the recovery of their peroxidatic activity is generally accomplished by thioredoxin (Trx). Corynebacterium glutamicum mycothiol peroxidase (Mpx) is a member of the CysGPx family. We discovered that its recycling is controlled by both the Trx and the mycothiol (MSH) pathway. After H2 O2 reduction, a sulfenic acid (-SOH) is formed on the peroxidatic cysteine (Cys36), which then reacts with the resolving cysteine (Cys79), forming an intramolecular disulfide (S-S), which is reduced by Trx. Alternatively, the sulfenic acid reacts with MSH and forms a mixed disulfide. Mycoredoxin 1 (Mrx1) reduces the mixed disulfide, in which Mrx1 acts in combination with MSH and mycothiol disulfide reductase as a biological relevant monothiol reducing system. Remarkably, Trx can also take over the role of Mrx1 and reduce the Mpx-MSH mixed disulfide using a dithiol mechanism. Furthermore, Mpx is important for cellular survival under H2 O2 stress, and its gene expression is clearly induced upon H2 O2 challenge. These findings add a new dimension to the redox control and the functioning of CysGPxs in general. PMID:25766783

  13. Melatonin Improved Anthocyanin Accumulation by Regulating Gene Expressions and Resulted in High Reactive Oxygen Species Scavenging Capacity in Cabbage

    PubMed Central

    Zhang, Na; Sun, Qianqian; Li, Hongfei; Li, Xingsheng; Cao, Yunyun; Zhang, Haijun; Li, Shuangtao; Zhang, Lei; Qi, Yan; Ren, Shuxin; Zhao, Bing; Guo, Yang-Dong

    2016-01-01

    In this work, we found, that exogenous melatonin pretreatment improved anthocyanin accumulation (1- to 2-fold) in cabbage. To verify the relationship with melatonin and anthocyanin, an Arabidopsis mutant, snat, which expresses a defective form of the melatonin biosynthesis enzyme SNAT (Serotonin N-acetyl transferase), was employed. Under cold conditions, the foliage of wild-type Arabidopsis exhibited a deeper red color than the snat mutant. This finding further proved, that exogenous melatonin treatment was able to affect anthocyanin accumulation. To gain a better understanding of how exogenous melatonin upregulates anthocyanin, we measured gene expression in cabbage samples treated with melatonin and untreated controls. We found that the transcript levels of anthocyanin biosynthetic genes were upregulated by melatonin treatment. Moreover, melatonin treatment increased the expression levels of the transcription factors MYB, bHLH, and WD40, which constitute the transcriptional activation complex responsible for coordinative regulation of anthocyanin biosynthetic genes. We found, that free radical generation was downregulated, whereas the osmotic adjustment and antioxidant capacities were upregulated in exogenous melatonin-treated cabbage plants. We concluded, that melatonin increases anthocyanin production and benefits cabbage growth. PMID:27047496

  14. Essential Oil from Flowers and Leaves of Elaeagnus Angustifolia (Elaeagnaceae): Composition, Radical Scavenging and General Toxicity Activities

    PubMed Central

    Torbati, Mohammadali; Asnaashari, Solmaz; Heshmati Afshar, Fariba

    2016-01-01

    Purpose: The aim of this work was to identify the chemical composition of the essential oils obtained from the flowers and leaves of Elaeagnus angostifolia (Elaeagnaceae) along with evaluate the radical scavenging and general toxicity activities. Methods: A combination of GC-MS and GC-FID were utilized for analyzing the chemical profile of the essential oils extracted by hydro-distillation from the leaves and flowers of E. angustifolia. The essential oils were subjected to general toxicity and radical scavenging assays using brine shrimp lethality test and DPPH method, respectively. Results: In total, 53 and 25 components were identified and quantified in the essential oils of flowers and leaves, accounting for 96.59% and 98.97% of the oil, respectively. The both oils were observed to be rich in ester compounds. The most abundant components of the oil from flowers were E-ethyl cinnamate (60.00%), hexahydrofarnesyl acetone (9.99%), palmitic acid (5.20%) and phytol (3.29%). The major constituents of the oil from leaves were E-ethyl cinnamate (37.27%), phytol (12.08%), nonanal (10.74%) and Z-3-hexenyl benzoate (7.65%). Both oils showed moderate activity in DPPH assay; however, they exhibited potent tocixity in brine shrimp lethality test. Conclusion: The remarkable toxicity effects of the oils are worthy to further investigation to find the probable mechanisms of action accountable for the noticeable toxic effect of these essential oils. PMID:27478777

  15. Mutagenicity, genotoxicity, and scavenging activities of extracts from the soft coral Chromonephthea braziliensis: a possibility of new bioactive compounds.

    PubMed

    Carpes, R M; Fleury, B G; Lages, B G; Pinto, A C; Aiub, C A F; Felzenszwalb, I

    2013-01-01

    Coral reefs are diverse ecosystems that have a high density of biodiversity leading to intense competition among species. These species may produce unknown substances, many with pharmacological value. Chromonephthea braziliensis is an invasive soft coral from the Indo-Pacific Ocean that is possibly transported by oil platforms and whose presence can be a threat to a region's biodiversity. This species produces secondary metabolites that are responsible for inducing damage to the local ecosystem. In the present study, extracts were prepared from dried colonies of C. braziliensis (solvents: hexane, dichloromethane, ethyl acetate, and methanol). We evaluated their mutagenicity using the Salmonella reverse mutation assay (TA97, TA98, TA100, and TA102 strains), their genotoxicity using the DNA breakage analysis and micronucleus assay, and scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl-free radical assay. Cytotoxicity and mutagenicity were not observed for any of the extracts. Genotoxicity was observed for the dichloromethane, ethyl acetate, and methanol extracts at high concentrations, but no DNA damage was observed in the micronucleus assay. Scavenging activity was not detected. PMID:24085422

  16. Effects of UV-B irradiation on the levels of anthocyanin, rutin and radical scavenging activity of buckwheat sprouts.

    PubMed

    Tsurunaga, Yoko; Takahashi, Tetsuya; Katsube, Takuya; Kudo, Akihide; Kuramitsu, Osamu; Ishiwata, Masaki; Matsumoto, Shingo

    2013-11-01

    The effects of various light compositions on the levels of anthocyanin, rutin and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity in buckwheat (Fagopyrum esculentum Moench) sprouts were evaluated. Dark-grown 6-day-old buckwheat sprouts were irradiated with different sources of visible and ultraviolet (UV) light. Particularly, we examined the effect of UV-B at wavelengths of 260-320 nm, 280-320 nm, and 300-320 nm on the production of flavonoid compounds, using multiple fluorescent lights and cylinders that filter out certain portions of the UV-B. The results showed that irradiation with UV-B>300 nm increased the levels of anthocyanin and rutin, as well as the DPPH radical scavenging activity. When sprouts were irradiated with UV-B light at wavelengths of 260-300 nm, yellowing or withering occurred within 24h of irradiation, indicating that wavelengths in this range are detrimental to the growth of buckwheat sprouts. PMID:23768393

  17. HPLC analysis of vitamin E isoforms in human epidermis: correlation with minimal erythema dose and free radical scavenging activity.

    PubMed

    Fuchs, Jürgen; Weber, Stefan; Podda, Maurizio; Groth, Norbert; Herrling, Thomas; Packer, Lester; Kaufmann, Roland

    2003-02-01

    The content and composition of different vitamin E isoforms was analyzed in normal human skin. Interestingly the epidermis contained 1% alpha-tocotrienol, 3% gamma-tocotrienol, 87% alpha-tocopherol, and 9% gamma-tocopherol. Although the levels of tocotrienol in human epidermis appear to be considerably lower than reported in the hairless mouse, the presence of significant amounts of tocotrienol levels leads to speculation about the physiological function of tocotrienols in skin. Besides antioxidant activity and photoprotection, tocotrienols may have skin barrier and growth-modulating properties. A good correlation was found for epidermal alpha-tocopherol (r = 0.7909, p <.0003), gamma-tocopherol (r = 0.556, p <.025), and the total vitamin E content (r = 0.831, p <.0001) with the free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging in epidermis, as assessed by electron paramagnetic resonance (EPR) spectroscopy. In human epidermis, alpha-tocopherol is quantitatively the most important vitamin E isoform present and comprises the bulk of first line free radical defense in the lipid compartment. Epidermal tocotrienol levels were not correlated with DPPH scavenging activity. The minimal erythema dose (MED), an individual measure for sun sensitivity and a crude indicator for skin cancer susceptibility, did not correlate with the epidermal content of the vitamin E isoforms. Hence it is concluded that vitamin E alone is not a determinant of individual photosensitivity in humans. PMID:12543248

  18. Ionizing Radiation Induces Macrophage Foam Cell Formation and Aggregation Through JNK-Dependent Activation of CD36 Scavenger Receptors

    SciTech Connect

    Katayama, Ikuo; Hotokezaka, Yuka; Matsuyama, Toshifumi; Sumi, Tadateru; Nakamura, Takashi

    2008-03-01

    Purpose: Irradiated arteries of cancer patients can be associated with atherosclerosis-like lesions containing cholesterol-laden macrophages (foam cells). Endothelial cell damage by irradiation does not completely explain the foam cell formation. We investigated the possible underlying mechanisms for ionizing radiation (IR)-induced foam cell formation. Methods and Materials: Human peripheral blood monocytes were activated by macrophage colony-stimulating factor and then treated with varying doses of IR in vitro in the absence of endothelial cells. Scavenger receptor expression and foam cell formation of IR-treated macrophages were investigated in the presence or absence of oxidized low-density lipoprotein. We also assessed the importance of mitogen-activated protein kinase activity in the macrophage colony-stimulating factor-activated human monocytes (macrophages) for the foam cell formation. Results: We found that IR treatment of macrophage colony-stimulating factor-activated human peripheral blood monocytes resulted in the enhanced expression of CD36 scavenger receptors and that cholesterol accumulated in the irradiated macrophages with resultant foam cell formation in the presence of oxidized low-density lipoprotein. Furthermore, when cultured on collagen gels, human macrophages formed large foam cell aggregates in response to IR. Antibodies against CD36 inhibited the IR-induced foam cell formation and aggregation, indicating that the IR-induced foam cell formation and the subsequent aggregation are dependent on functional CD36. In addition, we found that IR of human macrophages resulted in c-Jun N-terminal kinase activation and that c-Jun N-terminal kinase inhibition suppressed IR-induced CD36 expression and the subsequent foam cell formation and aggregation. Conclusion: Taken together, these results suggest that IR-induced foam cell formation is mediated by c-Jun N-terminal kinase-dependent CD36 activation.

  19. A Geospatial Scavenger Hunt

    ERIC Educational Resources Information Center

    Martinez, Adriana E.; Williams, Nikki A.; Metoyer, Sandra K.; Morris, Jennifer N.; Berhane, Stephen A.

    2009-01-01

    With the use of technology such as Global Positioning System (GPS) units and Google Earth for a simple-machine scavenger hunt, you will transform a standard identification activity into an exciting learning experience that motivates students, incorporates practical skills in technology, and enhances students' spatial-thinking skills. In the…

  20. Induction of benzo[a]pyrene Mono-oxygenase in liver cell culture by the photochemical generation of active oxygen species. Evidence for the involvement of singlet oxygen and the formation of a stable inducing intermediate.

    PubMed Central

    Paine, A J

    1976-01-01

    1. The photochemical generation of excited states of oxygen in liver cell culture by the mild ilumination of culture medium containing riboflavin, results in stimulation of benzo[a]pyrene 3-mono-oxygenase, a cytochrome P-450-linked mono-oxygenase. 2. The same large increase in mono-oxygenase activity was found when medium containing riboflavin was illuminated in the absence of cells and then stored in the dark for 24h before contact with the cells. From this it may be inferred that stimulation is due to the formation of a stable inducer in the culture medium. Further experiments indicate that the stable inducer is due to the photo-oxidation of an amino acid. 3. Evidence that singlet oxygen is responsible for initiating the stimulation of the mono-oxygenase is based on the use of molecules that scavenge particular active oxygen species. Of all the scavengers tested, only those that scavenge single oxygen inhibited the stimulation. 4. A hypothesis is developed to relate the stimulation of the mono-oxygenase by singlet oxygen in cultured cells to the regulation of the cytochrome P-450 enzyme system in vivo. It is suggested that single oxygen generation within cells may be a common factor linking the many structurally diverse inducers of the enzyme system. PMID:962887

  1. Induction of benzo[a]pyrene Mono-oxygenase in liver cell culture by the photochemical generation of active oxygen species. Evidence for the involvement of singlet oxygen and the formation of a stable inducing intermediate.

    PubMed

    Paine, A J

    1976-07-15

    1. The photochemical generation of excited states of oxygen in liver cell culture by the mild ilumination of culture medium containing riboflavin, results in stimulation of benzo[a]pyrene 3-mono-oxygenase, a cytochrome P-450-linked mono-oxygenase. 2. The same large increase in mono-oxygenase activity was found when medium containing riboflavin was illuminated in the absence of cells and then stored in the dark for 24h before contact with the cells. From this it may be inferred that stimulation is due to the formation of a stable inducer in the culture medium. Further experiments indicate that the stable inducer is due to the photo-oxidation of an amino acid. 3. Evidence that singlet oxygen is responsible for initiating the stimulation of the mono-oxygenase is based on the use of molecules that scavenge particular active oxygen species. Of all the scavengers tested, only those that scavenge single oxygen inhibited the stimulation. 4. A hypothesis is developed to relate the stimulation of the mono-oxygenase by singlet oxygen in cultured cells to the regulation of the cytochrome P-450 enzyme system in vivo. It is suggested that single oxygen generation within cells may be a common factor linking the many structurally diverse inducers of the enzyme system. PMID:962887

  2. A novel nematode effector suppresses plant immunity by activating host reactuve oxygen species-scavenging system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxidative burst is a hallmark event of the pathogen-associated molecular pattern (PAMP) triggered immunity (PTI), which is the first line of plant defense mechanisms, but it remains unclear how nematodes can overcome this defense mechanism. In this study, we show that plant-parasitic nematode Meloid...

  3. Correlation of antioxidants and antioxidant enzymes to oxygen radical scavenging activities in berries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Berry fruits contain high levels of antioxidant compounds. In addition to the usual nutrients such as vitamins and minerals, berry fruits are also rich in flavonols, anthocyanidins, proanthocyanidins, catechins, flavones, and their glycosides. These antioxidants are capable of performing a number of...

  4. Responses of reactive oxygen scavenging enzymes, proline and malondialdehyde to water deficits among six secondary successional seral species in Loess Plateau.

    PubMed

    Du, Feng; Shi, Huijun; Zhang, Xingchang; Xu, Xuexuan

    2014-01-01

    Drought can impact local vegetation dynamics in a long term. In order to predict the possible successional pathway of local community under drought, the responses of some drought resistance indices of six successional seral species in the semi-arid Loss Hilly Region of China were illustrated and compared on three levels of soil water deficits along three growing months (7, 8 and 9). The results showed that: 1) the six species had significant differences in SOD, POD activities and MDA content. The rank correlations between SOD, POD activities and the successional niche positions of the six species were positive, and the correlation between MDA content and the niche positions was negative; 2) activities of SOD, CAT and POD, and content of proline and MDA had significant differences among the three months; 3) there existed significant interactions of SOD, CAT, POD activities and MDA content between months and species. With an exception, no interaction of proline was found. Proline in leaves had a general decline in reproductive month; 4) SOD, CAT, POD activities and proline content had negative correlations with MDA content. Among which, the correlation between SOD activity and MDA content was significant. The results implied that, in arid or semiarid region, the species at later successional stage tend to have strong drought resistance than those at early stage. Anti-drought indices can partially interpret the pathway of community succession in the drought impacted area. SOD activity is more distinct and important on the scope of protecting membrane damage through the scavenging of ROS on exposure to drought. PMID:24914928

  5. Development of an in Silico Model of DPPH• Free Radical Scavenging Capacity: Prediction of Antioxidant Activity of Coumarin Type Compounds.

    PubMed

    Goya Jorge, Elizabeth; Rayar, Anita Maria; Barigye, Stephen J; Jorge Rodríguez, María Elisa; Sylla-Iyarreta Veitía, Maité

    2016-01-01

    A quantitative structure-activity relationship (QSAR) study of the 2,2-diphenyl-l-picrylhydrazyl (DPPH•) radical scavenging ability of 1373 chemical compounds, using DRAGON molecular descriptors (MD) and the neural network technique, a technique based on the multilayer multilayer perceptron (MLP), was developed. The built model demonstrated a satisfactory performance for the training ( R 2 = 0.713 ) and test set ( Q ext 2 = 0.654 ) , respectively. To gain greater insight on the relevance of the MD contained in the MLP model, sensitivity and principal component analyses were performed. Moreover, structural and mechanistic interpretation was carried out to comprehend the relationship of the variables in the model with the modeled property. The constructed MLP model was employed to predict the radical scavenging ability for a group of coumarin-type compounds. Finally, in order to validate the model's predictions, an in vitro assay for one of the compounds (4-hydroxycoumarin) was performed, showing a satisfactory proximity between the experimental and predicted pIC50 values. PMID:27338348

  6. Development of an in Silico Model of DPPH• Free Radical Scavenging Capacity: Prediction of Antioxidant Activity of Coumarin Type Compounds

    PubMed Central

    Goya Jorge, Elizabeth; Rayar, Anita Maria; Barigye, Stephen J.; Jorge Rodríguez, María Elisa; Sylla-Iyarreta Veitía, Maité

    2016-01-01

    A quantitative structure-activity relationship (QSAR) study of the 2,2-diphenyl-l-picrylhydrazyl (DPPH•) radical scavenging ability of 1373 chemical compounds, using DRAGON molecular descriptors (MD) and the neural network technique, a technique based on the multilayer multilayer perceptron (MLP), was developed. The built model demonstrated a satisfactory performance for the training (R2=0.713) and test set (Qext2=0.654), respectively. To gain greater insight on the relevance of the MD contained in the MLP model, sensitivity and principal component analyses were performed. Moreover, structural and mechanistic interpretation was carried out to comprehend the relationship of the variables in the model with the modeled property. The constructed MLP model was employed to predict the radical scavenging ability for a group of coumarin-type compounds. Finally, in order to validate the model’s predictions, an in vitro assay for one of the compounds (4-hydroxycoumarin) was performed, showing a satisfactory proximity between the experimental and predicted pIC50 values. PMID:27338348

  7. Composition and Free Radical Scavenging Activity of Kernel Oil from Torreya grandis, Carya Cathayensis, and Myrica R ubra.

    PubMed

    Ni, Liang; Shi, Wei-Yong

    2014-01-01

    In this study, we measured the composition and free radical scavenging activity of several species of nuts, namely, Torreya grandis, Carya cathayensis, and Myrica rubra. The nut kernels of the aforementioned species are rich in fatty acids, particularly in unsaturated fatty acids, and have 51% oil content. T. grandis and C. cathayensis are mostly produced in ZheJiang province. The trace elements in the kernels of T. grandis and C. cathayensis were generally higher than those in M. rubra, except for Fe with a value of 64.41 mg/Kg. T. grandis is rich in selenium (52.91-68.71 mg/Kg). All three kernel oils have a certain free radical scavenging capacity, with the highest value in M. rubra. In the DPPH assay, the IC50 of M. rubra kernel oil was 60 μg/mL, and OH was 100 μg/mL. The results of this study provide basic data for the future development of the edible nut resources in ZheJiang province. PMID:24734074

  8. Antioxidant Activity of Oxygen Evolving Enhancer Protein 1 Purified from Capsosiphon fulvescens.

    PubMed

    Kim, Eun-Young; Choi, Youn Hee; Lee, Jung Im; Kim, In-Hye; Nam, Taek-Jeong

    2015-06-01

    This study was conducted to determine the antioxidant activity of a protein purified from Capsosiphon fulvescens. The purification steps included sodium acetate (pH 6) extraction and diethylaminoethyl-cellulose, reversed phase Shodex C4P-50 column chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis indicated that the molecular weight of the purified protein was 33 kDa. The N-terminus and partial peptide amino acid sequence of this protein was identical to the sequence of oxygen evolving enhancer (OEE) 1 protein. The antioxidant activity of the OEE 1 was determined in vitro using a scavenging test with 4 types of reactive oxygen species (ROS), including the 2,2-diphenyl-1-picrylhydrazyl radical, hydroxyl radical, superoxide anion, and hydrogen peroxide (H2 O2 ). OEE 1 had higher H2 O2 scavenging activity, which proved to be the result of enzymatic antioxidants rather than nonenzymatic antioxidants. In addition, OEE 1 showed less H2 O2 -mediated ROS formation in HepG2 cells. In conclusion, this study demonstrates that OEE 1 purified from C. fulvescens is an excellent antioxidant. PMID:25944160

  9. In vitro studies on α-glucosidase inhibition, antioxidant and free radical scavenging activities of Hedyotis biflora L.

    PubMed

    Nimal Christhudas, I V S; Praveen Kumar, P; Sunil, Christudas; Vajravijayan, S; Lakshmi Sundaram, R; Jenifer Siril, S; Agastian, P

    2013-06-01

    Aim of this study was to evaluate the in vitro α-glucosidase inhibition and antioxidant activity of hexane, ethyl acetate and methanol extracts of Hedyotis biflora L. (Rubiaceae). In in vitro α-glucosidase inhibition and antioxidant activity, the methanol extract showed potent effect compared to hexane and ethyl acetate extracts. The methanol extract of H. biflora (HBMe) showed 50% α-glucosidase inhibition at the concentration of 480.20 ± 2.37 μg/ml. The total phenolic content of HBMe was 206.81 ± 1.11 mg of catechol equivalents/g extract. HBMe showed great scavenging activity on 2,2-diphenyl-picrylhydrazyl (DPPH) (IC(50) 520.21 ± 1.02 μg/ml), hydroxyl (IC(50) 510.21 ± 1.51 μg/ml), nitric oxide (IC(50) 690.20 ± 2.13 μg/ml) and superoxide (IC(50) 510.31 ± 1.45 μg/ml) radicals, as well as high reducing power. HBMe also showed a strong suppressive effect on lipid peroxidation. Using the β-carotene method, the scavenging values of HBMe was significantly lower than BHT, and metal chelating ability of HBMe also showed a strong inhibition effect when compared to the reference standard. The active compound ursolic acid from HBMe was identified using various spectroscopical studies. The results obtained in this study clearly indicate that HBMe has a significant potential to use as a natural α-glucosidase inhibition, antioxidant agent. PMID:23411299

  10. Effect of UV-C irradiation and low temperature storage on bioactive compounds, antioxidant enzymes and radical scavenging activity of papaya fruit.

    PubMed

    Rivera-Pastrana, Dulce M; Gardea, Alfonso A; Yahia, Elhadi M; Martínez-Téllez, Miguel A; González-Aguilar, Gustavo A

    2014-12-01

    Mature green 'Maradol' papaya fruits were exposed to ultraviolet (UV)-C irradiation (1.48 kJ·m(-2)) and stored at 5 or 14 °C. Changes in total phenols, total flavonoids, enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), as well as the scavenging activity against 2,2-diphenyl-1picrylhydrazyl (DPPH) and 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals were investigated in peel and flesh tissues at 0, 5, 10 and 15 days of storage. UV-C irradiation increased significantly (P < 0.05) the flavonoid content (2.5 and 26 %) and ABTS radical scavenging activity (5.7 and 6 %) in flesh and peel at 14 °C respectively; and CAT activity (16.7 %) in flesh at 5 °C. Flavonoid contents, CAT and SOD activities were positively affected under low storage temperature (5 °C). DPPH and ABTS radical scavenging activities increased in both control and UV-C treated papaya peel during storage at 5 °C. UV-C irradiation effect on radical scavenging of papaya peel could be attributed to increased flavonoid content. Papaya antioxidant system was activated by UV-C and cold storage by increasing phenolic content and antioxidant enzymatic activities as a defense response against oxidative-stress. PMID:25477649

  11. Liquid chromatograpic-mass spectrometric analysis of phenolics and free radical scavenging activity of rosemary extract from different raw material.

    PubMed

    Almela, Luis; Sánchez-Muñoz, Blas; Fernández-López, José A; Roca, María J; Rabe, Virginia

    2006-07-01

    The antioxidant activity of rosemary (Rosmarinus officinalis) extract from different raw materials has been studied. Extracts were prepared from wild or drip-irrigated plants, as well as from the by-product resulting from the distillation of the aromatic essential oil. The radical scavenging activity of rosemary extracts was compared with that of antioxidants widely used in food, such as BHT and delta-tocopherol, using an optimization of the method based on the reduction of the radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). The results pointed the excellent antioxidant activity of the crude fresh rosemary extracts, which was almost identical to that of pure delta-tocopherol, and higher than that of BHT; extracts prepared from distilled rosemary showed the lowest activity, although they are also of interest due to the low cost of the raw material. High performance liquid chromatography (HPLC) combined with diode array (DAD) and electrospray (ESI)-ion trap-MS detection was used to separate and identify the compounds present in the rosemary extracts. Rosmarinic acid, carnosic acid and seven of their terpene-type metabolites, and seven flavones were identified. The drying and/or distillation treatments used with the plant material strongly affected the content of the two compounds of higher antioxidant activity: rosmarinic acid and carnosic acid. PMID:16563403

  12. Cleavage of Type I Collagen by Fibroblast Activation Protein-α Enhances Class A Scavenger Receptor Mediated Macrophage Adhesion

    PubMed Central

    Mazur, Anna; Holthoff, Emily; Vadali, Shanthi; Kelly, Thomas; Post, Steven R.

    2016-01-01

    Pathophysiological conditions such as fibrosis, inflammation, and tumor progression are associated with modification of the extracellular matrix (ECM). These modifications create ligands that differentially interact with cells to promote responses that drive pathological processes. Within the tumor stroma, fibroblasts are activated and increase the expression of type I collagen. In addition, activated fibroblasts specifically express fibroblast activation protein-α (FAP), a post-prolyl peptidase. Although FAP reportedly cleaves type I collagen and contributes to tumor progression, the specific pathophysiologic role of FAP is not clear. In this study, the possibility that FAP-mediated cleavage of type I collagen modulates macrophage interaction with collagen was examined using macrophage adhesion assays. Our results demonstrate that FAP selectively cleaves type I collagen resulting in increased macrophage adhesion. Increased macrophage adhesion to FAP-cleaved collagen was not affected by inhibiting integrin-mediated interactions, but was abolished in macrophages lacking the class A scavenger receptor (SR-A/CD204). Further, SR-A expressing macrophages localize with activated fibroblasts in breast tumors of MMTV-PyMT mice. Together, these results demonstrate that FAP-cleaved collagen is a substrate for SR-A-dependent macrophage adhesion, and suggest that by modifying the ECM, FAP plays a novel role in mediating communication between activated fibroblasts and macrophages. PMID:26934296

  13. Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations.

    PubMed

    Slavova-Kazakova, Adriana K; Angelova, Silvia E; Veprintsev, Timur L; Denev, Petko; Fabbri, Davide; Dettori, Maria Antonietta; Kratchanova, Maria; Naumov, Vladimir V; Trofimov, Aleksei V; Vasil'ev, Rostislav F; Delogu, Giovanna; Kancheva, Vessela D

    2015-01-01

    This study compares the ability to scavenge different peroxyl radicals and to act as chain-breaking antioxidants of monomers related to curcumin (1): dehydrozingerone (2), zingerone (3), (2Z,5E)-ethyl 2-hydroxy-6-(4-hydroxy-3-methoxyphenyl)-4-oxohexa-2,5-dienoate (4), ferulic acid (5) and their corresponding C 2-symmetric dimers 6-9. Four models were applied: model 1 - chemiluminescence (CL) of a hydrocarbon substrate used for determination of the rate constants (k A) of the reactions of the antioxidants with peroxyl radicals; model 2 - lipid autoxidation (lipidAO) used for assessing the chain-breaking antioxidant efficiency and reactivity; model 3 - oxygen radical absorbance capacity (ORAC), which yields the activity against peroxyl radicals generated by an azoinitiator; model 4 - density functional theory (DFT) calculations at UB3LYP/6-31+G(d,p) level, applied to explain the structure-activity relationship. Dimers showed 2-2.5-fold higher values of k A than their monomers. Model 2 gives information about the effects of the side chains and revealed much higher antioxidant activity for monomers and dimers with α,β-unsaturated side chains. Curcumin and 6 in fact are dimers of the same monomer 2. We conclude that the type of linkage between the two "halves" by which the molecule is made up does not exert influence on the antioxidant efficiency and reactivity of these two dimers. The dimers and the monomers demonstrated higher activity than Trolox (10) in aqueous medium (model 3). A comparison of the studied compounds with DL-α-tocopherol (11), Trolox and curcumin is made. All dimers are characterized through lower bond dissociation enthalpies (BDEs) than their monomers (model 4), which qualitatively supports the experimental results. PMID:26425195

  14. Antioxidant potential of curcumin-related compounds studied by chemiluminescence kinetics, chain-breaking efficiencies, scavenging activity (ORAC) and DFT calculations

    PubMed Central

    Slavova-Kazakova, Adriana K; Angelova, Silvia E; Veprintsev, Timur L; Denev, Petko; Fabbri, Davide; Dettori, Maria Antonietta; Kratchanova, Maria; Naumov, Vladimir V; Trofimov, Aleksei V; Vasil’ev, Rostislav F

    2015-01-01

    Summary This study compares the ability to scavenge different peroxyl radicals and to act as chain-breaking antioxidants of monomers related to curcumin (1): dehydrozingerone (2), zingerone (3), (2Z,5E)-ethyl 2-hydroxy-6-(4-hydroxy-3-methoxyphenyl)-4-oxohexa-2,5-dienoate (4), ferulic acid (5) and their corresponding C 2-symmetric dimers 6–9. Four models were applied: model 1 – chemiluminescence (CL) of a hydrocarbon substrate used for determination of the rate constants (k A) of the reactions of the antioxidants with peroxyl radicals; model 2 – lipid autoxidation (lipidAO) used for assessing the chain-breaking antioxidant efficiency and reactivity; model 3 – oxygen radical absorbance capacity (ORAC), which yields the activity against peroxyl radicals generated by an azoinitiator; model 4 – density functional theory (DFT) calculations at UB3LYP/6-31+G(d,p) level, applied to explain the structure–activity relationship. Dimers showed 2–2.5-fold higher values of k A than their monomers. Model 2 gives information about the effects of the side chains and revealed much higher antioxidant activity for monomers and dimers with α,β-unsaturated side chains. Curcumin and 6 in fact are dimers of the same monomer 2. We conclude that the type of linkage between the two “halves” by which the molecule is made up does not exert influence on the antioxidant efficiency and reactivity of these two dimers. The dimers and the monomers demonstrated higher activity than Trolox (10) in aqueous medium (model 3). A comparison of the studied compounds with DL-α-tocopherol (11), Trolox and curcumin is made. All dimers are characterized through lower bond dissociation enthalpies (BDEs) than their monomers (model 4), which qualitatively supports the experimental results. PMID:26425195

  15. Free radicals scavenging action and anti-enzyme activities of procyanidines from Vitis vinifera. A mechanism for their capillary protective action.

    PubMed

    Maffei Facino, R; Carini, M; Aldini, G; Bombardelli, E; Morazzoni, P; Morelli, R

    1994-05-01

    The scavenging by procyanidines (polyphenol oligomers from Vitis vinifera seeds, CAS 85594-37-2) of reactive oxygen species (ROS) involved in the onset (HO degrees) and the maintenance of microvascular injury (lipid radicals R degrees, RO degrees, ROO degrees) has been studied in phosphatidylcholine liposomes (PCL), using two different models of free radical generation: a) iron-promoted and b) ultrasound-induced lipid peroxidation. In a) lipid peroxidation was assessed by determination of thiobarbituric acid-reactive substances (TBARS); in b) by determination of conjugated dienes, formation of breakdown carbonyl products (as 2,4-dinitrophenylhydrazones) and loss of native phosphatidylcholine. In the iron-promoted (Fenton-driven) model, procyanidines had a remarkable, dose-dependent antilipoperoxidant activity (IC50 = 2.5 mumol/l), more than one order of magnitude greater than that of the monomeric unit catechin (IC50 = 50 mumol/l), activity which is due, at least in part, to their metal-chelating properties. In the more specific model b), which discriminates between the initiator (hydroxyl radical from water sonolysis) and the propagator species of lipid peroxidation (the peroxyl radical, from autooxidation of C-centered radicals), procyanidines are highly effective in preventing conjugated diene formation in both the induction (IC50 = 0.1 mumol/l) and propagation (IC50 = 0.05 mumol/l) phases (the scavenging effect of alpha-tocopherol was weaker, with IC50 of 1.5 and 1.25 mumol/l). In addition, procyanidines at 0.5 mumol/l markedly delayed the onset of the breakdown phase (48 h), totally inhibiting during this time the formation of degradation products (the lag-time induced by alpha-tocopherol was only of 24 h at 10 mumol/l concentration). The HO degrees entrapping capacity of these compounds was further confirmed by UV studies and by electron spin resonance (ESR) spectroscopy, using DMPO as spin trapper: procyanidines markedly reduced, in a dose-dependent fashion

  16. In vitro synthesis of betaxanthins using recombinant DOPA 4,5-dioxygenase and evaluation of their radical-scavenging activities.

    PubMed

    Sekiguchi, Hiroshi; Ozeki, Yoshihiro; Sasaki, Nobuhiro

    2010-12-01

    Betalamic acid, the chromophore of betaxanthins, was enzymatically synthesized on a large scale from l-dihydroxyphenylalanine (L-DOPA) using recombinant Mirabilis jalapa DOPA 4,5-dioxygenase. After synthesis, proline was directly added to the concentrated reaction mixture to generate proline-betaxanthin. The molecular mass and nuclear magnetic resonance spectrum of the purified product were identical to those previously reported for proline-betaxanthin. Twenty-four betaxanthin species were synthesized by the condensation reaction of purified betalamic acid and amino acids or amines. An HPLC protocol was established for identifying the different betaxanthin species. Proline-, dopamine-, and γ-aminobutyric acid (GABA)-betaxanthins were prepared as representative betaxanthins under large-scale conditions, and their 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activities were compared against those of known antioxidants. GABA-betaxanthin showed comparatively low activity, whereas dopamine-betaxanthin had similar activity to the red pigment betanin and the anthocyanin cyanidin 3-glucoside. Proline-betaxanthin had the highest activity of the three synthesized compounds and was similar to the flavonoid quercetin. PMID:21058725

  17. Free Radical Scavenging, Cytotoxic and Hemolytic Activities from Leaves of Acacia nilotica (L.) Wild. ex. Delile subsp. indica (Benth.) Brenan

    PubMed Central

    Kalaivani, T.; Rajasekaran, C.; Suthindhiran, K.; Mathew, Lazar

    2011-01-01

    Dietary intake of phytochemicals having antioxidant activity is associated with a lower risk of mortality from many diseases. Therefore, the aim of this study was to determine the free radical scavenging, cytotoxic and hemolytic activities of leaves of Acacia nilotica by using various methods. The results of the present study revealed that ethanol extract was the most effective and IC50 value was found to be 53.6 μg mL−1 for Vero cell lines and 28.9 μg mL−1 for Hela cell lines in cytotoxicity assays. The zone of color retention was 14.2 mm in β-carotene bleaching assay, which was as significant as positive control, butylated hydroxy toluene. None of the tested extracts possessed any hemolytic activity against rat and human erythrocytes revealing their cytotoxic mechanism and non-toxicity. Thus, only the ethanol extract could be considered as a potential source of anticancer and antioxidant compounds. Further phytochemical studies will be performed for specification of the biologically active principles. PMID:21799676

  18. Pharmacognostic standardization, antioxidant and free radical scavenging activity of the seeds of Triticum aestivum L - A dietary staple

    PubMed Central

    Khan, Ghulam M.; Ansari, Shahid H.; Ahmad, Feroz

    2013-01-01

    Aims To establish the Quality standards of Triticum aestivum L, seeds as per WHO guidelines. To study the antioxidant and hepatoprotective profile of T. aestivum L. seeds. Methods Pharmacognostic studies like morphological, microscopical, physico-chemical, phytochemical evaluation, fluorescence analysis, TLC, HPTLC, phytochemical analysis etc. of various extracts of the seeds of T. aestivum were carried out as per established methods. The ethanolic extract was evaluated for antioxidant and hepatoprotective activity using rat model. Results Preliminary phytochemical analysis mainly revealed the presence of carbohydrates, phenolics, proteins, resins, lipids and flavonoids. T. aestivum at different doses, i.e. 5-45 μg/ml showed free radical scavenging activity in dose dependent manner. The amount of phenolic components was found to be 313.5 μg/mg indicating considerable antioxidant activity. The ethanolic extract of T. aestivum was administered at dose level of 100 mg/kg/day, every day for 21 days along with CCl4. Biochemical and histopathological results conclude that the seeds have hepatoprotective activity. PMID:24023455

  19. SAFETY ASPECTS OF OXYGEN AERATION ACTIVATED SLUDGE SYSTEMS

    EPA Science Inventory

    This project was carried out to assess the impact of the use of oxygen and oxygen-enriched air for aeration of activated sludge systems on the safety of municipal waste-water treatment plants and their personnel. The tasks included (1) determination of oxygen combustion hazards f...

  20. Henry's Law Activity of Oxygen in Molten Iron

    NASA Astrophysics Data System (ADS)

    Matousek, J. W.

    2015-09-01

    A model is proposed for the solubility of oxygen in molten iron in dilute solutions in which the oxygen exists in two states, free and associated. Only the free oxygen has thermodynamic activity in the sense of interaction with an electrochemical cell to produce the voltage described by the Nernst equation.

  1. BIOLOGICALLY ENHANCED OXYGEN TRANSFER IN THE ACTIVATED SLUDGE PROCESS (JOURNAL)

    EPA Science Inventory

    Biologically enhanced oxgyen transfer has been a hypothesis to explain observed oxygen transfer rates in activated sludge systems that were well above that predicted from aerator clean-water testing. The enhanced oxygen transfer rates were based on tests using BOD bottle oxygen ...

  2. Anti-inflammatory, free radical scavenging and alpha-glucosidase inhibitory activities of Hamelia patens and its chemical constituents.

    PubMed

    Jiménez-Suárez, Verónica; Nieto-Camacho, Antonio; Jiménez-Estrada, Manuel; Alvarado Sánchez, Brenda

    2016-09-01

    Context Hamelia patens Jacq. (Rubiaceae) is traditionally used to treat wounds, inflammation and diabetes. However, there is still a lack of scientific evidence to support these applications. Objective The objective of this study is to evaluate the anti-inflammatory, antioxidant and antidiabetic activities of Hamelia patens, and identify its bioactive compounds. Materials and methods Four extracts were obtained by maceration and liquid-liquid extraction: HEX, DCM-EtOAc, MeOH-EtOAc and MeOH-Aq. The anti-inflammatory effect was evaluated orally on rat paw carrageenan-induced oedema over 6 h (50, 200 and 500 mg/kg), and topically in mouse ear oedema induced by 12-tetradecanoylphorbol-13-acetate (TPA) after 4 h (0.5 and 1 mg/ear). We also evaluated myeloperoxidase levels in ear tissue, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging ability, and in vitro α-glucosidase inhibition. The chemical compounds were separated by column chromatography and identified by spectroscopic analysis. Results We found that the oral administration of the HEX extract at 500 and 200 mg/kg significantly decreased the carrageenan-induced inflammation after 1 and 3 h, respectively. The MeOH-EtOAc extract significantly inhibited myeloperoxidase activity (83.5%), followed by the DCM-EtOAc extract (76%), β-sitosterol/stigmasterol (72.7%) and the HEX extract (55%), which significantly decreased oedema induced by TPA at both doses, giving a similar effect to indomethacin. We also found that the MeOH-EtOAc, MeOH-Aq and DCM-EtOAc extracts showed good DPPH scavenging activity (IC50 values of 18.6, 93.9 and 158.2 μg/mL, respectively). The HEX extract showed the lowest α-glucosidase inhibition (an IC50 value of 26.07 μg/mL), followed by the MeOH-EtOAc extract (an IC50 value of 30.18 μg/mL), β-sitosterol/stigmasterol (IC50 34.6 μg/mL) and compound A ((6E,10E,14E,18E)-2,6,10,14,18,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene, an IC50 value of 114.6 μg/mL), which were

  3. DPPH scavenging, PRAP activities and essential oil composition of edible Lathyrus ochrus L. (Cyprus Vetch, Luvana) from Cyprus.

    PubMed

    Polatoğlu, Kaan; Arsal, Seniha; Demirci, Betül; Başer, Kemal Hüsnü Can

    2015-01-01

    The essential oil of the aerial parts of edible Lathyrus ochrus L. was investigated by simultaneous GC, GC/MS analyses under the same conditions. Trace amount of oil (0.01> mL) obtained by hydro distillation of 200 g fresh plants was trapped in 1 mL n-hexane. Twenty components were detected representing 91.55 ± 0.56 % of the oil. The main components were phytol 49.39 ± 0.44 %, hexadecanoic acid 20.64 ± 0.89 % and pentacosane 4.20 ± 0.09 %. Essential oil solution (1% oil: n-hexane) afforded similar DPPH scavenging activity (9.28 ± 1.30 %) when compared with positive controls α-tocopherol (9.74 ± 0.21 %) and BHT (7.79 ± 0.26 %) at the same concentrations. Antioxidant activity of the oil was determined using a new HPTLC-PRAP assay. The oil afforded two fold higher reducing activity of phosphomolybdenum complex (594.85 ± 5.14 AU) when compared with positive controls α- tocopherol (271.10 ± 2.86 AU) and BHT (210.53 ± 1.81 AU) at the same concentration. PMID:25757435

  4. Changes of Major Antioxidant Compounds and Radical Scavenging Activity of Palm Oil and Rice Bran Oil during Deep-Frying

    PubMed Central

    Abdul Hamid, Azizah; Pak Dek, Mohd Sabri; Tan, Chin Ping; Mohd Zainudin, Mohd Asraf; Wee Fang, Evelyn Koh

    2014-01-01

    Changes in antioxidant properties and degradation of bioactives in palm oil (PO) and rice bran oil (RBO) during deep-frying were investigated. The alpha (α)-tocopherol, gamma (γ)-tocotrienol and γ-oryzanol contents of the deep-fried oils were monitored using high performance liquid chromatography, and antioxidant activity was determined using 2-diphenyl-1-picryl hydrazyl (DPPH) radical scavenging activity. Results revealed that the antioxidant activity of PO decreased significantly (p < 0.05), while that of RBO was preserved after deep-frying of fries. As expected, the concentration of α-tocopherol in PO and γ-tocotrienol in both PO and RBO decreased significantly (p < 0.05) with increased frying. Results also showed that γ-tocotrienol was found to be more susceptible to degradation compared to that of α-tocopherol in both PO and RBO. Interestingly, no significant degradation of α-tocopherol was observed in RBO. It is suggested that the presence of γ-oryzanol and γ-tocotrienol in RBO may have a protective effect on α-tocopherol during deep-frying. PMID:26785067

  5. Changes of hydrogen peroxide and radical-scavenging activity of raspberry during osmotic, convective, and freeze-drying.

    PubMed

    Novaković, Miroslav M; Stevanović, Snežana M; Gorjanović, Stanislava Ž; Jovanovic, Predrag M; Tešević, Vele V; Janković, Miodrag A; Sužnjević, Desanka Ž

    2011-05-01

    This study was conducted to investigate the influence of different drying treatments on antioxidant (AO) activity and phenolic content of raspberry (Rubus idaeus), cultivar Willamette. Whole raspberry fruits were dried convectively (air-drying), osmotically, and freeze-dried. Acetone-water extracts of fresh and dried raspberries were assessed for total phenolic content by standard Folin-Ciocalteau method. Two AO assays were applied, a recently developed direct current (DC) polarographic assay based on decrease of anodic oxidation current of hydrogen peroxide and widely used radical scavenge against the 1,1-diphenyl-2-picrylhydrazyl (DPPH). Strong correlation has been obtained between both AO assays and total phenolic content. In addition, some individual phenolic compounds present in raspberry have been assessed using DPPH and DC polarographic assay. Comparison and evaluation of drying methods has been based on preservation of AO activity and total phenolic content. Obtained results confirmed superiority of freeze-drying; convective drying caused slight changes while osmotic dehydration showed a significant decrease of phenolic compounds and AO activity. PMID:22417351

  6. Correlation of In Vivo and In Vitro Assay Results for Assessment of Free Radical Scavenging Activity of Green Tea Nutraceuticals.

    PubMed

    Abd-ElSalam, Heba-Alla H; Al-Ghobashy, Medhat A; Al-Shorbagy, Muhammad; Nassar, Noha; Zaazaa, Hala E; Ibrahim, Mohamed A

    2016-07-01

    Green tea (GT)-derived catechins; epigallocatechin gallate (EGCG) in particular are commonly used nutraceuticals for their free-radical scavenging activity (FRSA). The influence of photodegradation on the protective power of GT nutracenticals against oxidative stress was thoroughly explored. Photodegradation of GT extracts was carried out and monitored using orthogonal stability-indicating testing protocol; in vitro and in vivo assays. Total polyphenol content (TPC) and FRSA were determined spectrophotometrically while EGCG was selectively monitored using SPE-HPLC. In vivo assessment of photodegraded samples was investigated via measuring a number of biomarkers for hepatic oxidative stress and apoptosis (caspase-3, inducible nitric oxide synthase, nitric oxide, mitogen-activated protein kinase, glutathione, thiobarbituric acid reactive substances, nuclear factor kappa beta, and nuclear factor erythroid 2-related factor) as well as liver damage (alanine transaminase and aspartate transaminase) in serum of rats previously subjected to oxidative stress. Results showed complete degradation of EGCG in photodegraded green tea samples with no correlation with either TPC or FRSA. On the other hand, in vivo assay results revealed not only loss of activity but formation of harmful pro-oxidants. Photostability was found crucial for the protective effect of GT extract against lead acetate insult. Results confirmed that careful design of quality control protocols requires correlation of chemical assays to bioassays to verify efficacy, stability, and most importantly safety of nutraceuticals. PMID:27275932

  7. The flavonoid content and antiproliferative, hypoglycaemic, anti-inflammatory and free radical scavenging activities of Annona dioica St. Hill

    PubMed Central

    2013-01-01

    Background Annona dioica St. Hill (Annonacaeae) is a Brazilian plant used in folk medicine for the treatment of several types of rheumatisms and diarrhoea. The focus of this work was to evaluate the in vitro antiproliferative and antioxidant activity and the in vivo hypoglycaemic and anti-inflammatory activity of A. dioica and identify the principal constituents of this plant. Methods The crude methanol extract (EAD) and hexane (HF), chloroform (CF), ethyl acetate (EAF) and hydromethanol fractions (HMF) were evaluated for free radical scavenging activity using the DPPH assay. The EAD and EAF were assayed for hypoglycaemic activity in rats. The EAD was tested in an antiproliferation assay and for anti-inflammatory effects in paw oedema, in addition to myeloperoxidase activity induced by carrageenan (Cg) in mice. The EAF was assayed using chromatographic methods. Results The fractionation of the EAF through chromatographic methods identified derivatives of the flavonoids quercetin and kaempferol. Among all the tested fractions, the ethyl acetate and hydromethanol fractions were the most potent, exhibiting an IC50 of 8.53 and 10.57 μg/mL, respectively, which is comparable to that of the commercial antioxidant butylated hydroxytoluene (BHT). The oral administration of the EAD (100 mg/kg) and EAF (15 mg/kg) inhibited the increase of glucose levels, resulting in a hypoglycaemic effect. The EAD (30 to 300 mg/kg) exhibited an anti-oedematogenic effect in Cg-induced paw oedema in a time- and dose-dependent manner. The results showed a reduction of MPO activity by A. dioica 6 h after the induction of paw oedema at all doses tested with maximal inhibition at 300 mg/kg. Conclusions Our results reveal for the first time that compounds contained in the A. dioica leaves exert anti-inflammatory, hypoglycaemic, antiproliferative, and antioxidant effects. The antioxidant activity may be associated with the presence of flavonoids. PMID:23311341

  8. From Synthesis to Biological Impact of Pd (II) Complexes: Synthesis, Characterization, and Antimicrobial and Scavenging Activity

    PubMed Central

    Sharma, Nitin Kumar; Ameta, Rakesh Kumar; Singh, Man

    2016-01-01

    The Pd (II) complexes with a series of halosubstituted benzylamine ligands (BLs) have been synthesized and characterized with different spectroscopic technique such as FTIR, UV/Vis, LCMS, 1H, and 13C NMR. Their molecular sustainability in different solvents such as DMSO, DMSO : H2O, and DMSO : PBS at physiological condition (pH 7.2) was determined by UV/Vis spectrophotometer. The in vitro antibacterial and antifungal activities of the complexes were investigated against Gram-positive and Gram-negative microbes and two different fungi indicated their significant biological potential. Additionally, their antioxidant activity has been analyzed with DPPH• free radical through spectrophotometric method and the result inferred them as an antioxidant. The stronger antibacterial and antioxidant activities of the synthesized complexes suggested them as a stronger antimicrobial agent. Our study advances the biological importance of palladium (II) amine complexes in the field of antimicrobial and antioxidant activities. PMID:27119023

  9. From Synthesis to Biological Impact of Pd (II) Complexes: Synthesis, Characterization, and Antimicrobial and Scavenging Activity.

    PubMed

    Sharma, Nitin Kumar; Ameta, Rakesh Kumar; Singh, Man

    2016-01-01

    The Pd (II) complexes with a series of halosubstituted benzylamine ligands (BLs) have been synthesized and characterized with different spectroscopic technique such as FTIR, UV/Vis, LCMS, (1)H, and (13)C NMR. Their molecular sustainability in different solvents such as DMSO, DMSO : H2O, and DMSO : PBS at physiological condition (pH 7.2) was determined by UV/Vis spectrophotometer. The in vitro antibacterial and antifungal activities of the complexes were investigated against Gram-positive and Gram-negative microbes and two different fungi indicated their significant biological potential. Additionally, their antioxidant activity has been analyzed with DPPH(•) free radical through spectrophotometric method and the result inferred them as an antioxidant. The stronger antibacterial and antioxidant activities of the synthesized complexes suggested them as a stronger antimicrobial agent. Our study advances the biological importance of palladium (II) amine complexes in the field of antimicrobial and antioxidant activities. PMID:27119023

  10. Scavenger Activity Evaluation of the Clove Bud Essential Oil (Eugenia caryophyllus) and Eugenol Derivatives Employing ABTS+• Decolorization

    PubMed Central

    Merchán Arenas, Diego R.; Acevedo, Amner Muñoz; Vargas Méndez, Leonor Y.; Kouznetsov, Vladimir V.

    2011-01-01

    The essential oil (EO) of clove bud dried fruits from Eugenia caryophyllus was obtained by a conventional hydrodistillation process in an excellent yield (11.7 %). Its chemical composition was analyzed by GC-MS, identifying eugenol as a main constituent (60.5%). Four eugenol-like molecules, γ-diisoeugenol, hydroxymethyleugenol, dihydroeugenol and 1,3-dioxanylphenol, were synthesized using eugenol or isoeugenol as initial precursors under green chemistry protocols. To evaluate the possible antioxidant capacity of eugenol compounds including the clove bud EO, the Trolox® Equivalent Antioxidant Capacity value, obtained by the ABTS+• radical-cation discoloration method, was employed. The methodology was performed in a UV-Vis reader of 96-well microplates (dilution methodology), using well-known antioxidant agents (BHA, BHT and vitamin E) as reference compounds. It was found that the prepared eugenol derivatives had a more potent free radical scavenger activity than the reference compounds. In particular, the most active molecules, γ-diisoeugenol and 1,3-dioxanylphenol, were ca. 3-fold more potent than vitamin E. PMID:22145105

  11. Class A scavenger receptor promotes osteoclast differentiation via the enhanced expression of receptor activator of NF-{kappa}B (RANK)

    SciTech Connect

    Takemura, Kenichi; Sakashita, Naomi; Fujiwara, Yukio; Komohara, Yoshihiro; Lei, XiaoFeng; Ohnishi, Koji; Suzuki, Hiroshi; Kodama, Tatsuhiko; Mizuta, Hiroshi; Takeya, Motohiro

    2010-01-22

    Osteoclasts originate from bone marrow monocyte/macrophage lineage cells, and their differentiation depends on macrophage colony-stimulating factor (M-CSF) and receptor activator nuclear factor kappa B (RANK) ligand. Class A scavenger receptor (SR-A) is one of the principal functional molecules of macrophages, and its level of expression declines during osteoclast differentiation. To investigate the role of SR-A in osteoclastogenesis, we examined pathological changes in femoral bone and the expression levels of osteoclastogenesis-related molecules in SR-A{sup -/-} mice. The femoral osseous density of SR-A{sup -/-} mice was higher than that of SR-A{sup +/+} mice, and the number of multinucleated osteoclasts was significantly decreased. An in vitro differentiation assay revealed that the differentiation of multinucleated osteoclasts from bone marrow-derived progenitor cells is impaired in SR-A{sup -/-} mice. Elimination of SR-A did not alter the expression level of the M-CSF receptor, c-fms; however, the expression levels of RANK and RANK-related osteoclast-differentiation molecules such as nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1) and microphthalmia-associated transcription factor (MITF) significantly decreased. Furthermore, acetylated low-density lipoprotein (AcLDL), an SR-A ligand, significantly increased the expression level of RANK and MITF during osteoclast differentiation. These data indicate that SR-A promotes osteoclastogenesis via augmentation of the expression level of RANK and its related molecules.

  12. Alternative activation of macrophages and pulmonary fibrosis are modulated by scavenger receptor, macrophage receptor with collagenous structure.

    PubMed

    Murthy, Shubha; Larson-Casey, Jennifer L; Ryan, Alan J; He, Chao; Kobzik, Lester; Carter, A Brent

    2015-08-01

    Alternative activation of alveolar macrophages is linked to fibrosis following exposure to asbestos. The scavenger receptor, macrophage receptor with collagenous structure (MARCO), provides innate immune defense against inhaled particles and pathogens; however, a receptor for asbestos has not been identified. We hypothesized that MARCO acts as an initial signaling receptor for asbestos, polarizes macrophages to a profibrotic M2 phenotype, and is required for the development of asbestos-induced fibrosis. Compared with normal subjects, alveolar macrophages isolated from patients with asbestosis express higher amounts of MARCO and have greater profibrotic polarization. Arginase 1 (40-fold) and IL-10 (265-fold) were higher in patients. In vivo, the genetic deletion of MARCO attenuated the profibrotic environment and pulmonary fibrosis in mice exposed to chrysotile. Moreover, alveolar macrophages from MARCO(-/-) mice polarize to an M1 phenotype, whereas wild-type mice have higher Ym1 (>3.0-fold) and nearly 7-fold more active TGF-β1 in bronchoalveolar lavage (BAL) fluid (BALF). Arg(432) and Arg(434) in domain V of MARCO are required for the polarization of macrophages to a profibrotic phenotype as mutation of these residues reduced FIZZ1 expression (17-fold) compared with cells expressing MARCO. These observations demonstrate that a macrophage membrane protein regulates the fibrotic response to lung injury and suggest a novel target for therapeutic intervention. PMID:25953850

  13. Crocin and geniposide profiles and radical scavenging activity of gardenia fruits (Gardenia jasminoides Ellis) from different cultivars and at the various stages of maturation.

    PubMed

    Chen, Yang; Zhang, Hao; Li, Yi-Xin; Cai, Le; Huang, Juan; Zhao, Can; Jia, Lin; Buchanan, Ryan; Yang, Ting; Jiang, Li-Juan

    2010-06-01

    The major components of gardenia fruits are geniposide and water soluble pigment crocins. In this study, we investigate crocins and geniposide profiles of gardenia fruits from different cultivars and at the various stages of maturation. DPPH scavenging activity of gardenia fruits from different cultivars and at the various stages of fruit maturation was also assayed. Quantitative determination of crocins in the gardenia at the various stages of maturation revealed a significant increase when ripening. However, geniposide content was negatively correlated with ripening stages. A significant difference was observed when comparing crocin content of different gardenia from various cultivars and geniposide content also showed marked variety. Current study indicated no relationship between crocin and geniposide content in gardenia fruits at the various stages of maturation and DPPH radical scavenging activity. Data showed that, although crocins feature markedly less DPPH scavenging activity than gardenia ethanol extract, total crocin content of gardenias collected in various cultivars correlate, to a certain degree, with radical scavenging effects of the Chinese traditional medicine (r=0.75). PMID:19815056

  14. FREE RADICAL SCAVENGING CAPACITY AND ANTIOXIDANT ENZYME ACTIVITY IN DEERBERRY (Vaccinium stamineum L.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit from three genotypes (B-76, B-59 and SHF-3A) of deerberry [Vaccinium stamineum L.] were evaluated for fruit quality, total anthocyanin and phenolic contents, antioxidants, antioxidant capacity, and antioxidant enzyme activity. The fruit soluble solids, titratable acids, total anthocyanins, an...

  15. Proton-Coupled Electron-Transfer Mechanism for the Radical Scavenging Activity of Cardiovascular Drug Dipyridamole

    PubMed Central

    Barzegar, Abolfazl

    2012-01-01

    Dipyridamole (DIP) is a well-known pharmaceutical drug used as a coronary vasodilator and anti-platelet agent in clinics for treating several cardiovascular diseases. Primarily, the therapeutic effects of the drug are attributed to its antioxidant potency. In this research, we aim to declare the unknown antioxidant mechanism of DIP as well as its potent chain-breaking antioxidant activity in polar aqueous medium inside the cells, using different experimental methods and theoretical quantum calculations. Data demonstrated the higher antioxidant capacity of DIP against ROS and free radicals in polar cell's interior. DIP is capable of generating long living and noninvasive DIP• radicals in oxidant condition that leads to an effective “chain-breaking antioxidant” activity. Quantum computational data indicated that DIP antioxidant has more favorable ionization potential than trolox which means DIP has higher antioxidant activity. Also, data showed that the direct hydrogen-transfer is not a favorable process to construct DIP• because of high barrier energy, though electron-transfer process can more easily to produce DIP•+ with the lowest barrier energy. Altogether, the electron donating potency of DIP to reduce ferric ion, having the low anodic oxidation peak potential, producing long lived stable DIP• radicals and protecting myoblast cells from oxidation, proposed the excellent “chain-breaking antioxidant” potency via electron-transfer mechanism of this vasodilator DIP drug in polar aqueous medium. PMID:22745807

  16. Thioamides as radical scavenging compounds: Methods for screening antioxidant activity and detection.

    PubMed

    Chernov'yants, Margarita S; Kolesnikova, Tatiana S; Karginova, Anastasia O

    2016-03-01

    Heteroaromatic thiols and thiones attracted the attention of chemists, pharmacologists and biochemists because of participation in the interception of free radicals. For the first time offered independent and reliable methods for evaluating of the antioxidant activity of thioamides-derivatives of pyridine, quinoline, imidazole, triazole, tetrazole, pyrimidine, pyrrolidine and 7-mercapto-4-methylcoumarin -based on kinetic parameters of the thioamide reaction with chromogenic radical (rate constant, M(-1)min(-1) and time to decrease concentration of test free radical by 50%, TEC50, min) or thermodynamics of the thioamides reaction with molecular iodine (extent of thioamide conversion, %). To compare the antioxidant activity of thioamides and widely used standard-antioxidant Trolox (6-Hydroxy-2,5,7,8-tetramethylchromane-2-carboxylic acid) we have proposed to use a value of relative antioxidant activity constant. As it was established, the kinetics of interaction between the chromogenic radical and thioamides in the presence of an excess of 2,2'-diphenyl-1-picrylhydrazyl (DPPH) is described by the kinetics of the pseudo first order with respect to the reacting components. A kinetic-spectrophotometric method for the quantification of heteroaromatic thioamides is elaborated and was tested in the analysis of urine. Thioamides were detected at concentrations of 1.53μgml(-1), RSD=4.6% (2-mercaptoimidazole, V), 2.08μgml(-1), RSD=1.8% (1-methylimidazoline-2-thione, VI), 1.45μgml(-1), RSD=4.3% (2-mercaptopyridine, IX).The proposed procedures show good precision and accuracy of the results obtained. PMID:26717847

  17. Pharmacological Activities of Ruthenium Complexes Related to Their NO Scavenging Properties.

    PubMed

    Castellarin, Anna; Zorzet, Sonia; Bergamo, Alberta; Sava, Gianni

    2016-01-01

    Angiogenesis is considered responsible for the growth of primary tumours and of their metastases. With the present study, the effects of three ruthenium compounds, potassiumchlorido (ethylendiamminotetraacetate)rutenate(III) (RuEDTA), sodium (bis-indazole)tetrachloro-ruthenate(III), Na[trans-RuCl₄Ind₂] (KP1339) and trans-imidazoledimethylsulphoxidetetrachloro-ruthenate (NAMI-A), are studied in vitro in models mimicking the angiogenic process. The ruthenium compounds reduced the production and the release of nitrosyls from either healthy macrophages and immortalized EA.hy926 endothelial cells. The effects of NAMI-A are qualitatively similar and sometimes quantitatively superior to those of RuEDTA and KP1339. NAMI-A reduces the production and release of nitric oxide (NO) by the EA.hy926 endothelial cells and correspondingly inhibits their invasive ability; it also strongly inhibits the angiogenesis in matrigel sponges implanted subcutaneously in healthy mice. Taken together, these data support the anti-angiogenic activity of the tested ruthenium compounds and they contribute to explain the selective activity of NAMI-A against solid tumour metastases, the tumour compartment on which angiogenesis is strongly involved. This anti-angiogenic effect may also contribute to the inhibition of the release of metastatic cells from the primary tumour. Investigations on the anti-angiogenic effects of NAMI-A at this level will increase knowledge of its pharmacological properties and it will give a further impulse to the development of this class of innovative metal-based drugs. PMID:27490542

  18. Pharmacological Activities of Ruthenium Complexes Related to Their NO Scavenging Properties

    PubMed Central

    Castellarin, Anna; Zorzet, Sonia; Bergamo, Alberta; Sava, Gianni

    2016-01-01

    Angiogenesis is considered responsible for the growth of primary tumours and of their metastases. With the present study, the effects of three ruthenium compounds, potassiumchlorido (ethylendiamminotetraacetate)rutenate(III) (RuEDTA), sodium (bis-indazole)tetrachloro-ruthenate(III), Na[trans-RuCl4Ind2] (KP1339) and trans-imidazoledimethylsulphoxidetetrachloro-ruthenate (NAMI-A), are studied in vitro in models mimicking the angiogenic process. The ruthenium compounds reduced the production and the release of nitrosyls from either healthy macrophages and immortalized EA.hy926 endothelial cells. The effects of NAMI-A are qualitatively similar and sometimes quantitatively superior to those of RuEDTA and KP1339. NAMI-A reduces the production and release of nitric oxide (NO) by the EA.hy926 endothelial cells and correspondingly inhibits their invasive ability; it also strongly inhibits the angiogenesis in matrigel sponges implanted subcutaneously in healthy mice. Taken together, these data support the anti-angiogenic activity of the tested ruthenium compounds and they contribute to explain the selective activity of NAMI-A against solid tumour metastases, the tumour compartment on which angiogenesis is strongly involved. This anti-angiogenic effect may also contribute to the inhibition of the release of metastatic cells from the primary tumour. Investigations on the anti-angiogenic effects of NAMI-A at this level will increase knowledge of its pharmacological properties and it will give a further impulse to the development of this class of innovative metal-based drugs. PMID:27490542

  19. Free radical scavenging activity from different extracts of leaves of Bauhinia vahlii Wight & Arn.

    PubMed Central

    Sowndhararajan, Kandhasamy; Kang, Sun Chul

    2013-01-01

    The objectives of this study were to determine phenolic content and antioxidant activities of chloroform, acetone, methanol and hot water extracts of Bauhinia vahlii leaves. The hot water extract afforded the highest yield (6.3%) while the lowest yield was obtained from the chloroform extract (2.1%). The methanol extract contains higher levels of total phenolics (48.7 ± 0.7 g GAE/100 g extract), tannins (21.7 ± 0.7 g GAE/100 g extract) and flavonoids (10.3 ± 0.2 RE/100 g extract). The extracts were subjected to assess their antioxidant potential using various in vitro systems such as DPPH•, ABTS•+, FRAP, OH•, β-carotene linoleic acid bleaching system, phosphomolybdenum reduction and Fe2+ chelation. It is concluded that the methanolic extract of B. vahlii leaves have strong antioxidant potential. Further study is necessary for isolation and characterization of the active antioxidants, which may serve as a potential source of natural antioxidants. PMID:24235867

  20. PARALLEL EVALUATION OF AIR- AND OXYGEN-ACTIVATED SLUDGE

    EPA Science Inventory

    To provide data on the relative merits of air and oxygen in the activated sludge process, two 1900-cu m/day (0.5-mgd) activated sludge pilot plant, one air and one oxygen system, were operated side-by-side at the Joint Water Pollution Control Plant, Carson, California. Both of th...

  1. Syntheses, structural characterization, and DPPH radical scavenging activity of cocrystals of caffeine with 1- and 2-naphthoxyacetic acids

    NASA Astrophysics Data System (ADS)

    Suresh Kumar, G. S.; Seethalakshmi, P. G.; Sumathi, D.; Bhuvanesh, N.; Kumaresan, S.

    2013-03-01

    Caffeine:1-naphthoxyacetic acid [(caf)(1-naa)] and caffeine:2-naphthoxyacetic acid [(caf)(2-naa)] cocrystals have been synthesized and single crystals were grown by slow evaporation technique. The structures of the grown crystals were elucidated using single crystal X-ray diffraction analysis. Both the cocrystals belong to the monoclinic crystallographic system with space group P21/c, Z = 4, and α = γ = 90°, whereas β = 111.4244(18)° for [(caf)(1-naa)] and β = 109.281(6)° for [(caf)(2-naa)]. The crystal packing is predominantly stabilized by hydrogen bonding and π-π stacking interactions. The presence of unionized -COOH functional group in both the cocrystals was identified by FTIR spectral analysis. Thermal behavior and stability of both the cocrystals were studied by TGA/DTA analyses. Solvent-free formation of these cocrystals was confirmed by powder X-ray diffraction analyses. The theoretical energy of cocrystals showed that the formers have higher energy than cocrystals 1 and 2. DPPH radical scavenging activity of cocrystals 1 and 2 is slightly greater than the formers.

  2. Free radical scavenging activity and comparative metabolic profiling of in vitro cultured and field grown Withania somnifera roots.

    PubMed

    Senthil, Kalaiselvi; Thirugnanasambantham, Pankajavalli; Oh, Taek Joo; Kim, So Hyun; Choi, Hyung Kyoon

    2015-01-01

    Free radical scavenging activity (FRSA), total phenolic content (TPC), and total flavonoid content (TFC) of in vitro cultured and field grown Withania somnifera (Ashwagandha) roots were investigated. Withanolides analysis and comprehensive metabolic profiling between 100% methanol extracts of in vitro and field grown root tissues was performed using high performance thin layer chromatography (HPTLC) and gas chromatography-mass spectrometry (GC-MS), respectively. Significantly higher levels of FRSA, TPC, and TFC were observed in in-vitro cultured roots compared with field grown samples. In addition, 30 day-cultured in vitro root samples (1 MIR) exhibited a significantly higher FRSA (IC50 81.01 μg/mL), TPC (118.91 mg GAE/g), and TFC (32.68 mg CE/g) compared with those in 45 day-cultured samples (1.5 MIR). Total of 29 metabolites were identified in in vitro cultured and field grown roots by GC-MS analysis. The metabolites included alcohols, organic acids, purine, pyrimidine, sugars, and putrescine. Vanillic acid was only observed in the in vitro cultured root samples, and higher level of the vanillic acid was observed in 1 MIR when compared to 1.5 MIR. Therefore, it is suggested that 1 MIR might serve as an alternative to field grown roots for the development of medicinal and functional food products. PMID:25874568

  3. Free Radical Scavenging Activity and Comparative Metabolic Profiling of In Vitro Cultured and Field Grown Withania somnifera Roots

    PubMed Central

    Senthil, Kalaiselvi; Thirugnanasambantham, Pankajavalli; Oh, Taek Joo; Kim, So Hyun; Choi, Hyung Kyoon

    2015-01-01

    Free radical scavenging activity (FRSA), total phenolic content (TPC), and total flavonoid content (TFC) of in vitro cultured and field grown Withania somnifera (Ashwagandha) roots were investigated. Withanolides analysis and comprehensive metabolic profiling between 100% methanol extracts of in vitro and field grown root tissues was performed using high performance thin layer chromatography (HPTLC) and gas chromatography-mass spectrometry (GC-MS), respectively. Significantly higher levels of FRSA, TPC, and TFC were observed in in-vitro cultured roots compared with field grown samples. In addition, 30 day-cultured in vitro root samples (1MIR) exhibited a significantly higher FRSA (IC50 81.01 μg/mL), TPC (118.91 mg GAE/g), and TFC (32.68 mg CE/g) compared with those in 45 day-cultured samples (1.5MIR). Total of 29 metabolites were identified in in vitro cultured and field grown roots by GC-MS analysis. The metabolites included alcohols, organic acids, purine, pyrimidine, sugars, and putrescine. Vanillic acid was only observed in the in vitro cultured root samples, and higher level of the vanillic acid was observed in 1MIR when compared to 1.5MIR. Therefore, it is suggested that 1MIR might serve as an alternative to field grown roots for the development of medicinal and functional food products. PMID:25874568

  4. Determination of free radical scavenging activity from aqueous extract of Curcuma mangga by DPPH method

    NASA Astrophysics Data System (ADS)

    Indis, N. A.; Kurniawan, F.

    2016-04-01

    Curcuma mangga (mango ginger) belongs to the family of Zingiberaceae. The rhizome of C. mangga are morphologically similar to ginger (Zingiber officinale) with a little mango flavour. C. mangga can growth in tropical areas and easy found in Indonesia. The rhizomes of C. mangga were washed and cut into the small piece, then drying at room temperature for 6 days, and then grinded until get the powder of C. mangga. The powder of C. mangga was extracted with deminerahzed water by maceration for 6 hours. C. mangga extract was analysed with FTIR spectrophotometer to determine its functional groups. C. mangga extract was diluted at various of concentration (5, 10, 25, 50, 100, 250, 500 mg/L) using deminerahzed water. C. mangga extracts were tested the antioxidant activity using 0.002% DPPH at 517nm with UV-Vis spectrophotometer, and the IC50 value of C. mangga extract is 212.70 mg/L.

  5. Antioxidant and Free Radical Scavenging Activity of Phenolics from Bidens humilis.

    PubMed

    Vera Saltos, Mariela Beatriz; Naranjo Puente, Blanca Fabiola; Milella, Luigi; De Tommasi, Nunziatina; Dal Piaz, Fabrizio; Braca, Alessandra

    2015-08-01

    A bioassay-oriented approach led to the isolation of 11 compounds, including three new natural flavonoids, (2S)-isookanin 7-O-α-L-arabinopyranoside (1), (2S)-isookanin 7-O-(2''-acetyl)-α-L-arabinopyranoside (2), and luteolin 7-O-β-D-glucopyranosyl-(1 → 6)-β-D-galactopyranoside (6), from Bidens humilis aerial parts. Their structures were determined via spectroscopic analyses including two-dimensional nuclear magnetic resonance. The antioxidant activity of all compounds was also tested by three different assays. The Relative Antioxidant Capacity Index (RACI) is applied herein, from the perspective of statistics, by integrating the antioxidant capacity data determined by these chemical methods. PMID:25905594

  6. Macrocyclic nickel(II) complexes: Synthesis, characterization, superoxide scavenging activity and DNA-binding

    NASA Astrophysics Data System (ADS)

    Ramadan, Abd El-Motaleb M.

    2012-05-01

    A new series of nickel(II) complexes with the tetraaza macrocyclic ligand have been synthesized as possible functional models for nickel-superoxide dismutase enzyme. The reaction of 5-amino-3-methyl-1-phenylpyrazole-4-carbaldehyde (AMPC) with itself in the presence of nickel(II) ion yields, the new macrocyclic cationic complex, [NiL(NO3)2], containing a ligand composed of the self-condensed AMPC (4 mol) bound to a single nickel(II) ion. A series of metathetical reactions have led to the isolation of a number of newly complexes of the types [NiL]X2; X = ClO4 and BF4, [NiLX2], X = Cl and Br (Scheme 1). Structures and characterizations of these complexes were achieved by several physicochemical methods namely, elemental analysis, magnetic moment, conductivity, and spectral (IR and UV-Vis) measurements. The electrochemical properties and thermal behaviors of these chelates were investigated by using cyclic voltammetry and thermogravimetric analysis (TGA and DTG) techniques. A distorted octahedral stereochemistry has been proposed for the six-coordinate nitrato, and halogeno complexes. For the four-coordinate, perchlorate and fluoroborate, complex species a square-planar geometry is proposed. The measured superoxide dismutase mimetic activities of the complexes indicated that they are potent NiSOD mimics and their activities are compared with those obtained previously for nickel(II) complexes. The probable mechanistic implications of the catalytic dismutation of O2rad - by the synthesized nickel(II) complexes are discussed. The DNA-binding properties of representative complexes [NiLCl2] and [NiL](PF4)2 have been investigated by the electronic absorption and fluorescence measurements. The results obtained suggest that these complexes bind to DNA via an intercalation binding mode and the binding affinity for DNA follows the order: [NiLCl2] □ [NiL](PF4)2.

  7. Direct ROS scavenging activity of CueP from Salmonella enterica serovar Typhimurium.

    PubMed

    Yoon, Bo-Young; Yeom, Ji-Hyun; Kim, Jin-Sik; Um, Si-Hyeon; Jo, Inseong; Lee, Kangseok; Kim, Yong-Hak; Ha, Nam-Chul

    2014-02-01

    Salmonella enterica serovar Typhimurium (S. Typhimurium) is an intracellular pathogen that has evolved to survive in the phagosome of macrophages. The periplasmic copper-binding protein CueP was initially known to confer copper resistance to S. Typhimurium. Crystal structure and biochemical studies on CueP revealed a putative copper binding site surrounded by the conserved cysteine and histidine residues. A recent study reported that CueP supplies copper ions to periplasmic Cu, Zn-superoxide dismutase (SodCII) at a low copper concentration and thus enables the sustained SodCII activity in the periplasm. In this study, we investigated the role of CueP in copper resistance at a high copper concentration. We observed that the survival of a cueP-deleted strain of Salmonella in macrophage phagosome was significantly reduced. Subsequent biochemical experiments revealed that CueP specifically mediates the reduction of copper ion using electrons released during the formation of the disulfide bond. We observed that the copper ion-mediated Fenton reaction in the presence of hydrogen peroxide was blocked by CueP. This study provides insight into how CueP confers copper resistance to S. Typhimurium in copper-rich environments such as the phagosome of macrophages. PMID:24598994

  8. Assessment of Free Radical Scavenging Potential and Oxidative DNA Damage Preventive Activity of Trachyspermum ammi L. (Carom) and Foeniculum vulgare Mill. (Fennel) Seed Extracts

    PubMed Central

    2014-01-01

    Oxidation of biomolecules such as carbohydrates, proteins, lipids, and nucleic acids results in generation of free radicals in an organism which is the major cause of onset of various degenerative diseases. Antioxidants scavenge these free radicals, thereby protecting the cell from damage. The present study was designed to examine the free radical scavenging potential and oxidative DNA damage preventive activity of traditionally used spices Trachyspermum ammi L. (carom) and Foeniculum vulgare Mill. (fennel). The aqueous, methanolic, and acetonic extracts of T. ammi and F. vulgare seeds were prepared using soxhlet extraction assembly and subjected to qualitative and quantitative estimation of phytochemical constituents. Free radical scavenging potential was investigated using standard methods, namely, DPPH radical scavenging assay and ferric reducing antioxidant power assay along with the protection against oxidative DNA damage. The results stated that acetonic seed extracts (AAcSE and FAcSE) of both the spices possessed comparatively high amount of total phenolics whereas methanolic seed extracts (AMSE and FMSE) were found to have highest amount of total flavonoids. At 1 mg/mL concentration, highest DPPH radical scavenging activity was shown by FMSE (96.2%), AAcSE was recorded with highest FRAP value (2270.27 ± 0.005 μmol/L), and all the seed extracts have been shown to mitigate the damage induced by Fenton reaction on calf thymus DNA. Therefore, the study suggests that T. ammi and F. vulgare seed extracts could contribute as a highly significant bioresource of antioxidants to be used in our day-to-day life and in food and pharmaceutical industry. PMID:25143939

  9. Khat (Catha edulis) generates reactive oxygen species and promotes hepatic cell apoptosis via MAPK activation.

    PubMed

    Abid, Morad Dirhem Naji; Chen, Juan; Xiang, Min; Zhou, Jie; Chen, Xiaoping; Gong, Feili

    2013-08-01

    A number of studies have suggested an association between khat (Catha edulis) chewing and acute liver lesions or chronic liver disease. However, little is known about the effects of khat on hepatic cells. In the current study, we investigated the mechanism behind khat-induced apoptosis in the L02 human hepatic cell line. We used cell growth inhibition assay, flow cytometry and Hoechst 33258 staining to measure hepatocyte apoptosis induced by khat. Western blot analysis was used to detect the expression levels of caspase-8 and -9, as well as those of Bax and Bcl-2. We also measured reactive oxygen species production. The results indicated that khat induced significant hepatocyte apoptosis in L02 cells. We found that khat activated caspase-8 and -9, upregulated Bax protein expression and downregulated Bcl-2 expression levels, which resulted in the coordination of apoptotic signals. Khat-induced hepatocyte apoptosis is primarily regulated through the sustained activation of the c-Jun NH2-terminal kinase (JNK) pathway and only partially via the extracellular signal-regulated kinase (ERK) cascade. Furthermore, the khat-induced reactive oxygen species (ROS) production and the activation of the ROS scavenger, N-acetyl-L-cysteine (NAC), attenuated the khat-induced activation of JNK and ERK. Our results demonstrate that khat triggers the generation of intracellular ROS and sequentially induces the sustainable activation of JNK, which in turn results in a decrease in cell viability and an increase in cell apoptosis. PMID:23708648

  10. Active site densities, oxygen activation and adsorbed reactive oxygen in alcohol activation on npAu catalysts.

    PubMed

    Wang, Lu-Cun; Friend, C M; Fushimi, Rebecca; Madix, Robert J

    2016-07-01

    The activation of molecular O2 as well as the reactivity of adsorbed oxygen species is of central importance in aerobic selective oxidation chemistry on Au-based catalysts. Herein, we address the issue of O2 activation on unsupported nanoporous gold (npAu) catalysts by applying a transient pressure technique, a temporal analysis of products (TAP) reactor, to measure the saturation coverage of atomic oxygen, its collisional dissociation probability, the activation barrier for O2 dissociation, and the facility with which adsorbed O species activate methanol, the initial step in the catalytic cycle of esterification. The results from these experiments indicate that molecular O2 dissociation is associated with surface silver, that the density of reactive sites is quite low, that adsorbed oxygen atoms do not spill over from the sites of activation onto the surrounding surface, and that methanol reacts quite facilely with the adsorbed oxygen atoms. In addition, the O species from O2 dissociation exhibits reactivity for the selective oxidation of methanol but not for CO. The TAP experiments also revealed that the surface of the npAu catalyst is saturated with adsorbed O under steady state reaction conditions, at least for the pulse reaction. PMID:27376884

  11. Isofraxidin, a potent reactive oxygen species (ROS) scavenger, protects human leukemia cells from radiation-induced apoptosis via ROS/mitochondria pathway in p53-independent manner.

    PubMed

    Li, Peng; Zhao, Qing-Li; Wu, Li-Hua; Jawaid, Paras; Jiao, Yu-Fei; Kadowaki, Makoto; Kondo, Takashi

    2014-06-01

    Ionizing radiation (IR) leads to oxidizing events such as excessive reactive oxygen species (ROS) in the exposed cells, resulting in further oxidative damage to lipids, proteins and DNA. To screen the potential radio-protective drug, the intracellular ROS was measured in irradiated U937 cells pretreated with 80 candidate traditional herbal medicine, respectively. Isofraxidin (IF) was one possible radio-protector in these 80 drugs. This study investigated the radio-protective role of IF, a Coumarin compound, in human leukemia cell lines, for the first time. Results indicate that IF protects against IR-induced apoptosis in U937 cells in the time- and concentration- dependent manner. IF decreases IR-induced intracellular ROS generation, especially hydroxyl radicals formation, inhibits IR-induced mitochondrial membrane potential loss and reduces IR-induced high intracellular Ca(2+) levels regardless of ER stress. IF down-regulates the expression of caspase-3, phospho-JNK, phospho-p38 and activates Bax in mitochondria. IF inhibits cytochrome c release from mitochondria to cytosol. IF also moderates IR-induced Fas externalization and caspase-8 activation. IF also exhibits significant protection against IR-induced cell death in other leukemia cell lines such as Molt-4 cells and HL60 cells regardless of p53. Taken together, the data demonstrate that IF protects leukemia cells from radiation-induced apoptosis via ROS/mitochondria pathway in a p53-independent manner. PMID:24692054

  12. Development and validation of a simple high performance thin layer chromatography method combined with direct 1,1-diphenyl-2-picrylhydrazyl assay to quantify free radical scavenging activity in wine.

    PubMed

    Agatonovic-Kustrin, Snezana; Morton, David W; Yusof, Ahmad P

    2016-04-15

    The aim of this study was to: (a) develop a simple, high performance thin layer chromatographic (HPTLC) method combined with direct 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay to rapidly assess and compare free radical scavenging activity or anti-oxidant activity for major classes of polyphenolics present in wines; and (b) to investigate relationship between free radical scavenging activity to the total polyphenolic content (TPC) and total antioxidant capacity (TAC) in the wine samples. The most potent free radical scavengers that we tested for in the wine samples were found to be resveratrol (polyphenolic non-flavonoid) and rutin (flavonoid), while polyphenolic acids (caffeic acid and gallic acid) although present in all wine samples were found to be less potent free radical scavengers. Therefore, the total antioxidant capacity was mostly affected by the presence of resveratrol and rutin, while total polyphenolic content was mostly influenced by the presence of the less potent free radical scavengers gallic and caffeic acids. PMID:26616951

  13. Free radical scavenging and anti-oxidative activities of an ethanol-soluble pigment extract prepared from fermented Zijuan Pu-erh tea.

    PubMed

    Fan, Jiang Ping; Fan, Chong; Dong, Wen Min; Gao, Bin; Yuan, Wei; Gong, Jia Shun

    2013-09-01

    An ethanol-soluble pigment extract was separated from fermented Zijuan Pu-erh tea. The compositions of the ethanol soluble pigment extract were analyzed by high-performance liquid chromatography-tandem mass spectroscopy (HPLC-MS/MS). The extract was prepared into a series of ethanol solutions and analyzed for free radical-scavenging activities (against two free radicals: 1,1-diphenyl-2-picrylhydrazyl (DPPH) and (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)) and in vitro anti-oxidative properties. Electron spin resonance spectroscopy showed that the peaks of DPPH and TEMPO decreased with increasing extract concentration, suggesting that the extract had excellent free radical-scavenging activities. In vitro cell culture suggested that, at 50-200 mg/L, the extract had no measurable effect on the viability of vascular endothelial cells (ECV340) but produced significant protective effects for cells that underwent oxidative injuries due to hydrogen peroxide (H₂O₂) treatment. Compared with the H₂O₂ treatment alone cells group, 200 mg/L of the extract increased the activity of superoxide dismutase (SOD) in cells by 397.3%, and decreased the concentration of malondialdehyde (MDA) and the activity of lactate acid dehydrogenase (LDH) by 47.8% and 69.6%, respectively. These results suggest that the extract has excellent free radical scavenging and anti-oxidative properties. PMID:23831194

  14. Oxygen-independent induction of enzyme activities related to oxygen metabolism in yeast by copper.

    PubMed

    Galiazzo, F; Schiesser, A; Rotilio, G

    1988-04-14

    Aerobic growth of Saccharomyces cerevisiae in the presence of CuSO4 (between 0.1 and 1 mM) caused a generalized induction of major enzyme activities involved in 'housekeeping' routes of oxygen metabolism (cytochrome oxidase, glutathione peroxidases and catalase) which were comparable to or higher than that observed with Cu,Zn-superoxide dismutase. Fumarase and glutathione transferase, tested as controls for oxygen-unrelated activities, were found to decrease under the same conditions. In the absence of oxygen, copper addition to yeast resulted in significant increases of Cu,Zn-superoxide dismutase and glutathione peroxidases and a slight increase of cytochrome oxidase, with catalase remaining undetectable irrespective of whether or not copper was present. Other metal ions tested (Mn2+, Co2+) were unable to produce such effects. It is concluded that copper has a general inducing effect on enzymes related to metabolism of oxygen and oxygen derivatives, which is mediated neither by formation of O2-. and H2O2 nor by interaction with copper-specific apoproteins. These results point to a general role of copper as regulator of the expression of major enzyme activities involved in biological oxygen activation. PMID:2831994

  15. Winery by-products: extraction optimization, phenolic composition and cytotoxic evaluation to act as a new source of scavenging of reactive oxygen species.

    PubMed

    Melo, Priscilla Siqueira; Massarioli, Adna Prado; Denny, Carina; dos Santos, Luciana Ferracini; Franchin, Marcelo; Pereira, Giuliano Elias; Vieira, Thais Maria Ferreira de Souza; Rosalen, Pedro Luiz; de Alencar, Severino Matias

    2015-08-15

    Nearly 20 million tons of winery by-products, with many biological activities, are discarded each year in the world. The extraction of bioactive compounds from Chenin Blanc, Petit Verdot, and Syrah grape by-products, produced in the semi-arid region in Brazil, was optimized by a Central Composite Rotatable Design. The phenolic compounds profile, antioxidant capacity against synthetic free radicals (DPPH and ABTS), reactive oxygen species (ROS; peroxyl radical, superoxide radical, hypochlorous acid), cytotoxicity assay (MTT) and quantification of TNF-α production in RAW 264.7 cells were conducted. Gallic acid, syringic acid, procyanidins B1 and B2, catechin, epicatechin, epicatechin gallate, quercetin 3-β-d-glucoside, delfinidin 3-glucoside, peonidin 3-O-glucoside, and malvidin 3-glucoside were the main phenolic compounds identified. In general, rachis showed higher antioxidant capacity than pomace extract, especially for Chenin Blanc. All extracts showed low cytotoxicity against RAW 264.7 cells and Petit Verdot pomace suppressed TNF-α liberation in vitro. Therefore, these winery by-products can be considered good sources of bioactive compounds, with great potential for application in the food and pharmaceutical industries. PMID:25794735

  16. Comparative analysis of radical scavenging and antioxidant activity of phenolic compounds present in everyday use spice plants by means of spectrophotometric and chromatographic methods.

    PubMed

    Stankevičius, Mantas; Akuņeca, Ieva; Jãkobsone, Ida; Maruška, Audrius

    2011-06-01

    Comparative analysis of radical scavenging and antioxidant activities of phenolic compounds present in everyday use spice plants was carried out by means of spectrophotometric and chromatographic methods. Six spice plant samples, namely onion (Allium cepa), parsley (Petroselinum crispum) roots and leaves, celery (Apium graveolens) roots and leaves and leaves of dill (Anethum graveolens) were analyzed. Total amount of phenolic compounds and radical scavenging activity (RSA) was the highest in celery leaves and dill extracts and was the lowest in celery roots. Comparing commonly used spectrophotometric analysis of 2,2-diphenyl-1-picrylhydrazyl (DPPH) RSA of extracts with the results obtained using reversed-phase chromatographic separation with on-line post-column radical scavenging reaction detection, good correlation was obtained (R(2)=0.848). Studies using HPLC system with electrochemical detector showed that bioactive phytochemicals can be separated and antioxidant activities of individual compounds evaluated without the need of a complex HPLC system with reaction detector. The results obtained using electrochemical detection correlate with the RSA assayed using spectrophotometric method (R(2)=0.893). PMID:21504067

  17. Radical-scavenging Activity and Antioxidative Effects of Olive Leaf Components Oleuropein and Hydroxytyrosol in Comparison with Homovanillic Alcohol.

    PubMed

    Umeno, Aya; Takashima, Mizuki; Murotomi, Kazutoshi; Nakajima, Yoshihiro; Koike, Taisuke; Matsuo, Toshiki; Yoshida, Yasukazu

    2015-01-01

    Olive leaf has great potential as a natural antioxidant, and one of its major phenolic components is oleuropein. In this study, the antioxidant activity of oleuropein against oxygen-centered radicals was measured by examining its sparing effects on the peroxyl radical-induced decay of fluorescein and pyrogallol red, in comparison with related compounds. The antioxidant capacity of oleuropein against lipid peroxidation was also assessed through its effect on the free radical-induced oxidation of methyl linoleate in a micelle system. On a molar basis, oleuropein and hydroxytyrosol inhibited the decay of fluorescein for longer than both homovanillic alcohol and the vitamin-E mimic 2-carboxy-2,5,7,8-tetramethyl-6-chromanol (Trolox), but did not suppress pyrogallol red decay in a concentration-dependent manner. Measurement of the fluorescein decay period revealed that the stoichiometric number of oleuropein and hydroxytyrosol against peroxyl radicals was twice that of Trolox, which is substantially higher than expectations based on chemical structure. Oleuropein and hydroxytyrosol were also more effective than Trolox and homovanillic alcohol at suppressing the oxidation of methyl linoleate in the micelle system. Thus, both oleuropein and hydroxytyrosol exhibit high antioxidative activity against lipid peroxidation induced by oxygen-centered radicals, but the high reactivity of phenolic/catecholic radicals makes their mechanism of action complex. PMID:26136177

  18. Probing Oxygen Activation Sites in Two Flavoprotein Oxidases Using Chloride as an Oxygen Surrogate

    SciTech Connect

    Kommoju, Phaneeswara-Rao; Chen, Zhi-wei; Bruckner, Robert C.; Mathews, F. Scott; Jorns, Marilyn Schuman

    2011-08-16

    A single basic residue above the si-face of the flavin ring is the site of oxygen activation in glucose oxidase (GOX) (His516) and monomeric sarcosine oxidase (MSOX) (Lys265). Crystal structures of both flavoenzymes exhibit a small pocket at the oxygen activation site that might provide a preorganized binding site for superoxide anion, an obligatory intermediate in the two-electron reduction of oxygen. Chloride binds at these polar oxygen activation sites, as judged by solution and structural studies. First, chloride forms spectrally detectable complexes with GOX and MSOX. The protonated form of His516 is required for tight binding of chloride to oxidized GOX and for rapid reaction of reduced GOX with oxygen. Formation of a binary MSOX-chloride complex requires Lys265 and is not observed with Lys265Met. Binding of chloride to MSOX does not affect the binding of a sarcosine analogue (MTA, methylthioactetate) above the re-face of the flavin ring. Definitive evidence is provided by crystal structures determined for a binary MSOX-chloride complex and a ternary MSOX-chloride-MTA complex. Chloride binds in the small pocket at a position otherwise occupied by a water molecule and forms hydrogen bonds to four ligands that are arranged in approximate tetrahedral geometry: Lys265:NZ, Arg49:NH1, and two water molecules, one of which is hydrogen bonded to FAD:N5. The results show that chloride (i) acts as an oxygen surrogate, (ii) is an effective probe of polar oxygen activation sites, and (iii) provides a valuable complementary tool to the xenon gas method that is used to map nonpolar oxygen-binding cavities.

  19. A superoxide anion-scavenger, 1,3-selenazolidin-4-one suppresses serum deprivation-induced apoptosis in PC12 cells by activating MAP kinase

    SciTech Connect

    Nishina, Atsuyoshi; Kimura, Hirokazu; Kozawa, Kunihisa; Sommen, Geoffroy; Nakamura, Takao; Heimgartner, Heinz; Koketsu, Mamoru; Furukawa, Shoei

    2011-12-15

    Synthetic organic selenium compounds, such as ebselen, may show glutathione peroxidase-like antioxidant activity and have a neurotrophic effect. We synthesized 1,3-selenazolidin-4-ones, new types of synthetic organic selenium compounds (five-member ring compounds), to study their possible applications as antioxidants or neurotrophic-like molecules. Their superoxide radical scavenging effects were assessed using the quantitative, highly sensitive method of real-time kinetic chemiluminescence. At 166 {mu}M, the O{sub 2}{sup -} scavenging activity of 1,3-selenazolidin-4-ones ranged from 0 to 66.2%. 2-[3-(4-Methoxyphenyl)-4-oxo-1,3-selenazolidin-2-ylidene]malononitrile (compound b) showed the strongest superoxide anion-scavenging activity among the 6 kinds of 2-methylene-1,3-selenazolidin-4-ones examined. Compound b had a 50% inhibitory concentration (IC{sub 50}) at 92.4 {mu}M and acted as an effective and potentially useful O{sub 2}{sup -} scavenger in vitro. The effect of compound b on rat pheochromocytome cell line PC12 cells was compared with that of ebselen or nerve growth factor (NGF) by use of the MTT [3-(4, 5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide] assay. When ebselen was added at 100 {mu}M or more, toxicity toward PC12 cells was evident. On the contrary, compound b suppressed serum deprivation-induced apoptosis in PC12 cells more effectively at a concentration of 100 {mu}M. The activity of compound b to phosphorylate mitogen-activated protein kinase/extracellular signal-regulated protein kinase (ERK) 1/2 (MAP kinase) in PC12 cells was higher than that of ebselen, and the former at 100 {mu}M induced the phosphorylation of MAP kinase to a degree similar to that induced by NGF. From these results, we conclude that this superoxide anion-scavenger, compound b, suppressed serum deprivation-induced apoptosis by promoting the phosphorylation of MAP kinase. -- Highlights: Black-Right-Pointing-Pointer We newly synthesized 1,3-selenazolidin-4-ones to

  20. Natural anthraquinone derivatives from a marine mangrove plant-derived endophytic fungus Eurotium rubrum: structural elucidation and DPPH radical scavenging activity.

    PubMed

    Li, Dong-Li; Li, Xiao-Ming; Wang, Bin-Gui

    2009-07-01

    There is considerable interest in the isolation of potent radical scavenging compounds from natural resources to treat diseases involving oxidative stress. In this report, four new fungal metabolites including one new bisdihydroanthracenone derivative (1, eurorubrin), two new seco-anthraquinone derivatives [3, 2-O-methyl-9-dehydroxyeurotinone and 4, 2-Omethyl- 4-O-(alpha-D-ribofuranosyl)-9-dehydroxyeurotinone], and one new anthraquinone glycoside [6, 3-O-(alpha-D-ribofuranosyl)- questin], were isolated and identified from Eurotium rubrum, an endophytic fungal strain that was isolated from the inner tissue of the stem of the marine mangrove plant Hibiscus tiliaceus. In addition, three known compounds including asperflavin (2), 2-O-methyleurotinone (5), and questin (7) were also isolated and identified. Their structures were elucidated on the basis of spectroscopic analysis. All of the isolated compounds were evaluated for 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical scavenging activity. PMID:19652514

  1. Radical scavenging activities of Tyr-, Trp-, Cys- and Met-Gly and their protective effects against AAPH-induced oxidative damage in human erythrocytes.

    PubMed

    Zheng, Lin; Dong, Hongzhu; Su, Guowan; Zhao, Qiangzhong; Zhao, Mouming

    2016-04-15

    Radical scavenging activities of Tyr-, Trp-, Cys- and Met-Gly and their protective effects against AAPH-induced oxidative damage in erythrocytes were evaluated in this study. This damage includes hemolysis, oxidation of hemoglobin, formation of MDA and the depletion of glutathione (GSH) and catalase (CAT). Results showed that Tyr- and Trp-Gly could quench the radicals effectively in ABTS and ORAC assays with TE (Trolox equivalent) values of more than 1.0 μmol TE/μmol, followed by Cys- and Met-Gly. All these dipeptides could protect erythrocytes against AAPH-induced hemolysis in a dose-dependent manner. They could also significantly (p<0.05) retard the oxidation of hemoglobin and depletion of GSH in erythrocytes. The protective effects of these dipeptides decreased in the following order: Trp-Gly>Tyr-Gly>Met-Gly>Cys-Gly, which were consistent with their peroxyl radical scavenging activities. It suggested that these dipeptides might protect erythrocytes against AAPH-induced oxidative damage, mainly by acting as the direct radical scavengers. PMID:26617020

  2. Antioxidant and radical scavenging properties of curcumin.

    PubMed

    Ak, Tuba; Gülçin, Ilhami

    2008-07-10

    Curcumin (diferuoyl methane) is a phenolic compound and a major component of Curcuma longa L. In the present paper, we determined the antioxidant activity of curcumin by employing various in vitro antioxidant assays such as 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH*) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity, N,N-dimethyl-p-phenylenediamine dihydrochloride (DMPD) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, total reducing ability determination by the Fe(3+)-Fe(2+) transformation method, superoxide anion radical scavenging by the riboflavin/methionine/illuminate system, hydrogen peroxide scavenging and ferrous ions (Fe(2+)) chelating activities. Curcumin inhibited 97.3% lipid peroxidation of linoleic acid emulsion at 15 microg/mL concentration (20 mM). On the other hand, butylated hydroxyanisole (BHA, 123 mM), butylated hydroxytoluene (BHT, 102 mM), alpha-tocopherol (51 mM) and trolox (90 mM) as standard antioxidants indicated inhibition of 95.4, 99.7, 84.6 and 95.6% on peroxidation of linoleic acid emulsion at 45 microg/mL concentration, respectively. In addition, curcumin had an effective DPPH* scavenging, ABTS*(+) scavenging, DMPD*(+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power and ferrous ions (Fe(2+)) chelating activities. Also, BHA, BHT, alpha-tocopherol and trolox, were used as the reference antioxidant and radical scavenger compounds. According to the present study, curcumin can be used in the pharmacological and food industry because of these properties. PMID:18547552

  3. The free radical scavenging and antioxidant activities of pod and seed extract of Clitoria fairchildiana (Howard)- an underutilized legume.

    PubMed

    Annegowda, H V; Bhat, Rajeev; Tze, Liong Min; Karim, A A; Mansor, S M

    2013-06-01

    We evaluated the phenolic content and antioxidant capacities of pod and seed extracts (in methanol, ethanol, and water) of an underutilized legume, Clitoria fairchildiana (Howard). The antioxidant capacity of the extracts was determined using the ferric reducing antioxidant potential assay, and the free radical-scavenging capacity was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical-scavenging and ABTS assays. In addition, the total flavonoids, flavonols, and tannin contents were also determined. Overall, the methanol extracts of the pod contained high concentration of phenolics and showed high antioxidant capacities compared to seed extracts. In addition, a positive correlation was found between total phenol and tannin versus antioxidant capacity. Results of the present study indicate pods and seeds of C. fairchildiana to possess rich amount of natural antioxidants, and can be further explored for their possible use as a natural additive in food or in pharmaceutical industries. PMID:24425949

  4. Free-radical scavenging and mitochondrial antioxidant activities of Reishi-Ganoderma lucidum (Curt: Fr) P. Karst and Arogyapacha-Trichopus zeylanicus Gaertn extracts.

    PubMed

    Cherian, Elizabeth; Sudheesh, Narayana P; Janardhanan, Kainoor K; Patani, George

    2009-01-01

    Endogenous damage to mitochondrial DNA by free radicals is believed to be a major contributory factor to aging. The current study examined the effects of the extracts of two important anti-fatigue and rejuvenating medicinal herbs Ganoderma lucidum and Trichopus zeylanicus for their free-radical scavenging property and for their effects on liver mitochondrial antioxidant activity in aged mice. Both extracts were administrated orally to aged BALB/c mice at doses of 50 and 250 mg/kg body weight for 15 days. Super oxide dismutase (SOD) and catalase (CAT) activity and levels of reduced glutathione (GSH) and lipid peroxidation as equivalents of malondialdehyde (MDA) formed were determined. Groups of young mice and aged mice (more than 15 months old) were taken as controls. Both G. lucidum and T. zeylanicus extracts increased antioxidant status in liver mitochondria of aged mice compared with the aged control. Higher levels of GSH, increased activity of SOD and CAT, and decreased level of MDA in both treated groups compared with the controls were evident. Both extracts possessed significant 2,2-diphenyl-1-picrylhydrazil (DPPH), 2, 2'-azinobis (3-ethylbenzothiazolin-6-sulphonic acid) (ABTS) radical scavenging activities and ferric reducing antioxidant power (FRAP). The DPPH, ABTS, and FRAP activities were higher in G. lucidum extract than in T. zeylanicus. G. lucidum extract also showed superoxide and hydroxyl radical scavenging activities. T. zeylanicus had significantly higher lipid peroxidation inhibiting activity than G. lucidum. Thus, we conclude that the antioxidative effect of the G. lucidum extract was higher than that of T. zeylanicus. Our findings suggest a potential therapeutic efficacy of G. lucidum extract to protect against aging and to a certain extent against age-related degenerative diseases. PMID:20214017

  5. Identification of the Active Species in Photochemical Hole Scavenging Reactions of Methanol on TiO2

    SciTech Connect

    Shen, Mingmin; Henderson, Michael A.

    2011-11-03

    Molecular and dissociative methanol adsorption species were prepared on rutile TiO2(110) surfaces to study photocatalytic oxidation of methanol in ultrahigh vacuum (UHV) using temperature-programmed desorption (TPD). Adsorbed methoxy groups (CH3O-) were found to be the photoactive form of adsorbed methanol converted to adsorbed formaldehyde and a surface OH group by hole-mediated C-H bond cleavage. These results suggest that adsorbed methoxy is the effective hole scavenger in photochemical reactions involving methanol.

  6. Melatonin and its precursors scavenge nitric oxide

    SciTech Connect

    Noda, Y.; Mori, A.; Liburdy, R.; Packer, L.

    1998-12-01

    Nitric oxide (NO) scavenging activity of melatonin, N-acetyl-5-hydroxytryptamine, serotonin, 5-hydroxytryptophan and L-tryptophan was examined by the Griess reaction using flow injection analysis. 1-Hydroxy-2-oxo-3-(N-methyl-3-aminopropyl)-3-methyl-1-triazene(NOC-7) was used as NO generator. The Griess reagent stoichiometrically reacts with NO2-, which was converted by a cadmium-copper reduction column from the stable end products of NO oxidation. Except for tryptophan, all the compounds examined scavenged NO in a dose-dependent manner. Melatonin, which has a methoxy group in the 5-position and an acetyl side chain, exhibited the most potent scavenging activity among the compounds tested. Serotonin, N-acetyl-5-hydroxytryptamine, and 5-hydroxytryptophan, respectively, showed moderate scavenging activity compared to melatonin. Tryptophan, which has neither a methoxy nor a hydroxyl group in the 5-position, exhibited the least NO scavenging activity.

  7. DNA Damage Protecting Activity and Free Radical Scavenging Activity of Anthocyanins from Red Sorghum (Sorghum bicolor) Bran

    PubMed Central

    Devi, P. Suganya; Kumar, M. Saravana; Das, S. Mohan

    2012-01-01

    There is increasing interest in natural food colorants like carotenoids and anthocyanins with functional properties. Red sorghum bran is known as a rich source for anthocyanins. The anthocyanin contents extracted from red sorghum bran were evaluated by biochemical analysis. Among the three solvent system used, the acidified methanol extract showed a highest anthocyanin content (4.7 mg/g of sorghum bran) followed by methanol (1.95 mg/g) and acetone (1 mg/g). Similarly, the highest total flavonoids (143 mg/g) and total phenolic contents (0.93 mg/g) were obtained in acidified methanol extracts than methanol and acetone extracts. To study the health benefits of anthocyanin from red sorghum bran, the total antioxidant activity was evaluated by biochemical and molecular methods. The highest antioxidant activity was observed in acidified methanol extracts of anthocyanin in dose-dependent manner. The antioxidant activity of the red sorghum bran was directly related to the total anthocyanin found in red sorghum bran. PMID:22400119

  8. Deciphering Scavenging Propensity Among Arthropod Predators.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Scavenging is a well documented feeding behavior among many arthrop predators. However, quantifying scavenging feeding activity is not well understood because many predators are small elusive. This makes directly observing predation events in nature almost impossible. If predators prefer dead prey ...

  9. Leukocytic oxygen activation and microbicidal oxidative toxins.

    PubMed

    Hurst, J K; Barrette, W C

    1989-01-01

    Following a brief introduction of cellular response to stimulation comprising leukocyte activation, three major areas are discussed: (1) the neutrophil oxidase; (2) myeloperoxidase (MPO)-dependent oxidative microbicidal reactions; and (3) MPO-independent oxidative reactions. Topics included in section (A) are current views on the activation mechanism, redox composition, structural and topographic organization of the oxidase, and its respiratory products. In section (B), emphasis is placed on recent research on cidal mechanisms of HOCl, including the oxidative biochemistry of active chlorine compounds, identification of sites of lesions in bacteria, and attendant metabolic consequences. In section (C), we review the (bio)chemistry of H2O2 and .OH microbicidal reactions, with particular attention being given to addressing the controversial issue of probe methods to identify .OH radical and critical assessment of the recent proposal that MPO-independent killing arises from site-specific metal-catalyzed Fenton-type chemistry. PMID:2548810

  10. OXYGEN UTILIZATION IN ACTIVATED SLUDGE PLANTS: SIMULATION AND MODEL CALIBRATION

    EPA Science Inventory

    The objective of the research described in the report is to apply recent advances in activated sludge process modeling to the simulation of oxygen utilization rates in full scale activated sludge treatment plants. This is accomplished by calibrating the International Association ...

  11. Oxygen tension limits nitric oxide synthesis by activated macrophages.

    PubMed Central

    McCormick, C C; Li, W P; Calero, M

    2000-01-01

    Previous studies have established that constitutive calcium-dependent ('low-output') nitric oxide synthase (NOS) is regulated by oxygen tension. We have investigated the role of oxygen tension in the synthesis of NO by the 'high-output' calcium-independent NOS in activated macrophages. Hypoxia increased macrophage NOS gene expression in the presence of one additional activator, such as lipopolysaccharide or interferon-gamma, but not in the presence of both. Hypoxia markedly reduced the synthesis of NO by activated macrophages (as measured by accumulation of nitrite and citrulline), such that, at 1% oxygen tension, NO accumulation was reduced by 80-90%. The apparent K(m) for oxygen calculated from cells exposed to a range of oxygen tensions was found to be 10.8%, or 137 microM, O(2) This value is considerably higher than the oxygen tension in tissues, and is virtually identical to that reported recently for purified recombinant macrophage NOS. The decrease in NO synthesis did not appear to be due to diminished arginine or cofactor availability, since arginine transport and NO synthesis during recovery in normoxia were normal. Analysis of NO synthesis during hypoxia as a function of extracellular arginine indicated that an altered V(max), but not K(m)(Arg), accounted for the observed decrease in NO synthesis. We conclude that oxygen tension regulates the synthesis of NO in macrophages by a mechanism similar to that described previously for the calcium-dependent low-output NOS. Our data suggest that oxygen tension may be an important physiological regulator of macrophage NO synthesis in vivo. PMID:10970783

  12. L-carnosine (beta-alanyl-L-histidine) and carcinine (beta-alanylhistamine) act as natural antioxidants with hydroxyl-radical-scavenging and lipid-peroxidase activities.

    PubMed Central

    Babizhayev, M A; Seguin, M C; Gueyne, J; Evstigneeva, R P; Ageyeva, E A; Zheltukhina, G A

    1994-01-01

    Carnosine (beta-alanyl-L-histidine) and carcinine (beta-alanylhistamine) are natural imidazole-containing compounds found in the non-protein fraction of mammalian tissues. Carcinine was synthesized by an original procedure and characterized. Both carnosine and carcinine (10-25 mM) are capable of inhibiting the catalysis of linoleic acid and phosphatidylcholine liposomal peroxidation (LPO) by the O2(-.)-dependent iron-ascorbate and lipid-peroxyl-radical-generating linoleic acid 13-monohydroperoxide (LOOH)-activated haemoglobin systems, as measured by thiobarbituric-acid-reactive substance. Carcinine and carnosine are good scavengers of OH. radicals, as detected by iron-dependent radical damage to the sugar deoxyribose. This suggests that carnosine and carcinine are able to scavenge free radicals or donate hydrogen ions. The iodometric, conjugated diene and t.l.c. assessments of lipid hydroperoxides (13-monohydroperoxide linoleic acid and phosphatidylcholine hydroperoxide) showed their efficient reduction and deactivation by carnosine and carcinine (10-25 mM) in the liberated and bound-to-artificial-bilayer states. This suggests that the peroxidase activity exceeded that susceptible to direct reduction with glutathione peroxidase. Imidazole, solutions of beta-alanine, or their mixtures with peptide moieties did not show antioxidant potential. Free L-histidine and especially histamine stimulated iron (II) salt-dependent LPO. Due to the combination of weak metal chelating (abolished by EDTA), OH. and lipid peroxyl radicals scavenging, reducing activities to liberated fatty acid and phospholipid hydroperoxides, carnosine and carcinine appear to be physiological antioxidants able to efficiently protect the lipid phase of biological membranes and aqueous environments. PMID:7998987

  13. Microfluidic Platform Generates Oxygen Landscapes for Localized Hypoxic Activation

    PubMed Central

    Rexius, Megan L.; Mauleon, Gerardo; Malik, Asrar B.; Rehman, Jalees; Eddington, David T.

    2014-01-01

    An open-well microfluidic platform generates an oxygen landscape using gas-perfused networks which diffuse across a membrane. The device enables real-time analysis of cellular and tissue responses to oxygen tension to define how cells adapt to heterogeneous oxygen conditions found in the physiological setting. We demonstrate that localized hypoxic activation of cells elicited specific metabolic and gene responses in human microvascular endothelial cells and bone marrow-derived mesenchymal stem cells. A robust demonstration of the compatibility of the device with standard laboratory techniques demonstrates the wide utility of the method. This platform is ideally suited to study real-time cell responses and cell-cell interactions within physiologically relevant oxygen landscapes. PMID:25315003

  14. Reactive Oxygen Species Mediated Activation of a Dormant Singlet Oxygen Photosensitizer: From Autocatalytic Singlet Oxygen Amplification to Chemicontrolled Photodynamic Therapy.

    PubMed

    Durantini, Andrés M; Greene, Lana E; Lincoln, Richard; Martínez, Sol R; Cosa, Gonzalo

    2016-02-01

    Here we show the design, preparation, and characterization of a dormant singlet oxygen ((1)O2) photosensitizer that is activated upon its reaction with reactive oxygen species (ROS), including (1)O2 itself, in what constitutes an autocatalytic process. The compound is based on a two segment photosensitizer-trap molecule where the photosensitizer segment consists of a Br-substituted boron-dipyrromethene (BODIPY) dye. The trap segment consists of the chromanol ring of α-tocopherol, the most potent naturally occurring lipid soluble antioxidant. Time-resolved absorption, fluorescence, and (1)O2 phosphorescence studies together with fluorescence and (1)O2 phosphorescence emission quantum yields collected on Br2B-PMHC and related bromo and iodo-substituted BODIPY dyes show that the trap segment provides a total of three layers of intramolecular suppression of (1)O2 production. Oxidation of the trap segment with ROS restores the sensitizing properties of the photosensitizer segment resulting in ∼40-fold enhancement in (1)O2 production. The juxtaposed antioxidant (chromanol) and prooxidant (Br-BODIPY) antagonistic chemical activities of the two-segment compound enable the autocatalytic, and in general ROS-mediated, activation of (1)O2 sensitization providing a chemical cue for the spatiotemporal control of (1)O2.The usefulness of this approach to selectively photoactivate the production of singlet oxygen in ROS stressed vs regular cells was successfully tested via the photodynamic inactivation of a ROS stressed Gram negative Escherichia coli strain. PMID:26789198

  15. An evaluation of extracts of five traditional medicinal plants from Iran on the inhibition of mushroom tyrosinase activity and scavenging of free radicals.

    PubMed

    Khazaeli, P; Goldoozian, R; Sharififar, F

    2009-10-01

    This study aimed to evaluate the free radical scavenging and inhibition properties of five medicinal plants, including Quercus infectoria Olive., Terminalia chebula Retz., Lavendula stoechas L., Mentha longifolia L., Rheum palmatum L., toward the activity of mushroom tyrosinase using L-tyrosine and L-3,4-dihydroxyphenylalanine (L-DOPA) as the substrate.The methanol extracts of Q. infectoria and T. chebula showed strong radical scavenging effect in 2,2'-dipheny L-1-picrylhydrazyl (DPPH) assay(IC50 = 15.3 and 82.2 microg mL)1 respectively).These plants also showed inhibitory effects against the activity of mushroom tyrosinase in hydroxylation of L-tyrosine (85.9% and 82.2% inhibition,respectively). These two plants also inhibited the oxidation of l-DOPA similar to kojic acid as positive control (IC50 = 102.8 and 192.6 microg mL)1 respectively). In general Q. infectoria and T. chebula significantly inhibited tyrosinase activity and DPPH radical. Both activities were concentration dependant but not in linear manner. It is needed to study the cytotoxicity of these plant extracts in pigment cell culture before further evaluation and moving to in vivo conditions. PMID:19467035

  16. Antiviral, immunomodulatory, and free radical scavenging activities of a protein-enriched fraction from the larvae of the housefly, Musca domestica.

    PubMed

    Ai, Hui; Wang, Furong; Zhang, Na; Zhang, Lingyao; Lei, Chaoliang

    2013-01-01

    In our previous study, protein-enriched fraction (PEF) that was isolated from the larvae of the housefly, Musca domestica L. (Diptera: Muscidae), showed excellent hepatoprotective activity as well as the potential for clinical application in therapy for liver diseases. In this study, antiviral, immunomodulatory, and free radical scavenging activities of PEF were evaluated. The antiviral results demonstrated that PEF inhibited the infection of avian influenza virus H9N2 and had a virucidal effect against the multicapsid nucleopolyhedrovirus of the alfalfa looper, Autographa californica Speyer (Lepidoptera: Noctuidae) in vitro. The mortality of silkworm larve in a PEF treatment group decreased significantly compared with a negative control. PEF showed excellent scavenging activity for 1,1-diphenyl-2-picrylhydrazyl and superoxide anion radicals, which were similar to those of ascorbic acid. The imunomodulatory results suggested that PEF could effectively improve immune function in experimental mice. Our results indicated that PEF could possibly be used for the prophylaxis and treatment of diseases caused by avian influenza virus infection. In addition, PEF with virucidal activity against insect viruses might provide useful for the development of antimicrobial breeding technology for economically important insects. As a natural product from insects, PEF could be a potential source for the discovery of potent antioxidant and immunomodulatory agents. PMID:24735244

  17. Effects of Comb Tooth Cap Medicinal Mushroom, Hericium ramosum (Higher Basidiomycetes) Mycelia on DPPH Radical Scavenging Activity and Nerve Growth Factor Synthesis.

    PubMed

    Suruga, Kohei; Kadokura, Kazunari; Sekino, Yoshihiro; Nakano, Takafumi; Matsuo, Koichi; Irie, Keiichi; Mishima, Kenichi; Yoneyama, Makoto; Komatsu, Yasuhiro

    2015-01-01

    The goal of this study was to evaluate the antioxidant effects of and nerve growth factor (NGF) synthesis caused by Hericium ramosum mycelia. Wild mushroom fruiting bodies were collected from nature to isolate their mycelia. Pieces of H. ramosum fruiting bodies were plated onto 90-mm Petri dishes with potato dextrose agar medium to isolate their mycelia. Antioxidant activity was measured using 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging activity in vitro; the ethanol extract from H. ramosum mycelia (63.11 µmol Trolox/g) was more potent than that of other mushroom mycelia extracts. There was a proportional relationship (R2 = 0.7929) between DPPH radical scavenging activity and total phenolic content in extracts of different mushroom mycelia. We investigated the ability of H. ramosum mycelia to inducing NGF synthesis in vivo. Oral administration of H. ramosum mycelia significantly increased concentrations of NGF in the hippocampus of intact mice. These results are the first concerning antioxidant activity and NGF synthesis of H. ramosum mycelia. These mushroom mycelia could be useful as food and/or nutritional supplements because of certain biological functions. PMID:25954959

  18. Antiviral, Immunomodulatory, and Free Radical Scavenging Activities of a Protein-Enriched Fraction from the Larvae of the Housefly, Musca domestica

    PubMed Central

    Ai, Hui; Wang, Furong; Zhang, Na; Zhang, Lingyao; Lei, Chaoliang

    2013-01-01

    In our previous study, protein-enriched fraction (PEF) that was isolated from the larvae of the housefly, Musca domestica L. (Diptera: Muscidae), showed excellent hepatoprotective activity as well as the potential for clinical application in therapy for liver diseases. In this study, antiviral, immunomodulatory, and free radical scavenging activities of PEF were evaluated. The antiviral results demonstrated that PEF inhibited the infection of avian influenza virus H9N2 and had a virucidal effect against the multicapsid nucleopolyhedrovirus of the alfalfa looper, Autographa californica Speyer (Lepidoptera: Noctuidae) in vitro. The mortality of silkworm larve in a PEF treatment group decreased significantly compared with a negative control. PEF showed excellent scavenging activity for 1,1-diphenyl-2-picrylhydrazyl and superoxide anion radicals, which were similar to those of ascorbic acid. The imunomodulatory results suggested that PEF could effectively improve immune function in experimental mice. Our results indicated that PEF could possibly be used for the prophylaxis and treatment of diseases caused by avian influenza virus infection. In addition, PEF with virucidal activity against insect viruses might provide useful for the development of antimicrobial breeding technology for economically important insects. As a natural product from insects, PEF could be a potential source for the discovery of potent antioxidant and immunomodulatory agents. PMID:24735244

  19. Standardizing Scavenger Receptor Nomenclature

    PubMed Central

    PrabhuDas, Mercy; Bowdish, Dawn; Drickamer, Kurt; Febbraio, Maria; Herz, Joachim; Kobzik, Lester; Krieger, Monty; Loike, John; Means, Terry K.; Moestrup, Soren K.; Post, Steven; Sawamura, Tatsuya; Silverstein, Samuel; Wang, Xiang-Yang; El Khoury, Joseph

    2014-01-01

    Scavenger receptors constitute a large family of proteins that are structurally diverse and participate in a wide range of biological functions. These receptors are expressed predominantly by myeloid cells and recognize a variety of ligands, including endogenous and modified host-derived molecules and microbial pathogens. There are currently eight classes of scavenger receptors, many of which have multiple names, leading to inconsistencies and confusion in the literature. To address this problem, a workshop was organized by the U.S. National Institute of Allergy and Infectious Diseases, National Institutes of Health to help develop a clear definition of scavenger receptors and a standardized nomenclature based on that definition. Fifteen experts in the scavenger receptor field attended the workshop and, after extensive discussion, reached a consensus regarding the definition of scavenger receptors and a proposed scavenger receptor nomenclature. Scavenger receptors were defined as cell surface receptors that typically bind multiple ligands and promote the removal of non-self or altered-self targets. They often function by mechanisms that include endocytosis, phagocytosis, adhesion, and signaling that ultimately lead to the elimination of degraded or harmful substances. Based on this definition, nomenclature and classification of these receptors into 10 classes were proposed. The discussion and nomenclature recommendations described in this report only refer to mammalian scavenger receptors. The purpose of this article is to describe the proposed mammalian nomenclature and classification developed at the workshop and to solicit additional feedback from the broader research community. PMID:24563502

  20. Botanical Scavenger Hunt

    ERIC Educational Resources Information Center

    Walker-Livingston, Wendy

    2009-01-01

    Why not combine the use of technology with the excitement of a scavenger hunt that moves middle-level students out into the "wilds" of their school campus to classify plants? In the lesson plan described here, students embark on a botanical scavenger hunt and then document their findings using a digital camera. This project was designed to allow…

  1. A QSAR study of radical scavenging antioxidant activity of a series of flavonoids using DFT based quantum chemical descriptors--the importance of group frontier electron density.

    PubMed

    Sarkar, Ananda; Middya, Tapas Ranjan; Jana, Atish Dipnakar

    2012-06-01

    In a pursuit of electronic level understanding of the antioxidant activity of a series of flavonoids, quantitative structure-activity relationship (QSAR) studies have been carried out using density functional theory (DFT) based quantum chemical descriptors. The best QSAR model have been selected for which the computed square correlation coefficient r(2) = 0.937 and cross-validated squared correlation coefficient q(2) =0.916. The QSAR model indicates that hardness (η), group electrophilic frontier electron density (F(E)(A)) and group philicity (ω(B)(+)) of individual molecules are responsible for in vitro biological activity. To the best our knowledge, the group electrophilic frontier electron density (F(E)(A)) has been used for the first time to explain the radical scavenging activity (RSA) of flavonoids. The excellent correlation between the RSA and the above mentioned DFT based descriptors lead us to predict new antioxidants having very good antioxidant activity. PMID:22080306

  2. Polyelectrolyte nanocomplex formation of heparin-photosensitizer conjugate with polymeric scavenger for photodynamic therapy.

    PubMed

    Li, Li; Cho, Hana; Kim, Sungwon; Kang, Han Chang; Huh, Kang Moo

    2015-05-01

    A polyelectrolyte nanocomplex was prepared via the ionic interaction between the anionic heparin-pheophorbide a (HPhA) conjugate, which served as a water-soluble polysaccharide photosensitizer (PS), and the cationic polyethylenimine (PEI)-β-carotene (PCAR) conjugate, which served as a polymeric scavenger. This nanocomplex was designed to improve the water solubility and tumor specificity of PhA and to only release singlet oxygen at the tumor cell. A stable 150 nm-sized nanocomplex could be formed in the weight ratio range (PCAR/HPhA) of 0.3-0.5 in an aqueous environment. The PCAR scavenger significantly diminished the generation of active singlet oxygen from HPhA in a buffer solution. Singlet oxygen scavenging activity was lost only when HPhA and PCAR were separated from each other due to the dissociation of the complex nanostructures. It was confirmed that HPhA itself has neither colloidal properties nor a decrease in its ability to produce singlet oxygen. At the same time, the HPhA/PEI complex produced singlet oxygen in response to light. In a cell culture system, the cytotoxicity of the HPhA/PCAR nanocomplex toward cancer cells was greatly enhanced due to the efficient generation of singlet oxygen under light irradiation; this finding implies that the scavenging activity of PCAR can be restricted to intracellular environments. These results suggest that the HPhA/PCAR nanocomplex could provide a new activatable PS platform that facilitates more accurate and reliable photodynamic therapy (PDT) with site-specific and controllable production of singlet oxygen to be used for the treatment of cancer. PMID:25659680

  3. Nitric Oxide Scavenging by Hemoglobin in Health, Disease, and Therapeutics

    NASA Astrophysics Data System (ADS)

    Kim-Shapiro, Daniel

    2007-11-01

    Nitric oxide (NO) is the endothelium-derived relaxing factor (EDRF). It is made in endothelial cells lining blood vessels and diffuses to smooth muscle cells where it leads to muscle relaxation, vessel dilatation, and increased blood flow and also plays a large role in controlling platelet aggregation and inflammation. Hemoglobin (Hb), the oxygen carrying molecule in the blood, reacts at nearly diffusion limited rates with nitric oxide to (in some reactions) form nitrate ands thereby destroy NO activity. The presence of such large amounts of such a potent NO scavenger in the blood challenges the idea that NO is indeed the EDRF. Encapsulation in red blood cells in healthy individuals limits NO scavenging by Hb. Biophysical experiments will be described exploring and evaluating these mechanisms. Other studies will be described discussing how red cells break open (lyse) in pathological situations and the cell-free Hb reduces NO bioavailability. Finally, methods to restore NO bioavailability through therapeutics will be discussed.

  4. REACTOR FUEL SCAVENGING MEANS

    DOEpatents

    Coffinberry, A.S.

    1962-04-10

    A process for removing fission products from reactor liquid fuel without interfering with the reactor's normal operation or causing a significant change in its fuel composition is described. The process consists of mixing a liquid scavenger alloy composed of about 44 at.% plutoniunm, 33 at.% lanthanum, and 23 at.% nickel or cobalt with a plutonium alloy reactor fuel containing about 3 at.% lanthanum; removing a portion of the fuel and scavenger alloy from the reactor core and replacing it with an equal amount of the fresh scavenger alloy; transferring the portion to a quiescent zone where the scavenger and the plutonium fuel form two distinct liquid layers with the fission products being dissolved in the lanthanum-rich scavenger layer; and the clean plutonium-rich fuel layer being returned to the reactor core. (AEC)

  5. Prolyl Hydroxylase PHD3 Activates Oxygen-dependent Protein Aggregation

    PubMed Central

    Rantanen, Krista; Pursiheimo, Juha; Högel, Heidi; Himanen, Virpi; Metzen, Eric

    2008-01-01

    The HIF prolyl hydroxylases (PHDs/EGLNs) are central regulators of the molecular responses to oxygen availability. One isoform, PHD3, is expressed in response to hypoxia and causes apoptosis in oxygenated conditions in neural cells. Here we show that PHD3 forms subcellular aggregates in an oxygen-dependent manner. The aggregation of PHD3 was seen under normoxia and was strongly reduced under hypoxia or by the inactivation of the PHD3 hydroxylase activity. The PHD3 aggregates were dependent on microtubular integrity and contained components of the 26S proteasome, chaperones, and ubiquitin, thus demonstrating features that are characteristic for aggresome-like structures. Forced expression of the active PHD3 induced the aggregation of proteasomal components and activated apoptosis under normoxia in HeLa cells. The apoptosis was seen in cells prone to PHD3 aggregation and the PHD3 aggregation preceded apoptosis. The data demonstrates the cellular oxygen sensor PHD3 as a regulator of protein aggregation in response to varying oxygen availability. PMID:18337469

  6. Excited states in the active media of oxygen - iodine lasers

    SciTech Connect

    Azyazov, V N

    2009-11-30

    A review of investigations of kinetic processes in active media oxygen - iodine lasers (OILs) performed in the last decade is presented. The mechanisms of pumping and quenching of electronically and vibrationally excited O{sub 2} and I{sub 2} molecules are considered, and dissociation mechanisms of I{sub 2} in the active medium of the OIL are analysed. The values of kinetic constants of processes proceeding in the active media of OILs are recommended. (review)

  7. Oxidative DNA adducts after Cu(2+)-mediated activation of dihydroxy PCBs: role of reactive oxygen species.

    PubMed

    Spencer, Wendy A; Lehmler, Hans-Joachim; Robertson, Larry W; Gupta, Ramesh C

    2009-05-15

    Polychlorinated biphenyls (PCBs) are toxic industrial chemicals, complete carcinogens, and efficacious tumor promoters. However, the mechanism(s) of PCB-mediated carcinogenicity remains largely undefined. One likely pathway by which these agents may play a role in carcinogenesis is the generation of oxidative DNA damage by redox cycling of dihydroxylated PCB metabolites. We have now employed a new (32)P-postlabeling system to examine novel oxidative DNA lesions induced by Cu(2+)-mediated activation of PCB metabolites. (32)P postlabeling of DNA incubated with various PCB metabolites resulted in over a dozen novel polar oxidative DNA adducts that were chromatographically similar for all active agents. The most potent metabolites tested were the hydroquinones (hydroxyl groups arranged para to each other), yielding polar oxidative adduct levels ranging from 55 to 142 adducts/10(6) nucleotides. PCB catechols, or ortho-dihydroxy metabolites, were up to 40% less active than their corresponding hydroquinone congeners, whereas monohydroxylated and quinone metabolites did not produce detectable oxidative damage over that of vehicle. With the exception of 2,4,5-Cl-2',5'-dihydroxybiphenyl, this oxidative DNA damage seemed to be inversely related to chlorine content: no chlorine approximately mono->di->trichlorinated metabolites. Importantly, copper, but not iron, was essential for activation of the PCB metabolites to these polar oxidative DNA adducts, because in its absence or in the presence of the Cu(+)-specific scavenger bathocuproine, no adducts were detected. Intervention studies with known reactive oxygen species (ROS) modifiers suggested that H(2)O(2), singlet oxygen, hydroxyl radical, and superoxide may also be involved in this PCB-mediated oxidative DNA damage. These data indicate a mechanistic role for several ROS, in addition to copper, in PCB-induced DNA damage and provide further support for oxidative DNA damage in PCB-mediated carcinogenesis. PMID:19233261

  8. Crystal structure, DFT and HF calculations and radical scavenging activities of (E)-4,6-dibromo-3-methoxy-2-[(3-methoxyphenylimino)methyl]phenol

    NASA Astrophysics Data System (ADS)

    Alaşalvar, Can; Soylu, Mustafa Serkan; Güder, Aytaç; Albayrak, Çiğdem; Apaydın, Gökhan; Dilek, Nefise

    In this study, (E)-4,6-dibromo-3-methoxy-2-[(3-methoxyphenylimino)methyl]phenol has been synthesized and characterized by using X-ray technique and FT-IR experimentally and using B3LYP/6-31G(d,p) and HF/6-31G(d,p) methods theoretically. The intermolecular and intramolecular interactions of the title compound have been determined according to X-ray results. The molecular geometry, vibrational frequencies of the title compound in the ground state have been calculated using the density functional B3LYP and HF method with the 6-31G(d,p) basis set and calculated bond parameters and vibrational frequencies values show good agreement with experimental values. Theoretical and experimental results show that tautomeric form of the structure is phenol-imine form. Besides HOMO-LUMO energy gap, molecular electrostatic potential map were performed at B3LYP/6-31G(d,p) level. It is worthy note of that, the free radical scavenging activities of the title compound were assessed using DPPHrad , DMPDrad +, and ABTSrad + assays. The obtained results show that the title compound has effective DPPHrad (SC50 2.61 ± 0.09 μg/mL), DMPDrad + (SC50 2.82 ± 0.14 μg/mL), and ABTSrad + (SC50 4.91 ± 0.18 μg/mL) radical scavenging activities when compared with standard antioxidants (BHA, rutin, and trolox).

  9. Studies on cytotoxic, hydroxyl radical scavenging and topoisomerase inhibitory activities of extracts of Tabernaemontana divaricata (L.) R.Br. ex Roem. and Schult.

    PubMed

    Thind, Tarunpreet Singh; Agrawal, Satyam Kumar; Saxena, A K; Arora, Saroj

    2008-08-01

    In the present investigation, the cytotoxic, hydroxyl radical scavenging and topoisomerase inhibition activities of Tabernaemontana divaricata (Apocynaceae) were evaluated. The extracts from leaves of the plant were prepared with different solvents viz. chloroform, methanol, ethyl acetate and hexane. In, in vitro cytotoxicity assay, with cell lines viz HCT-15 (Colon), HT-29 (Colon), 502713 (Colon), MCF-7 (Breast), PC- 3 (Prostrate), it was observed that the ethyl acetate extract was effective against only one colon cell line (502713) at the lowest dose i.e. 10 micro g/ml, whereas the chloroform extract was effective against all the three colon cancer cell lines, at 30 microg/ ml. In order to evaluate the mechanism of cytotoxicity of these extracts, they were assessed for their ability to scavenge hydroxyl radicals in plasmid nicking assay with pBR322. It was observed that all the extracts effectively inhibited the unwinding of supercoiled DNA except hexane extract, which showed the least effect. Since the expression of topo enzymes is linked with cell proliferation so the extracts were also checked for topo I and topo II inhibitory activities. It was noticed that ethyl acetate extract selectively showed inhibition of topo II in topoisomerase II relaxation assay. PMID:18577413

  10. Early oxygen-utilization and brain activity in preterm infants.

    PubMed

    Tataranno, Maria Luisa; Alderliesten, Thomas; de Vries, Linda S; Groenendaal, Floris; Toet, Mona C; Lemmers, Petra M A; Vosse van de, Renè E; van Bel, Frank; Benders, Manon J N L

    2015-01-01

    The combined monitoring of oxygen supply and delivery using Near-InfraRed spectroscopy (NIRS) and cerebral activity using amplitude-integrated EEG (aEEG) could yield new insights into brain metabolism and detect potentially vulnerable conditions soon after birth. The relationship between NIRS and quantitative aEEG/EEG parameters has not yet been investigated. Our aim was to study the association between oxygen utilization during the first 6 h after birth and simultaneously continuously monitored brain activity measured by aEEG/EEG. Forty-four hemodynamically stable babies with a GA < 28 weeks, with good quality NIRS and aEEG/EEG data available and who did not receive morphine were included in the study. aEEG and NIRS monitoring started at NICU admission. The relation between regional cerebral oxygen saturation (rScO2) and cerebral fractional tissue oxygen extraction (cFTOE), and quantitative measurements of brain activity such as number of spontaneous activity transients (SAT) per minute (SAT rate), the interval in seconds (i.e. time) between SATs (ISI) and the minimum amplitude of the EEG in μV (min aEEG) were evaluated. rScO2 was negatively associated with SAT rate (β=-3.45 [CI=-5.76- -1.15], p=0.004) and positively associated with ISI (β=1.45 [CI=0.44-2.45], p=0.006). cFTOE was positively associated with SAT rate (β=0.034 [CI=0.009-0.059], p=0.008) and negatively associated with ISI (β=-0.015 [CI=-0.026- -0.004], p=0.007). Oxygen delivery and utilization, as indicated by rScO2 and cFTOE, are directly related to functional brain activity, expressed by SAT rate and ISI during the first hours after birth, showing an increase in oxygen extraction in preterm infants with increased early electro-cerebral activity. NIRS monitored oxygenation may be a useful biomarker of brain vulnerability in high-risk infants. PMID:25965343

  11. The evaluation of potential limonene scavengers

    SciTech Connect

    Roth, R.; Ebert, D.; Shepodd, T.J.

    1995-01-01

    This work is the study of different scavengers of limonene. Limonene is a citrus-based, low toxicity, hydrocarbon solvent for cleaning circuit boards and other parts. Though almost all limonene evaporates after cleaning procedures, trace residual limonene would be a concern if allowed to migrate freely through a sealed system. This work was charted to investigate materials that would effectively scavenge and permanently immobilize trace limonene. The requirements of a successful scavenger are the following: it must remove >90% of 30 mg/l limonene from a sealed volume with 3 months, at 20--25 C; it must not release any volatiles over prolonged aging; it must be packaged such that limonene vapors can access the scavenger, but not such that the scavenging medium can migrate; and it must operate in the presence of water, oxygen, pentane, toluene, and carbon dioxide gases. A number of adsorbents were evaluated. Additionally, a scheme for scavenging limonene by chemical reaction was investigated at Sandia. This attempt was not successful. The details of this investigation are found at the end of this report.

  12. Changes to coral health and metabolic activity under oxygen deprivation.

    PubMed

    Murphy, James W A; Richmond, Robert H

    2016-01-01

    On Hawaiian reefs, the fast-growing, invasive algae Gracilaria salicornia overgrows coral heads, restricting water flow and light, thereby smothering corals. Field data shows hypoxic conditions (dissolved oxygen (DO2) < 2 mg/L) occurring underneath algal mats at night, and concurrent bleaching and partial tissue loss of shaded corals. To analyze the impact of nighttime oxygen-deprivation on coral health, this study evaluated changes in coral metabolism through the exposure of corals to chronic hypoxic conditions and subsequent analyses of lactate, octopine, alanopine, and strombine dehydrogenase activities, critical enzymes employed through anaerobic respiration. Following treatments, lactate and octopine dehydrogenase activities were found to have no significant response in activities with treatment and time. However, corals subjected to chronic nighttime hypoxia were found to exhibit significant increases in alanopine dehydrogenase activity after three days of exposure and strombine dehydrogenase activity starting after one overnight exposure cycle. These findings provide new insights into coral metabolic shifts in extremely low-oxygen environments and point to ADH and SDH assays as tools for quantifying the impact of hypoxia on coral health. PMID:27114888

  13. Changes to coral health and metabolic activity under oxygen deprivation

    PubMed Central

    Richmond, Robert H.

    2016-01-01

    On Hawaiian reefs, the fast-growing, invasive algae Gracilaria salicornia overgrows coral heads, restricting water flow and light, thereby smothering corals. Field data shows hypoxic conditions (dissolved oxygen (DO2) < 2 mg/L) occurring underneath algal mats at night, and concurrent bleaching and partial tissue loss of shaded corals. To analyze the impact of nighttime oxygen-deprivation on coral health, this study evaluated changes in coral metabolism through the exposure of corals to chronic hypoxic conditions and subsequent analyses of lactate, octopine, alanopine, and strombine dehydrogenase activities, critical enzymes employed through anaerobic respiration. Following treatments, lactate and octopine dehydrogenase activities were found to have no significant response in activities with treatment and time. However, corals subjected to chronic nighttime hypoxia were found to exhibit significant increases in alanopine dehydrogenase activity after three days of exposure and strombine dehydrogenase activity starting after one overnight exposure cycle. These findings provide new insights into coral metabolic shifts in extremely low-oxygen environments and point to ADH and SDH assays as tools for quantifying the impact of hypoxia on coral health. PMID:27114888

  14. Activated oxygen alters cerebral microvascular responses in newborn pigs

    SciTech Connect

    Leffler, C.W.; Busiia, D.W.; Armstead, W.M.; Mirro, R.; Thelin, O. )

    1990-02-26

    In piglets, cerebral ischemia/reperfusion blocks prostanoid dependent cerebral vasodilation to hypercapnia (CO{sub 2}) and hypotension but not prostanoid independent dilation to isoproterenol (Isu) or constriction to norepinephrine (NE). Ischemia/reperfusion increases activated-O{sub 2} production by piglet brains. Using cranial windows in piglets, the authors investigated the hypothesis that activated oxygen can block prostanoid dependent cerebral vasodilator responses to CO{sub 2} and hypotension without altering responses to Isu and NE. Exposure to an activated oxygen generating system of xanthine oxidase, hypoxanthine, and Fe that made about 3 times the activated-O{sub 2} on the brain surface as ischemia/reperfusion caused reversible pial arteriolar dilation. After exposure, pial arteriolar dilation was reduced to CO{sub 2} and hypotension but not to Isu. NE constrictor responses were also unaltered. H{sub 2}O{sub 2} or H{sub 2}O{sub 2} + Fe caused constriction followed by reversible dilation. After exposure, pial arteriolar dilation in response to CO{sub 2} and hypotension was not altered. However, addition of xanthine oxidase and hypoxanthine with H{sub 2}O{sub 2} and Fe totally eliminated pial arteriolar dilator responses to CO{sub 2} and hypotension but did not decrease dilation caused by Isu or constriction caused by NE. The authors conclude that activated oxygen could produce the altered prostanoid dependent pial arteriolar responses observed following ischemia in piglets.

  15. Investigation into Seasonal Scavenging Patterns of Raccoons on Human Decomposition.

    PubMed

    Jeong, Yangseung; Jantz, Lee Meadows; Smith, Jake

    2016-03-01

    Although raccoons are known as one of the most common scavengers in the U.S., scavenging by these animals has seldom been studied in terms of forensic significance. In this research, the seasonal pattern of raccoon scavenging and its effect on human decomposition was investigated using 178 human cadavers placed at the Anthropological Research Facility (ARF) of the University of Tennessee, Knoxville (UTK) between February 2011 and December 2013. The results reveal that (i) the frequency of scavenging increases during summer, (ii) scavenging occurs relatively immediately and lasts shorter in summer months, and (iii) scavenging influences the decomposition process by hollowing limbs and by disturbing insect activities, both of which eventually increases the chance of mummification on the affected body. This information is expected to help forensic investigators identify raccoon scavenging as well as make a more precise interpretation of the effect of raccoon scavenging on bodies at crime scenes. PMID:27404620

  16. Modulation of the antioxidant activity of HO* scavengers by albumin binding: a 19F-NMR study.

    PubMed

    Aime, Silvio; Digilio, Giuseppe; Bruno, Erik; Mainero, Valentina; Baroni, Simona; Fasano, Mauro

    2003-08-01

    The interaction between different HO(z.rad;) radical scavengers in a three-component antioxidant system has been investigated by means of 19F-NMR spectroscopy. This system is composed of bovine serum albumin (BSA), trolox, and N-(4-hydroxyphenyl)-trifluoroacetamide (CF(3)PAF). The antioxidant capacity of BSA and trolox has been assessed by measuring the amount of trifluoroacetamide (TFAM) arising from the radical mediated decomposition of CF(3)PAF. When assayed separately, both trolox and BSA behaved as antioxidants, as they were effective to protect CF(3)PAF from HO* radical-mediated decomposition. By contrast, trolox enhanced the production of TFAM in the presence of BSA, thus behaving as a pro-oxidant. Urate, carnosine, glucose, and propylgallate showed antioxidant properties both with or without BSA. CF(3)PAF and trolox were found to bind to BSA with association constants in the order of 5 x 10(3)M(-1) and to compete for the same binding sites. These results have been discussed in terms of BSA-catalysed cross-reactions between trolox-derived secondary radicals and CF(3)PAF. PMID:12878205

  17. In Vivo Processing of Ceria Nanoparticles inside Liver: Impact on Free-Radical Scavenging Activity and Oxidative Stress

    PubMed Central

    Tseng, Michael T.; Jasinski, Jacek B.; Yokel, Robert A.; Unrine, Jason M.; Davis, Burtron H.; Dozier, Alan K.; Hardas, Sarita S.; Sultana, Rukhsana; Grulke, Eric A.; Allan Butterfield, D.

    2015-01-01

    The cytotoxicity of ceria ultimately lies in its electronic structure, which is defined by the crystal structure, composition, and size. Despite previous studies focused on ceria uptake, distribution, biopersistance, and cellular effects, little is known about its chemical and structural stability and solubility once sequestered inside the liver. Mechanisms will be presented that elucidate the in vivo transformation in the liver. In vivo processed ceria reveals a particle-size effect towards the formation of ultrafines, which represent a second generation of ceria. A measurable change in the valence reduction of the second-generation ceria can be linked to an increased free-radical scavenging potential. The in vivo processing of the ceria nanoparticles in the liver occurs in temporal relation to the brain cellular and protein clearance responses that stem from the ceria uptake. This information is critical to establish a possible link between cellular processes and the observed in vivo transformation of ceria. The temporal linkage between the reversal of the pro-oxidant effect (brain) and ceria transformation (liver) suggests a cause–effect relationship. PMID:26322251

  18. Reactive oxygen species mediate TNFR1 increase after TRPV1 activation in mouse DRG neurons

    PubMed Central

    Ma, Fei; Zhang, Liping; Westlund, Karin N

    2009-01-01

    Background Transient receptor potential vanilloid subtype 1 (TRPV1) is activated by low pH/protons and is well known to be involved in hyperalgesia during inflammation. Tumor necrosis factor α (TNF-α), a proinflammatory cytokine, is involved in nociceptive responses causing hyperalgesia through TNF receptor type 1 (TNFR1) activation. Reactive oxygen species (ROS) production is also prominently increased in inflamed tissue. The present study investigated TNFR1 receptors in primary cultured mouse dorsal root ganglion (DRG) neurons after TRPV1 activation and the involvement of ROS. C57BL/6 mice, both TRPV1 knockout and wild type, were used for immunofluorescent and live cell imaging. The L4 and L5 DRGs were dissected bilaterally and cultured overnight. TRPV1 was stimulated with capsaicin or its potent analog, resiniferatoxin. ROS production was measured with live cell imaging and TNFR1 was detected with immunofluorescence in DRG primary cultures. The TRPV1 knockout mice, TRPV1 antagonist, capsazepine, and ROS scavenger, N-tert-Butyl-α-phenylnitrone (PBN), were employed to explore the functional relationship among TRPV1, ROS and TNFR1 in these studies. Results The results demonstrate that TRPV1 activation increases TNFR1 receptors and ROS generation in primary cultures of mouse DRG neurons. Activated increases in TNFR1 receptors and ROS production are absent in TRPV1 deficient mice. The PBN blocks increases in TNFR1 and ROS production induced by capsaicin/resiniferatoxin. Conclusion TRPV1 activation increases TNFR1 in cultured mouse DRG neurons through a ROS signaling pathway, a novel sensitization mechanism in DRG neurons. PMID:19531269

  19. Activation of molecular oxygen and the nature of the active oxygen species for CO oxidation on oxide supported Au catalysts.

    PubMed

    Widmann, D; Behm, R J

    2014-03-18

    Although highly dispersed Au catalysts with Au nanoparticles (NPs) of a few nanometers in diameter are well-known for their high catalytic activity for several oxidation and reduction reactions already at rather low temperatures for almost 30 years, central aspects of the reaction mechanism are still unresolved. While most studies focused on the active site, the active Au species, and the effect of the support material, the most crucial step during oxidation reactions, the activation of molecular oxygen and the nature of the resulting active oxygen species (Oact), received more attention just recently. This is topic of this Account, which focuses on the formation, location, and nature of the Oact species present on metal oxide supported Au catalysts under typical reaction conditions, at room temperature and above. It is mainly based on quantitative temporal analysis of products (TAP) reactor measurements, which different from most spectroscopic techniques are able to detect and quantify these species even at the extremely low concentrations present under realistic reaction conditions. Different types of pulse experiments were performed, during which the highly dispersed, realistic powder catalysts are exposed to very low amounts of reactants, CO and/or O2, in order to form and reactively remove Oact species and gain information on their formation, nature, and the active site for Oact formation. Our investigations have shown that the active oxygen species for CO oxidation on Au/TiO2 for reaction at 80 °C and higher is a highly stable atomic species, which at 80 °C is formed only at the perimeter of the Au-oxide interface and whose reactive removal by CO is activated, but not its formation. From these findings, it is concluded that surface lattice oxygen represents the Oact species for the CO oxidation. Accordingly, the CO oxidation proceeds via a Au-assisted Mars-van Krevelen mechanism, during which surface lattice oxygen close to the Au NPs is removed by reaction

  20. Removal of Biologically Active Organic Contaminants using Atomic Oxygen

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor); Banks, Michael A. (Inventor); Banks, Eric B. (Inventor)

    2003-01-01

    Biomedical devices that are to come into contact with living tissue, such as prosthetic and other implants for the human body and the containers used to store and transport them, are together cleaned of non-living, but biologically active organic materials, including endotoxins such as lipopolysaccharides, and assembled into a hermetically sealed package without recontamination. This is achieved by cleaning both the device and package components together in an apparatus, which includes a hermetically sealed chamber, in which they are contacted with atomic oxygen which biocleans them, by oxidizing the biologically active organic materials. The apparatus also includes means for manipulating the device and container and hermetically sealing the cleaned device into the cleaned container to form the package. A calibrated witness coupon visually indicates whether or not the device and container have received enough exposure to the atomic oxygen to have removed the organic materials from their surfaces. Gamma radiation is then used to sterilize the device in the sealed container.

  1. Charge transfer induced activity of graphene for oxygen reduction

    NASA Astrophysics Data System (ADS)

    Shen, Anli; Xia, Weijun; Zhang, Lipeng; Dou, Shuo; Xia, Zhenhai; Wang, Shuangyin

    2016-05-01

    Tetracyanoethylene (TCNE), with its strong electron-accepting ability, was used to dope graphene as a metal-free electrocatalyst for the oxygen reduction reaction (ORR). The charge transfer process was observed from graphene to TCNE by x-ray photoelectron spectroscopy and Raman characterizations. Our density functional theory calculations found that the charge transfer behavior led to an enhancement of the electrocatalytic activity for the ORR.

  2. Contribution of Endogenously Produced Reactive Oxygen Species to the Activation of Podocyte NLRP3 Inflammasomes in Hyperhomocysteinemia

    PubMed Central

    Abais, Justine M.; Xia, Min; Li, Guangbi; Gehr, Todd W. B.; Boini, Krishna M.; Li, Pin-Lan

    2013-01-01

    Hyperhomocysteinemia (hHcys) is an important pathogenic factor contributing to the progression of end-stage renal disease. Recent studies have demonstrated the implication of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-mediated NLRP3 inflammasome activation in the development of podocyte injury and glomerular sclerosis during hHcys. However, it remains unknown which reactive oxygen species (ROS) are responsible for this activation of NLRP3 inflammasomes and how such action of ROS is controlled. The present study tested the contribution of common endogenous ROS including superoxide (O2•−), hydrogen peroxide (H2O2), and hydroxyl radical (•OH) to the activation of NLRP3 inflammasomes in mouse podocytes and glomeruli. In vitro, confocal microscopy and size exclusion chromatography demonstrated that dismutation of O2•− by 4-Hydroxy-2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPOL) and decomposition of H2O2 by catalase prevented Hcys-induced aggregation of NLRP3 inflammasome proteins and inhibited Hcys-induced caspase-1 activation and IL-1β production in mouse podocytes. However, •OH scavenger tetramethylthiourea (TMTU) had no significant effect on either Hcys-induced NLRP3 inflammasome formation or activation. In vivo, scavenging of O2•− by TEMPOL and removal of H2O2 by catalase substantially inhibited NLRP3 inflammasome formation and activation in glomeruli of hHcys mice as shown by reduced colocalization of NLRP3 with ASC or caspase-1 and inhibition of caspase-1 activation and IL-1β production. Furthermore, TEMPOL and catalase significantly attenuated hHcys-induced glomerular injury. In conclusion, endogenously produced O2•− and H2O2 primarily contribute to NLRP3 inflammasome formation and activation in mouse glomeruli resulting in glomerular injury or consequent sclerosis during hHcys. PMID:24140862

  3. An efficient one pot syntheses of aryl-3,3'-bis(indolyl)methanes and studies on their spectral characteristics, DPPH radical scavenging-, antimicrobial-, cytotoxicity-, and antituberculosis activity

    NASA Astrophysics Data System (ADS)

    Suresh Kumar, G. S.; Kumaresan, S.; Antony Muthu Prabhu, A.; Bhuvanesh, N.; Seethalakshmi, P. G.

    2013-01-01

    An efficient one-pot syntheses of aryl-3,3'-bis(indolyl)methanes (BIMs) from indole/2-methylindole and formylphenoxyaliphatic acid(s) is described. Esterification of carboxylic acid and aromatic electrophilic substitution reactions are achieved simultaneous in the presence of potash alum as a catalyst. This catalyst could be recovered and reused without substantial loss in its catalytic activity and the methodology could be applied on a range of closely related substrates. The solvation characteristics in ground and excited states of the compounds by monitoring the absorbance and fluorescence band maxima have been studied. The fluorescence studies in protic and aprotic solvents were rationalized on the basis of solute-solvent interaction and substituents effect on these photophysical processes analyzed. The compounds prepared showed efficient antimicrobial effect against human pathogens, cytotoxicity against A431 cell line, and DPPH radical scavenging effect. Single crystal XRD studies have been carried out for a few compounds synthesized in this work.

  4. Studies on the syntheses, structural characterization, antimicrobial-, and DPPH radical scavenging activity of the cocrystals caffeine:cinnamic acid and caffeine:eosin dihydrate

    NASA Astrophysics Data System (ADS)

    Suresh Kumar, G. S.; Seethalakshmi, P. G.; Bhuvanesh, N.; Kumaresan, S.

    2013-10-01

    Two organic cocrystals namely, caffeine:cinnamic acid [(caf)(ca)] (1) and caffeine:eosin dihydrate [(caf)(eos)]·2H2O (2) were synthesized and studied by FT-IR, TGA/DTA, and single crystal XRD. The crystal system of cocrystal 1 is triclinic with space group P-1 and Z = 2 and that of cocrystal 2 is monoclinic with space group P21/C and Z = 4. An imidazole-carboxylic acid synthon is observed in the cocrystal 1. The intermolecular hydrogen bond, O-H⋯N and π-π interactions play a major role in stabilizing 1 whereas the intermolecular hydrogen bonds, O-H⋯O, O-H⋯N, and intramolecular hydrogen bond, O-H⋯Br; along with π-π interactions together play a vital role in stabilizing the structure of 2. The antimicrobial- and DPPH radical scavenging activities of both the cocrystals were studied.

  5. Changes in polyphenolic content and radical-scavenging activity of sweet potato (Ipomoea batatas L.) during storage at optimal and low temperatures.

    PubMed

    Ishiguro, Koji; Yahara, Shoji; Yoshimoto, Makoto

    2007-12-26

    Polyphenolic content and radical-scavenging activities (RSA) of four sweet potato (Ipomoea batatas L.) cultivars were characterized after storage at optimal (15 degrees C) or low temperature (5 degrees C) for 0, 13, 26, and 37 days. The polyphenolic content increased during storage in three cultivars but not in 'Murasakimasari'. The change in 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity (DPPH-RSA) correlated very well with polyphenolic content. The increases in polyphenolics and the RSA in 'Benimasari' were significantly greater during storage at 5 degrees C than at 15 degrees C. The main polyphenolic components in all cultivars were chlorogenic acid (ChA) and 3,5-di-O-caffeoylquinic acid (3,5-diCQA). ChA level increased more at 5 degrees C than at 15 degrees C, whereas that of 3,5-diCQA was greater at 15 degrees C. Caffeoylquinic acids and RSA in 'Murasakimasari', which contains a large amount of anthocyanin in flesh tissue, were extremely high at the beginning of storage and remained nearly constant or decreased over time. A non-caffeoylquinic acid component that increased during storage, especially in 'J-Red' at 15 degrees C, was purified by successive chromatographic steps. The isolate was identified as caffeoyl sucrose [CSu, 6-O-caffeoyl-(beta- d-fructofuranosyl-(2-->1))-alpha-D-glucopyranoside] by fast atom bombardment-mass spectroscopy (FAB-MS), infrared spectroscopy (IR), and nuclear magnetic resonance spectroscopy (NMR). These results suggest that storage under cultivar-dependent, controlled temperature is one approach for increasing desirable physiologic function associated with RSA of polyphenolic compounds in sweet potato roots. PMID:18038989

  6. Crystal structure, DFT and HF calculations and radical scavenging activities of (E)-4,6-dibromo-3-methoxy-2-[(3-methoxyphenylimino)methyl]phenol.

    PubMed

    Alaşalvar, Can; Soylu, Mustafa Serkan; Güder, Aytaç; Albayrak, Çiğdem; Apaydın, Gökhan; Dilek, Nefise

    2014-05-01

    In this study, (E)-4,6-dibromo-3-methoxy-2-[(3-methoxyphenylimino)methyl]phenol has been synthesized and characterized by using X-ray technique and FT-IR experimentally and using B3LYP/6-31G(d,p) and HF/6-31G(d,p) methods theoretically. The intermolecular and intramolecular interactions of the title compound have been determined according to X-ray results. The molecular geometry, vibrational frequencies of the title compound in the ground state have been calculated using the density functional B3LYP and HF method with the 6-31G(d,p) basis set and calculated bond parameters and vibrational frequencies values show good agreement with experimental values. Theoretical and experimental results show that tautomeric form of the structure is phenol-imine form. Besides HOMO-LUMO energy gap, molecular electrostatic potential map were performed at B3LYP/6-31G(d,p) level. It is worthy note of that, the free radical scavenging activities of the title compound were assessed using DPPH˙, DMPD˙(+), and ABTS˙(+) assays. The obtained results show that the title compound has effective DPPH˙ (SC50 2.61±0.09 μg/mL), DMPD˙(+) (SC50 2.82±0.14 μg/mL), and ABTS˙(+) (SC50 4.91±0.18 μg/mL) radical scavenging activities when compared with standard antioxidants (BHA, rutin, and trolox). PMID:24566110

  7. Gamma irradiation of Tetrapleura tetraptera fruit as a post-harvest technique and its subsequent effect on some phytochemicals, free scavenging activity and physicochemical properties

    NASA Astrophysics Data System (ADS)

    Darfour, B.; Agbenyegah, S.; Ofosu, D. O.; Okyere, A. A.; Asare, I. K.

    2014-09-01

    Herbs, spices and medicinal plants have been cherished by many ancient cultures for their use in curing common ailments and promoting good health. The dry fruit of Tetrapleura tetraptera has a pleasant aroma and hence used as a spice for seasoning in many parts of Ghana. Contamination of the fruit can occur at any stage during harvesting, drying, processing, transportation and storage. T. tetraptera is prone to microbial contamination and insect infestation resulting in quality deterioration and economic loss. The study aimed at establishing the effect of gamma irradiation as a post-harvest processing technique on T. tetraptera fruit and the subsequent effect of the gamma irradiation on some phytochemicals, free radical scavenging activity and physicochemical properties. The T. tetraptera powder was packed in polythene bags and gamma irradiated with Cobalt 60 source at 5 kGy and 10 kGy at room temperature at a dose rate of 2 kGy/h. The total phenolic content, total flavonoid and DPPH free radical scavenging activity, pH, lactic acid, vitamin C, moisture, carbohydrate, protein and trace element content of the samples were analysed. The antioxidant potential of the T. tetraptera extract was observed to be enhanced in the solvent used for the extraction after the irradiation but not the radiation dose used. Irradiation only had substantial impacts on carbohydrate and protein, Cu, Mg, and Mn. The T. tetraptera studied was safe for human consumption as far as trace metal levels are concerned. This study therefore suggest that gamma irradiation up to 10 kGy could be used as a post-harvest technique in T. tetraptera as a spice or herb.

  8. Radical Scavenging Activity-Based and AP-1-Targeted Anti-Inflammatory Effects of Lutein in Macrophage-Like and Skin Keratinocytic Cells

    PubMed Central

    Oh, Jueun; Kim, Ji Hye; Park, Jae Gwang; Yi, Young-Su; Park, Kye Won; Rho, Ho Sik; Lee, Min-Seuk; Yoo, Jae Won; Kang, Seung-Hyun; Hong, Yong Deog; Shin, Song Seok; Cho, Jae Youl

    2013-01-01

    Lutein is a naturally occurring carotenoid with antioxidative, antitumorigenic, antiangiogenic, photoprotective, hepatoprotective, and neuroprotective properties. Although the anti-inflammatory effects of lutein have previously been described, the mechanism of its anti-inflammatory action has not been fully elucidated. Therefore, in the present study, we aimed to investigate the regulatory activity of lutein in the inflammatory responses of skin-derived keratinocytes or macrophages and to elucidate the mechanism of its inhibitory action. Lutein significantly reduced several skin inflammatory responses, including increased expression of interleukin-(IL-) 6 from LPS-treated macrophages, upregulation of cyclooxygenase-(COX-) 2 from interferon-γ/tumor necrosis-factor-(TNF-) α-treated HaCaT cells, and the enhancement of matrix-metallopeptidase-(MMP-) 9 level in UV-irradiated keratinocytes. By evaluating the intracellular signaling pathway and the nuclear transcription factor levels, we determined that lutein inhibited the activation of redox-sensitive AP-1 pathway by suppressing the activation of p38 and c-Jun-N-terminal kinase (JNK). Evaluation of the radical and ROS scavenging activities further revealed that lutein was able to act as a strong anti-oxidant. Taken together, our findings strongly suggest that lutein-mediated AP-1 suppression and anti-inflammatory activity are the result of its strong antioxidative and p38/JNK inhibitory activities. These findings can be applied for the preparation of anti-inflammatory and cosmetic remedies for inflammatory diseases of the skin. PMID:23533312

  9. Chlorhexidine markedly potentiates the oxidants scavenging abilities of Candida albicans.

    PubMed

    Ginsburg, I; Koren, E; Feuerstein, O; Zogakis, I P; Shalish, M; Gorelik, S

    2015-10-01

    The oxidant scavenging ability (OSA) of catalase-rich Candida albicans is markedly enhanced by chlorhexidine digluconate (CHX), polymyxin B, the bile salt ursodeoxycholate and by lysophosphatidylcholine, which all act as detergents facilitating the penetration of oxidants and their intracellular decomposition. Quantifications of the OSA of Candida albicans were measured by a highly sensitive luminol-dependent chemiluminescence assay and by the Thurman's assay, to quantify hydrogen peroxide (H2O2). The OSA enhancing activity by CHX depends to some extent on the media on which candida grew. The OSA of candida treated by CHX was modulated by whole human saliva, red blood cells, lysozyme, cationic peptides and by polyphenols. Concentrations of CHX, which killed over 95 % of Candida albicans cells, did not affect the cells' abilities to scavenge reactive oxygen species (ROS). The OSA of Candida cells treated by CHX is highly refractory to H2O2 (50 mM) but is strongly inhibited by hypochlorous acid, lecithin, trypan blue and by heparin. We speculate that similarly to catalase-rich red blood cells, Candida albicans and additional catalase-rich microbiota may also have the ability to scavenge oxidants and thus can protect catalase-negative anaerobes and facultative anaerobes cariogenic streptococci against peroxide and thus secure their survival in the oral cavity. PMID:26223507

  10. Differential contractile actions of reactive oxygen species on rat aorta: selective activation of ATP receptor by H2O2.

    PubMed

    Shen, J Z; Zheng, X F; Kwan, C Y

    2000-04-14

    This study aims to examine the effects of different reactive oxygen species (ROS) on the resting tension of endothelium-denuded rat aortic rings. In these preparations, H2O2 (30 microM) induced a fast and transient contraction, which could be abolished by pretreatment of catalase (800 U/ml), but not affected by superoxide anion scavenger, superoxide dismutase (SOD; 150 U/ml) or the hydroxyl free radical scavenger, DMSO/mannitol (each 3 mM). In contrast, pyrogallol, a putative superoxide anion donor, induced a biphasic contraction, which could be abolished by SOD, but not by catalase or DMSO/mannitol. Unlike H2O2 and pyrogallol, Vitamin C(VitC)/Fe2+ (each 100 microM), a commonly used hydroxyl radical-generating system, triggered a tonic contraction which could be prevented by DMSO/mannitol, but not by SOD or catalase. Interestingly, H2O2-induced contraction could be concentration-dependently (10-100 microM) inhibited by suramin and reactive blue-2 (RB-2), two widely used ATP receptor antagonists. On the other hand, suramin or RB-2, at concentration up to 100 microM, affected neither pyrogallol nor VitC/Fe2+-induced contraction. In conclusion, we showed for the first time that different ROS could contract rat aorta with different mechanisms of action, and H2O2 elicits a transient contraction probably as a result of the ATP receptor activation. PMID:10823352

  11. Active Oxygen Metabolites and Thromboxane in Phorbol Myristate Acetate Toxicity to the Isolated, Perfused Rat Lung.

    NASA Astrophysics Data System (ADS)

    Carpenter, Laurie Jean

    When administered intravenously or intratracheally to rats, rabbits and sheep, phorbol myristate acetate (PMA) produces changes in lung morphology and function are similar to those seen in humans with the adult respiratory distress syndrome (ARDS). Therefore, it is thought that information about the mechanism of ARDS development can be gained from experiments using PMA-treated animals. Currently, the mechanisms by which PMA causes pneumotoxicity are unknown. Results from other studies in rabbits and in isolated, perfused rabbit lungs suggest that PMA-induced lung injury is mediated by active oxygen species from neutrophils (PMN), whereas studies in sheep and rats suggest that PMN are not required for the toxic response. The role of PMN, active oxygen metabolites and thromboxane (TxA_2) in PMA-induced injury to isolated, perfused rat lungs (IPLs) was examined in this thesis. To determine whether PMN were required for PMA to produce toxicity to the IPL, lungs were perfused for 30 min with buffer containing various concentrations of PMA (in the presence or absence of PMN). When concentrations >=q57 ng/ml were added to medium devoid of added PMN, perfusion pressure and lung weight increased. When a concentration of PMA (14-28 ng/ml) that did not by itself cause lungs to accumulate fluid was added to the perfusion medium containing PMN (1 x 10 ^8), perfusion pressure increased, and lungs accumulated fluid. These results indicate that high concentrations of PMA produce lung injury which is independent of PMN, whereas injury induced by lower concentrations is PMN-dependent. To examine whether active oxygen species were involved in mediating lung injury induced by PMA and PMN, lungs were coperfused with the oxygen radical scavengers SOD and/or catalase. Coperfusion with either or both of these enzymes totally protected lungs against injury caused by PMN and PMA. These results suggest that active oxygen species (the hydroxyl radical in particular), mediate lung injury in

  12. Support nanostructure boosts oxygen transfer to catalytically active platinum nanoparticles.

    PubMed

    Vayssilov, Georgi N; Lykhach, Yaroslava; Migani, Annapaola; Staudt, Thorsten; Petrova, Galina P; Tsud, Nataliya; Skála, Tomáš; Bruix, Albert; Illas, Francesc; Prince, Kevin C; Matolín, Vladimír; Neyman, Konstantin M; Libuda, Jörg

    2011-04-01

    Interactions of metal particles with oxide supports can radically enhance the performance of supported catalysts. At the microscopic level, the details of such metal-oxide interactions usually remain obscure. This study identifies two types of oxidative metal-oxide interaction on well-defined models of technologically important Pt-ceria catalysts: (1) electron transfer from the Pt nanoparticle to the support, and (2) oxygen transfer from ceria to Pt. The electron transfer is favourable on ceria supports, irrespective of their morphology. Remarkably, the oxygen transfer is shown to require the presence of nanostructured ceria in close contact with Pt and, thus, is inherently a nanoscale effect. Our findings enable us to detail the formation mechanism of the catalytically indispensable Pt-O species on ceria and to elucidate the extraordinary structure-activity dependence of ceria-based catalysts in general. PMID:21423188

  13. Support nanostructure boosts oxygen transfer to catalytically active platinum nanoparticles

    NASA Astrophysics Data System (ADS)

    Vayssilov, Georgi N.; Lykhach, Yaroslava; Migani, Annapaola; Staudt, Thorsten; Petrova, Galina P.; Tsud, Nataliya; Skála, Tomáš; Bruix, Albert; Illas, Francesc; Prince, Kevin C.; MatolíN, VladimíR.; Neyman, Konstantin M.; Libuda, Jörg

    2011-04-01

    Interactions of metal particles with oxide supports can radically enhance the performance of supported catalysts. At the microscopic level, the details of such metal-oxide interactions usually remain obscure. This study identifies two types of oxidative metal-oxide interaction on well-defined models of technologically important Pt-ceria catalysts: (1) electron transfer from the Pt nanoparticle to the support, and (2) oxygen transfer from ceria to Pt. The electron transfer is favourable on ceria supports, irrespective of their morphology. Remarkably, the oxygen transfer is shown to require the presence of nanostructured ceria in close contact with Pt and, thus, is inherently a nanoscale effect. Our findings enable us to detail the formation mechanism of the catalytically indispensable Pt-O species on ceria and to elucidate the extraordinary structure-activity dependence of ceria-based catalysts in general.

  14. Orally active antioxidative copper(II) aspirinate: synthesis, structure characterization, superoxide scavenging activity, and in vitro and in vivo antioxidative evaluations.

    PubMed

    Fujimori, T; Yamada, S; Yasui, H; Sakurai, H; In, Y; Ishida, T

    2005-12-01

    Ever since it was proposed that reactive oxygen species (ROS) are involved in the pathogeneses of various diseases, superoxide dismutase (SOD)-mimetic complexes have been intensively studied. We prepared copper(II) aspirinate [Cu2(asp)4] from Cu(II) and aspirin, which has been in use for many years as an antipyretic, an analgesic, and an anti-inflammatory agent. However, Cu2(asp)4 has been found to have additional activities, including anti-inflammatory, antiulcer, anti-ischemic/reperfusion agent, anticancer, antimutagenic, and antimicrobial activities. The activity of copper salicylate [Cu(sal)2] was also compared with that of Cu2(asp)4. The structure of the Cu2(asp)4 was determined using X-ray structure analysis. Its SOD-mimetic activity was determined using cytochrome c, electron spin resonance (ESR) spectroscopy, and ESR spin trap methods. The activity of Cu2(asp)4 was slightly greater than CuSO4 and copper acetate [Cu(ace)2] and slightly less than that of Cu(sal)2. The in vitro antioxidant activity, evaluated in human epithelial or transformed neoplastic keratinocyte cells, HaCaT, and normal dermal fibroblasts in terms of cell survival following ultraviolet B (UVB) irradiation, was significantly increased in the presence of Cu2(asp)4, Cu(sal)2, and CuSO4. Further, ROS generation following UVA irradiation in the skin of hairless mice following oral treatment with Cu2(asp)4 for three consecutive days was significantly suppressed compared to the vehicle- or Cu(ace)2-treated mice. On the basis of these results, Cu2(asp)4 was observed to be a potent antioxidative compound possessing antioxidative activity in biological systems. In conclusion, Cu2(asp)4 is a potent antioxidative agent that may be useful for future treatment of diseases resulting from ROS. PMID:16261369

  15. A joint application of spectroscopic, electrochemical and theoretical approaches in evaluation of the radical scavenging activity of 3-OH flavones and their iron complexes towards different radical species.

    PubMed

    Dimitrić Marković, Jasmina M; Marković, Zoran S; Pašti, Igor A; Brdarić, Tanja P; Popović-Bijelić, Ana; Mojović, Miloš

    2012-06-28

    Combined spectroscopic (UV/visible, MS and EPR), electrochemical (CV) and theoretical approaches were used to evaluate the relevant interactions of morin and quercetin, as well as their respective iron(III) complexes with DPPH, tempone, hydroxyl and superoxide radicals. The results on iron complexation specify the stoichiometry and the relevant structural forms entering the chelation of the molecules. The spectroscopic DPPH assay shows better antioxidant activity of quercetin and its iron complex both in terms of EC(50) values and stoichiometry. The results of 2-deoxyribose degradation suggest that antioxidant activities of morin and quercetin may originate from their combined effect of iron chelation and radical scavenging. The distinctive difference in the EPR spectra of morin and quercetin radicals suggests different positions of the radical centers which may account for different sequences of their activities towards investigated radicals. Activity ranking of quercetin and morin, established by cyclic voltammetry, confirms their activity sequence obtained by EPR results and is also in agreement with the results of conformational analysis. The equilibrium geometries, optimized with the M052X functionals and 6-311G(d,p) basis set, predict structural modifications between the ligand molecules in the free state and in the complex structures. The arguments gained through experimental results can also be rationalized in terms of overall molecular geometry and structural features governing antioxidant behavior i.e. substitution pattern of the ring B. PMID:22576733

  16. Molecular hydrogen inhibits lipopolysaccharide-triggered NLRP3 inflammasome activation in macrophages by targeting the mitochondrial reactive oxygen species.

    PubMed

    Ren, Jian-Dong; Wu, Xiao-Bo; Jiang, Rui; Hao, Da-Peng; Liu, Yi

    2016-01-01

    The NLRP3 inflammasome, an intracellular multi-protein complex controlling the maturation of cytokine interleukin-1β, plays an important role in lipopolysaccharide (LPS)-induced inflammatory cascades. Recently, the production of mitochondrial reactive oxygen species (mtROS) in macrophages stimulated with LPS has been suggested to act as a trigger during the process of NLRP3 inflammasome activation that can be blocked by some mitochondria-targeted antioxidants. Known as a ROS scavenger, molecular hydrogen (H2) has been shown to possess therapeutic benefit on LPS-induced inflammatory damage in many animal experiments. Due to the unique molecular structure, H2 can easily target the mitochondria, suggesting that H2 is a potential antagonist of mtROS-dependent NLRP3 inflammasome activation. Here we have showed that, in mouse macrophages, H2 exhibited substantial inhibitory activity against LPS-initiated NLRP3 inflammasome activation by scavenging mtROS. Moreover, the elimination of mtROS by H2 resultantly inhibited mtROS-mediated NLRP3 deubiquitination, a non-transcriptional priming signal of NLRP3 in response to the stimulation of LPS. Additionally, the removal of mtROS by H2 reduced the generation of oxidized mitochondrial DNA and consequently decreased its binding to NLRP3, thereby inhibiting the NLRP3 inflammasome activation. Our findings have, for the first time, revealed the novel mechanism underlying the inhibitory effect of molecular hydrogen on LPS-caused NLRP3 inflammasome activation, highlighting the promising application of this new antioxidant in the treatment of LPS-associated inflammatory pathological damage. PMID:26488087

  17. Effects of combinations of ROS scavengers on oxidative DNA damage caused by visible-light-activated camphorquinone/N,N-dimethyl-p-toluidine.

    PubMed

    Lee, Seungbum; Pagoria, Dustin; Raigrodski, Ariel; Geurtsen, Werner

    2007-11-01

    The objective of this investigation was to analyze whether various combinations of the ROS scavengers glutathione (GSH), N-acetyl-cysteine (NAC), and vitamins C and E decrease DNA damage due to visible-light-irradiated (VL-irradiated) camphorquinone/N,N-dimethyl-p-toluidine (CQ/DMT) compared with individual vitamin C or E. PhiX-174 RF plasmid DNA was used to determine single and double strand breaks as parameters of DNA damage. Individual ROS scavengers and combinations of the antioxidants were added to plasmid DNA treated with VL-irradiated CQ/DMT/Cu (II). After incubation, DNA was loaded into a 1% agarose gel. Following electrophoresis, gels stained with 0.5 microg/mL ethidium bromide were photographed under ultraviolet illumination and analyzed with NIH ImageJ software. Results were evaluated between groups for statistical significance using Student's paired t-test (p < 0.05). Glutathione significantly reduced oxidative DNA damage at all test concentrations when combined with vitamin C or vitamin E. The concentration of damaged DNA observed in the presence of combinations of GSH with vitamin C or vitamin E was significantly lower compared with all other combinations of antioxidants investigated in our study (p < 0.05). In contrast to GSH, NAC was not able to compensate the pro-oxidative effects of vitamin C and vitamin E. Only at a concentration of 2 mM, NAC combined with vitamin C efficiently prevented CQ/DMT/Cu (II)-associated DNA damage. Our data indicate that solely the combinations of GSH with vitamin C or vitamin E significantly reduce the severity of oxidative DNA damage caused by CQ/DMT, whereas NAC may even increase the pro-oxidant activity of vitamin C and vitamin E. PMID:17443666

  18. On the determination of oxygen abundances in chromospherically active stars

    NASA Astrophysics Data System (ADS)

    Morel, T.; Micela, G.

    2004-08-01

    We discuss oxygen abundances derived from [O I] λ6300s and the O I triplet in stars spanning a wide range in chromospheric activity level, and show that these two indicators yield increasingly discrepant results with higher chromospheric/coronal activity measures. While the forbidden and permitted lines give fairly consistent results for solar-type disk dwarfs, spuriously high O I triplet abundances are observed in young Hyades and Pleiades stars, as well as in individual components of RS CVn binaries (up to 1.8 dex). The distinct behaviour of the [O I]-based abundances which consistently remain near-solar suggests that this phenomenon mostly results from large departures from LTE affecting the O I triplet at high activity level that are currently unaccounted for, but also possibly from a failure to adequately model the atmospheres of K-type stars. These results suggest that some caution should be exercised when interpreting oxygen abundances in active binaries or young open cluster stars. Based on observations collected at the European Southern Observatory, Chile (Proposals 64.L-0249 and 071.D-0260). Table \\ref{tab_data} is only available in electronic form at http://www.edpsciences.org

  19. A Geometric Scavenger Hunt

    ERIC Educational Resources Information Center

    Smart, Julie; Marshall, Jeff

    2007-01-01

    Children possess a genuine curiosity for exploring the natural world around them. One third grade teacher capitalized on this inherent trait by leading her students on "A Geometric Scavenger Hunt." The four-lesson inquiry investigation described in this article integrates mathematics and science. Among the students' discoveries was the fact that…

  20. Device for measuring oxygen activity in liquid sodium

    DOEpatents

    Roy, P.; Young, R.S.

    1973-12-01

    A composite ceramic electrolyte in a configuration (such as a closed end tube or a plate) suitable to separate liquid sodium from a reference electrode with a high impedance voltmeter connected to measure EMF between the sodium and the reference electrode as a measure of oxygen activity in the sodium is described. The composite electrolyte consists of zirconiacalcia with a bonded layer of thoria-yttria. The device is used with a gaseous reference electrode on the zirconia-calcia side and liquid sodium on the thoria-yttria side of the electrolyte. (Official Gazette)

  1. Bioreductively Activated Reactive Oxygen Species (ROS) Generators as MRSA Inhibitors.

    PubMed

    Khodade, Vinayak S; Sharath Chandra, Mallojjala; Banerjee, Ankita; Lahiri, Surobhi; Pulipeta, Mallikarjuna; Rangarajan, Radha; Chakrapani, Harinath

    2014-07-10

    The number of cases of drug resistant Staphylococcus aureus infections is on the rise globally and new strategies to identify drug candidates with novel mechanisms of action are in urgent need. Here, we report the synthesis and evaluation of a series of benzo[b]phenanthridine-5,7,12(6H)-triones, which were designed based on redox-active natural products. We find that the in vitro inhibitory activity of 6-(prop-2-ynyl)benzo[b]phenanthridine-5,7,12(6H)-trione (1f) against methicillin-resistant Staphylococcus aureus (MRSA), including a panel of patient-derived strains, is comparable or better than vancomycin. We show that the lead compound generates reactive oxygen species (ROS) in the cell, contributing to its antibacterial activity. PMID:25050164

  2. Phytochemicals of Salacia oblonga responsible for free radical scavenging and antiproliferative activity against breast cancer cell lines (MDA-MB-231).

    PubMed

    Musini, Anjaneyulu; Rao, Jayaram Prakash; Giri, Archana

    2015-10-01

    Salacia oblonga, an inhabitant of tropical regions has been used in traditional Indian medicinal systems. Phytochemicals were extracted in methanol from the plant and analyzed for various biological activities. The results of biochemical tests for total phenolics (297 ± 0.005 and 275 ± 0.006) and flavonoids (95 ± 0.004 and 61.6 ± 0.004) in the aerial and root parts were indicated as Gallic acid and quercetin equivalents respectively. The Aerial and root extracts showed strong reducing ability based on reducing power and FRAP assays. The extracts exhibited significant IC50 values in DPPH, super oxide and nitric oxide radical scavenging assays. The extracts displayed low IC50 values (<50 μg/ml) when assessed for antiproliferative activity against breast cancer cell lines using the MTT assay. GC-MS analysis of methanolic extracts have revealed the presence of compounds viz. n-Hexadecanoic acid, N-Methoxy-N-methylacetamide, Ursa-9(11), 12-dien-3-ol, Gamma-sitosterol etc., that might be potential candidates for the biological activity exhibited by the extract. PMID:26600684

  3. Radical-Scavenging Activity and Ferric Reducing Ability of Juniperus thurifera (L.), J. oxycedrus (L.), J. phoenicea (L.) and Tetraclinis articulata (L.).

    PubMed

    El Jemli, Meryem; Kamal, Rabie; Marmouzi, Ilias; Zerrouki, Asmae; Cherrah, Yahia; Alaoui, Katim

    2016-01-01

    Objective. The aim of this work is to study and compare the antioxidant properties and phenolic contents of aqueous leaf extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus Phoenicea, and Tetraclinis articulata from Morocco. Methods. Antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging ability, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) assays. Also the total phenolic and flavonoids contents of the extracts were determined spectrophotometrically. Results. All the extracts showed interesting antioxidant activities compared to the standard antioxidants (butylated hydroxytoluene (BHT), quercetin, and Trolox). The aqueous extract of Juniperus oxycedrus showed the highest antioxidant activity as measured by DPPH, TEAC, and FRAP assays with IC50 values of 17.91 ± 0.37 μg/mL, 19.80 ± 0.55 μg/mL, and 24.23 ± 0.07 μg/mL, respectively. The strong correlation observed between antioxidant capacities and their total phenolic contents indicated that phenolic compounds were a major contributor to antioxidant properties of these plants extracts. Conclusion. These results suggest that the aqueous extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus phoenicea, and Tetraclinis articulata can constitute a promising new source of natural compounds with antioxidants ability. PMID:27293428

  4. Radical-Scavenging Activity and Ferric Reducing Ability of Juniperus thurifera (L.), J. oxycedrus (L.), J. phoenicea (L.) and Tetraclinis articulata (L.)

    PubMed Central

    Kamal, Rabie; Marmouzi, Ilias; Zerrouki, Asmae; Cherrah, Yahia; Alaoui, Katim

    2016-01-01

    Objective. The aim of this work is to study and compare the antioxidant properties and phenolic contents of aqueous leaf extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus Phoenicea, and Tetraclinis articulata from Morocco. Methods. Antioxidant activities of the extracts were evaluated by 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging ability, Trolox equivalent antioxidant capacity (TEAC), and ferric reducing antioxidant power (FRAP) assays. Also the total phenolic and flavonoids contents of the extracts were determined spectrophotometrically. Results. All the extracts showed interesting antioxidant activities compared to the standard antioxidants (butylated hydroxytoluene (BHT), quercetin, and Trolox). The aqueous extract of Juniperus oxycedrus showed the highest antioxidant activity as measured by DPPH, TEAC, and FRAP assays with IC50 values of 17.91 ± 0.37 μg/mL, 19.80 ± 0.55 μg/mL, and 24.23 ± 0.07 μg/mL, respectively. The strong correlation observed between antioxidant capacities and their total phenolic contents indicated that phenolic compounds were a major contributor to antioxidant properties of these plants extracts. Conclusion. These results suggest that the aqueous extracts of Juniperus thurifera, Juniperus oxycedrus, Juniperus phoenicea, and Tetraclinis articulata can constitute a promising new source of natural compounds with antioxidants ability. PMID:27293428

  5. Reactive oxygen species-activated nanomaterials as theranostic agents.

    PubMed

    Kim, Kye S; Lee, Dongwon; Song, Chul Gyu; Kang, Peter M

    2015-01-01

    Reactive oxygen species (ROS) are generated from the endogenous oxidative metabolism or from exogenous pro-oxidant exposure. Oxidative stress occurs when there is excessive production of ROS, outweighing the antioxidant defense mechanisms which may lead to disease states. Hydrogen peroxide (H2O2) is one of the most abundant and stable forms of ROS, implicated in inflammation, cellular dysfunction and apoptosis, which ultimately lead to tissue and organ damage. This review is an overview of the role of ROS in different diseases. We will also examine ROS-activated nanomaterials with emphasis on hydrogen peroxide, and their potential medical implications. Further development of the biocompatible, stimuli-activated agent responding to disease causing oxidative stress, may lead to a promising clinical use. PMID:26328770

  6. Reactive oxygen species-activated nanomaterials as theranostic agents

    PubMed Central

    Kim, Kye S; Lee, Dongwon; Song, Chul Gyu; Kang, Peter M

    2015-01-01

    Reactive oxygen species (ROS) are generated from the endogenous oxidative metabolism or from exogenous pro-oxidant exposure. Oxidative stress occurs when there is excessive production of ROS, outweighing the antioxidant defense mechanisms which may lead to disease states. Hydrogen peroxide (H2O2) is one of the most abundant and stable forms of ROS, implicated in inflammation, cellular dysfunction and apoptosis, which ultimately lead to tissue and organ damage. This review is an overview of the role of ROS in different diseases. We will also examine ROS-activated nanomaterials with emphasis on hydrogen peroxide, and their potential medical implications. Further development of the biocompatible, stimuli-activated agent responding to disease causing oxidative stress, may lead to a promising clinical use. PMID:26328770

  7. Mononuclear copper (II) salicylate complexes with 1,2-dimethylimidazole and 2-methylimidazole: Synthesis, spectroscopic and crystal structure characterization and their superoxide scavenging activities

    NASA Astrophysics Data System (ADS)

    Abuhijleh, A. Latif

    2010-09-01

    The complexes cis-bis (1,2-dimethylimidazole) bis (salicylato) copper (II) ( 1) and tris (2-methylimidazole) (salicylato) copper (II) ( 2) have been prepared by the reaction of appropriate methylimidazole derivative with binuclear copper (II) aspirinate. Spectral and X-ray structural studies for complex 1 showed that the copper ion is coordinated in a cis arrangement to two imidazole nitrogen atoms and two carboxylate oxygen atoms from the salicylate mono-anion ligands. The second carboxylate oxygen atoms form weak axial interactions with the copper ion. Spectral, magnetic and analytical data for complex 2 showed that the copper ion is bonded to three 2-methylimidazole nitrogen atoms and one doubly deprotonated salicylate di-anion, which is chelated to Cu (II) ion through one of its carboxylate oxygen atoms and the deprotonated hydroxyl oxygen atom to form distorted square-pyramidal geometry having CuN 3O + O chromophore. The superoxide dismutase (SOD) mimetic activities (IC 50) of the complexes 1, 2 and the structurally known mixture complexes Cu (imidazole) n(salicylato) 2( 3) (where n = 2, 5 and 6) were determined using the xanthine-xanthine oxidase assay and compared with those reported for other copper (II) complexes with anti-inflammatory drugs. The results obtained indicated that complexes 1- 3 have high SOD-like activities, which may act as good mimics for native Cu, Zn-SOD enzyme.

  8. Synthesis, crystal structure investigation, DFT studies and DPPH radical scavenging activity of 1-(furan-2-ylmethyl)-2,4,5-triphenyl-1H-imidazole derivatives

    NASA Astrophysics Data System (ADS)

    Rajaraman, D.; Sundararajan, G.; Rajkumar, R.; Bharanidharan, S.; Krishnasamy, K.

    2016-03-01

    A new series of 1-(furan-2ylmethyl)-2,4,5-triphenyl-1H-imidazole derivatives are conveniently synthesized and characterized by IR, 1H NMR and 13C NMR spectral techniques. The compound 5a also characterized by HSQC correlation spectra. All the newly synthesized compounds were evaluated for their antioxidant activities with DPPH radical scavenging activity. The structure of 5e was also confirmed by single crystal XRD analysis and optimized bond parameters are calculated by density functional theory (DFT) method at B3LYP/6-31G (d, p) level of theory. The optimized geometrical parameters obtained by DFT calculation are in good agreement with single crystal XRD data. The experimentally observed FT-IR and FT-Raman bands were assigned to different normal modes of the molecule. The stability and charge delocalization of the molecule were also studied by natural bond orbital (NBO) analysis. The HOMO-LUMO energies describe the charge transfer takes place within the molecule. Molecular electrostatic potential has been analyzed. The reported 5e molecule used as a potential NLO material since it has high μβ0 value.

  9. Evaluation of DNA binding, DNA cleavage, protein binding, radical scavenging and in vitro cytotoxic activities of ruthenium(II) complexes containing 2,4-dihydroxy benzylidene ligands.

    PubMed

    Mohanraj, Maruthachalam; Ayyannan, Ganesan; Raja, Gunasekaran; Jayabalakrishnan, Chinnasamy

    2016-12-01

    The new ruthenium(II) complexes with hydrazone ligands, 4-Methyl-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL(1)), 4-Methoxy-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL(2)), 4-Bromo-benzoic acid (2,4-dihydroxy-benzylidene)-hydrazide (HL(3)), were synthesized and characterized by various spectro analytical techniques. The molecular structures of the ligands were confirmed by single crystal X-ray diffraction technique. The DNA binding studies of the ligands and complexes were examined by absorption, fluorescence, viscosity and cyclic voltammetry methods. The results indicated that the ligands and complexes could interact with calf thymus DNA (CT-DNA) through intercalation. The DNA cleavage activity of the complexes was evaluated by gel electrophoresis assay, which revealed that the complexes are good DNA cleaving agents. The binding interaction of the ligands and complexes with bovine serum albumin (BSA) was investigated using fluorescence spectroscopic method. Antioxidant studies showed that the complexes have a strong radical scavenging properties. Further, the cytotoxic effect of the complexes examined on cancerous cell lines showed that the complexes exhibit significant anticancer activity. PMID:27612830

  10. In vitro antioxidant activities, free radical scavenging capacity, and tyrosinase inhibitory of flavonoid compounds and ferulic acid from Spiranthes sinensis (Pers.) Ames.

    PubMed

    Liang, Chung Pin; Chang, Chia Hao; Liang, Chien Cheng; Hung, Kuei Yu; Hsieh, Chang Wei

    2014-01-01

    In this study, ultrasound-assisted extraction (UAE) and other methods of extracting flavonoid compounds and ferulic acid (FA) from S. sinensis were investigated. Five different extraction methods, including water extraction (W), water extraction using UAE (W+U), 75% ethanol extraction (E), 75% ethanol extraction using UAE (E+U), and supercritical CO2 extraction (SFE) were applied in the extraction of bioactive compounds (flavonoids and ferulic acid) in order to compare their efficiency. The highest yield of flavonoids (4.28 mg/g) and ferulic acid (4.13 mg/g) content was detected in the E+U extract. Furthermore, S. sinensis extracts obtained by E+U show high antioxidant activity, and IC50 values of 0.47 mg/mL for DPPH radicals and 0.205 mg/mL for metal chelating activity. The total antioxidant assay shows superoxide radical scavenging capacity and in vitro mushroom tyrosinase inhibition in a dose-dependent manner, suggesting that E+U can be used for extraction of bioactive compounds from S. sinensis. PMID:24739930

  11. Synthesis, characterization and crystal structure of cobalt(III) complexes containing 2-acetylpyridine thiosemicarbazones: DNA/protein interaction, radical scavenging and cytotoxic activities.

    PubMed

    Manikandan, Rajendran; Viswanathamurthi, Periasamy; Velmurugan, Krishnaswamy; Nandhakumar, Raju; Hashimoto, Takeshi; Endo, Akira

    2014-01-01

    The synthesis, structure and biological studies of cobalt(III) complexes supported by NNS-tridentate ligands are reported. Reactions of 2-acetylpyridine N-substituted thiosemicarbazone (HL(1-3)) with [CoCl2(PPh3)2] resulted [Co(L(1-3))2]Cl (1-3) which were characterized by elemental analysis and various spectral studies. The molecular structure of the complex 1 has been determined by single crystal X-ray diffraction studies. In vitro DNA binding studies of complexes 1-3 carried out by fluorescence studies and the results revealed the binding of complexes to DNA via intercalation. The binding constant (Kb) values of complexes 1-3 from fluorescence experiments showed that the complex 3 has greater binding propensity for DNA. The DNA cleavage activity of the complexes 1 and 3 were ascertained by gel electrophoresis assay which revealed that the complexes are good DNA cleavage agents. Further, the interactions of the complexes with bovine serum albumin (BSA) were also investigated using fluorescence spectroscopic method, which showed that the complexes 1-3 could bind strongly with BSA. The antioxidant property of the complexes was evaluated to test their free-radical scavenging ability. Furthermore, in vitro cytotoxicity of the complexes against MCF-7 and A431 cell lines was assayed which showed higher activity and efficiently vanished the cancer cells even at low concentrations. PMID:24342132

  12. VARIATIONS IN FREE RADICAL SCAVENGING CAPACITY AND ANTIPROLIFERATIVE ACTIVITY AMONG DIFFERENT GENOTYPES OF AUTUMN OLIVE (Elaeagnus umbellate Thunb).

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fruit from six genotypes of autumn olive Brilliant Rose, Delightful, Jewel, Natural 1, Natural 2, and Sweet Tart) were evaluated for fruit quality, phenolic contents, carotenoids, antioxidants, antioxidant capacity, antioxidant enzyme activity, and anti-cancer properties. The fruit soluble solids, ...

  13. The interrelationship between muscle oxygenation, muscle activation, and pulmonary oxygen uptake to incremental ramp exercise: influence of aerobic fitness.

    PubMed

    Boone, Jan; Barstow, Thomas J; Celie, Bert; Prieur, Fabrice; Bourgois, Jan

    2016-01-01

    We investigated whether muscle and ventilatory responses to incremental ramp exercise would be influenced by aerobic fitness status by means of a cross-sectional study with a large subject population. Sixty-four male students (age: 21.2 ± 3.2 years) with a heterogeneous peak oxygen uptake (51.9 ± 6.3 mL·min(-1)·kg(-1), range 39.7-66.2 mL·min(-1)·kg(-1)) performed an incremental ramp cycle test (20-35 W·min(-1)) to exhaustion. Breath-by-breath gas exchange was recorded, and muscle activation and oxygenation were measured with surface electromyography and near-infrared spectroscopy, respectively. The integrated electromyography (iEMG), mean power frequency (MPF), deoxygenated [hemoglobin and myoglobin] (deoxy[Hb+Mb]), and total[Hb+Mb] responses were set out as functions of work rate and fitted with a double linear function. The respiratory compensation point (RCP) was compared and correlated with the breakpoints (BPs) (as percentage of peak oxygen uptake) in muscle activation and oxygenation. The BP in total[Hb+Mb] (83.2% ± 3.0% peak oxygen uptake) preceded (P < 0.001) the BP in iEMG (86.7% ± 4.0% peak oxygen uptake) and MPF (86.3% ± 4.1% peak oxygen uptake), which in turn preceded (P < 0.01) the BP in deoxy[Hb+Mb] (88.2% ± 4.5% peak oxygen uptake) and RCP (87.4% ± 4.5% peak oxygen uptake). Furthermore, the peak oxygen uptake was significantly (P < 0.001) positively correlated to the BPs and RCP, indicating that the BPs in total[Hb+Mb] (r = 0.66; P < 0.001), deoxy[Hb+Mb] (r = 0.76; P < 0.001), iEMG (r = 0.61; P < 0.001), MPF (r = 0.63; P < 0.001), and RCP (r = 0.75; P < 0.001) occurred at a higher percentage of peak oxygen uptake in subjects with a higher peak oxygen uptake. In this study a close relationship between muscle oxygenation, activation, and pulmonary oxygen uptake was found, occurring in a cascade of events. In subjects with a higher aerobic fitness level this cascade occurred at a higher relative intensity. PMID:26701120

  14. Identification of the bacteria scavenging atmospheric CO and evaluation of the impact of land-use change on their distribution and activity

    NASA Astrophysics Data System (ADS)

    Constant, P.; Quiza, L.; Lalonde, I.

    2013-12-01

    Soil bacteria scavenging carbon monoxide (CO) are responsible for the biological sink of atmospheric CO. These bacteria mitigate an important fraction of the global emissions of CO from natural and anthropogenic sources. This ubiquitous soil ecosystem service is of critical importance since CO indirectly regulates the atmospheric lifetime of methane - the second most powerful greenhouse gas. So far, only few carboxydovore bacteria were shown to oxidize atmospheric CO. The CO-dehydrogenase (CODH) is the enzyme catalyzing the CO oxidation reaction in these bacteria. The enzyme is a dimer of heterotrimers encoded by the genes coxS, coxM and coxL. CoxL is the large subunit of the CODH. Phylogenetic analyzes revealed that coxL gene sequences encompass two main clusters: BMS and OMP groups but the version conferring a high affinity for CO and the ability to scavenge atmospheric CO is unknown. The objective of this investigation was to relate the diversity of coxL gene sequences with CO soil uptake activity and soil physicochemical properties. For this purpose, we collected soil samples in three neighbouring sites encompassing different land-use types: an undisturbed deciduous forest, a maize field and a larch monoculture. We analyzed (i) coxL diversity in the three environments, using a new coxL PCR detection assay targeting both OMP and BMS groups, (ii) CO oxidation activity using a gas chromatography assay and, (iii) soil physicochemical properties. Our results demonstrate that land-use change exerts a significant impact on coxL diversity as well as CO oxidation activity, with significant loss of the potential CO soil uptake activity following the conversion of native forest to maize or larch plantation. Most of the coxL gene sequences retrieved from the soil samples were not affiliated to sequences derived from microbial genome databases, impairing a taxonomic identification of the potential CO-oxidizing bacteria detected in soil. Canonical ordination analysis allowed

  15. Activated carbon becomes active for oxygen reduction and hydrogen evolution reactions.

    PubMed

    Yan, Xuecheng; Jia, Yi; Odedairo, Taiwo; Zhao, Xiaojun; Jin, Zhao; Zhu, Zhonghua; Yao, Xiangdong

    2016-06-21

    We utilized a facile method for creating unique defects in the activated carbon (AC), which makes it highly active for the oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER). The ORR activity of the defective AC (D-AC) is comparable to the commercial Pt/C in alkaline medium, and the D-AC also exhibits excellent HER activity in acidic solution. PMID:27277286

  16. Synthesis, characterization, DNA interactions, DNA cleavage, radical scavenging activity, antibacterial, anti-proliferative and docking studies of new transition metal complexes.

    PubMed

    Chennam, Kishan Prasad; Ravi, Mudavath; Ushaiah, B; Srinu, V; Eslavath, Ravi Kumar; Devi, Ch Sarala

    2016-01-01

    The compound N-(2-hydroxybenzylidene)-1-ethyl-1, 4-dihydro-7-methyl-4-oxo-1, 8 naphthyridine-3-carbohydrazide (LH) and its Cu (II), Co (II) and Zn (II) complexes were synthesized and characterized. The absorption spectral titrations and competitive DNA binding studies depicted those complexes of title compound bind to CT-DNA through intercalation. Interestingly [Cu (II)-(L2)] showed relatively high binding constant value (6.61 x 10(5) M(-1)) compared to [Co (II)-(L2)] (4.378× 10(5) M(-1)) and [Zn (II)-(L2)] (3.1x10(5) M(-1)). Ligand and its complexes were also examined for DNA nuclease activity against pBR-322 plasmid DNA, which showed that [Cu (II)-(L2)] had the best hydrolytic cleavage property displaying prominent double-strand DNA cleavage. In addition, antioxidant activities of the ligand and its metal complexes investigated through scavenging effects for DPPH radical in- vitro, indicated their potentiality as good antioxidants. The in vitro anti-bacterial study inferred the better anti-bacterial activity of [Cu (II)-(L2)] and this was also correlated theoretically by employing docking studies wherein [Cu (II)-(L2)] displayed good Gold score and Chem score. Finally the in vitro anti- proliferative activity of studied compounds was tested against HeLa and MCF-7 cell lines. Interestingly [Cu (II)-(L2)] displayed lower IC50 value and lower percentage of viability in both HeLa and MCF-7 cell lines. PMID:26545354

  17. Interaction of gold nanoparticles with free radicals and their role in enhancing the scavenging activity of ascorbic acid.

    PubMed

    Razzaq, Humaira; Saira, Farhat; Yaqub, Azra; Qureshi, Rumana; Mumtaz, Misbah; Saleemi, Samia

    2016-08-01

    The present study investigates the interaction of citrate stabilized gold nanoparticles (12±1.5nm) (GNPs) with free radicals; 1,1-diphenyl-2-picrylhydrazyl (DPPH) stable and electrochemically generated superoxide, O2(-). Different experiments were designed to understand the interaction between GNPs and DPPH by employing cyclic voltammetry, UV-vis spectroscopy and computational chemistry using 6-311G basis set. The increase in heterogeneous rate constant, ksh, of DPPH upon addition of GNPs pointed towards possible complex formation, DPPH-GNPs which were further explained by a model assuming surface adsorption of DPPH on GNPs. Further, the model was validated by studying interaction of GNPs with a biologically important free radical, O2(-). Exciting result in terms of disappearance of anodic peak after GNPs addition confirmed that gold nanoparticles interacted with stable as well as unstable free radicals. Also, the stoichiometry of the most stable complex GNP-DPPH was determined from UV-vis spectroscopy by applying Job's method. The GNP-DPPH complex was found to be active with 46.0% reduction of the IC50 value of standard antioxidant, ascorbic acid (AA), indicating its role in enhancing antioxidant activity. Hence, this study presents a simple and potential approach to enhance the efficiency of natural antioxidants without modifying their structure, or involving the complex functionalization of GNPs with antioxidants. PMID:27288656

  18. Scavenger Hunt: Middle School Earth Science "Test."

    ERIC Educational Resources Information Center

    Owens, Katharine D.; Sanders, Richard L.

    1997-01-01

    Describes a scavenger hunt activity that has been used successfully with middle school students in an earth science course. This activity includes items that call for library research rather than the collection of objects, emphasize real-world connections, are skill-oriented, ask for originality and creativity, and are just for fun. (JRH)

  19. Scavenger Hunts: Chasing Down Scientific Answers.

    ERIC Educational Resources Information Center

    Griffin, Marshall S.; Dew, Nancy; Kronberg, Joyce R.

    2000-01-01

    Describes a scavenger hunt activity that stimulates active learning. Presents objectives, examples, pitfalls, grading methods, and evaluation based on course experiences with the technique. Although the method was used with lower division biology courses, it is applicable to a wide variety of science courses at various levels. (SAH)

  20. Changes in the radical-scavenging activity of bitter gourd (Momordica charantia L.) during freezing and frozen storage with or without blanching.

    PubMed

    Myojin, C; Enami, N; Nagata, A; Yamaguchi, T; Takamura, H; Matoba, T

    2008-09-01

    The effects of blanching, freezing, and frozen storage on the retention of radical-scavenging activity (RSA), total phenolics, and ascorbic acid in bitter gourd were investigated. Blanching of sliced bitter gourd resulted in considerable losses of RSA and total phenolics, and most extensively, of ascorbic acid. In the subsequent frozen storage at -18 degrees C, RSA and total phenolic content of unblanched and blanched bitter gourd underwent little change for 90 d then gradually declined, but at -40 degrees C, they practically remained unchanged throughout the entire storage period. On the contrary, ascorbic acid content of both unblanched and blanched bitter gourd decreased abruptly at the early stage in frozen storage. The results show that blanching of bitter gourd improves the retention of RSA and total phenolics during subsequent frozen storage but markedly aggravated loss of ascorbic acid. Finally, it is to be noted that RSA, total phenolics, and ascorbic acid originally contained in the raw bitter gourd were overall best retained by quick freezing followed by frozen storage at -40 degrees C without preceding blanching. PMID:18803700

  1. Phlomis mauritanica extracts reduce the xanthine oxidase activity, scavenge the superoxide anions, and inhibit the aflatoxin B1-, sodium azide-, and 4-nitrophenyldiamine-induced mutagenicity in bacteria.

    PubMed

    Limem, Ilef; Bouhlel, Ines; Bouchemi, Meriem; Kilani, Soumaya; Boubaker, Jihed; Ben-Sghaier, Mohamed; Skandrani, Ines; Behouri, Wissem; Neffati, Aicha; Ghedira, Kamel; Chekir-Ghedira, Leila

    2010-06-01

    Four extracts were prepared from the leaves of Phlomis mauritanica: lyophilized infusion, total oligomer flavonoids, methanol, and ethyl acetate extracts. The antimutagenic properties of these extracts were investigated by assessing the inhibition of the mutagenic effects of direct-acting mutagens such as sodium azide and 4-nitrophenylenediamine and indirect-acting mutagens like aflatoxin B1 (AFB1) using the Ames assay. The four extracts prepared from P. mauritanica strongly inhibit the mutagenicity induced by AFB1 in both Salmonella typhimurium TA 100 and TA 98 assay systems. Lyophilized infusion and methanol extracts at the dose of 250 microg per plate reduced AFB1 mutagenicity by 93% and 91%, respectively, in S. typhymurium strain TA 100. We examined also the antioxidant effect of these extracts by the enzymatic xanthine/xanthine oxidase assay. Result indicated that total oligomer flavonoids and ethyl acetate and methanol extracts were potent inhibitors of xanthine oxidase activity. In contrast, lyophilized infusion, total oligomer flavonoids, and methanol extracts exhibited a high degree of superoxide anion scavenging. Our findings emphasize the potential of P. mauritanica extracts to prevent mutations and oxidant effects. Furthermore, the results presented here could be an additional argument to support the use of this species as a medicinal and dietary plant. PMID:20406134

  2. Intracellular ROS Scavenging Activity and Downregulation of Inflammatory Mediators in RAW264.7 Macrophage by Fresh Leaf Extracts of Pseuderanthemum palatiferum

    PubMed Central

    Sittisart, Patcharawan

    2014-01-01

    Beneficial antioxidant phytochemicals are found in many medicinal plants. Pseuderanthemum palatiferum (PP), a well-known Vietnamese traditional medicinal plant in Thailand, has long been used in folk medicine for curing inflammatory diseases, often with limited support of scientific research. Therefore, this study aimed to determine antioxidant and modulation of inflammatory mediators of ethanol and water extracts of PP (EEP and WEP, resp.). WEP had significantly higher phenolic and flavonoid levels and DPPH radical scavenging activity than EEP. However, EEP exhibited greater reducing power than WEP. A greater decrease of tert-butyl hydroperoxide-induced oxidative stress in RAW264.7 macrophage cells was also observed with EEP. Modulation of inflammatory mediators of EEP and WEP was evaluated on LPS plus IFN-γ-stimulated RAW264.7 cells. EEP more potently suppressed LPS plus IFN-γ-induced nitric oxide (NO) production than WEP. Both EEP and WEP also suppressed the expression of iNOS and COX-2 protein levels. Collectively, these results suggest that PP possesses strong antioxidant and anti-inflammatory properties. PMID:24744809

  3. Antioxidant and free radical scavenging effects of the tannins of Terminalia catappa L.

    PubMed

    Lin, C C; Hsu, Y F; Lin, T C

    2001-01-01

    Reactive oxygen species (ROS) react with biological molecules and destroy the structure of cells and eventually cause free radical-induced disease such as inflammation and cancer. Previous studies showed that an aqueus extract of Terminalia catappa L. exhibited superoxide radical scavenger activity and modification of mitomycin C-induced clasto-genicity. In order to investigate the multiple antioxidant effect of the tannin components of T. catappa L., their ability to prevent lipid peroxidation, superoxide formation and their free radical scavenging activity were evaluated. The results indicated that all of these components showed potent antioxidant activity. Punicalagin and punicalin were the most abundant components and had the strongest anti-oxidative effects of this group of tannins. PMID:11299741

  4. Evaluation of chemical constituents and free-radical scavenging activity of Swarnabhasma (gold ash), an ayurvedic drug.

    PubMed

    Mitra, A; Chakraborty, S; Auddy, B; Tripathi, P; Sen, S; Saha, A V; Mukherjee, B

    2002-05-01

    From ancient times, Swarnabhasma (gold ash) has been used in several clinical manifestations including loss of memory, defective eyesight, infertility, overall body weakness and incidence of early aging. Swarnabhasma has been used by Ayurvedic physicians to treat different diseases like bronchial asthma, rheumatoid arthritis, diabetes mellitus, nervous disorders, etc. In the present investigation, Swarnabhasma was prepared after proper purification and calcination as per Ayurvedic pharmacy which consisted of Realger (As(2)S(2)), Lead oxide (Pb(3)O(4)), Pure gold (Au) and Latex of Calotropis gigantea. Qualitative analyses indicated that Swarnabhasma contained not only gold but also several microelements (Fe, Al, Cu, Zn, Co, Mg, Ca, As, Pb, etc.). Infrared spectroscopy showed that the material was free from any organic compound. The metal content in the bhasma was determined by atomic absorption spectrometry. Acute oral administration of Swarnabhasma showed no mortality in mice (up to 1 ml /20 g b.w. of Swarnabhasma suspension containing 1mg of drug). Chronic administration of Swarnabhasma also showed no toxicity as judged by SGPT, SGOT, serum creatinine and serum urea level and histological studies. In an experimental animal model, chronic Swarnabhasma-treated animals showed significantly increased superoxide dismutase and catalase activity, two enzymes that reduce free radical concentrations in the body. PMID:12007704

  5. Toxic effects of heavy metals (Cd, Cr and Pb) on seed germination and growth and DPPH-scavenging activity in Brassica rapa var. turnip.

    PubMed

    Siddiqui, Maryam Mehmood; Abbasi, Bilal Haider; Ahmad, Nisar; Ali, Mohammad; Mahmood, Tariq

    2014-04-01

    Toxicity of heavy metal is a wide spread environmental problem affecting all life forms including plants. In the present study the toxic effects of heavy metals, cadmium (Cd), chromium (Cr) and lead (Pb) on seed germination rate (%), germination index (G-index) and growth (mm) of Brassica rapa var. turnip have been investigated. The seeds were soaked either in distilled water (control) or in aqueous solutions of Cd, Cr and Pb (1 g/l, 2.5 g/l and 5 g/l) at 4°C in dark for 24 hours. Prior to inoculation onto MS0 medium, the soaked seeds were either washed with sterile distilled water or inoculated without washing on solidified MS0 medium at 25 ± 2°C with 16/8-hour photoperiod in a growth chamber to germinate in vitro. Such stress conditions revealed that by increasing the concentration of heavy metals, the germination rate (%), G-index value and growth (mm) decreased significantly, suggesting their toxic effect on B. rapa var. turnip. This study further revealed that experiment with seed washing resulted in less toxicity of selected heavy metals on germination and growth of B. rapa var. turnip, as compared to experiment without washing. However, the resulting toxicity order of the selected heavy metals remained the same (Cd > Cr > Pb). Significant decrease has been observed in seed viability and germination potential and finally heavy metals completely ceased further growth and development of plants. The 2, 2-diphenyl-1-picrylhydrazyl (DPPH)-scavenging activity revealed that significantly higher activity was observed in control plants without heavy metals treatment. Furthermore, the Cd-treated plants showed decreased antioxidant activity. Cr and Pb were less toxic as compared to Cd (control > Pb > Cr > Cd). This study revealed that selected heavy metals not only affected plant development but also disturbed plant metabolic pathways. PMID:22872632

  6. TRPA1 activation leads to neurogenic vasodilatation: involvement of reactive oxygen nitrogen species in addition to CGRP and NO

    PubMed Central

    Aubdool, Aisah A; Kodji, Xenia; Abdul‐Kader, Nayaab; Heads, Richard; Fernandes, Elizabeth S; Bevan, Stuart

    2016-01-01

    Abstract Background and Purpose Transient receptor potential ankyrin‐1 (TRPA1) activation is known to mediate neurogenic vasodilatation. We investigated the mechanisms involved in TRPA1‐mediated peripheral vasodilatation in vivo using the TRPA1 agonist cinnamaldehyde. Experimental Approach Changes in vascular ear blood flow were measured in anaesthetized mice using laser Doppler flowmetry. Key Results Topical application of cinnamaldehyde to the mouse ear caused a significant increase in blood flow in the skin of anaesthetized wild‐type (WT) mice but not in TRPA1 knockout (KO) mice. Cinnamaldehyde‐induced vasodilatation was inhibited by the pharmacological blockade of the potent microvascular vasodilator neuropeptide CGRP and neuronal NOS‐derived NO pathways. Cinnamaldehyde‐mediated vasodilatation was significantly reduced by treatment with reactive oxygen nitrogen species (RONS) scavenger such as catalase and the SOD mimetic TEMPOL, supporting a role of RONS in the downstream vasodilator TRPA1‐mediated response. Co‐treatment with a non‐selective NOS inhibitor L‐NAME and antioxidant apocynin further inhibited the TRPA1‐mediated vasodilatation. Cinnamaldehyde treatment induced the generation of peroxynitrite that was blocked by the peroxynitrite scavenger FeTPPS and shown to be dependent on TRPA1, as reflected by an increase in protein tyrosine nitration in the skin of WT, but not in TRPA1 KO mice. Conclusion and Implications This study provides in vivo evidence that TRPA1‐induced vasodilatation mediated by cinnamaldehyde requires neuronal NOS‐derived NO, in addition to the traditional neuropeptide component. A novel role of peroxynitrite is revealed, which is generated downstream of TRPA1 activation by cinnamaldehyde. This mechanistic pathway underlying TRPA1‐mediated vasodilatation may be important in understanding the role of TRPA1 in pathophysiological situations. PMID:27189253

  7. Reactive Oxygen and Nitrogen Species in Defense/Stress Responses Activated by Chitosan in Sycamore Cultured Cells

    PubMed Central

    Malerba, Massimo; Cerana, Raffaella

    2015-01-01

    Chitosan (CHT) is a non-toxic and inexpensive compound obtained by deacetylation of chitin, the main component of the exoskeleton of arthropods as well as of the cell walls of many fungi. In agriculture CHT is used to control numerous diseases on various horticultural commodities but, although different mechanisms have been proposed, the exact mode of action of CHT is still unknown. In sycamore (Acer pseudoplatanus L.) cultured cells, CHT induces a set of defense/stress responses that includes production of H2O2 and nitric oxide (NO). We investigated the possible signaling role of these reactive molecules in some CHT-induced responses by means of inhibitors of production and/or scavengers. The results show that both reactive nitrogen and oxygen species are not only a mere symptom of stress conditions but are involved in the responses induced by CHT in sycamore cells. In particular, NO appears to be involved in a cell death form induced by CHT that shows apoptotic features like DNA fragmentation, increase in caspase-3-like activity and release of cytochrome c from the mitochondrion. On the contrary, reactive oxygen species (ROS) appear involved in a cell death form induced by CHT that does not show these apoptotic features but presents increase in lipid peroxidation. PMID:25642757

  8. Reactive oxygen and nitrogen species in defense/stress responses activated by chitosan in sycamore cultured cells.

    PubMed

    Malerba, Massimo; Cerana, Raffaella

    2015-01-01

    Chitosan (CHT) is a non-toxic and inexpensive compound obtained by deacetylation of chitin, the main component of the exoskeleton of arthropods as well as of the cell walls of many fungi. In agriculture CHT is used to control numerous diseases on various horticultural commodities but, although different mechanisms have been proposed, the exact mode of action of CHT is still unknown. In sycamore (Acer pseudoplatanus L.) cultured cells, CHT induces a set of defense/stress responses that includes production of H2O2 and nitric oxide (NO). We investigated the possible signaling role of these reactive molecules in some CHT-induced responses by means of inhibitors of production and/or scavengers. The results show that both reactive nitrogen and oxygen species are not only a mere symptom of stress conditions but are involved in the responses induced by CHT in sycamore cells. In particular, NO appears to be involved in a cell death form induced by CHT that shows apoptotic features like DNA fragmentation, increase in caspase-3-like activity and release of cytochrome c from the mitochondrion. On the contrary, reactive oxygen species (ROS) appear involved in a cell death form induced by CHT that does not show these apoptotic features but presents increase in lipid peroxidation. PMID:25642757

  9. Time-resolved chemiluminescence study of the TiO2 photocatalytic reaction and its induced active oxygen species.

    PubMed

    Min, Lingyue; Wu, Xing-Zheng; Tetsuya, Shimada; Inoue, Haruo

    2007-01-01

    The time-resolved chemiluminescence (CL) method has been applied to study the TiO(2) photocatalytic reaction on a micros-ms timescale. The experimental set-up for time-resolved CL was improved for confirmation of the unique luminol CL induced by the photocatalytic reaction. The third harmonic light (355 nm) from an Nd:YAG laser was used for the light source of the TiO(2) photocatalytic reaction. Luminol CL induced by this reaction was detected by a photomultiplier tube (PMT) and a preamplifier was used for amplifying the CL signal. Experimental conditions affecting the photocatalytically induced CL were discussed in detail. The involvement of active oxygen species such as .OH, O(2) (.-) and H(2)O(2) in the CL was examined by adding their scavengers. It is concluded that .OH was greatly involved in the CL on a micros-ms timescale, especially in time periods <100 micros after illumination of the pulse laser. On the other hand, CL generated by O(2) (.-) began to increase after 100 micros and became dominant after 2.5 ms. A small part of the CL might be generated by H(2)O(2) on the whole micros-ms timescale. A CL reaction mechanism related with .OH and dissolved oxygen was proposed to explain the photocatalytically induced luminol CL on a micros-ms timescale, especially in periods <100 micros. PMID:17089368

  10. Capsaicin, a tasty free radical scavenger: mechanism of action and kinetics.

    PubMed

    Galano, Annia; Martínez, Ana

    2012-01-26

    The free radical scavenging activity of capsaicin (CAP), which is the pungent component of hot chili peppers, has been studied in aqueous and lipid solutions, using the density functional theory. Different mechanisms of reaction have been considered: single electron transfer (SET), hydrogen transfer (HT), and radical adduct formation (RAF). Rate constants and branching ratios of the different channels of reaction are provided, as well as an interpretation of the UV-vis spectra. CAP is predicted to react faster in aqueous solution than in nonpolar media with oxygenated free radicals, and it was found to be a more efficient scavenger than melatonin and caffeine. It was also found that while SET does not contribute to the overall reactivity of CAP toward (•)OOH, (•)OOCH(3), and (•)OCH(3) radicals, it might be important for the reactions with more electrophilic radicals such as (•)OH, (•)OCCl(3), and (•)OOCCl(3). The main process, responsible for the peroxyl scavenging activity of CAP, was found to be the HT from the OH phenolic group. For the reaction with (•)OCH(3), on the other hand, the HT from allylic sites are predicted to be the main channels of reaction. In this particular case a wider product distribution is predicted. This supports the role of the reacting free radical on the preponderant mechanism of action of free radical scavengers. PMID:22188587

  11. Protective effect of paeoniflorin on irradiation-induced cell damage involved in modulation of reactive oxygen species and the mitogen-activated protein kinases.

    PubMed

    Li, Chun Rong; Zhou, Zhe; Zhu, Dan; Sun, Yu Ning; Dai, Jin Ming; Wang, Sheng Qi

    2007-01-01

    Ionizing radiation can induce DNA damage and cell death by generating reactive oxygen species (ROS). The objective of this study was to investigate the radioprotective effect of paeoniflorin (PF, a main bioactive component in the traditional Chinese herb peony) on irradiated thymocytes and discover the possible mechanisms of protection. We found 60Co gamma-ray irradiation increased cell death and DNA fragmentation in a dose-dependent manner while increasing intracellular ROS. Pretreatment of thymocytes with PF (50-200 microg/ml) reversed this tendency and attenuated irradiation-induced ROS generation. Hydroxyl-scavenging action of PF in vitro was detected through electron spin resonance assay. Several anti-apoptotic characteristics of PF, including the ability to diminish cytosolic Ca2+ concentration, inhibit caspase-3 activation, and upregulate Bcl-2 and downregulate Bax in 4Gy-irradiated thymocytes were determined. Extracellular regulated kinase (ERK), c-Jun NH2-terminal kinase (JNK), and p38 kinase were activated by 4Gy irradiation, whereas its activations were partly blocked by pretreatment of cells with PF. The presence of ERK inhibitor PD98059, JNK inhibitor SP600125 and p38 inhibitor SB203580 decreased cell death in 4Gy-irradiated thymocytes. These results suggest PF protects thymocytes against irradiation-induced cell damage by scavenging ROS and attenuating the activation of the mitogen-activated protein kinases. PMID:17097910

  12. Cryogenic Propellant Scavenging

    NASA Technical Reports Server (NTRS)

    Louie, B.; Kemp, N. J.; Daney, D. E.

    1985-01-01

    A detailed description of a computer model that has been developed for assessing the feasibility of low g cryogen propellant scavenging from the space shuttle External Tank (ET) is given. Either pump-assisted or pressure-induced propellant transfer may be selected. The program will accept a wide range of input variables, including the fuel to be transferred (LOX or LH2), heat leaks, tank temperatures, and piping and equipment specifications. The model has been parametrically analyzed to determine initial design specification for the system.

  13. Protective effects of kaempferol against reactive oxygen species-induced hemolysis and its antiproliferative activity on human cancer cells.

    PubMed

    Liao, Wenzhen; Chen, Luying; Ma, Xiang; Jiao, Rui; Li, Xiaofeng; Wang, Yong

    2016-05-23

    The protective effects of kaempferol against reactive oxygen species (ROS)-induced hemolysis and its antiproliferative activity on human cancer cells were evaluated in this study. Kaempferol exhibited strong cellular antioxidant ability (CAA) with a CAA value of 59.80 ± 0.379 μM of quercetin (QE)/100 μM (EC50 = 7.74 ± 0.049 μM). Pretreatment with kaempferol significantly attenuated the ROS-induced hemolysis of human erythrocyte (87.4% hemolysis suppressed at 100 μg/mL) and reduced the accumulation of toxic lipid peroxidation product malondialdehyde (MDA). The anti-hemolytic activity of kaempferol was mainly through scavenging excessive ROS and preserving the intrinsic antioxidant enzymes (superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GPx) activities in normal levels. Additionally, kaempferol showed significant antiproliferative activity on a panel of human cancer cell lines including human breast carcinoma (MCF-7) cells, human stomach carcinoma (SGC-7901) cells, human cervical carcinoma (Hela) cells and human lung carcinoma (A549) cells. Kaemperol induced apoptosis of MCF-7 cells accompanied with nuclear condensation and mitochondria dysfunction. PMID:26974372

  14. Observations on the Activity and Life History of the Scavenging Isopod Natatolana borealisLilljeborg (Isopoda: Cirolanidae) from Loch Fyne, Scotland

    NASA Astrophysics Data System (ADS)

    Wong, Y. M.; Moore, P. G.

    1996-02-01

    The activity and life history of the cirolanid isopod Natatolana borealisLilljeborg has been studied using (primarily) fish-baited traps deployed at a deep-water station (190 m) in Loch Fyne, Scotland. A voracious scavenger, it burrows into soft mud, emerging to feed when suitable food odours are detected in the water. Isopods were attracted significantly to baited vs. non-baited traps. Underwater video observations revealed that most animals were active in the vicinity of traps, that capture efficiency was low, but retention complete. Only traps on the sea-bed captured mancas or juveniles in any numbers. Any seasonal pattern in catch rate through the year was confounded by high variability. Only one (manca-)brooding female was ever caught in a trap (in April). It is assumed that brooding females desist from feeding. The sex ratio of isopods in most trap collections was thus significantly male dominated. Mancas were trapped during February to August. Growth rate was slowest in adults and was similar for males and females. The maximum growth rate occurred during autumn associated with the seasonal cycle in bottom water temperatures. Longevity was estimated (by following peaks in the size-frequency distributions with time) to be c. 2·5 years, with sexual maturity (based on oostegites/spurred appendix masculinae) achieved after c. 19 months. Semelparity is suggested. A low incidence of an unnamed epicaridean parasite is reported from the Clyde population. Natatolana borealisalso carried peritrich ciliate epizoites on their antennae. Possible predators are swimming crabs and gadid fish, e.g. whiting and cod.

  15. Effect of oxygen on the microbial activities of thermophilic anaerobic biomass.

    PubMed

    Pedizzi, C; Regueiro, L; Rodriguez-Verde, I; Lema, J M; Carballa, M

    2016-07-01

    Low oxygen levels (μgO2L(-1)) in anaerobic reactors are quite common and no relevant consequences are expected. On the contrary, higher concentrations could affect the process. This work aimed to study the influence of oxygen (4.3 and 8.8mgO2L(-1), respectively) on the different microbial activities (hydrolytic, acidogenic and methanogenic) of thermophilic anaerobic biomass and on the methanogenic community structure. Batch tests in presence of oxygen were conducted using specific substrates for each biological activity and a blank (with minimum oxygen) was included. No effect of oxygen was observed on the hydrolytic and acidogenic activities. In contrast, the methane production rate decreased by 40% in all oxygenated batches and the development of active archaeal community was slower in presence of 8.8mgO2L(-1). However, despite this sensitivity of methanogens to oxygen at saturation levels, the inhibition was reversible. PMID:27020398

  16. Putative free radical-scavenging activity of an extract of Cineraria maritima in preventing selenite-induced cataractogenesis in Wistar rat pups

    PubMed Central

    Anitha, Thirugnanasambandhar Sivasubramanian; Muralidharan, Arumugam Ramachandran; Annadurai, Thangaraj; Jesudasan, Christdas Arul Nelson; Thomas, Philip Aloysius

    2013-01-01

    Purpose To investigate the possible free radical-scavenging activity of an extract of Cineraria maritima on selenite-induced cataractous lenses in Wistar rat pups. Methods In the present study, Wistar rat pups were divided into three experimental groups. On P10, Group I (control) rat pups received an intraperitoneal injection of 0.89% saline. Rats in groups II (selenite-challenged, untreated) and III (selenite-challenged, C. maritima treated) received a subcutaneous injection of sodium selenite (19 μmol/kg bodyweight); Group III rat pups also received an intraperitoneal injection of the extract of C. maritima (350 mg/kg bodyweight) once daily P9–14. Both eyes of each pup were examined from P16 until P30. Cytochemical localization of nitroblue tetrazolium salts and generation of superoxide, hydroxyl, and nitric oxide levels were measured. The expression of the inducible nitric oxide synthase gene was evaluated with reverse transcription-PCR. Immunoblot analysis was also performed to confirm the differential expression of the inducible nitric oxide synthase protein. Results Subcutaneous injection of sodium selenite led to severe oxidative damage in the lenticular tissues, shown by increased formation of formazan crystals, elevated generation of superoxide, hydroxyl, and nitric oxide radicals, and elevated inducible nitric oxide synthase gene and protein expression that possibly contributed to the opacification of the lens and thus cataract formation. When rat pups were treated with intraperitoneal administration of the extract of C. maritima, the generation of free radicals as well as the messenger ribonucleic acid and protein expression of inducible nitric oxide synthase were maintained at near normal levels. Conclusions The data generated by this study suggest that an ethanolic extract of C. maritima possibly prevents cataractogenesis in a rat model by minimizing free radical generation. PMID:24357923

  17. Brain ischaemia induces shedding of a BDNF-scavenger ectodomain from TrkB receptors by excitotoxicity activation of metalloproteinases and γ-secretases.

    PubMed

    Tejeda, Gonzalo S; Ayuso-Dolado, Sara; Arbeteta, Raquel; Esteban-Ortega, Gema M; Vidaurre, Oscar G; Díaz-Guerra, Margarita

    2016-04-01

    Stroke remains a leading cause of death and disability in the world with limited therapies available to restrict brain damage or improve functional recovery after cerebral ischaemia. A promising strategy currently under investigation is the promotion of brain-derived neurotrophic factor (BDNF) signalling through tropomyosin-related kinase B (TrkB) receptors, a pathway essential for neuronal survival and function. However, TrkB and BDNF-signalling are impaired by excitotoxicity, a primary pathological process in stroke also associated with neurodegenerative diseases. Pathological imbalance of TrkB isoforms is critical in neurodegeneration and is caused by calpain processing of BDNF high affinity full-length receptor (TrkB-FL) and an inversion of the transcriptional pattern of the Ntrk2 gene, to favour expression of the truncated isoform TrkB-T1 over TrkB-FL. We report here that both TrkB-FL and neuronal TrkB-T1 also undergo ectodomain shedding by metalloproteinases activated after ischaemic injury or excitotoxic damage of cortical neurons. Subsequently, the remaining membrane-bound C-terminal fragments (CTFs) are cleaved by γ-secretases within the transmembrane region, releasing their intracellular domains (ICDs) into the cytosol. Therefore, we identify TrkB-FL and TrkB-T1 as new substrates of regulated intramembrane proteolysis (RIP), a mechanism that highly contributes to TrkB-T1 regulation in ischaemia but is minor for TrkB-FL which is mainly processed by calpain. However, since the secreted TrkB ectodomain acts as a BDNF scavenger and significantly alters BDNF/TrkB signalling, the mechanism of RIP could contribute to neuronal death in excitotoxicity. These results are highly relevant since they reveal new targets for the rational design of therapies to treat stroke and other pathologies with an excitotoxic component. Copyright © 2015 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. PMID:26712630

  18. Adaptations of a deep sea scavenger: high ammonia tolerance and active NH₄⁺ excretion by the Pacific hagfish (Eptatretus stoutii).

    PubMed

    Clifford, Alexander M; Goss, Greg G; Wilkie, Michael P

    2015-04-01

    The Pacific hagfish (Eptatretus stoutii) has an exceptional ability to both withstand and recover from exposure to high external ammonia (HEA). This tolerance is likely due to the feeding behavior of this scavenger, which feeds on intermittent food falls of carrion (e.g. fish, large marine mammals) during which time it may be exposed to high concentrations of total ammonia (T(Amm)=NH3+NH4(+)) while burrowed inside the decomposing carcass. Here we exposed hagfish to 20 mmol L(-1) T(Amm) for periods of up to 48 h and then let animals recover in ammonia-free seawater. During the 48 h HEA exposure period, plasma T(Amm) increased 100-fold to over 5000 μmol L(-1) while ammonia excretion (J(amm)) was transiently inhibited. This increase in plasma T(Amm) resulted from NH3 influx down massive inwardly directed ΔP(NH3) gradients, which also led to a short-lived metabolic alkalosis. Plasma [T(Amm)] stabilized after 24-48 h, possibly through a reduction in NH3 permeability across the body surface, which lowered NH3 influx. Ammonia balance was subsequently maintained through the re-establishment of J(amm) against an inwardly directed ΔP(NH3). Calculations of the Nernst potential for ammonia strongly indicated that J(amm) was also taking place against a large inwardly directed NH4(+) electrochemical gradient. Recovery from HEA in ammonia-free water was characterized by a large ammonia washout, and the restoration of plasma TAmm concentrations to near control concentrations. Ammonia clearance was also accompanied by a residual metabolic acidosis, which likely offset the ammonia-induced metabolic alkalosis seen in the early stages of HEA exposure. We conclude that restoration of J(amm) by the Pacific hagfish during ammonia exposure likely involves secondary active transport of NH4(+), possibly mediated by Na(+)/NH4(+) (H(+)) exchange. PMID:25499242

  19. Evaluation of free radical-scavenging and antihemolytic activities of quince (Cydonia oblonga) leaf: a comparative study with green tea (Camellia sinensis).

    PubMed

    Costa, Rossana M; Magalhães, Ana S; Pereira, José A; Andrade, Paula B; Valentão, Patrícia; Carvalho, Márcia; Silva, Branca M

    2009-04-01

    This study aimed to determine the phenolic profile and to investigate the antioxidant potential of quince (Cydonia oblonga) leaf, comparing it with green tea (Camellia sinensis). For these purposes, methanolic extracts were prepared and phenolics content of quince leaf was determined by HPLC/UV. The antioxidant properties were assessed by Folin-Ciocalteu reducing capacity assay and by the ability to quench the stable free radical 2,2'-diphenyl-1-picrylhydrazyl (DPPH) and to inhibit the 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH)-induced oxidative hemolysis of human erythrocytes.5-O-Caffeoylquinic acid was found to be the major phenolic compound in quince leaf extract. Quince leaf exhibited a significantly higher reducing power than green tea (mean value of 227.8 +/- 34.9 and 112.5 +/- 1.5 g/kg dry leaf, respectively). Quince leaf extracts showed similar DPPH radical-scavenging activities (EC50 mean value of 21.6 +/- 3.5 microg/ml) but significantly lower than that presented by green tea extract (EC50 mean value of 12.7 +/- 0.1 microg/ml). Under the oxidative action of AAPH, quince leaf methanolic extract significantly protected the erythrocyte membrane from hemolysis in a similar manner to that found for green tea (IC50 mean value of 30.7 +/- 6.7 and 24.3 +/- 9.6 microg/ml, respectively, P > 0.05). These results point that quince leaf may have application as preventive or therapeutic agent in diseases in which free radicals are involved. PMID:19271320

  20. Studies on the self-catalyzed Knoevenagel condensation, characterization, DPPH radical scavenging activity, cytotoxicity, and molecular properties of 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6-diones using single crystal XRD and DFT techniques

    NASA Astrophysics Data System (ADS)

    Suresh Kumar, G. S.; Antony Muthu Prabhu, A.; Bhuvanesh, N.

    2014-10-01

    We have studied the self-catalyzed Knoevenagel condensation, spectral characterization, DPPH radical scavenging activity, cytotoxicity, and molecular properties of 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6-diones using single crystal XRD and DFT techniques. In the absence of any catalyst, a series of novel 5-arylidene-2,2-dimethyl-1,3-dioxane-4,6-diones were synthesized using Meldrum’s acid and formylphenoxyaliphatic acid(s) in water. These molecules are arranged in the dimer form through intermolecular H-bonding in the single crystal XRD structure. Compounds have better DPPH radical scavenging activity and cytotoxicity against A431 cancer cell line. The optimized molecular structure, natural bond orbital analysis, electrostatic potential map, HOMO-LUMO energies, molecular properties, and atomic charges of these molecules have been studied by performing DFT/B3LYP/3-21G(*) level of theory in gas phase.

  1. Oxidative DNA Adducts Following Cu2+-Mediated Activation of Dihydroxy PCBs: Role of Reactive Oxygen Species1

    PubMed Central

    Spencer, Wendy A.; Lehmler, Hans-Joachim; Robertson, Larry W.; Gupta, Ramesh C.

    2009-01-01

    Polychlorinated biphenyls (PCBs) are toxic industrial chemicals, complete carcinogens and efficacious tumor promoters. However, the mechanism(s) of PCB-mediated carcinogenicity remains largely undefined. One likely pathway by which these agents may play a role in carcinogenesis is the generation of oxidative DNA damage by redox cycling of dihydroxylated PCB metabolites. We have now employed a new 32P-postlabeling system to examine novel oxidative DNA lesions induced by Cu2+-mediated activation of PCB metabolites. 32P-Postlabeling of DNA incubated with various PCB metabolites resulted in over a dozen novel polar oxidative DNA adducts that were chromatographically similar for all active agents. The most potent metabolites tested were the hydroquinones (hydroxyl groups arranged para to each other) yielding polar oxidative adduct levels ranging from 55 to 142 adducts/106 nucleotides. PCB catechols, or ortho-dihydroxy metabolites, were up to 40% less active than their corresponding hydroquinone congeners while mono hydroxylated and quinone metabolites did not produce detectable oxidative damage over that of vehicle. With the exception of 2,4,5-Cl-2′,5′-dihydroxybiphenyl, this oxidative DNA damage appeared to be inversely related to chlorine content: no chlorine ≈ mono- > di- > tri-chlorinated metabolites. Importantly, copper, but not iron, was essential for activation of the PCB metabolites to these polar oxidative DNA adducts since in its absence or in the presence of the Cu+-specific scavenger, bathocuproine, no adducts were detected. Intervention studies with known reactive oxygen species (ROS) modifiers suggested that H2O2, singlet oxygen, hydroxyl radical and superoxide may also be involved in this PCB-mediated oxidative DNA damage. These data indicate a mechanistic role of several ROS, in addition to copper, in PCB-induced DNA damage and provide further support for oxidative DNA damage in PCB-mediated carcinogenesis. PMID:19233261

  2. In vitro antioxidant activity of Holarrhena antidysenterica Wall. methanolic leaf extract

    PubMed Central

    Ganapathy, P. S. Sujan; Ramachandra, Y. L.; Rai, S. Padmalatha

    2011-01-01

    Antioxidative potential of methanolic leaf extract of Holarrhena antidysenterica was evaluated using hydroxyl radical, superoxide anion scavenging and reducing power assays. The antioxidant activity of the methanol extract increased in a concentration-dependent manner. The extract showed significant reactive oxygen species (ROS) scavenging activity in all in vitro antioxidant assays and contained high level of total phenolic content PMID:24826020

  3. Prevention of granulocyte-mediated oxidant lung injury in rats by a hydroxyl radical scavenger, dimethylthiourea.

    PubMed Central

    Fox, R B

    1984-01-01

    Toxic, partially reduced metabolites of oxygen (toxic oxygen radicals) are increasingly implicated in acute leukocyte-mediated tissue injury. To further probe the roles of oxygen radicals in acute lung edema, I studied the effects of a recently described and very potent oxygen radical scavenger, dimethylthiourea (DMTU) (Fox, R. B., R. N. Harada, R. M. Tate, and J. E. Repine, 1983, J. Appl. Physiol., 55:1456-1459) on polymorphonuclear leukocyte (PMN) oxidant function and on two types of lung injury mediated by oxygen radicals and PMN. DMTU (10 mM) blocked 79% of hydroxyl radical (OH) production by PMN in vitro without interfering with other PMN functions, such as O-2 production, myeloperoxidase activity, chemotaxis, degranulation, or aggregation. When isolated rat lung preparations were perfused with PMN activated to produce OH, lung weights were increased from 2.3 +/- 0.2 to 11.2 +/- 0.8 g. DMTU (10 mM) prevented 70% of these increases (lung weights, 5.0 +/- 1.1 g, P less than 0.005). Finally, when intact rats were exposed to 100% O2 for 66 h, lung weight:body weight ratios were increased from 5.78 +/- 0.33 to 8.87 +/- 0.16 g. DMTU (500 mg/kg) prevented 83% of this hyperoxia-induced lung edema in vivo (lung:body weight ratios, 6.05 +/- 0.21, P less than 0.001). Pharmacokinetic studies showed that DMTU diffused effectively into lung interstitial fluids and had a relatively long half-life (25-35 h) in the circulation. Because a variety of oxygen radicals, such as superoxide (O-2), hydrogen peroxide (H2O2), or OH are produced by PMN, there is usually some uncertainty about which one is responsible for injury. However, in these studies, DMTU did not scavenge O-2 and scavenged H2O2 only very slowly while scavenging OH very effectively. Therefore, DMTU may be useful in the investigation of the roles of oxygen radicals, especially OH, in acute granulocyte-mediated tissue injury. PMID:6090504

  4. A ligand field chemistry of oxygen generation by the oxygen-evolving complex and synthetic active sites

    PubMed Central

    Betley, Theodore A; Surendranath, Yogesh; Childress, Montana V; Alliger, Glen E; Fu, Ross; Cummins, Christopher C; Nocera, Daniel G

    2007-01-01

    Oxygen–oxygen bond formation and O2 generation occur from the S4 state of the oxygen-evolving complex (OEC). Several mechanistic possibilities have been proposed for water oxidation, depending on the formal oxidation state of the Mn atoms. All fall under two general classifications: the AB mechanism in which nucleophilic oxygen (base, B) attacks electrophilic oxygen (acid, A) of the Mn4Ca cluster or the RC mechanism in which radical-like oxygen species couple within OEC. The critical intermediate in either mechanism involves a metal oxo, though the nature of this oxo for AB and RC mechanisms is disparate. In the case of the AB mechanism, assembly of an even-electron count, high-valent metal-oxo proximate to a hydroxide is needed whereas, in an RC mechanism, two odd-electron count, high-valent metal oxos are required. Thus the two mechanisms give rise to very different design criteria for functional models of the OEC active site. This discussion presents the electron counts and ligand geometries that support metal oxos for AB and RC O–O bond-forming reactions. The construction of architectures that bring two oxygen functionalities together under the purview of the AB and RC scenarios are described. PMID:17971328

  5. Radical scavenging potentials of single and combinatorial herbal formulations in vitro

    PubMed Central

    Ojiako, Okey A.; Chikezie, Paul C.; Ogbuji, Agomuo C.

    2015-01-01

    Reactive oxygen and nitrogen species (RONS) are involved in deleterious/beneficial biological processes. The present study sought to investigate the capacity of single and combinatorial herbal formulations of Acanthus montanus, Emilia coccinea, Hibiscus rosasinensis, and Asystasia gangetica to act as superoxide radicals (SOR), hydrogen peroxide (HP), nitric oxide radical (NOR), hydroxyl radical (HR), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical antagonists using in vitro models. The herbal extracts were single herbal formulations (SHfs), double herbal formulations (DHfs), triple herbal formulations (THfs), and a quadruple herbal formulation (QHf). The phytochemical composition and radical scavenging capacity index (SCI) of the herbal formulations were measured using standard methods. The flavonoids were the most abundant phytochemicals present in the herbal extracts. The SCI50 defined the concentration (μg/mL) of herbal formulation required to scavenge 50% of the investigated radicals. The SHfs, DHfs, THfs, and QHf SCI50 against the radicals followed the order HR > SOR > DPPH radical > HP > NOR. Although the various herbal formulations exhibited ambivalent antioxidant activities in terms of their radical scavenging capabilities, a broad survey of the results of the present study showed that combinatorial herbal formulations (DHfs, THfs, and QHf) appeared to exhibit lower radical scavenging capacities than those of the SHfs in vitro. PMID:27114938

  6. Radical scavenging potentials of single and combinatorial herbal formulations in vitro.

    PubMed

    Ojiako, Okey A; Chikezie, Paul C; Ogbuji, Agomuo C

    2016-04-01

    Reactive oxygen and nitrogen species (RONS) are involved in deleterious/beneficial biological processes. The present study sought to investigate the capacity of single and combinatorial herbal formulations of Acanthus montanus, Emilia coccinea, Hibiscus rosasinensis, and Asystasia gangetica to act as superoxide radicals (SOR), hydrogen peroxide (HP), nitric oxide radical (NOR), hydroxyl radical (HR), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical antagonists using in vitro models. The herbal extracts were single herbal formulations (SHfs), double herbal formulations (DHfs), triple herbal formulations (THfs), and a quadruple herbal formulation (QHf). The phytochemical composition and radical scavenging capacity index (SCI) of the herbal formulations were measured using standard methods. The flavonoids were the most abundant phytochemicals present in the herbal extracts. The SCI50 defined the concentration (μg/mL) of herbal formulation required to scavenge 50% of the investigated radicals. The SHfs, DHfs, THfs, and QHf SCI50 against the radicals followed the order HR > SOR > DPPH radical > HP > NOR. Although the various herbal formulations exhibited ambivalent antioxidant activities in terms of their radical scavenging capabilities, a broad survey of the results of the present study showed that combinatorial herbal formulations (DHfs, THfs, and QHf) appeared to exhibit lower radical scavenging capacities than those of the SHfs in vitro. PMID:27114938

  7. Oxygen reduction reaction activity on Pt{111} surface alloys.

    PubMed

    Attard, Gary A; Brew, Ashley; Ye, Jin-Yu; Morgan, David; Sun, Shi-Gang

    2014-07-21

    PtM overlayers (where M=Fe, Co or Ni) supported on Pt{111} are prepared via thermal annealing in either a nitrogen/water or hydrogen ambient of dilute aqueous droplets containing M(Z+) cations directly attached to the electrode. Two different PtM phases are detected depending on the nature of the post-annealing cooling environment. The first of these consists of small (<20 nm), closely packed microcrystals comprised of a central metallic core and a shell (several monolayers thick) of mixed metal oxides/hydroxides. The second type of PtM phase is prepared by cooling in a stream of hydrogen gas. Although this second phase also consists of numerous microcrystals covering the Pt{111} electrode surface, these are both flatter than before and moreover are entirely metallic in character. A positive shift in the onset of PtM oxide formation correlates with increased activity towards the oxygen reduction reaction (ORR), which we ascribe to the greater availability of platinum metallic sites under ORR conditions. PMID:24986646

  8. Atmospheric scavenging exhaust

    NASA Technical Reports Server (NTRS)

    Fenton, D. L.; Purcell, R. Y.

    1977-01-01

    Solid propellant rocket exhaust was directly utilized to ascertain raindrop scavenging rates for hydrogen chloride. The airborne HCl concentration varied from 0.2 to 10.0 ppm and the raindrop sizes tested included 0.55 mm, 1.1 mm, and 3.0 mm. Two chambers were used to conduct the experiments. A large, rigid walled, spherical chamber stored the exhaust constituents while the smaller chamber housing all the experiments was charged as required with rocket exhaust HCl. Surface uptake experiments demonstrated an HCl concentration dependence for distilled water. Sea water and brackish water HCl uptake was below the detection limit of the chlorine-ion analysis technique employed. Plant life HCl uptake experiments were limited to corn and soybeans. Plant age effectively correlated the HCl uptake data. Metallic corrosion was not significant for single 20 minute exposures to the exhaust HCl under varying relative humidity.

  9. Weight savings in aerospace vehicles through propellant scavenging

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J.; Reed, Brian D.

    1988-01-01

    Vehicle payload benefits of scavenging hydrogen and oxygen propellants are addressed. The approach used is to select a vehicle and a mission and then select a scavenging system for detailed weight analysis. The Shuttle 2 vehicle on a Space Station rendezvous mission was chosen for study. The propellant scavenging system scavenges liquid hydrogen and liquid oxygen from the launch propulsion tankage during orbital maneuvers and stores them in well insulated liquid accumulators for use in a cryogenic auxiliary propulsion system. The fraction of auxiliary propulsion propellant which may be scavenged for propulsive purposes is estimated to be 45.1 percent. The auxiliary propulsion subsystem dry mass, including the proposed scavenging system, an additional 20 percent for secondary structure, an additional 5 percent for electrical service, a 10 percent weight growth margin, and 15.4 percent propellant reserves and residuals is estimated to be 6331 kg. This study shows that the fraction of the on-orbit vehicle mass required by the auxiliary propulsion system of this Shuttle 2 vehicle using this technology is estimated to be 12.0 percent compared to 19.9 percent for a vehicle with an earth-storable bipropellant system. This results in a vehicle with the capability of delivering an additional 7820 kg to the Space Station.

  10. Free radical scavenging in vitro and biological activity of diphenyl diselenide-loaded nanocapsules: DPDS-NCS antioxidant and toxicological effects

    PubMed Central

    Stefanello, Sílvio Terra; Dobrachinski, Fernando; de Carvalho, Nélson Rodrigues; Amaral, Guilherme Pires; Barcelos, Rômulo Pillon; Oliveira, Vitor Antunes; Oliveira, Cláudia Sirlene; Giordani, Camila Ferrazza Alves; Pereira, Maria Ester; Rodrigues, Oscar Endrigo Dorneles; Soares, Félix Alexandre Antunes

    2015-01-01

    Selenium compounds, such as diphenyl diselenide (DPDS), have been shown to exhibit biological activity, including antioxidant effects. However, the use of DPDS in pharmacology is limited due to in vivo pro-oxidative effects. In addition, studies have shown that DPDS-loaded nanocapsules (DPDS-NCS) have greater bioavailability than free DPDS in mice. Accordingly, the aim of this study was to investigate the antioxidant properties of DPDS-NCS in vitro and biological activity in mice. Our in vitro results suggested that DPDS-NCS significantly reduced the production of reactive oxygen species and Fe(II)-induced lipid peroxidation (LPO) in brain. The administration of DPDS-NCS did not result in death or change the levels of endogenous reduced or oxidized glutathione after 72 hours of exposure. Moreover, ex vivo assays demonstrated that DPDS-NCS significantly decreased the LPO and reactive oxygen species levels in the brain. In addition, the highest dose of DPDS-NCS significantly reduced Fe(II)- and sodium nitroprusside-induced LPO in the brain and Fe(II)-induced LPO in the liver. Also, δ-aminolevulinate acid dehydratase within the brain was inhibited only in the highest dose of DPDS-NCS. In conclusion, our data demonstrated that DPDS-NCS exhibited low toxicity in mice and have significant antioxidant characteristics, indicating that nanoencapsulation is a safer method of DPDS administration. PMID:26379436

  11. Growth enhancement and gene expression of Arabidopsis thaliana irradiated with active oxygen species

    NASA Astrophysics Data System (ADS)

    Watanabe, Satoshi; Ono, Reoto; Hayashi, Nobuya; Shiratani, Masaharu; Tashiro, Kosuke; Kuhara, Satoru; Inoue, Asami; Yasuda, Kaori; Hagiwara, Hiroko

    2016-07-01

    The characteristics of plant growth enhancement effect and the mechanism of the enhancement induced by plasma irradiation are investigated using various active species in plasma. Active oxygen species in oxygen plasma are effective for growth enhancement of plants. DNA microarray analysis of Arabidopsis thaliana indicates that the genes coding proteins that counter oxidative stresses by eliminating active oxygen species are expressed at significantly high levels. The size of plant cells increases owing to oxygen plasma irradiation. The increases in gene expression levels and cell size suggest that the increase in the expression level of the expansin protein is essential for plant growth enhancement phenomena.

  12. Free radical scavenging actions of hippocampal metallothionein isoforms and of antimetallothioneins: an electron spin resonance spectroscopic study.

    PubMed

    Kumari, M V; Hiramatsu, M; Ebadi, M

    2000-05-01

    The high concentration of zinc in the hippocampal mossy fiber axon boutons is localized in the vesicles and is mobilized by exocytosis of the zinc-laden vesicles. Furthermore, the mammalian hippocampi contain metallothionein (MT) isoforms which regulate the steady state concentration of zinc, an important antioxidant. Indeed, zinc deprivation leads to an increased lipid peroxidation, reduces the activity of Cu++-Zn++ superoxide dismutase, and protect against oxidative stress such as exposure to ultraviolet A irradiation. By employing electron spin resonance (ESR) spectroscopy, we have demonstrated that rat hippocampal MT isoforms 1 and 2 were able to scavenge 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), hydroxyl radicals (*OH) generated in a Fenton reaction, and superoxide anions (O2*-) generated by the hypoxanthine and xanthine oxidase system. In addition, MT-1 isoform protected the isolated hepatocytes from lipid peroxidation as determined by thiobarbituric acid bound malondialdehyde. MT antibodies scavenged DPPH radicals, hydroxyl radicals and reactive oxygen species but not superoxide anions. The results of these studies suggest that although both isoforms of MT are able to scavenge free radicals, the MT-1 appears to be a superior scavenger of superoxide anions and 1,1-diphenyl-2-picrylhydrazyl radicals. Moreover, antibodies formed against MT isoform retain some, but not all, free radical scavenging actions exhibited by MT-1 and MT-2. PMID:10872749

  13. DPPH radical-scavenging effect of several phenylpropanoid compounds and their glycoside derivatives.

    PubMed

    Tominaga, Hitoshi; Kobayashi, Yuka; Goto, Takashi; Kasemura, Kazuo; Nomura, Masato

    2005-04-01

    Eugenol, isoeugenol, caffeic acid, ferulic acid, isoferulic acid, estragole, trans-anethole, and paeonol are components of a Chinese herbal medicine used as a painkiller and stomachic. We investigated the potential role of these compounds as antioxidants. We studied the DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging effect of these molecules, together with some glycoside derivatives, to ascertain their potential in reducing the levels of activated oxygen species in vivo. The DPPH radical-scavenging effects of eugenol, isoeugenol, and the glycoside derivatives of caffeic acid, ferulic acid, and isoferulic acid (SC(50)=8-28 microM) were similar to those of alpha-tocopherol, which was used as a positive control. PMID:15802883

  14. The potential of Angeli’s salt to decrease nitric oxide scavenging by plasma hemoglobin

    PubMed Central

    He, Xiaojun; Azarov, Ivan; Jeffers, Anne; Presley, Tennille; Richardson, Jodi; King, S. Bruce; Gladwin, Mark T.; Kim-Shapiro, Daniel B.

    2008-01-01

    Release of hemoglobin from the erythrocyte during intravascular hemolysis contributes to the pathology of a variety of diseased states. This effect is partially due to the enhanced ability of cell-free plasma hemoglobin, which is primarily found in the ferrous, oxygenated state, to scavenge nitric oxide. Oxidation of the cell-free hemoglobin to methemoglobin, which does not effectively scavenge nitric oxide, using inhaled nitric oxide has been shown to be effective in limiting pulmonary and systemic vasoconstriction. However, the ferric heme species may be reduced back to ferrous hemoglobin in plasma and has the potential to drive injurious redox chemistry. We propose that compounds that selectively convert cell-free hemoglobin to ferric, and ideally iron-nitrosylated heme species that do not actively scavenge nitric oxide would effectively treat intravascular hemolysis. We show here that nitroxyl, generated by Angeli’s salt (Sodium α-oxyhyponitrite, Na2N2O3), preferentially reacts with cell-free hemoglobin compared to that encapsulated in the red blood cell under physiologically relevant conditions. Nitroxyl oxidizes oxygenated ferrous hemoglobin to methemoglobin and can convert the methemoglobin to a more stable, less toxic species, iron-nitrosyl hemoglobin. These results support the notion that Angeli’s salt or a similar compound could be used to effectively treat conditions associated with intravascular hemolysis. PMID:18243145

  15. In vitro propagation by asymbiotic seed germination and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity studies of tissue culture raised plants of three medicinally important species of dendrobium.

    PubMed

    Lo, Shu-Fung; Nalawade, Satish Manohar; Mulabagal, Vanisree; Matthew, Susan; Chen, Chung-Li; Kuo, Chao-Lin; Tsay, Hsin-Sheng

    2004-05-01

    A simple and efficient plant propagation system has been developed by asymbiotic germination of seeds in three medicinally important Dendrobium species, namely, Dendrobium tosaense, Dendrobium moniliforme, and Dendrobium linawianum. Plants obtained from natural habitats were grown in the greenhouse. The flowers were hand pollinated. Seeds of the capsules derived after 12 weeks of hand-pollination germinated asymbiotically (50-74%) on half strength Murashige and Skoog's (MS) basal medium with 3% sucrose and solidified with 0.9% Difco agar. Active growth in the germinated seedlings was achieved by re-culturing on full strength MS basal medium supplemented with 8% banana homogenate, 8% potato homogenate, 8% coconut water, 1.5% sucrose and 0.9% Difco agar. Healthy plantlets, transferred to plastic trays containing moss or moss and tree fern, successfully acclimatized (84-100%) in the greenhouse. A marked varied response was observed in the free radical scavenging activity of methanolic extracts of in vitro propagated plants, on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical using a UV spectrophotometer assay. Methanolic extracts were prepared by dissolving the powdered plant material, obtained from six months old in vitro propagated plants, each about 5 g, in boiling methanol. The percentage of scavenging effect of D. tosaense extract was 95.9% at 0.4 mg/ml concentration, whereas D. monoliforme, and D. linawianum extracts scavenged 83.4% and 92.3%, respectively, at a concentration of 0.4 mg/ml. All the extracts scavenged DPPH radical significantly in a concentration dependent manner. PMID:15133256

  16. Atmospheric hydrogen scavenging: from enzymes to ecosystems.

    PubMed

    Greening, Chris; Constant, Philippe; Hards, Kiel; Morales, Sergio E; Oakeshott, John G; Russell, Robyn J; Taylor, Matthew C; Berney, Michael; Conrad, Ralf; Cook, Gregory M

    2015-02-01

    We have known for 40 years that soils can consume the trace amounts of molecular hydrogen (H2) found in the Earth’s atmosphere.This process is predicted to be the most significant term in the global hydrogen cycle. However, the organisms and enzymes responsible for this process were only recently identified. Pure culture experiments demonstrated that several species of Actinobacteria, including streptomycetes and mycobacteria, can couple the oxidation of atmospheric H2 to the reduction of ambient O2. A combination of genetic, biochemical, and phenotypic studies suggest that these organisms primarily use this fuel source to sustain electron input into the respiratory chain during energy starvation. This process is mediated by a specialized enzyme, the group 5 [NiFe]-hydrogenase, which is unusual for its high affinity, oxygen insensitivity, and thermostability. Atmospheric hydrogen scavenging is a particularly dependable mode of energy generation, given both the ubiquity of the substrate and the stress tolerance of its catalyst. This minireview summarizes the recent progress in understanding how and why certain organisms scavenge atmospheric H2. In addition, it provides insight into the wider significance of hydrogen scavenging in global H2 cycling and soil microbial ecology. PMID:25501483

  17. Atmospheric Hydrogen Scavenging: from Enzymes to Ecosystems

    PubMed Central

    Constant, Philippe; Hards, Kiel; Morales, Sergio E.; Oakeshott, John G.; Russell, Robyn J.; Taylor, Matthew C.; Berney, Michael; Conrad, Ralf; Cook, Gregory M.

    2014-01-01

    We have known for 40 years that soils can consume the trace amounts of molecular hydrogen (H2) found in the Earth's atmosphere. This process is predicted to be the most significant term in the global hydrogen cycle. However, the organisms and enzymes responsible for this process were only recently identified. Pure culture experiments demonstrated that several species of Actinobacteria, including streptomycetes and mycobacteria, can couple the oxidation of atmospheric H2 to the reduction of ambient O2. A combination of genetic, biochemical, and phenotypic studies suggest that these organisms primarily use this fuel source to sustain electron input into the respiratory chain during energy starvation. This process is mediated by a specialized enzyme, the group 5 [NiFe]-hydrogenase, which is unusual for its high affinity, oxygen insensitivity, and thermostability. Atmospheric hydrogen scavenging is a particularly dependable mode of energy generation, given both the ubiquity of the substrate and the stress tolerance of its catalyst. This minireview summarizes the recent progress in understanding how and why certain organisms scavenge atmospheric H2. In addition, it provides insight into the wider significance of hydrogen scavenging in global H2 cycling and soil microbial ecology. PMID:25501483

  18. Copper(I)-catalyzed azide-alkyne cycloadditions in microflow: catalyst activity, high-T operation, and an integrated continuous copper scavenging unit.

    PubMed

    Varas, Alvaro Carlos; Noël, Timothy; Wang, Qi; Hessel, Volker

    2012-09-01

    AVOIDING THE COPPERS: A continuous-flow synthesis for the Cu(I) -catalyzed azide-alkyne cycloaddition reaction using [Cu(phenanthroline)(PPh₃)₂]NO₃ as a homogeneous catalyst is developed (up to 92 % isolated yield). Elevated temperatures allow achieving full conversions and using lower catalyst loadings. Residual copper in the triazole compound is efficiently removed via an inline extraction process, employing aqueous EDTA as a copper scavenger. PMID:22753337

  19. Molecular dioxygen enters the active site of 12/15-lipoxygenase via dynamic oxygen access channels.

    PubMed

    Saam, Jan; Ivanov, Igor; Walther, Matthias; Holzhütter, Hermann-Georg; Kuhn, Hartmut

    2007-08-14

    Cells contain numerous enzymes that use molecular oxygen for their reactions. Often, their active sites are buried deeply inside the protein, which raises the question whether there are specific access channels guiding oxygen to the site of catalysis. Choosing 12/15-lipoxygenase as a typical example for such oxygen-dependent enzymes, we determined the oxygen distribution within the protein and defined potential routes for oxygen access. For this purpose, we have applied an integrated strategy of structural modeling, molecular dynamics simulations, site-directed mutagenesis, and kinetic measurements. First, we computed the 3D free-energy distribution for oxygen, which led to identification of four oxygen channels in the protein. All channels connect the protein surface with a region of high oxygen affinity at the active site. This region is localized opposite to the nonheme iron providing a structural explanation for the reaction specificity of this lipoxygenase isoform. The catalytically most relevant path can be obstructed by L367F exchange, which leads to a strongly increased Michaelis constant for oxygen. The blocking mechanism is explained in detail by reordering the hydrogen-bonding network of water molecules. Our results provide strong evidence that the main route for oxygen access to the active site of the enzyme follows a channel formed by transiently interconnected cavities whereby the opening and closure are governed by side chain dynamics. PMID:17675410

  20. A mechanism of oxygen sensing in yeast. Multiple oxygen-responsive steps in the heme biosynthetic pathway affect Hap1 activity.

    PubMed

    Hon, Thomas; Dodd, Athena; Dirmeier, Reinhard; Gorman, Nadia; Sinclair, Peter R; Zhang, Li; Poyton, Robert O

    2003-12-12

    Heme plays central roles in oxygen sensing and utilization in many living organisms. In yeast, heme mediates the effect of oxygen on the expression of many genes involved in using or detoxifying oxygen. However, a direct link between intracellular heme level and oxygen concentration has not been vigorously established. In this report, we have examined the relationships among oxygen levels, heme levels, Hap1 activity, and HAP1 expression. We found that Hap1 activity is controlled in vivo by heme and not by its precursors and that heme activates Hap1 even in anoxic cells. We also found that Hap1 activity exhibits the same oxygen dose-response curves as Hap1-dependent aerobic genes and that these dose-response curves have a sharp break at approximately 1 microM O2. The results show that the intracellular signaling heme level, reflected as Hap1 activity, is closely correlated with oxygen concentration. Furthermore, we found that bypass of all heme synthetic steps but ferrochelatase by deuteroporphyrin IX does not circumvent the need for oxygen in Hap1 full activation by heme, suggesting that the last step of heme synthesis, catalyzed by ferrochelatase, is also subjected to oxygen control. Our results show that multiple heme synthetic steps can sense oxygen concentration and provide significant insights into the mechanism of oxygen sensing in yeast. PMID:14512429

  1. The behavior of ROS-scavenging nanoparticles in blood

    PubMed Central

    Shimizu, Madoka; Yoshitomi, Toru; Nagasaki, Yukio

    2014-01-01

    Here, we report an interaction between blood and redox nanoparticles, prepared by self-assembly of amphiphilic block copolymers possessing 2,2,6,6-tetramethylpiperidine-N-oxyls as a side chain of hydrophobic segment. When 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl was added to rat whole blood, its electron spin resonance signal disappeared rapidly. In contrast, the signal from redox nanoparticles remained for a long period of time, indicating that nitroxide radicals were protected in the blood by their compartmentalization in the core of nanoparticle. Although most 2,2,6,6-tetramethylpiperidine-N-oxyls were located in the nanoparticle core, reactive oxygen species-scavenging activity was found outside of blood cells. For example, redox nanoparticles suppressed superoxide anion-induced hemolysis effectively, while 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl did not. It was revealed that redox nanoparticles were not internalized into the healthy blood cells, which was in sharp contrast to 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl. Due to its internalization into healthy platelets, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl induced mitochondrial dysfunction, while redox nanoparticles did not. Redox nanoparticles suppressed platelet adhesion and extended blood coagulation time, in contrast to 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl. These results indicate that redox nanoparticles scavenge reactive oxygen species outside of cells, but do not interfere with normal redox reactions inside of the cell. Based on these results, we determine that an anti-oxidative strategy based on nanotechnology is a rational and safe therapeutic approach. PMID:24895479

  2. AMPKα1 knockout enhances nociceptive behaviors and spinal glutamatergic synaptic activities via production of reactive oxygen species in the spinal dorsal horn.

    PubMed

    Maixner, Dylan W; Yan, Xisheng; Hooks, Shelley B; Weng, Han-Rong

    2016-06-21

    Emerging studies have shown that pharmacological activation of adenosine monophosphate-activated protein kinase (AMPK) produces potent analgesic effects in different animal pain models. Currently, the spinal molecular and synaptic mechanism by which AMPK regulates the pain signaling system remains unclear. To address this issue, we utilized the Cre-LoxP system to conditionally knockout the AMPKα1 gene in the nervous system of mice. We demonstrated that AMPKα1 is imperative for maintaining normal nociception, and mice deficient for AMPKα1 exhibit mechanical allodynia. This is concomitantly associated with increased glutamatergic synaptic activities in neurons located in the superficial spinal dorsal horn, which results from the increased glutamate release from presynaptic terminals and function of ligand-gated glutamate receptors at the postsynaptic neurons. Additionally, AMPKα1 knockout mice have increased activities of extracellular signal-regulated kinases (ERK) and p38 mitogen-activated protein kinases (p38), as well as elevated levels of interleukin-1β (IL-1β), reactive oxygen species (ROS), and heme oxygenase 1 (HO-1) in the spinal dorsal horn. Systemic administration of a non-specific ROS scavenger (phenyl-N-tert-butylnitrone, PBN) or a HO-1 activator (Cobalt protoporphyrin IX, CoPP) attenuated allodynia in AMPKα1 knockout mice. Bath-perfusion of the ROS scavenger or HO-1 activator effectively attenuated the increased ROS levels and glutamatergic synaptic activities in the spinal dorsal horn. Our findings suggest that ROS are the key down-stream signaling molecules mediating the behavioral hypersensitivity in AMPKα1 knockout mice. Thus, targeting AMPKα1 may represent an effective approach for the treatment of pathological pain conditions associated with neuroinflammation at the spinal dorsal horn. PMID:27058143

  3. Contributions of reactive oxygen species and mitogen-activated protein kinase signaling in arsenite-stimulated hemeoxygenase-1 production

    SciTech Connect

    Cooper, Karen L.; Liu, Ke Jian; Hudson, Laurie G. . E-mail: lhudson@salud.unm.edu

    2007-01-15

    Hemeoxygenase-1 (HO-1) is an oxidative stress responsive gene upregulated by various physiological and exogenous stimuli. HO-1 has cytoprotective activities and arsenite is a potent inducer of HO-1 in many cell types and tissues, including epidermal keratinocytes. We investigated the potential contributions of reactive oxygen species (ROS) generation and mitogen-activated protein kinase (MAPK) activation to arsenite-dependent regulation of HO-1 in HaCaT cells, an immortalized human keratinocyte line. Both epidermal growth factor (EGF) and arsenite stimulated ROS production was detected by dihydroethidium (DHE) staining and fluorescence microscopy. Arsenite induced HO-1 in a time- and concentration-dependent manner, while HO-1 expression in response to EGF was modest and evident at extended time points (48-72 h). Inhibition of EGF receptor, MEK I/II or Src decreased arsenite-stimulated HO-1 expression by 20-30%. In contrast, addition of a superoxide scavenger or inhibition of p38 activity decreased the arsenite-dependent response by 80-90% suggesting that ROS and p38 are required for HO-1 induction. However, ROS generation alone was insufficient for the observed arsenite-dependent response as use of a xanthine/xanthine oxidase system to generate ROS did not produce an equivalent upregulation of HO-1. Cooperation between ERK signaling and ROS generation was demonstrated by synergistic induction of HO-1 in cells co-treated with EGF and xanthine/xanthine oxidase resulting in a response nearly equivalent to that observed with arsenite. These findings suggest that the ERK/MAPK activation is necessary but not sufficient for optimal arsenite-stimulated HO-1 induction. The robust and persistent upregulation of HO-1 may have a role in cellular adaptation to chronic arsenic exposure.

  4. Cell death induced by direct laser activation of singlet oxygen at 1270 nm

    NASA Astrophysics Data System (ADS)

    Anquez, F.; El Yazidi Belkoura, I.; Suret, P.; Randoux, S.; Courtade, E.

    2013-02-01

    Singlet oxygen plays a major role in many chemical and biological photo-oxidation processes. It has a high chemical reactivity, which is commonly harnessed for therapeutic issues. Indeed, singlet oxygen is recognized as the major cytotoxic agent in photodynamic therapy. In this treatment of cancer, singlet oxygen is created, among other reactive species, by an indirect transfer of energy from light to molecular oxygen via excitation of a photosensitizer. In this paper, we show that the conventional singlet oxygen production scheme can be simplified. Production of singlet oxygen is achieved in living cells from photosensitizer-free 1270 nm laser excitation of the electronic ground state of molecular oxygen. The quantity of singlet oxygen produced in this way is sufficient to induce an oxidative stress leading to cell death. Other effects such as thermal stress are discriminated, and we conclude that cell death is only due to singlet oxygen creation. This new simplified scheme of singlet oxygen activation can be seen as a breakthrough for phototherapies of malignant diseases and/or as a non-invasive possibility to generate reactive oxygen species in a tightly controlled manner.

  5. Neuroprotection by Minocycline Caused by Direct and Specific Scavenging of Peroxynitrite*

    PubMed Central

    Schildknecht, Stefan; Pape, Regina; Müller, Nathalie; Robotta, Marta; Marquardt, Andreas; Bürkle, Alexander; Drescher, Malte; Leist, Marcel

    2011-01-01

    Minocycline prevents oxidative protein modifications and damage in disease models associated with inflammatory glial activation and oxidative stress. Although the drug has been assumed to act by preventing the up-regulation of proinflammatory enzymes, we probed here its direct chemical interaction with reactive oxygen species. The antibiotic did not react with superoxide or •NO radicals, but peroxynitrite (PON) was scavenged in the range of ∼1 μm minocycline and below. The interaction of pharmacologically relevant minocycline concentrations with PON was corroborated in several assay systems and significantly exceeded the efficacy of other antibiotics. Minocycline was degraded during the reaction with PON, and the resultant products lacked antioxidant properties. The antioxidant activity of minocycline extended to cellular systems, because it prevented neuronal mitochondrial DNA damage and glutathione depletion. Maintenance of neuronal viability under PON stress was shown to be solely dependent on direct chemical scavenging by minocycline. We chose α-synuclein (ASYN), known from Parkinsonian pathology as a biologically relevant target in chemical and cellular nitration reactions. Submicromolar concentrations of minocycline prevented tyrosine nitration of ASYN by PON. Mass spectrometric analysis revealed that minocycline impeded nitrations more effectively than methionine oxidations and dimerizations of ASYN, which are secondary reactions under PON stress. Thus, PON scavenging at low concentrations is a novel feature of minocycline and may help to explain its pharmacological activity. PMID:21081502

  6. The French Paradox: Determining the Superoxide-Scavenging Capacity of Red Wine and Other Beverages

    ERIC Educational Resources Information Center

    Logan, Barry A.; Hammond, Matthew P.; Stormo, Benjamin M.

    2008-01-01

    Plant-derived phenolic compounds such as those found in red wine, tea, and certain fruit juices may protect against cardiovascular disease by detoxifying (scavenging) superoxide and other unstable reactive oxygen species. We present a laboratory exercise that can be used to assess the superoxide-scavenging capacity of beverages. Among the…

  7. 5-AIQ inhibits H{sub 2}O{sub 2}-induced apoptosis through reactive oxygen species scavenging and Akt/GSK-3β signaling pathway in H9c2 cardiomyocytes

    SciTech Connect

    Park, Eun-Seok; Kang, Jun Chul; Kang, Do-Hyun; Jang, Yong Chang; Yi, Kyu Yang; Chung, Hun-Jong; Park, Jong Seok; Kim, Bokyung; Feng, Zhong-Ping; Shin, Hwa-Sup

    2013-04-01

    Poly(adenosine 5′-diphosphate ribose) polymerase (PARP) is a nuclear enzyme activated by DNA strand breaks and plays an important role in the tissue injury associated with ischemia and reperfusion. The aim of the present study was to investigate the protective effect of 5-aminoisoquinolinone (5-AIQ), a PARP inhibitor, against oxidative stress-induced apoptosis in H9c2 cardiomyocytes. 5-AIQ pretreatment significantly protected against H{sub 2}O{sub 2}-induced cell death, as determined by the XTT assay, cell counting, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay, and Western blot analysis of apoptosis-related proteins such as caspase-3, Bax, and Bcl-2. Upregulation of antioxidant enzymes such as manganese superoxide dismutase and catalase accompanied the protective effect of 5-AIQ on H{sub 2}O{sub 2}-induced cell death. Our data also showed that 5-AIQ pretreatment protected H9c2 cells from H{sub 2}O{sub 2}-induced apoptosis by triggering activation of Akt and glycogen synthase kinase-3β (GSK-3β), and that the protective effect of 5-AIQ was diminished by the PI3K inhibitor LY294002 at a concentration that effectively abolished 5-AIQ-induced Akt and GSK-3β activation. In addition, inhibiting the Akt/GSK-3β pathway by LY294002 significantly attenuated the 5-AIQ-mediated decrease in cleaved caspase-3 and Bax activation and H9c2 cell apoptosis induction. Taken together, these results demonstrate that 5-AIQ prevents H{sub 2}O{sub 2}-induced apoptosis in H9c2 cells by reducing intracellular reactive oxygen species production, regulating apoptosis-related proteins, and activating the Akt/GSK-3β pathway. - Highlights: ► 5-AIQ, a PARP inhibitor, decreased H{sub 2}O{sub 2}-induced H9c2 cell death and apoptosis. ► 5-AIQ upregulated antioxidant Mn-SOD and catalase, while decreasing ROS production. ► 5-AIQ decreased H{sub 2}O{sub 2}-induced increase in cleaved caspase-3 and Bax and decrease in Bcl2. ► 5-AIQ activated Akt and GSK-3

  8. Method of Separating Oxygen From Spacecraft Cabin Air to Enable Extravehicular Activities

    NASA Technical Reports Server (NTRS)

    Graf, John C.

    2013-01-01

    Extravehicular activities (EVAs) require high-pressure, high-purity oxygen. Shuttle EVAs use oxygen that is stored and transported as a cryogenic fluid. EVAs on the International Space Station (ISS) presently use the Shuttle cryo O2, which is transported to the ISS using a transfer hose. The fluid is compressed to elevated pressures and stored as a high-pressure gas. With the retirement of the shuttle, NASA has been searching for ways to deliver oxygen to fill the highpressure oxygen tanks on the ISS. A method was developed using low-pressure oxygen generated onboard the ISS and released into ISS cabin air, filtering the oxygen from ISS cabin air using a pressure swing absorber to generate a low-pressure (high-purity) oxygen stream, compressing the oxygen with a mechanical compressor, and transferring the high-pressure, high-purity oxygen to ISS storage tanks. The pressure swing absorber (PSA) can be either a two-stage device, or a single-stage device, depending on the type of sorbent used. The key is to produce a stream with oxygen purity greater than 99.5 percent. The separator can be a PSA device, or a VPSA device (that uses both vacuum and pressure for the gas separation). The compressor is a multi-stage mechanical compressor. If the gas flow rates are on the order of 5 to 10 lb (.2.3 to 4.6 kg) per day, the compressor can be relatively small [3 16 16 in. (.8 41 41 cm)]. Any spacecraft system, or other remote location that has a supply of lowpressure oxygen, a method of separating oxygen from cabin air, and a method of compressing the enriched oxygen stream, has the possibility of having a regenerable supply of highpressure, high-purity oxygen that is compact, simple, and safe. If cabin air is modified so there is very little argon, the separator can be smaller, simpler, and use less power.

  9. Scavenging for Better Library Instruction.

    ERIC Educational Resources Information Center

    Cocking, Terry S.; Schafer, Susan A.

    1994-01-01

    Describes the Library Scavenger Hunt program at Baylor University (part of the reading and study skills program) which emphasizes learning what sources are available in a college library, where they are located, and how to use them. (SR)

  10. The Effect of 30% Oxygen on Visuospatial Performance and Brain Activation: An Fmri Study

    ERIC Educational Resources Information Center

    Chung, S.C.; Tack, G.R.; Lee, B.; Eom, G.M.; Lee, S.Y.; Sohn, J.H.

    2004-01-01

    This study aimed to investigate the hypothesis that administration of the air with 30% oxygen compared with normal air (21% oxygen) enhances cognitive functioning through increased activation in the brain. A visuospatial task was presented while brain images were scanned by a 3 T fMRI system. The results showed that there was an improvement in…

  11. Apoptosis Induction by the Total Flavonoids from Arachniodes exilis in HepG2 Cells through Reactive Oxygen Species-Mediated Mitochondrial Dysfunction Involving MAPK Activation

    PubMed Central

    Chen, Jing; Xiong, Chaomei; Wei, Han; Yin, Changchang; Ruan, Jinlan

    2014-01-01

    Arachniodes exilis is used as a folk medicine in China and proved to have antibacterial, anti-inflammatory, and sedative activities. In the present study, the antitumor effect of the total flavonoids of A. exilis (TFAE) against HepG2 cells was evaluated. The results showed that TFAE inhibited the growth of HepG2 cells in a dosage- and time-dependent manner. Flow cytometry and Hoechst 33342 fluorescence staining results showed that TFAE could significantly increase the apoptosis ratio of HepG2 cells, which is accompanied with increased intracellular reactive oxygen species (ROS) production and decreased mitochondrial membrane potential (ΔΨm). Western blotting indicated that TFAE downregulated the ratio of Bcl-2/Bax, increased cytochrome c release, and activated the caspases-3 and -9. Further analysis showed that TFAE stimulated the mitogen-activated protein kinase (MAPK). However, treatment with NAC (reactive oxygen species scavenger) and MAPK-specific inhibitors (SP600125 and SB203580) could reverse the changes of these apoptotic-related proteins. These results suggested that TFAE possessed potential anticancer activity in HepG2 cells through ROS-mediated mitochondrial dysfunction involving MAPK pathway. PMID:24976852

  12. Atmospheric oxygen plasma activation of silicon (100) surfaces

    SciTech Connect

    Habib, Sara B.; Gonzalez, Eleazar II; Hicks, Robert F.

    2010-05-15

    Silicon (100) surfaces were converted to a hydrophilic state with a water contact angle of <5 deg. by treatment with a radio frequency, atmospheric pressure helium, and oxygen plasma. A 2 in. wide plasma beam, operating at 250 W, 1.0 l/min O{sub 2}, 30 l/min He, and a source-to-sample distance of 3{+-}0.1 mm, was scanned over the sample at 100{+-}2 mm/s. Plasma oxidation of HF-etched silicon caused the dispersive component of the surface energy to decrease from 55.1 to 25.8 dyn/cm, whereas the polar component of the surface energy increased from 0.3 to 42.1 dyn/cm. X-ray photoelectron spectroscopy revealed that the treatment generated a monolayer of covalently bonded oxygen on the Si(100) surface 0.15{+-}0.10 nm thick. The surface oxidation kinetics have been measured by monitoring the change in water contact angle with treatment time, and are consistent with a process that is limited by the mass transfer of ground-state oxygen atoms to the silicon surface.

  13. Design of high pressure oxygen filter for extravehicular activity life support system, volume 1

    NASA Technical Reports Server (NTRS)

    Wilson, B. A.

    1977-01-01

    The experience of the National Aeronautics and Space Administration (NASA) with extravehicular activity life support emergency oxygen supply subsystems has shown a large number of problems associated with particulate contamination. These problems have resulted in failures of high pressure oxygen component sealing surfaces. A high pressure oxygen filter was designed which would (a) control the particulate contamination level in the oxygen system to a five-micron glass bead rating, ten-micron absolute condition (b) withstand the dynamic shock condition resulting from the sudden opening of 8000 psi oxygen system shutoff valve. Results of the following program tasks are reported: (1) contaminant source identification tests, (2) dynamic system tests, (3) high pressure oxygen filter concept evaluation, (4) design, (5) fabrication, (6) test, and (7) application demonstration.

  14. The role of supplemental ultraviolet-B radiation in altering the metabolite profile, essential oil content and composition, and free radical scavenging activities of Coleus forskohlii, an indigenous medicinal plant.

    PubMed

    Takshak, Swabha; Agrawal, S B

    2016-04-01

    The effects of supplemental ultraviolet-B (s-UV-B; 3.6 kJ m(-2) day(-1) above ambient) radiation were investigated on plant metabolite profile, essential oil content and composition, and free radical scavenging capacities of methanolic extracts of Coleus forskohlii (an indigenous medicinal plant) grown under field conditions. Essential oil was isolated using hydrodistillation technique while alterations in metabolite profile and oil composition were determined via gas chromatography-mass spectroscopy (GC-MS). Leaf and root methanolic extracts were investigated via various in vitro assays for their DPPH radical-, superoxide radical-, hydrogen peroxide-, hydroxyl radical-, and nitric oxide radical scavenging activities, ferrous ion chelating activity, and reducing power. Phytochemical analysis revealed the presence of alkaloids, anthocyanins, coumarins, flavonoids, glycosides, phenols, saponins, steroids, tannins, and terpenoids. Oil content was found to be reduced (by ∼7 %) in supplemental UV-B (s-UV-B) treated plants; the composition of the plant extracts as well as essential oil was also considerably altered. Methanolic extracts from treated plant organs showed more potency as free radical scavengers (their EC50 values being lower than their respective controls). Anomalies were observed in Fe(2+) chelating activity for both leaves and roots. The present study concludes that s-UV-B adversely affects oil content in C. forskohlii and also alters the composition and contents of metabolites in both plant extracts and oil. The results also denote that s-UV-B treated plant organs might be more effective in safeguarding against oxidative stress, though further studies are required to authenticate these findings. PMID:26681329

  15. Melatonin: detoxification of oxygen and nitrogen-based toxic reactants.

    PubMed

    Reiter, Russel J; Tan, Dun-Xian; Manchester, Lucien C; Lopez-Burillo, Silvia; Sainz, Rosa M; Mayo, Juan C

    2003-01-01

    In the last decade, melatonin has been found to be highly protective against damage to macromolecules resulting from oxygen and nitrogen-based reactants. Considering this, numerous studies have examined the mechanisms whereby this indoleamine directly detoxifies these damaging agents. The evidence is compelling that melatonin scavenges several oxygen-derived reactive agents including the hydroxyl radical (OH), hydrogen peroxide (H2O2), singlet oxygen (1O2) and hypochlorous acid (HOCl). Additionally, melatonin reportedly reacts with nitric oxide (NO), the peroxynitrite anion (ONOO-) and/or peroxynitrous acid (ONOOH) to detoxify them. In some cases the products that are formed as a consequence of melatonin's scavenging actions have been identified. Whereas the ability of melatonin to neutralize these toxic agents likely accounts, in part, for the antioxidant activity of melatonin, it is not the only means by which melatonin serves to protect molecules from oxygen and nitrogen-based reactive metabolites. PMID:15206772

  16. ‘Neanderthal bone flutes’: simply products of Ice Age spotted hyena scavenging activities on cave bear cubs in European cave bear dens

    PubMed Central

    Diedrich, Cajus G.

    2015-01-01

    Punctured extinct cave bear femora were misidentified in southeastern Europe (Hungary/Slovenia) as ‘Palaeolithic bone flutes’ and the ‘oldest Neanderthal instruments’. These are not instruments, nor human made, but products of the most important cave bear scavengers of Europe, hyenas. Late Middle to Late Pleistocene (Mousterian to Gravettian) Ice Age spotted hyenas of Europe occupied mainly cave entrances as dens (communal/cub raising den types), but went deeper for scavenging into cave bear dens, or used in a few cases branches/diagonal shafts (i.e. prey storage den type). In most of those dens, about 20% of adult to 80% of bear cub remains have large carnivore damage. Hyenas left bones in repeating similar tooth mark and crush damage stages, demonstrating a butchering/bone cracking strategy. The femora of subadult cave bears are intermediate in damage patterns, compared to the adult ones, which were fully crushed to pieces. Hyenas produced round–oval puncture marks in cub femora only by the bone-crushing premolar teeth of both upper and lower jaw. The punctures/tooth impact marks are often present on both sides of the shaft of cave bear cub femora and are simply a result of non-breakage of the slightly calcified shaft compacta. All stages of femur puncturing to crushing are demonstrated herein, especially on a large cave bear population from a German cave bear den. PMID:26064624

  17. 'Neanderthal bone flutes': simply products of Ice Age spotted hyena scavenging activities on cave bear cubs in European cave bear dens.

    PubMed

    Diedrich, Cajus G

    2015-04-01

    Punctured extinct cave bear femora were misidentified in southeastern Europe (Hungary/Slovenia) as 'Palaeolithic bone flutes' and the 'oldest Neanderthal instruments'. These are not instruments, nor human made, but products of the most important cave bear scavengers of Europe, hyenas. Late Middle to Late Pleistocene (Mousterian to Gravettian) Ice Age spotted hyenas of Europe occupied mainly cave entrances as dens (communal/cub raising den types), but went deeper for scavenging into cave bear dens, or used in a few cases branches/diagonal shafts (i.e. prey storage den type). In most of those dens, about 20% of adult to 80% of bear cub remains have large carnivore damage. Hyenas left bones in repeating similar tooth mark and crush damage stages, demonstrating a butchering/bone cracking strategy. The femora of subadult cave bears are intermediate in damage patterns, compared to the adult ones, which were fully crushed to pieces. Hyenas produced round-oval puncture marks in cub femora only by the bone-crushing premolar teeth of both upper and lower jaw. The punctures/tooth impact marks are often present on both sides of the shaft of cave bear cub femora and are simply a result of non-breakage of the slightly calcified shaft compacta. All stages of femur puncturing to crushing are demonstrated herein, especially on a large cave bear population from a German cave bear den. PMID:26064624

  18. Nrf2 activation supports cell survival during hypoxia and hypoxia/reoxygenation in cardiomyoblasts; the roles of reactive oxygen and nitrogen species.

    PubMed

    Kolamunne, Rajitha T; Dias, Irundika H K; Vernallis, Ann B; Grant, Melissa M; Griffiths, Helen R

    2013-01-01

    Adaptive mechanisms involving upregulation of cytoprotective genes under the control of transcription factors such as Nrf2 exist to protect cells from permanent damage and dysfunction under stress conditions. Here we explore of the hypothesis that Nrf2 activation by reactive oxygen and nitrogen species modulates cytotoxicity during hypoxia (H) with and without reoxygenation (H/R) in H9C2 cardiomyobla