A discussion of the several types of two-stroke-cycle engines

NASA Technical Reports Server (NTRS)

Venediger, Herbert J

1935-01-01

This report discusses different types of two-stroke engines as well as the three most important design factors: volume of scavenge and charge delivery, scavenging process (scavenging result), and result of charge. Some of the types of engines discussed include: single cylinder with crank-chamber scavenge pump and auxiliary suction piston linked to working connecting rod; and two cylinder engines with a rotary scavenge pump arrangement. Three and four cylinder engines are also discussed in various designs.

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

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

PubMed

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

2013-03-01

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.

Differential Scavenging Among Pig, Rabbit, and Human Subjects.

PubMed

Steadman, Dawnie Wolfe; Dautartas, Angela; Kenyhercz, Michael W; Jantz, Lee M; Mundorff, Amy; Vidoli, Giovanna M

2018-04-12

Different animal species have been used as proxies for human remains in decomposition studies for decades, although few studies have sought to validate their use in research aimed at estimating the postmortem interval. This study examines 45 pig, rabbit, and human subjects placed in three seasonal trials at the Anthropology Research Facility. In an earlier paper, we found that overall decomposition trends did vary between species that could be due to differential insect and scavenger behavior. This study specifically examines if scavenger behavior differs by carrion species. Daily photographs, game camera photographs, written observations, and Total Body Score (TBS) documented scavenging and decomposition changes. Results show that raccoons were the most commonly observed vertebrate scavenger, that scavenging was most extensive in winter, and that certain human subjects were preferred over other humans and all non-human subjects. Finally, scavenging activity greatly reduces the accuracy of postmortem interval estimates based on TBS. © 2018 American Academy of Forensic Sciences.

Gas-phase ozonolysis of ethene in the presence of carbonyl-oxide scavengers

NASA Astrophysics Data System (ADS)

Wolff, Silke; Boddenberg, Axel; Thamm, Jürgen; Turner, Walter V.; Gäb, Siegmar

Potential carbonyl-oxide scavengers are included in gas-phase ozonolysis experiments in an attempt to determine the extent to which the Criegee mechanism is involved. The scavengers selected are those whose reaction mechanism in the liquid phase is understood; water, hydrogen peroxide, alcohols and carboxylic acids have thus far been examined. The products of the ozonolysis of ethene in the gas phase depend on whether carbonyl-oxide scavengers are present. In the absence of scavengers, formaldehyde and formic acid are the major products, and only minor amounts of H 2O 2 and hydroxymethyl hydroperoxide are found. In the presence of a scavenger, certain products observed in addition to these can be regarded as arising from addition of the scavenger to the carbonyl oxide. Thus, H 2O 2 leads to the formation of hydroperoxymethyl hydroperoxide, while alcohols and formic acid give alkoxymethyl hydroperoxides and hydroperoxymethyl formate, respectively.

Multiple scavengers respond rapidly to pulsed carrion resources at the land-ocean interface

NASA Astrophysics Data System (ADS)

Schlacher, Thomas A.; Strydom, Simone; Connolly, Rod M.

2013-04-01

Sandy beaches are the globe's longest interface region between the oceans and the continents, forming highly permeable boundaries across which matter flows readily. Stranded marine carrion supplies a high-quality food source to scavengers, but the role of animal carcasses is generally under-reported in sandy-beach food webs. We examined the response of scavengers to pulsed subsidies in the form of experimental additions of fish carcasses to the dune-beach interface in eastern Australia. Ghost crabs (Ocypode spp.) are the dominant invertebrate scavengers in these habitats and they responded strongly and consistently to changed resource availability: densities increased significantly within days of carrion augmentations. Carcasses added experimentally also formed local nuclei for a diversity of vertebrate scavengers that aggregated at food falls; these included large lizards, several species of birds (including raptors), and foxes. Consumption of fish carrion by the vertebrate scavengers was rapid and often complete. There is also evidence for higher-order interactions, where responses of invertebrate scavengers became depressed in plots where vertebrate scavenger activity was intense. Our findings emphasize that carrion can be a pivotal component of beach food webs.

Reactive oxygen species and lipid peroxidation product-scavenging ability of yogurt organisms.

PubMed

Lin, M Y; Yen, C L

1999-08-01

The antioxidative activity of the intracellular extracts of yogurt organisms was investigated. All 11 strains tested, including five strains of Streptococcus thermophilus and six strains of Lactobacillus delbrueckii ssp. bulgaricus, demonstrated an antioxidative effect on the inhibition of linoleic acid peroxidation. The antioxidative effect of intracellular extracts of 10(8) cells of yogurt organisms was equivalent to 25 to 96 ppm butylated hydroxytoluene, which indicated that all strains demonstrated excellent antioxidative activity. The scavenging of reactive oxygen species, hydroxyl radical, and hydrogen peroxide was studied for intracellular extracts of yogurt organisms. All strains showed reactive oxygen species-scavenging ability. Lactobacillus delbrueckii ssp. bulgaricus Lb demonstrated the highest hydroxyl radical-scavenging ability at 234 microM. Streptococcus thermophilus MC and 821 and L. delbrueckii ssp. bulgaricus 448 and 449 scavenged the most hydrogen peroxide at approximately 50 microM. The scavenging ability of lipid peroxidation products, t-butylhydroperoxide and malondialdehyde, was also evaluated. Results showed that the extracts were not able to scavenge the t-butylhydroperoxide. Nevertheless, malondialdehyde was scavenged well by most strains.

Scavenger Receptors: Emerging Roles in Cancer Biology and Immunology

PubMed Central

Yu, Xiaofei; Guo, Chunqing; Fisher, Paul B.; Subjeck, John R.; Wang, Xiang-Yang

2015-01-01

Scavenger receptors constitute a large family of evolutionally conserved protein molecules that are structurally and functionally diverse. Although scavenger receptors were originally identified based on their capacity to scavenge modified lipoproteins, these molecules have been shown to recognize and bind to a broad spectrum of ligands, including modified and unmodified host-derived molecules or microbial components. As a major subset of innate pattern recognition receptors, scavenger receptors are mainly expressed on myeloid cells and function in a wide range of biological processes, such as endocytosis, adhesion, lipid transport, antigen presentation, and pathogen clearance. In addition to playing a crucial role in maintenance of host homeostasis, scavenger receptors have been implicated in the pathogenesis of a number of diseases, e.g., atherosclerosis, neurodegeneration, or metabolic disorders. Emerging evidence has begun to reveal these receptor molecules as important regulators of tumor behavior and host immune responses to cancer. This review summarizes our current understanding on the newly identified, distinct functions of scavenger receptors in cancer biology and immunology. The potential of scavenger receptors as diagnostic biomarkers and novel targets for therapeutic interventions to treat malignancies is also highlighted. PMID:26216637

Fisetin Protects DNA Against Oxidative Damage and Its Possible Mechanism

PubMed Central

Wang, Tingting; Lin, Huajuan; Tu, Qian; Liu, Jingjing; Li, Xican

2016-01-01

Purpose: The paper tries to assess the protective effect of fisetin against •OH-induced DNA damage, then to investigate the possible mechanism. Methods: The protective effect was evaluated based on the content of malondialdehyde (MDA). The possible mechanism was analyzed using various antioxidant methods in vitro, including •OH scavenging (deoxyribose degradation), •O2- scavenging (pyrogallol autoxidation), DPPH• scavenging, ABTS•+ scavenging, and Cu2+-reducing power assays. Results: Fisetin increased dose-dependently its protective percentages against •OH-induced DNA damage (IC50 value =1535.00±29.60 µM). It also increased its radical-scavenging percentages in a dose-dependent manner in various antioxidants assays. Its IC50 values in •OH scavenging, •O2- scavenging, DPPH• scavenging, ABTS•+ scavenging, and Cu2+-reducing power assays, were 47.41±4.50 µM, 34.05±0.87 µM, 9.69±0.53 µM, 2.43±0.14 µM, and 1.49±0.16 µM, respectively. Conclusion: Fisetin can effectively protect DNA against •OH-induced oxidative damage possibly via reactive oxygen species (ROS) scavenging approach, which is assumed to be hydrogen atom (H•) and/or single electron (e) donation (HAT/SET) pathways. In the HAT pathway, the 3’,4’-dihydroxyl moiety in B ring of fisetin is thought to play an important role, because it can be ultimately oxidized to a stable ortho-benzoquinone form. PMID:27478791

Mechanism of Action of Sulforaphane as a Superoxide Radical Anion and Hydrogen Peroxide Scavenger by Double Hydrogen Transfer: A Model for Iron Superoxide Dismutase.

PubMed

Prasad, Ajit Kumar; Mishra, P C

2015-06-25

The mechanism of action of sulforaphane as a scavenger of superoxide radical anion (O2(•-)) and hydrogen peroxide (H2O2) was investigated using density functional theory (DFT) in both gas phase and aqueous media. Iron superoxide dismutase (Fe-SOD) involved in scavenging superoxide radical anion from biological media was modeled by a complex consisting of the ferric ion (Fe(3+)) attached to three histidine rings. Reactions related to scavenging of superoxide radical anion by sulforaphane were studied using DFT in the presence and absence of Fe-SOD represented by this model in both gas phase and aqueous media. The scavenging action of sulforaphane toward both superoxide radical anion and hydrogen peroxide was found to involve the unusual mechanism of double hydrogen transfer. It was found that sulforaphane alone, without Fe-SOD, cannot scavenge superoxide radical anion in gas phase or aqueous media efficiently as the corresponding reaction barriers are very high. However, in the presence of Fe-SOD represented by the above-mentioned model, the scavenging reactions become barrierless, and so sulforaphane scavenges superoxide radical anion by converting it to hydrogen peroxide efficiently. Further, sulforaphane was found to scavenge hydrogen peroxide also very efficiently by converting it into water. Thus, the mechanism of action of sulforaphane as an excellent antioxidant has been unravelled.

Antioxidant and analgesic activities of turpentine of Pinus nigra Arn. subsp. pallsiana (Lamb.) Holmboe.

PubMed

Gülçin, Ilhami; Büyükokuroglu, M Emin; Oktay, Münir; Küfrevioglu, O Irfan

2003-05-01

The aim of this study is to examine possible antioxidant and analgesic activities of turpentine exudes from Pinus nigra Arn. subsp. pallsiana (Lamb.) Holmboe (TPN). Total antioxidant activity, reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities were studied. The total antioxidant activity increased with the increasing amount of extracts (100, 300, and 500 microg) added to linoleic acid emulsion. All of the doses of TPN showed higher antioxidant activity than alpha-tocopherol. The samples showed 49, 70, and 91% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, the 300 microg of alpha-tocopherol showed 40% inhibition on peroxidation of linoleic acid emulsion. There is correlation between antioxidant activity and the reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities. Like antioxidant activity, the reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities of TPN depending on concentration and increasing with increased concentration of TPN. These properties may be the major reasons for the inhibition of lipid peroxidation. The results obtained in the present study indicate that the TPN has a potential source of natural antioxidant. In addition, analgesic effect of TPN was investigated in present study and TPN had strong analgesic effect. The analgesic effect of TPN compared with metamizol as a standard analgesic compound.

Spectroscopic studies on the antioxidant activity of ellagic acid

NASA Astrophysics Data System (ADS)

Kilic, Ismail; Yeşiloğlu, Yeşim; Bayrak, Yüksel

2014-09-01

Ellagic acid (EA, C14H6O8) is a natural dietary polyphenol whose benefits in a variety of diseases shown in epidemiological and experimental studies involve anti-inflammation, anti-proliferation, anti-angiogenesis, anticarcinogenesis and anti-oxidation properties. In vitro radical scavenging and antioxidant capacity of EA were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. EA inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), α-tocopherol and ascorbic acid displayed 69.8%, 66.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, EA had an effective DPPH• scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that EA can be used in the pharmacological, food industry and medicine because of these properties.

Spectroscopic studies on the antioxidant activity of p-coumaric acid

NASA Astrophysics Data System (ADS)

Kiliç, Ismail; Yeşiloğlu, Yeşim

2013-11-01

p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2‧-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe2+) chelating activity and ferric ions (Fe3+) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45 μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPHrad scavenging, ABTSrad + scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe3+) reducing power and ferrous ions (Fe2+) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties.

Role of Free Radicals/Reactive Oxygen Species in MeHg Photodegradation: Importance of Utilizing Appropriate Scavengers.

PubMed

Han, Xiaoxiao; Li, Yanbin; Li, Dan; Liu, Chang

2017-04-04

A variety of free radicals (FR)/reactive oxygen species (ROS) have been proposed to dominate methylmercury (MeHg) photodegradation, primarily based on the results of FR/ROS scavenger addition experiments. However, in addition to eliminating FR/ROS, the added scavengers may also affect the experimental results by altering some water chemical properties, resulting in a misleading assessment of the importance of FR/ROS. In this study, 20 common FR/ROS scavengers were evaluated in terms of their influence on light absorbance, pH, MeHg analysis, MeHg-dissolved organic matter (DOM) complexation, and the scavenger-induced degradation of MeHg. Only nine scavengers were identified to be appropriate for investigating MeHg photodegradation. By utilizing these appropriate scavengers, direct photodegradation of MeHg-DOM complexes was found to be the major pathway of MeHg photodegradation in Laoshan Reservoir water and Stone Old Beach seawater. In contrast, MeHg photodegradation in Ink River water primarily occurs through both ·OH and 3 DOM* mediated indirect pathways and direct photodegradation of MeHg-DOM complexes. The diverse pathways of MeHg photodegradation in the tested water may be due to differences in water chemical properties. A severe overestimation of the role of FR/ROS was observed when several improper but commonly used scavengers were adopted, highlighting the necessity of utilizing appropriate scavengers.

Shepherds' local knowledge and scientific data on the scavenging ecosystem service: Insights for conservation.

PubMed

Morales-Reyes, Zebensui; Martín-López, Berta; Moleón, Marcos; Mateo-Tomás, Patricia; Olea, Pedro P; Arrondo, Eneko; Donázar, José A; Sánchez-Zapata, José A

2018-05-05

Integrating indigenous and local knowledge (ILK) and scientific knowledge (SK) in the evaluation of ecosystem services has been recommended by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. We examined the similarities and contradictions between shepherds' ILK and SK on the scavenging service provided by vertebrates in Spain. We conducted 73 face-to-face surveys with shepherds to evaluate their ILK. We collected scientific information on 20 scavenger species by monitoring the consumption of 45 livestock carcasses with camera traps. We found a high consistency between ILK and SK regarding the provision of the scavenging service by vertebrates, which was also consistent over the range of shepherd ages and experience. Our findings support the importance of ILK held by shepherds to better understand and to collect information on the scavenging service, particularly at the species level. The integration of ILK and SK into the management strategies of scavengers can benefit the conservation of globally endangered scavengers and the ecosystem services they provide.

Some dinophycean red tide plankton species generate a superoxide scavenging substance.

PubMed

Sato, Emiko; Niwano, Yoshimi; Matsuyama, Yukihiko; Kim, Daekyung; Nakashima, Takuji; Oda, Tatsuya; Kohno, Masahiro

2007-03-01

Recent studies indicate that some raphidophycean red tide flagellates produce substances able to scavenge superoxide, whereas there have been no reports on superoxide scavenger production by dinophycean red tide flagellates. In this study, we examined the superoxide-scavenging activity of aqueous extracts from dinophycean red tide flagellates, Gymnodinium spp., Scrippsiella trochoidea, and Karenia sp., by a luminol analog L-012-dependent chemiluminescence (CL) method and an electron spin resonance (ESR)-spin trapping method, and compared the activity to that of raphidophycean red tide flagellates, Chattonella spp., Heterosigma akashiwo, and Fibrocapsa japonica. In the experiment applying the L-012-dependent CL method, only the aqueous extracts from raphidophycean red tide flagellates showed superoxide-scavenging activity. On the other hand, applying the ESR-spin trapping method, we found that the aqueous extracts from dinophycean red tide flagellates also showed superoxide-scavenging activity. This is the first report on the production of a superoxide-scavenger by dinophycean red tide flagellates.

Applying Knowledge of Species-Typical Scavenging Behavior to the Search and Recovery of Mammalian Skeletal Remains.

PubMed

Young, Alexandria; Stillman, Richard; Smith, Martin J; Korstjens, Amanda H

2016-03-01

Forensic investigations involving animal scavenging of human remains require a physical search of the scene and surrounding areas. However, there is currently no standard procedure in the U.K. for physical searches of scavenged human remains. The Winthrop and grid search methods used by police specialist searchers for scavenged remains were examined through the use of mock red fox (Vulpes vulpes) scatter scenes. Forty-two police specialist searchers from two different regions within the U.K. were divided between those briefed and not briefed with fox-typical scavenging information. Briefing searchers with scavenging information significantly affected the recovery of scattered bones (χ(2) = 11.45, df = 1, p = 0.001). Searchers briefed with scavenging information were 2.05 times more likely to recover bones. Adaptions to search methods used by searchers were evident on a regional level, such that searchers more accustom to a peri-urban to rural region recovered a higher percentage of scattered bones (58.33%, n = 84). © 2015 American Academy of Forensic Sciences.

Effect of concentration and molecular weight of chitosan and its derivative on the free radical scavenging ability.

PubMed

Li, Huili; Xu, Qing; Chen, Yun; Wan, Ajun

2014-03-01

Chitosan is a biodegradable and biocompatible natural scaffold material, which has numerous applications in biomedical sciences. In this study, the in vitro antioxidant activity of chitosan scaffold material was investigated by the chemiluminescence signal generated from the hydroxyl radical (•OH) scavenging assay. The scavenging mechanism was also discussed. The results indicated that the free radical scavenging ability of chitosan scaffold material significantly depends on the chitosan concentration and shows interesting kinetic change. Within the experimental concentration range, the optimal concentration of chitosan was 0.2 mg/mL. The molecular weight of chitosan also attributed to the free radical scavenging ability. Comparison between chitosan and its derivative found that carboxymethyl chitosan possessed higher scavenging ability. Copyright © 2013 Society of Plastics Engineers.

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)

Could Tyrannosaurus rex have been a scavenger rather than a predator? An energetics approach.

PubMed

Ruxton, Graeme D; Houston, David C

2003-04-07

Arguments on whether Tyrannosaurus rex was likely to have been an active predator or a scavenger have been based on evidence from jaw morphology and/or dentition. Here, we adopt an entirely novel approach, using energetic arguments to estimate the minimum productivity that would be required for an ecosystem to support a scavenger of the size of T. rex. We argue that an ecosystem as productive as the current Serengeti would provide sufficient carrion for such a scavenger. Hence, T. rex need not have been an active predator and could have found sufficient food purely by scavenging.

Effects of vulture exclusion on carrion consumption by facultative scavengers.

PubMed

Hill, Jacob E; DeVault, Travis L; Beasley, James C; Rhodes, Olin E; Belant, Jerrold L

2018-03-01

Vultures provide an essential ecosystem service through removal of carrion, but globally, many populations are collapsing and several species are threatened with extinction. Widespread declines in vulture populations could increase the availability of carrion to other organisms, but the ways facultative scavengers might respond to this increase have not been thoroughly explored. We aimed to determine whether facultative scavengers increase carrion consumption in the absence of vulture competition and whether they are capable of functionally replacing vultures in the removal of carrion biomass from the landscape. We experimentally excluded 65 rabbit carcasses from vultures during daylight hours and placed an additional 65 carcasses that were accessible to vultures in forested habitat in South Carolina, USA during summer (June-August). We used motion-activated cameras to compare carrion use by facultative scavenging species between the experimental and control carcasses. Scavenging by facultative scavengers did not increase in the absence of competition with vultures. We found no difference in scavenger presence between control carcasses and those from which vultures were excluded. Eighty percent of carcasses from which vultures were excluded were not scavenged by vertebrates, compared to 5% of carcasses that were accessible to vultures. At the end of the 7-day trials, there was a 10.1-fold increase in the number of experimental carcasses that were not fully scavenged compared to controls. Facultative scavengers did not functionally replace vultures during summer in our study. This finding may have been influenced by the time of the year in which the study took place, the duration of the trials, and the spacing of carcass sites. Our results suggest that under the warm and humid conditions of our study, facultative scavengers would not compensate for loss of vultures. Carcasses would persist longer in the environment and consumption of carrion would likely shift from vertebrates to decomposers. Such changes could have substantial implications for disease transmission, nutrient cycling, and ecosystem functioning.

Biomass Flow and Scavengers Use of Carcasses after Re-Colonization of an Apex Predator

PubMed Central

Wikenros, Camilla; Sand, Håkan; Ahlqvist, Per; Liberg, Olof

2013-01-01

Background Reestablishment of apex predators influences the availability and distribution of biomass for scavengers and can therefore be an important agent for structuring species communities. We studied how the re-colonization of the Scandinavian Peninsula by wolves (Canis lupus) affected the amount and temporal variation in use of moose (Alces alces) carcasses. Methodology/Principal Findings We compared the availability of biomass from remains at wolf kills with those killed by hunters, vehicle collisions and natural death. Movement-triggered cameras monitored patterns of use on wolf kills and remains from hunter harvest by scavengers (n = 15 276) in relation to time of year, available carcass biomass, time since the death of the moose and presence of wolves. Remains from hunter harvest were the largest food source for scavengers both within wolf territories (57%) and in areas without wolves (81%). The total annual biomass available were similar in areas with (25 648 kg) and without (24 289 kg) wolves. Presence of wolves lowered the peak biomass available from hunter harvest in October (20%) and increased biomass available during December to August (38–324% per month). The probability of scavengers being present decreased faster with time at remains from hunter harvest compared to wolf kills and both the probability of being present and the number of visits by scavengers to wolf kills increased as the amount of biomass available on the carcass increased. Conclusions/Significance Wolves reduced the seasonal variation of biomass from moose carcasses and most important increased it during spring. Scavengers also visited wolf kills most frequently during spring when most scavenging species have young, which may lead to an increase in survival and/or reproductive success of scavengers within wolf territories. This applies both for abundant scavenging species that were the most frequent visitors at wolf kills and threatened scavengers with lower visit frequency. PMID:24194881

Spectroscopic studies on the antioxidant activity of p-coumaric acid.

PubMed

Kiliç, Ismail; Yeşiloğlu, Yeşim

2013-11-01

p-coumaric acid (4-hydroxycinnamic acid), a phenolic acid, is a hydroxyl derivative of cinnamic acid. It decreases low density lipoprotein (LDL) peroxidation and reduces the risk of stomach cancer. In vitro radical scavenging and antioxidant capacity of p-coumaric acid were clarified using different analytical methodologies such as total antioxidant activity determination by ferric thiocyanate, hydrogen peroxide scavenging, 1,1-diphenyl-2-picryl-hydrazyl free radical (DPPH) scavenging, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging activity and superoxide anion radical scavenging, ferrous ions (Fe(2+)) chelating activity and ferric ions (Fe(3+)) reducing ability. p-Coumaric acid inhibited 71.2% lipid peroxidation of a linoleic acid emulsion at 45μg/mL concentration. On the other hand, butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), α-tocopherol and ascorbic acid displayed 66.8%, 69.8%, 64.5% and 59.7% inhibition on the peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, p-coumaric acid had an effective DPPH scavenging, ABTS(+) scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, ferric ions (Fe(3+)) reducing power and ferrous ions (Fe(2+)) chelating activities. Also, those various antioxidant activities were compared to BHA, BHT, α-tocopherol and ascorbic acid as references antioxidant compounds. These results suggested that p-coumaric acid can be used in the pharmacological and food industry because of these properties. Copyright © 2013 Elsevier B.V. All rights reserved.

Scavenging by spiders (Araneae) and its relationship to pest management of the brown recluse spider.

PubMed

Vetter, Richard S

2011-06-01

Experiments reported in Sandidge (2003; Nature 426: 30) indicated that the brown recluse spider, Loxosceles reclusa Gertsch & Mulaik, preferred to scavenge dead prey over live prey and that the spiders were not detrimentally affected when fed insecticide-killed crickets. Extrapolations made in subsequent media coverage disseminating the results of this research made counter-intuitive statements that pesticide treatment in houses would increase brown recluse populations in homes. This information was presented as if the scavenging behavior was specialized in the brown recluse; however, it was more likely that this behavior has not been well studied in other species. To provide a comparison, the current laboratory study examined the likelihood of non-Loxosceles spiders to scavenge dead prey. Of 100 non-Loxosceles spiders that were tested (from 11 families, 24 genera, and at least 29 species from a variety of spider hunting guilds), 99 scavenged dead crickets when offered in petri dishes. Some of the spiders were webspinners in which real-world scavenging of dead prey is virtually impossible, yet they scavenge when given the opportunity. Therefore, scavenging is a flexible opportunistic predatory behavior that is spread across a variety of taxa and is not a unique behavior in brown recluses. These findings are discussed in relation to pest management practices.

CBLB502, an agonist of Toll-like receptor 5, has antioxidant and scavenging free radicals activities in vitro.

PubMed

Li, Weiguang; Ge, Changhui; Yang, Liu; Wang, Ruixue; Lu, Yiming; Gao, Yan; Li, Zhihui; Wu, Yonghong; Zheng, Xiaofei; Wang, Zhaoyan; Zhang, Chenggang

2016-01-01

The bacterial protein flagellin is the known agonist of Toll-like receptor 5 (TLR5). It has been reported that CBLB502, a novel agonist of TLR5 derived from Salmonella flagellin, could reduce radiation toxicity in mouse and primate models, protect mice from dermatitis and oral mucositis caused by radiation, inhibit acute renal ischemic failure, and inhibit the growth of A549 lung cancer cell. The property of CBLB502 is able to bind to TLR5 and activates NF-κB signaling. In this study, we investigated the antioxidant potential and free radicals scavenging properties of CBLB502 in vitro. Interestingly, we found that CBLB502 has a direct and distinct antioxidant capacity and can efficiently scavenge a variety of free radicals, including superoxide anion, hydroxyl radical, and ABTS cation (ABTS(+)). Through wave scanning and kinetic evaluation of scavenging ABTS(+), we found that the ABTS(+) scavenging process of CBLB502 is relatively slow, and the ABTS(+) scavenging activity of CBLB502 has a consistently kinetics characteristics. In conclusion, our results suggested that CBLB502 has antioxidant and scavenging free radicals activities in vitro. It is implied that CBLB502 might partially promote the beneficial protective effect through its scavenging free radicals. Copyright © 2015. Published by Elsevier B.V.

Dielectric polymer: scavenging energy from human motion

NASA Astrophysics Data System (ADS)

Jean-Mistral, Claire; Basrour, Skandar; Chaillout, Jean-Jacques

2008-03-01

More and more sensors are embedded in human body for medical applications, for sport. The short lifetime of the batteries, available on the market, reveals a real problem of autonomy of these systems. A promising alternative is to scavenge the ambient energy such as the mechanical one. Up to now, few scavenging structures have operating frequencies compatible with ambient one. And, most of the developed structures are rigid and use vibration as mechanical source. For these reasons, we developed a scavenger that operates in a large frequency spectrum from quasi-static to dynamic range. This generator is fully flexible, light and does not hamper the human motion. Thus, we report in this paper an analytical model for dielectric generator with news electrical and mechanical characterization, and the development of an innovating application: scavenging energy from human motion. The generator is located on the knee and design to scavenge 0.1mJ per scavenging cycle at a frequency of 1Hz, enough to supply a low consumption system and with a poling voltage as low as possible to facilitate the power management. Our first prototype is a membrane with an area of 5*3cm and 31µm in thickness which scavenge 0.1mJ under 170V at constant charge Q.

Study on wet scavenging of atmospheric pollutants in south Brazil

NASA Astrophysics Data System (ADS)

Wiegand, Flavio; Pereira, Felipe Norte; Teixeira, Elba Calesso

2011-09-01

The present paper presents the study of in-cloud and below-cloud SO 2 and SO 42-scavenging processes by applying numerical models in the Candiota region, located in the state of Rio Grande do Sul, South Brazil. The BRAMS (Brazilian Regional Atmospheric Modeling System) model was applied to simulate the vertical structure of the clouds, and the B.V.2 (Below-Cloud Beheng Version 2) scavenging model was applied to simulate in-cloud and below-cloud scavenging processes of the pollutants SO 2 and SO 42-. Five events in 2004 were selected for this study and were sampled at the Candiota Airport station. The concentrations of SO 2 and SO 42- sampled in the air and the simulated meteorological parameters of rainfall episodes were used as input data in the B.V.2, which simulates raindrop interactions associated with the scavenging process. Results for the Candiota region showed that in-cloud scavenging processes were more significant than below-cloud scavenging processes for two of the five events studied, with a contribution of approximately 90-100% of SO 2 and SO 42- concentrations in rainwater. A few adjustments to the original version of B.V.2 were made to allow simulation of scavenging processes in several types of clouds, not only cumulus humilis and cumulus congestus.

Potent antioxidant and radical-scavenging activities of traditional Japanese cereal grains.

PubMed

Higashi-Okai, Kiyoka; Ishida, Emi; Nakamura, Yumiko; Fujiwara, Satomi; Okai, Yasuji

2008-12-01

To estimate the preventive potential of Japanese traditional cereals against oxygen radical-related chronic diseases such as cardiovascular diseases and diabetes, antioxidant and radical-scavenging activities in the extracts of five Japanese traditional cereal grains were analyzed by using an assay system of lipid peroxidation and a radical compound, 1,1-diphenyl-2-picrylhydrazyl (DPPH). DPPH radical-scavenging activities in the extracts of Japanese cereal grains were divided into two groups. One group including Japanese sorghum, black rice and red rice showed strong radical-scavenging activities, but the other group including Japanese barnyard millet and foxtail millet did not exhibit significant radical-scavenging activities. The DPPH radical-scavenging activities of these extracts were closely correlated to the contents of phenolic compound in the extracts, but not to the sugar or protein content in the extracts. In contrast, all the methanol and water extracts of the cereal grains caused significant antioxidant activities against hydroperoxide generation in the peroxidation of linoleic acid, in which the water extracts of these cereal grains caused much higher antioxidant activities than the methanol extracts of the same cereals. These results suggest that Japanese traditional cereals contain qualitatively different principles associated with antioxidant and radical-scavenging activities, and possible principles responsible for the antioxidant and radical-scavenging activities in the cereal grains are discussed.

Could Tyrannosaurus rex have been a scavenger rather than a predator? An energetics approach.

PubMed Central

Ruxton, Graeme D; Houston, David C

2003-01-01

Arguments on whether Tyrannosaurus rex was likely to have been an active predator or a scavenger have been based on evidence from jaw morphology and/or dentition. Here, we adopt an entirely novel approach, using energetic arguments to estimate the minimum productivity that would be required for an ecosystem to support a scavenger of the size of T. rex. We argue that an ecosystem as productive as the current Serengeti would provide sufficient carrion for such a scavenger. Hence, T. rex need not have been an active predator and could have found sufficient food purely by scavenging. PMID:12713747

The evaluation of potential limonene scavengers

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 prolongedmore » 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.« less

Smooth Interfacial Scavenging for Resistive Switching Oxide via the Formation of Highly Uniform Layers of Amorphous TaOx.

PubMed

Tsurumaki-Fukuchi, Atsushi; Nakagawa, Ryosuke; Arita, Masashi; Takahashi, Yasuo

2018-02-14

We demonstrate that the inclusion of a Ta interfacial layer is a remarkably effective strategy for forming interfacial oxygen defects at metal/oxide junctions. The insertion of an interfacial layer of a reactive metal, that is, a "scavenging" layer, has been recently proposed as a way to create a high concentration of oxygen defects at an interface in redox-based resistive switching devices, and growing interest has been given to the underlying mechanism. Through structural and chemical analyses of Pt/metal/SrTiO 3 /Pt structures, we reveal that the rate and amount of oxygen scavenging are not directly determined by the formation free energies in the oxidation reactions of the scavenging metal and unveil the important roles of oxygen diffusibility. Active oxygen scavenging and highly uniform oxidation via scavenging are revealed for a Ta interfacial layer with high oxygen diffusibility. In addition, the Ta scavenging layer is shown to exhibit a highly uniform structure and to form a very flat interface with SrTiO 3 , which are advantageous for the fabrication of a steep metal/oxide contact.

ROS evaluation for a series of CNTs and their derivatives using an ESR method with DMPO.

PubMed

Tsuruoka, S; Takeuchi, K; Koyama, K; Noguchi, T; Endo, M; Tristan, F; Terrones, M; Matsumoto, H; Saito, N; Usui, Y; Porter, D W; Castranova, V

Carbon nanotubes (CNTs) are important materials in advanced industries. It is a concern that pulmonary exposure to CNTs may induce carcinogenic responses. It has been recently reported that CNTs scavenge ROS though non-carbon fibers generate ROS. A comprehensive evaluation of ROS scavenging using various kinds of CNTs has not been demonstrated well. The present work specifically investigates ROS scavenging capabilities with a series of CNTs and their derivatives that were physically treated, and with the number of commercially available CNTs. CNT concentrations were controlled at 0.2 through 0.6 wt%. The ROS scavenging rate was measured by ESR with DMPO. Interestingly, the ROS scavenging rate was not only influenced by physical treatments, but was also dependent on individual manufacturing methods. Ratio of CNTs to DMPO/ hydrogen peroxide is a key parameter to obtain appropriate ROS quenching results for comparison of CNTs. The present results suggest that dangling bonds are not a sole factor for scavenging, and electron transfer on the CNT surface is not clearly determined to be the sole mechanism to explain ROS scavenging.

Evaluation of phenolic contents and antioxidant activity of various solvent extracts of Sonchus asper (L.) Hill

PubMed Central

2012-01-01

Background Sonchus asper (SA) is traditionally used for the treatment of various ailments associated with liver, lungs and kidneys. This study was aimed to investigate the therapeutic potential of nonpolar (hexane, SAHE; ethyl acetate, SAEE and chloroform, SACE) and polar (methanol, SAME) crude extracts of the whole plant. Methods To achieve these goals, several parameters including free-radical (DPPH•, ABTS•+, H2O2 and •OH) scavenging, iron chelating activity, scavenging of superoxide radicals, total flavonoids and total phenolic content (TPC) were examined. Results The SA extracts presented a remarkable capacity to scavenge all the tested reactive species with IC50 values being found at the μg ⁄ ml level. The SAME was shown to have the highest TPCs while lowest IC50 values for the DPPH•, ABTS•+ radical scavenging capacities and iron chelating scavenging efficiency, moreover, SAME had best activities in scavenging of superoxide radicals and hydrogen peroxide as well as potently scavenged the hydroxyl radicals. Conclusion These results suggest the potential of S. asper as a medicine against free-radical-associated oxidative damage. PMID:22305477

Antioxidant activity of methanol extract of Helichrysum foetidum Moench.

PubMed

Tirillini, Bruno; Menghini, Luigi; Leporini, Lidia; Scanu, Nadia; Marino, Stefania; Pintore, Giorgio

2013-01-01

Methanol extract of Helichrysum foetidum Moench (Asteraceae) was investigated for antioxidative properties. The antioxidant activities were investigated by 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging, ß-carotene/linoleic acid assay, scavenging of hydrogen peroxide (HRPO test), superoxide anion scavenging (S.A.S. test) and hypochlorous acid scavenging (taurine test). The antioxidant activity was reported as IC50 and reveals Trolox-like antioxidative effects.

Scavenging and recombination kinetics in a radiation spur: The successive ordered scavenging events

NASA Astrophysics Data System (ADS)

Al-Samra, Eyad H.; Green, Nicholas J. B.

2018-03-01

This study describes stochastic models to investigate the successive ordered scavenging events in a spur of four radicals, a model system based on a radiation spur. Three simulation models have been developed to obtain the probabilities of the ordered scavenging events: (i) a Monte Carlo random flight (RF) model, (ii) hybrid simulations in which the reaction rate coefficient is used to generate scavenging times for the radicals and (iii) the independent reaction times (IRT) method. The results of these simulations are found to be in agreement with one another. In addition, a detailed master equation treatment is also presented, and used to extract simulated rate coefficients of the ordered scavenging reactions from the RF simulations. These rate coefficients are transient, the rate coefficients obtained for subsequent reactions are effectively equal, and in reasonable agreement with the simple correction for competition effects that has recently been proposed.

Melatonin and its precursors scavenge nitric oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Noda, Y.; Mori, A.; Liburdy, R.

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.more » Tryptophan, which has neither a methoxy nor a hydroxyl group in the 5-position, exhibited the least NO scavenging activity.« less

Deciphering Scavenging Propensity Among Arthropod Predators.

USDA-ARS?s Scientific Manuscript database

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 ...

Electrochemically reduced water exerts superior reactive oxygen species scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water

PubMed Central

Hamasaki, Takeki; Harada, Gakuro; Nakamichi, Noboru; Kabayama, Shigeru; Teruya, Kiichiro; Fugetsu, Bunshi; Gong, Wei; Sakata, Ichiro; Shirahata, Sanetaka

2017-01-01

Electrochemically reduced water (ERW) is produced near a cathode during electrolysis and exhibits an alkaline pH, contains richly dissolved hydrogen, and contains a small amount of platinum nanoparticles. ERW has reactive oxygen species (ROS)-scavenging activity and recent studies demonstrated that hydrogen-dissolved water exhibits ROS-scavenging activity. Thus, the antioxidative capacity of ERW is postulated to be dependent on the presence of hydrogen levels; however, there is no report verifying the role of dissolved hydrogen in ERW. In this report, we clarify whether the responsive factor for antioxidative activity in ERW is dissolved hydrogen. The intracellular ROS scavenging activity of ERW and hydrogen-dissolved water was tested by both fluorescent stain method and immuno spin trapping assay. We confirm that ERW possessed electrolysis intensity-dependent intracellular ROS-scavenging activity, and ERW exerts significantly superior ROS-scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water. ERW retained its ROS-scavenging activity after removal of dissolved hydrogen, but lost its activity when autoclaved. An oxygen radical absorbance capacity assay, the 2,2-diphenyl-1-picrylhydrazyl assay and chemiluminescence assay could not detect radical-scavenging activity in both ERW and hydrogen-dissolved water. These results indicate that ERW contains electrolysis-dependent hydrogen and an additional antioxidative factor predicted to be platinum nanoparticles. PMID:28182635

Electrochemically reduced water exerts superior reactive oxygen species scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water.

PubMed

Hamasaki, Takeki; Harada, Gakuro; Nakamichi, Noboru; Kabayama, Shigeru; Teruya, Kiichiro; Fugetsu, Bunshi; Gong, Wei; Sakata, Ichiro; Shirahata, Sanetaka

2017-01-01

Electrochemically reduced water (ERW) is produced near a cathode during electrolysis and exhibits an alkaline pH, contains richly dissolved hydrogen, and contains a small amount of platinum nanoparticles. ERW has reactive oxygen species (ROS)-scavenging activity and recent studies demonstrated that hydrogen-dissolved water exhibits ROS-scavenging activity. Thus, the antioxidative capacity of ERW is postulated to be dependent on the presence of hydrogen levels; however, there is no report verifying the role of dissolved hydrogen in ERW. In this report, we clarify whether the responsive factor for antioxidative activity in ERW is dissolved hydrogen. The intracellular ROS scavenging activity of ERW and hydrogen-dissolved water was tested by both fluorescent stain method and immuno spin trapping assay. We confirm that ERW possessed electrolysis intensity-dependent intracellular ROS-scavenging activity, and ERW exerts significantly superior ROS-scavenging activity in HT1080 cells than the equivalent level of hydrogen-dissolved water. ERW retained its ROS-scavenging activity after removal of dissolved hydrogen, but lost its activity when autoclaved. An oxygen radical absorbance capacity assay, the 2,2-diphenyl-1-picrylhydrazyl assay and chemiluminescence assay could not detect radical-scavenging activity in both ERW and hydrogen-dissolved water. These results indicate that ERW contains electrolysis-dependent hydrogen and an additional antioxidative factor predicted to be platinum nanoparticles.

An update on the use of benzoate, phenylacetate and phenylbutyrate ammonia scavengers for interrogating and modifying liver nitrogen metabolism and its implications in urea cycle disorders and liver disease

PubMed Central

de las Heras, Javier; Aldámiz-Echevarría, Luis; Martínez-Chantar, María-Luz; Delgado, Teresa C.

2017-01-01

Introduction Ammonia-scavenging drugs, benzoate and phenylacetate (PA)/phenylbutyrate (PB), modulate hepatic nitrogen metabolism mainly by providing alternative pathways for nitrogen disposal. Areas Covered We review the major findings and potential novel applications of ammonia-scavenging drugs, focusing on urea cycle disorders and liver disease. Expert Opinion For over 40 years, ammonia-scavenging drugs have been used in the treatment of urea cycle disorders. Recently, the use of these compounds has been advocated in acute liver failure and cirrhosis for reducing hyperammonemic-induced hepatic encephalopathy. The efficacy and mechanisms underlying the antitumor effects of these ammonia-scavenging drugs in liver cancer are more controversial and are discussed in the review. Overall, as ammonia-scavenging drugs are usually safe and well tolerated among cancer patients, further studies should be instigated to explore the role of these drugs in liver cancer. Considering the relevance of glutamine metabolism to the progression and resolution of liver disease, we propose that ammonia-scavenging drugs might also be used to non-invasively probe liver glutamine metabolism in vivo. Finally, novel derivatives of classical ammonia-scavenging drugs with fewer and less severe adverse effects are currently being developed and used in clinical trials for the treatment of acute liver failure and cirrhosis. PMID:27860485

An update on the use of benzoate, phenylacetate and phenylbutyrate ammonia scavengers for interrogating and modifying liver nitrogen metabolism and its implications in urea cycle disorders and liver disease.

PubMed

De Las Heras, Javier; Aldámiz-Echevarría, Luis; Martínez-Chantar, María-Luz; Delgado, Teresa C

2017-04-01

Ammonia-scavenging drugs, benzoate and phenylacetate (PA)/phenylbutyrate (PB), modulate hepatic nitrogen metabolism mainly by providing alternative pathways for nitrogen disposal. Areas covered: We review the major findings and potential novel applications of ammonia-scavenging drugs, focusing on urea cycle disorders and liver disease. Expert opinion: For over 40 years, ammonia-scavenging drugs have been used in the treatment of urea cycle disorders. Recently, the use of these compounds has been advocated in acute liver failure and cirrhosis for reducing hyperammonemic-induced hepatic encephalopathy. The efficacy and mechanisms underlying the antitumor effects of these ammonia-scavenging drugs in liver cancer are more controversial and are discussed in the review. Overall, as ammonia-scavenging drugs are usually safe and well tolerated among cancer patients, further studies should be instigated to explore the role of these drugs in liver cancer. Considering the relevance of glutamine metabolism to the progression and resolution of liver disease, we propose that ammonia-scavenging drugs might also be used to non-invasively probe liver glutamine metabolism in vivo. Finally, novel derivatives of classical ammonia-scavenging drugs with fewer and less severe adverse effects are currently being developed and used in clinical trials for the treatment of acute liver failure and cirrhosis.

Fog scavenging of organic and inorganic aerosol in the Po Valley

NASA Astrophysics Data System (ADS)

Gilardoni, S.; Massoli, P.; Giulianelli, L.; Rinaldi, M.; Paglione, M.; Pollini, F.; Lanconelli, C.; Poluzzi, V.; Carbone, S.; Hillamo, R.; Russell, L. M.; Facchini, M. C.; Fuzzi, S.

2014-07-01

The interaction of aerosol with atmospheric water affects the processing and wet removal of atmospheric particles. Understanding such interaction is mandatory to improve model description of aerosol lifetime and ageing. We analyzed the aerosol-water interaction at high relative humidity during fog events in the Po Valley within the framework of the Agenzia Regionale per la Prevenzione e l'Ambiente (ARPA) - Emilia Romagna supersite project. For the first time in this area, the changes in particle chemical composition caused by fog are discussed along with changes in particle microphysics. During the experiment, 14 fog events were observed. The average mass scavenging efficiency was 70% for nitrate, 68% for ammonium, 61% for sulfate, 50% for organics, and 39% for black carbon. After fog formation, the interstitial aerosol was dominated by particles smaller than 200 nm Dva (vacuum aerodynamic diameter) and enriched in carbonaceous aerosol, mainly black carbon and water-insoluble organic aerosol. For each fog event, the size-segregated scavenging efficiency of nitrate and organic aerosol (OA) was calculated by comparing chemical species size distribution before and after fog formation. For both nitrate and OA, the size-segregated scavenging efficiency followed a sigmoidal curve, with values close to zero below 100 nm Dva and close to 1 above 700 nm Dva. OA was able to affect scavenging efficiency of nitrate in particles smaller than 300 nm Dva. A linear correlation between nitrate scavenging and particle hygroscopicity (κ) was observed, indicating that 44-51% of the variability of nitrate scavenging in smaller particles (below 300 nm Dva) was explained by changes in particle chemical composition. The size-segregated scavenging curves of OA followed those of nitrate, suggesting that organic scavenging was controlled by mixing with water-soluble species. In particular, functional group composition and OA elemental analysis indicated that more oxidized OA was scavenged more efficiently than less oxidized OA. Nevertheless, the small variability of organic functional group composition during the experiment did not allow us to discriminate the effect of different organic functionalities on OA scavenging.

Riparian reserves within oil palm plantations conserve logged forest leaf litter ant communities and maintain associated scavenging rates

PubMed Central

Gray, Claudia L; Lewis, Owen T; Chung, Arthur Y C; Fayle, Tom M

2015-01-01

The expansion of oil palm plantations at the expense of tropical forests is causing declines in many species and altering ecosystem functions. Maintaining forest-dependent species and processes in these landscapes may therefore limit the negative impacts of this economically important industry. Protecting riparian vegetation may be one such opportunity; forest buffer strips are commonly protected for hydrological reasons, but can also conserve functionally important taxa and the processes they support. We surveyed leaf litter ant communities within oil palm-dominated landscapes in Sabah, Malaysia, using protein baits. As the scavenging activity of ants influences important ecological characteristics such as nutrient cycling and soil structure, we quantified species-specific rates of bait removal to examine how this process may change across land uses and establish which changes in community structure underlie observed shifts in activity. Riparian reserves had similar ant species richness, community composition and scavenging rates to nearby continuous logged forest. Reserve width and vegetation structure did not affect ant species richness significantly. However, the number of foraging individuals decreased with increasing reserve width, and scavenging rate increased with vegetation complexity. Oil palm ant communities were characterized by significantly lower species richness than logged forest and riparian reserves and also by altered community composition and reduced scavenging rates. Reduced scavenging activity in oil palm was not explained by a reduction in ant species richness, nor by replacement of forest ant species by those with lower per species scavenging rates. There was also no significant effect of land use on the scavenging activity of the forest species that persisted in oil palm. Rather, changes in scavenging activity were best explained by a reduction in the mean rate of bait removal per individual ant across all species in the community. Synthesis and applications. Our results suggest that riparian reserves are comparable to areas of logged forest in terms of ant community composition and ant-mediated scavenging. Hence, in addition to protecting large continuous areas of primary and logged forest, maintaining riparian reserves is a successful strategy for conserving leaf litter ants and their scavenging activities in tropical agricultural landscapes. PMID:25678717

Enhanced protection of PDMS-embedded palladium catalysts by co-embedding of sulphide-scavengers.

PubMed

Comandella, Daniele; Ahn, Min Hyung; Kim, Hojeong; Mackenzie, Katrin

2017-12-01

For Pd-containing hydrodechlorination catalysts, coating with poly(dimethyl siloxane) (PDMS) was proposed earlier as promising protection scheme against poisoning. The PDMS coating can effectively repel non-permeating poisons (such as SO 3 2- ) retaining the hydrodechlorination Pd activity. In the present study, the previously achieved protection efficiency was enhanced by incorporation of sulphide scavengers into the polymer. The embedded scavengers were able to bind permeating non-ionic poisons (such as H 2 S) during their passage through PDMS prior to Pd contact which ensured an extended catalyst lifetime. Three scavenger types forming non-permeable sulphur species from H 2 S - alkaline, oxidative or iron-based compounds - were either incorporated into single-layer coats around individual Pd/Al 2 O 3 particles or into a second layer above Pd-containing PDMS films (Pd-PDMS). Hydrodechlorination and hydrogenation were chosen as model reactions, carried out in batch and continuous-flow reactors. Batch tests with all scavenger-containing catalysts showed extended Pd protection compared to scavenger-free catalysts. Solid alkaline compounds (Ca(OH) 2 , NaOH, CaO) and MnO 2 showed the highest instantaneous scavenger efficiencies (retained Pd activity=30-60%), while iron-based catalysts, such as nano zero-valent iron (nZVI) or ferrocene (FeCp 2 ), proved less efficient (1-10%). When stepwise poisoning was applied, the protection efficiency of iron-based and oxidizing compounds was higher in the long term than that of alkaline solids. Long-term experiments in mixed-flow reactors were performed with selected scavengers, revealing the following trend of protection efficiency: CaO 2 >Ca(OH) 2 >FeCp 2 . Under field-simulating conditions using a fixed-bed reactor, the combination of sulphide pre-oxidation in the water phase by H 2 O 2 and local scavenger-enhanced Pd protection was successful. The oxidizing agent H 2 O 2 does not disturb the Pd-catalysed reduction, while the PDMS-incorporated scavenger considerably extends the catalyst life in the presence of H 2 S. This work demonstrates that the scavenger-based protection strategy is an effective means to increase the resistance of PDMS-embedded Pd against permeating poisons. Copyright © 2017. Published by Elsevier B.V.

Bergenin Content and Free Radical Scavenging Activity of Bergenia Extracts. .

PubMed

Hendrychová, Helena; Martin, Jan; Tůmová, Lenka; Kočevar-Glavač, Nina

2015-07-01

Our research was focused on the evaluation of bergenin content and free radical scavenging activity of extracts prepared from three different species of Bergenia - B. crassifolia (L.) Fritsch., B. ciliata (Haw.) Sternb. and B. x ornata Stein. collected during different seasons. Using an HPLC method, the highest total amount of bergenin was revealed in the leaves of B. x ornata and B. crassifolia (4.9 - 5.1 mg x g(-1)). Free radical scavenging power was determined by two methods--FRAP and NADH. The best free radical scavengers were B. crassifolia (FRAP: 6.7 - 15.9 mg GAE. 100g(-1); NADH: 20.3 - 50.9%) and B. ornata (FRAP: 13.7 - 15.2 mg GAE. 100g(-1); NADH: 29.3 - 31.1%). The lowest content of bergenin and the weakest radical scavenger was B. ciliata (bergenin: 3.1 mg x g(-1); FRAP: 5.5 - 11.0 mg GAE.100g(-1); NADH: 23.2 - 25.6%). The presence of a large percentage of bergenin is responsible for the radical scavenging activity, as shown by the results from the FRAP and NADH assays. Significant, positive correlation was found between bergenin content and radical scavenging activity in both methods.

White sharks (Carcharodon carcharias) scavenging on whales and its potential role in further shaping the ecology of an apex predator.

PubMed

Fallows, Chris; Gallagher, Austin J; Hammerschlag, Neil

2013-01-01

Scavenging, a result of a temporary pulse of resources, occurs in virtually all ecosystems containing carnivores, and is an important energy transfer pathway that can impact ecosystem structure and function, and this ecological significance has largely been considered from a terrestrial standpoint; however, little is known about the role of scavenging in shaping the behavioral ecology of marine species, specifically apex predators. Here we present findings from multiple opportunistic observations of white sharks scavenging on whale carcasses in False Bay, South Africa. Observations of white sharks scavenging over successive days provided evidence of strategic and selective scavenging by this species. Moreover, extended daily observations permitted recordings of unique social, aggregative, and feeding behaviors. We further compare these data against observations of natural predation by sharks on seals in the study area. We discuss these data in relation to environmental conditions, shark social interactions, migration patterns, whale biology, and behaviorally-mediated trophic cascades. While the appearance of a whale carcass is largely a stochastic event, we propose that white shark scavenging on whales may represent an underestimated, yet significant component to the overall foraging ecology of this species, especially as individuals attain sexual maturity.

White Sharks (Carcharodon carcharias) Scavenging on Whales and Its Potential Role in Further Shaping the Ecology of an Apex Predator

PubMed Central

Fallows, Chris; Gallagher, Austin J.; Hammerschlag, Neil

2013-01-01

Scavenging, a result of a temporary pulse of resources, occurs in virtually all ecosystems containing carnivores, and is an important energy transfer pathway that can impact ecosystem structure and function, and this ecological significance has largely been considered from a terrestrial standpoint; however, little is known about the role of scavenging in shaping the behavioral ecology of marine species, specifically apex predators. Here we present findings from multiple opportunistic observations of white sharks scavenging on whale carcasses in False Bay, South Africa. Observations of white sharks scavenging over successive days provided evidence of strategic and selective scavenging by this species. Moreover, extended daily observations permitted recordings of unique social, aggregative, and feeding behaviors. We further compare these data against observations of natural predation by sharks on seals in the study area. We discuss these data in relation to environmental conditions, shark social interactions, migration patterns, whale biology, and behaviorally-mediated trophic cascades. While the appearance of a whale carcass is largely a stochastic event, we propose that white shark scavenging on whales may represent an underestimated, yet significant component to the overall foraging ecology of this species, especially as individuals attain sexual maturity. PMID:23585850

Effect of the chelation of metal cation on the antioxidant activity of chondroitin sulfates.

PubMed

Ajisaka, Katsumi; Oyanagi, Yutaka; Miyazaki, Tatsuo; Suzuki, Yasuhiro

2016-06-01

The antioxidant potencies of chondroitin sulfates (CSs) from shark cartilage, salmon cartilage, bovine trachea, and porcine intestinal mucosa were compared by three representative methods for the measurement of the antioxidant activity; DPPH radical scavenging activity, superoxide radical scavenging activity, and hydroxyl radical scavenging activity. CSs from salmon cartilage and bovine trachea showed higher potency in comparison with CSs from shark cartilage and porcine intestinal mucosa. Next, CS from salmon cartilage chelating with Ca(2+), Mg(2+), Mn(2+), or Zn(2+) were prepared, and their antioxidant potencies were compared. CS chelating with Ca(2+) or Mg(2+) ions showed rather decreased DPPH radical scavenging activity in comparison with CS of H(+) form. In contrast, CS chelating with Ca(2+) or Mg(2+) ion showed remarkably enhanced superoxide radical scavenging activity than CS of H(+) or Na(+) form. Moreover, CS chelating with divalent metal ions, Ca(2+), Mg(2+), Mn(2+), or Zn(2+), showed noticeably higher hydroxyl radical scavenging activity than CS of H(+) or Na(+) form. The present results revealed that the scavenging activities of, at least, superoxide radical and hydroxyl radical were enhanced by the chelation with divalent metal ions.

Preparation of reactive oxygen scavenging peptides from tilapia (Oreochromis niloticus) skin gelatin: optimization using response surface methodology.

PubMed

Zhuang, Yongliang; Sun, Liping

2011-04-01

Gelatin extracted from tilapia skin was hydrolyzed with Properase E. Response surface methodology (RSM) was applied to optimize the hydrolysis condition (temperature [T], enzyme-to-substrate ratio [E/S], pH and reaction time [t]), to obtain the hydrolysate with the highest hydroxyl radical (•OH) scavenging activity. The optimum conditions obtained were T of 44.2 °C, E/S of 2.2%, pH of 9.2, and t of 3.4 h. The predicted •OH scavenging activity of the hydrolysate under the optimum conditions was 60.7%, and the actually experimental scavenging activity was 60.8%. The hydrolysate was fractionated by ultrafiltration, and 4 fractions were collected. The fraction TSGH4 (MW<2000 Da) showed the strongest •OH scavenging activity with the highest yield. Furthermore, reactive oxygen species (ROS) scavenging activities of TSGH4 with different concentrations were investigated in 5 model systems, including superoxide anion radical (•O2), •OH, hydrogen peroxide (H2O2), peroxynitrite (ONOO-), and nitric oxide (NO•), compared with reduced glutathione (GSH). The results showed that TSGH4 significantly scavenged these ROS, and could be used as a functional ingredient in medicine and food industries.

Direct scavenging of nitric oxide and superoxide by green tea.

PubMed

Nakagawa, T; Yokozawa, T

2002-12-01

In the present study, we investigated the free radical scavenging effects of green tea extract and green tea tannin mixture and its components using a nitric oxide (NO) and superoxide (O(2)(-)) generating system in vitro. Green tea extract showed direct scavenging activity against NO and O(2)(-) and green tea tannin mixture, at the same concentration, showed high scavenging activity. Comparison of the activities of seven pure compounds isolated from green tea tannin mixture showed that (-)-epigallocatechin 3-O-gallate (EGCg), (-)-gallocatechin 3-O-gallate (GCg) and (-)-epicatechin 3-O-gallate (ECg) had higher scavenging activities than (-)-epigallocatechin (EGC), (+)-gallocatechin (GC), (-)-epicatechin (EC) and (+)-catechin (C), showing the importance of the structure of flavan-3-ol linked to gallic acid for this activity. Among the gallate-free tannins, EGC and GC were more effective O(2)(-) scavengers than EC and C, indicating the O-trihydroxy structure in the B ring is an important determinant of such activity. However, this structure did not affect the NO scavenging activity. These findings confirm that green tea tannin has excellent antioxidant properties, which may be involved in the beneficial effect of this compound.

Radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum.

PubMed

Yu, Huahua; Liu, Xiguang; Xing, Ronge; Liu, Song; Li, Cuiping; Li, Pengcheng

2005-05-16

In this study, radical scavenging activity of protein from tentacles of jellyfish Rhopilema esculentum (R. esculentum) was assayed including superoxide anion radical and hydroxyl radical scavenging. The protein samples showed strong scavenging activity on superoxide anion radical and values EC50 of full protein (FP), first fraction (FF), second fraction (SF), and 30% (NH4)2 SO4 precipitate (Fr-1) were 2.65, 7.28, 1.10, and 22.51 microg/mL, respectively, while values EC50 of BHA, BHT, and alpha-tocopherol were 31, 61, and 88 microg/mL, respectively. Also, the protein samples had strong scavenging effect on hydroxyl radical and the values EC50 of FP, FF, SF, Fr-1, and Fr-2 were 48.91, 27.72, 1.82, 16.36, and 160.93 microg/mL, but values EC50 of Vc and mannitol were 1907 and 4536 microg/mL, respectively. Of the five protein samples, SF had the strongest radical scavenging activity and may have a use as a possible supplement in the food and pharmaceutical industries. The radical scavenging activity was stable at high temperature so that R. esculentum may be used as a kind of natural functional food.

An illicit economy: scavenging and recycling of medical waste.

PubMed

Patwary, Masum A; O'Hare, William Thomas; Sarker, M H

2011-11-01

This paper discusses a significant illicit economy, including black and grey aspects, associated with medical waste scavenging and recycling in a megacity, considering hazards to the specific group involved in scavenging as well as hazards to the general population of city dwellers. Data were collected in Dhaka, Bangladesh, using a variety of techniques based on formal representative sampling for fixed populations (such as recycling operatives) and adaptive sampling for roaming populations (such as scavengers). Extremely hazardous items (including date expired medicines, used syringes, knives, blades and saline bags) were scavenged, repackaged and resold to the community. Some HCE employees were also observed to sell hazardous items directly to scavengers, and both employees and scavengers were observed to supply contaminated items to an informal plastics recycling industry. This trade was made possible by the absence of segregation, secure storage and proper disposal of medical waste. Corruption, a lack of accountability and individual responsibility were also found to be contributors. In most cases the individuals involved with these activities did not understand the risks. Although motivation was often for personal gain or in support of substance abuse, participants sometimes felt that they were providing a useful service to the community. Copyright © 2011 Elsevier Ltd. All rights reserved.

In vitro antioxidant evaluation and total phenolics of methanolic leaf extracts of Nyctanthes arbor-tristis L.

PubMed

Michael, J Savarimuthu; Kalirajan, A; Padmalatha, C; Singh, A J A Ranjit

2013-09-01

To investigate the in vitro antioxidant activity and total phenolic content of the methanolic leaf extract of Nyctanthes arbor-tristis L. (NA). The sample was tested using five in vitro antioxidant methods (1, 1-diphenyl-2-picryl hydrazine radical scavenging activity (DPPH), hydroxyl radical-scavenging activity (-OH), nitric oxide scavenging activity (NO), superoxide radical-scavenging activity, and total antioxidant activity) to evaluate the in vitro antioxidant potential of NA and the total phenolic content (Folin-Ciocalteu method). The extract showed good free radical scavenging property which was calculated as an IC50 value. IC50 (Half maximal inhibitory concentration) of the methanolic extract was found to be 57.93 μg·mL(-1) for DPPH, 98.61 μg·mL(-1) for -OH, 91.74 μg·mL(-1) for NO, and 196.07 μg·mL(-1) for superoxide radical scavenging activity. Total antioxidant capacity of the extract was found to be (1198 ± 24.05) mg ascorbic acid for the methanolic extract. Free radical scavenging activity observed in the extracts of NA showed a concentration-dependent reaction. The in vitro scavenging tested for free radicals was reported to be due to high phenolic content in the leaf extract. The leaf extract of NA showed the highest total phenolic content with a value of 78.48 ± 4.2 equivalent mg TAE/g (tannic acid equivalent). N. arbor-tristis leaf extract exhibited potent free radical scavenging activity. The finding suggests that N. arbor-tristis leaves could be a potential source of natural antioxidant. Copyright © 2013 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Deer carcass decomposition and potential scavenger exposure to chronic wasting disease

USGS Publications Warehouse

Jennelle, C.S.; Samuel, M.D.; Nolden, C.A.; Berkley, E.A.

2009-01-01

Chronic wasting disease (CWD) is a transmissible spongiform encephalopathy afflicting the Cervidae family in North America, causing neurodegeneration and ultimately death. Although there are no reports of natural cross-species transmission of CWD to noncervids, infected deer carcasses pose a potential risk of CWD exposure for other animals. We placed 40 disease-free white-tailed deer (Odocoileus virginianus) carcasses and 10 gut piles in the CWD-affected area of Wisconsin (USA) from September to April in 2003 through 2005. We used photos from remotely operated cameras to characterize scavenger visitation and relative activity. To evaluate factors driving the rate of carcass removal (decomposition), we used KaplanMeier survival analysis and a generalized linear mixed model. We recorded 14 species of scavenging mammals (6 visiting species) and 14 species of scavenging birds (8 visiting species). Prominent scavengers included American crows (Corvus brachyrhynchos), raccoons (Procyon lotor), and Virginia opossums (Didelphis virginiana). We found no evidence that deer consumed conspecific remains, although they visited gut piles more often than carcasses relative to temporal availability in the environment. Domestic dogs, cats, and cows either scavenged or visited carcass sites, which could lead to human exposure to CWD. Deer carcasses persisted for 18 days to 101 days depending on the season and year, whereas gut piles lasted for 3 days. Habitat did not influence carcass decomposition, but mammalian and avian scavenger activity and higher temperatures were positively associated with faster removal. Infected deer carcasses or gut piles can serve as potential sources of CWD prions to a variety of scavengers. In areas where surveillance for CWD exposure is practical, management agencies should consider strategies for testing primary scavengers of deer carcass material.

Wet scavenging of soluble gases in DC3 deep convective storms using WRF-Chem simulations and aircraft observations: DEEP CONVECTIVE WET SCAVENGING OF GASES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bela, Megan M.; Barth, Mary C.; Toon, Owen B.

We examine wet scavenging of soluble trace gases in storms observed during the Deep Convective Clouds and Chemistry (DC3) field campaign. We conduct high-resolution simulations with the Weather Research and Forecasting model with Chemistry (WRF-Chem) of a severe storm in Oklahoma. The model represents well the storm location, size, and structure as compared with Next Generation Weather Radar reflectivity, and simulated CO transport is consistent with aircraft observations. Scavenging efficiencies (SEs) between inflow and outflow of soluble species are calculated from aircraft measurements and model simulations. Using a simple wet scavenging scheme, we simulate the SE of each soluble speciesmore » within the error bars of the observations. The simulated SEs of all species except nitric acid (HNO3) are highly sensitive to the values specified for the fractions retained in ice when cloud water freezes. To reproduce the observations, we must assume zero ice retention for formaldehyde (CH2O) and hydrogen peroxide (H2O2) and complete retention for methyl hydrogen peroxide (CH3OOH) and sulfur dioxide (SO2), likely to compensate for the lack of aqueous chemistry in the model. We then compare scavenging efficiencies among storms that formed in Alabama and northeast Colorado and the Oklahoma storm. Significant differences in SEs are seen among storms and species. More scavenging of HNO3 and less removal of CH3OOH are seen in storms with higher maximum flash rates, an indication of more graupel mass. Graupel is associated with mixed-phase scavenging and lightning production of nitrogen oxides (NOx ), processes that may explain the observed differences in HNO3 and CH3OOH scavenging.« less

Space Transportation System (STS) propellant scavenging system study. Volume 1: Technical report

NASA Technical Reports Server (NTRS)

1985-01-01

The objectives are to define the most efficient and cost effective methods for scavenging cryogenic and storable propellants and then define the requirements for these scavenging systems. For cryogenic propellants, scavenging is the transfer of propellants from the Shuttle orbiter external tank (ET) and/or main propulsion subsystems (MPS) propellant lines into storage tanks located in the orbiter payload bay for delivery to the user station by a space based transfer stage or the Space Transportation System (STS) by direct insertion. For storable propellants, scavenging is the direct transfer from the orbital maneuvering subsystem (OMS) and/or tankage in the payload bay to users in LEO as well as users in the vicinity of the Space Station.

Radical scavenging propensity of Cu2 +, Fe3 + complexes of flavonoids and in-vivo radical scavenging by Fe3 +-primuletin

NASA Astrophysics Data System (ADS)

Jabeen, Erum; Janjua, Naveed Kausar; Ahmed, Safeer; Murtaza, Iram; Ali, Tahir; Hameed, Shahid

2017-01-01

Cu2 + and Fe3 + complexes of three flavonoids (morin or mo, quercetin or quer and primuletin or prim) were synthesized with the objective of improving antioxidant capacities of flavonoids. The radical scavenging activities of pure flavonoids and their metal complexes were assayed to monitor their tendencies towards sequestering of radicals at physiological conditions. The scavenger potencies of metal-flavonoid complexes were significantly higher than those of the parent flavonoids. Further, influence of the solvent polarity on the radical capturing by flavonoids and their metal complexes was in favor for the polar solvent. Fe3 +-prim displayed its radical scavenging ability via up gradation of CAT and SOD activities in in-vivo antioxidant assays.

Synthesis and Free Radical Scavenging Activity of New Hydroxybenzylidene Hydrazines.

PubMed

Sersen, Frantisek; Gregan, Fridrich; Kotora, Peter; Kmetova, Jarmila; Filo, Juraj; Loos, Dusan; Gregan, Juraj

2017-05-29

Hydroxybenzylidene hydrazines exhibit a wide spectrum of biological activities. Here, we report synthesis and free radical scavenging activity of nine new N-(hydroxybenzylidene)-N'-[2,6-dinitro-4-(trifluoromethyl)]phenylhydrazines. The chemical structures of these compounds were confirmed by 1H-NMR, 13C-NMR, 19F-NMR, IR spectroscopy, LC-MS, and elemental analysis. The prepared compounds were tested for their activity to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH), galvinoxyl radical (GOR), and 2,2'-azino-bis(3-ethylbenzothiazoline)-6-sulphonic acid (ABTS) radicals. The free radical scavenging activity expressed as SC50 values of these compounds varied in a wide range, from a strong to no radical scavenging effect. The most effective radical scavengers were hydroxybenzylidene hydrazines containing three hydroxyl groups in the benzylidene part of their molecules. The prepared compounds were also tested for their activity to inhibit photosynthetic electron transport in spinach chloroplasts. IC50 values of these compounds varied in wide range, from an intermediate to no inhibitory effect.

Health risk reduction behaviors model for scavengers exposed to solid waste in municipal dump sites in Nakhon Ratchasima Province, Thailand

PubMed Central

Thirarattanasunthon, Phiman; Siriwong, Wattasit; Robson, Mark; Borjan, Marija

2012-01-01

The aim of this study was to evaluate the effect of comprehensive health risk protection behaviors, knowledge, attitudes, and practices among scavengers in open dump sites. A control group of 44 scavengers and an intervention group of 44 scavengers participated in this study. Interventions included the use of personal protective equipment, health protection training, and other measures. The analysis showed significant differences before and after the intervention program and also between the control and intervention groups. These observations suggest that further action should be taken to reduce adverse exposure during waste collection. To reduce health hazards to workers, dump site scavenging should be incorporated into the formal sector program. Solid waste and the management of municipal solid waste has become a human and environmental health issue and future research should look at constructing a sustainable model to help protect the health of scavengers and drive authorities to adopt safer management techniques. PMID:22969307

Changes in free-radical scavenging ability of kombucha tea during fermentation.

PubMed

Jayabalan, R; Subathradevi, P; Marimuthu, S; Sathishkumar, M; Swaminathan, K

2008-07-01

Kombucha tea is a fermented tea beverage produced by fermenting sugared black tea with tea fungus (kombucha). Free-radical scavenging abilities of kombucha tea prepared from green tea (GTK), black tea (BTK) and tea waste material (TWK) along with pH, phenolic compounds and reducing power were investigated during fermentation period. Phenolic compounds, scavenging activity on DPPH radical, superoxide radical (xanthine-xanthine oxidase system) and inhibitory activity against hydroxyl radical mediated linoleic acid oxidation (ammonium thiocyanate assay) were increased during fermentation period, whereas pH, reducing power, hydroxyl radical scavenging ability (ascorbic acid-iron EDTA) and anti-lipid peroxidation ability (thiobarbituric assay) were decreased. From the present study, it is obvious that there might be some chances of structural modification of components in tea due to enzymes liberated by bacteria and yeast during kombucha fermentation which results in better scavenging performance on nitrogen and superoxide radicals, and poor scavenging performance on hydroxyl radicals. Copyright © 2007 Elsevier Ltd. All rights reserved.

Effect of Different Silage Storing Conditions on the Oxygen Concentration in the Silo and Fermentation Quality of Rice.

PubMed

Uegaki, Ryuichi; Kawano, Kazuo; Ohsawa, Ryo; Kimura, Toshiyuki; Yamamura, Kohji

2017-06-21

We investigated the effects of different silage storing conditions on the oxygen concentration in the silo and fermentation quality of rice (Oryza sativa L.). Forage rice was ensiled in bottles (with or without space at the bottlemouth, with solid or pinhole cap, and with oxygen scavenger, ethanol transpiration agent, oxygen scavenger and ethanol transpiration agent, or no adjuvant) and stored for 57 days. The oxygen concentration decreased with the addition of the oxygen scavenger and increased with that of the ethanol transpiration agent. The oxygen scavenger facilitated silage fermentation and fungus generation, whereas the ethanol transpiration agent suppressed silage fermentation and fungus generation. However, the combined use of the oxygen scavenger and ethanol transpiration agent facilitated silage fermentation and also suppressed fungus generation. Overall, this study revealed the negative effects of oxygen on the internal silo and the positive effects of the combined use of the oxygen scavenger and ethanol transpiration agent on silage fermentation quality.

Radical scavenging activity of lipophilized products from lipase-catalyzed transesterification of triolein with cinnamic and ferulic acids.

PubMed

Choo, Wee-Sim; Birch, Edward John

2009-02-01

Lipase-catalyzed transesterification of triolein with cinnamic and ferulic acids using an immobilized lipase from Candida antarctica (E.C. 3.1.1.3) was conducted to evaluate the antioxidant activity of the lipophilized products as model systems for enhanced protection of unsaturated oil. The lipophilized products were identified using ESI-MS. Free radical scavenging activity was determined using the DPPH radical method. The polarity of the solvents proved important in determining the radical scavenging activity of the substrates. Ferulic acid showed much higher radical scavenging activity than cinnamic acid, which has limited activity. The esterification of cinnamic acid and ferulic acid with triolein resulted in significant increase and decrease in the radical scavenging activity, respectively. These opposite effects were due to the effect of addition of electron-donating alkyl groups on the predominant mechanism of reaction (hydrogen atom transfer or electron transfer) of a species with DPPH. The effect of esterification of cinnamic acid was confirmed using ethyl cinnamate which greatly enhances the radical scavenging activity. Although, compared to the lipophilized cinnamic acid product, the activity was lower. The radical scavenging activity of the main component isolated from lipophilized cinnamic acid product using solid phase extraction, monocinnamoyl dioleoyl glycerol, was as good as the unseparated mixture of lipophilized product. Based on the ratio of a substrate to DPPH concentration, lipophilized ferulic acid was a much more efficient radical scavenger than lipophilized cinnamic acid.

Recovery of Li from alloys of Al- Li and Li- Al using engineered scavenger compounds

DOEpatents

Riley, W. D.; Jong, B. W.; Collins, W. K.; Gerdemann, S. J.

1994-01-01

A method of producing lithium of high purity from lithium aluminum alloys using an engineered scavenger compound, comprising: I) preparing an engineered scavenger compound by: a) mixing and heating compounds of TiO2 and Li2CO3 at a temperature sufficient to dry the compounds and convert Li.sub.2 CO.sub.3 to Li.sub.2 O; and b) mixing and heating the compounds at a temperature sufficient to produce a scavenger Li.sub.2 O.3TiO.sub.2 compound; II) loading the scavenger into one of two electrode baskets in a three electrode cell reactor and placing an Al-Li alloy in a second electrode basket of the three electrode cell reactor; III) heating the cell to a temperature sufficient to enable a mixture of KCl-LiCl contained in a crucible in the cell to reach its melting point and become a molten bath; IV) immersing the baskets in the bath until an electrical connection is made between the baskets to charge the scavenger compound with Li until there is an initial current and voltage followed by a fall off ending current and voltage; and V) making a connection between the basket electrode containing engineered scavenger compound and a steel rod electrode disposed between the basket electrodes and applying a current to cause Li to leave the scavenger compound and become electrodeposited on the steel rod electrode.

Americans with Disabilities Act Scavenger Hunt

ERIC Educational Resources Information Center

Ramsey, Ursula

2018-01-01

This article describes a scavenger hunt for Business Law students. Specifically, students compete in this scavenger hunt to identify accessible design features on campus to undergird their study of Title III of the Americans with Disabilities Act (ADA). Title III of the ADA prohibits public accommodations from discriminating on the basis of…

A multiple free-radical scavenging (MULTIS) study on the antioxidant capacity of a neuroprotective drug, edaravone as compared with uric acid, glutathione, and trolox.

PubMed

Kamogawa, Erisa; Sueishi, Yoshimi

2014-03-01

Edaravone (3-methyl-1-phenyl-2-pyrazoline-5-one) is a neuroprotective drug that has been used for brain ischemia injury treatment. Because its activity is speculated to be due to free radical scavenging activity, we carried out a quantitative determination of edaravone's free radical scavenging activity against multiple free radical species. Electron spin resonance (ESR) spin trapping-based multiple free-radical scavenging (MULTIS) method was employed, where target free radicals were hydroxyl radical, superoxide anion, alkoxyl radical, alkylperoxyl radical, methyl radical, and singlet oxygen. Edaravone showed relatively high scavenging abilities against hydroxyl radical (scavenging rate constant k=2.98×10(11) M(-1) s(-1)), singlet oxygen (k=2.75×10(7) M(-1) s(-1)), and methyl radical (k=3.00×10(7) M(-1) s(-1)). Overall, edaravone's scavenging activity against multiple free radical species is as robust as other known potent antioxidant such as uric acid, glutathione, and trolox. A radar chart illustration of the MULTIS activity relative to uric acid, glutathione, and trolox indicates that edaravone has a high and balanced antioxidant activity with low specificity. Copyright © 2014 Elsevier Ltd. All rights reserved.

Superoxide radical anion scavenging and dismutation by some Cu2+ and Mn2+ complexes: A pulse radiolysis study

NASA Astrophysics Data System (ADS)

Joshi, Ravi

2017-10-01

Copper (Cu) and manganese (Mn) ions are catalytic centers, in complexed form, in scavenging and dismutation process of superoxide radicals anion (O2.-) by superoxide dismutase enzyme. In the present work, fast reaction kinetics and mechanism of scavenging and dismutation of O2.- by Cu2+, Mn2+ and their complexes formed with some natural ligands have been studied using pulse radiolysis technique. Catechol, gentisic acid, tetrahydroxyquinone, tyrosine, tryptophan, embelin and bilirubin have been used as low molecular weight natural ligands for Cu2+ and Mn2+ to understand superoxide radical scavenging and dismutation reactions. These complexes have been found to be efficient scavengers of O2.- (k 107-109 M-1 s-1). The effects of nature of metal ion and ligand, and stoichiometry of complex on scavenging reaction rate constants are reported. Higher scavenging rate constants have been observed with complexes of: (1) Cu2+ as compared to Mn2+, and (2) at [ligand]/[metal] ratio of one as compared to two. A clear evidence of O2.- dismutation by free metal ions and some of the complexes has been observed. The study suggests that complexes of Cu2+ and Mn2+ with small natural ligands can also act as SOD mimics.

Functionalized graphene quantum dots loaded with free radicals combined with liquid chromatography and tandem mass spectrometry to screen radical scavenging natural antioxidants from Licorice and Scutellariae.

PubMed

Wang, Guoying; Niu, XiuLi; Shi, Gaofeng; Chen, Xuefu; Yao, Ruixing; Chen, Fuwen

2014-12-01

A novel screening method was developed for the detection and identification of radical scavenging natural antioxidants based on a free radical reaction combined with liquid chromatography with tandem mass spectrometry. Functionalized graphene quantum dots were prepared for loading free radicals in the complex screening system. The detection was performed with and without a preliminary exposure of the samples to specific free radicals on the functionalized graphene quantum dots, which can facilitate charge transfer between free radicals and antioxidants. The difference in chromatographic peak areas was used to identify potential antioxidants. This is a novel approach to simultaneously evaluate the antioxidant power of a component versus a free radical, and to identify it in a vegetal matrix. The structures of the antioxidants in the samples were identified using tandem mass spectrometry and comparison with standards. Fourteen compounds were found to possess potential antioxidant activity, and their free radical scavenging capacities were investigated. The order of scavenging capacity of 14 compounds was compared according to their free radical scavenging rate. 4',5,6,7-Tetrahydroxyflavone (radical scavenging rate: 0.05253 mL mg(-1) s(-1) ) showed the strongest capability for scavenging free radicals. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Creatinine and HMH (5-hydroxy-1-methylhydantoin, NZ-419) as intrinsic hydroxyl radical scavengers.

PubMed

Ienaga, K; Yokozawa, T

2011-08-01

Creatinine (Crn) is one of the main intrinsic hydroxyl radical (•OH) scavengers and an ideal one for healthy or normal mammals, although this fact has not yet become widely accepted. Our results from urinary data estimated that ca. 0.4-0.6% of Crn is used daily to scavenge •OH in normal mammals [ca. 50 μmole and ca. 400 pmole of •OH in healthy subjects and normal rats, respectively]. In human subjects, Crn reacts non-enzymatically with •OH to form creatol (CTL: 5-hydroxycreatinine) and demethylcreatinine (DMC) in a one to one ratio, and CTL partially decomposes to methylguanidine (MG). And so, the scavenged mole of •OH by Crn is nearly equal to their molar total sum (CTL + MG + DMC) or 2 × (CTL + MG). The molar ratio of (scavenged •OH)/Crn in healthy subjects and normal rats are 4.4 and 6.0 mmole/mole, respectively, i.e. almost similar, but in patients with chronic kidney disease (CKD) the ratio increases up to ca. 60 mmole/mole in proportion to the severity of CKD. Since the level of Crn might not be enough to scavenge all •OH, and MG starts accumulating as a uremic toxin, Crn is not really the ideal scavenger. 5-Hydroxy-1-methylhydantoin (HMH, NZ-419), a Crn metabolite, is another antioxidant, having •OH scavenging ability, and has been shown to inhibit the progression of CKD in rats in stead of Crn, if sufficient amounts are given orally.

Concretionary manganese-iron oxides in streams and their usefulness as a sample medium for geochemical prospecting

USGS Publications Warehouse

Nowlan, G.A.

1976-01-01

Correlation studies of 400 samples of sieved stream sediments and 325 samples of fluvial, concretionary Mn-Fe oxides from Maine resulted in the separation of elements into the following categories: (1) elements not scavenged by Mn-Fe oxides - B, Cr, K, Mg, Rb, Sc, Ti, V, and Zr; (2) elements probably not scavenged by Mn-Fe oxides - Ag, Be, Ca, Ga, La, Sb, and Y; (3) elements scavenged weakly by Mn-Fe oxides - Cu, Mo, Pb, and Sr; (4) elements scavenged strongly by Mn oxides - Ba, Cd, Co, Ni, Tl, and Zn; and (5) elements scavenged strongly by Fe oxides - As and In. Studies of the scavenged elements showed that the deviation from the mean is characteristically greater in oxide samples as compared to sieved sediments from the same locality. However, a significant increase in contrast between anomalous and background localities, when oxides are the sample medium, more than offsets the disadvantage of data scatter. The use of oxides as a sampling medium clearly and significantly accentuates anomalous localities. In general, non-ratioed data on oxides give very nearly the same results as data consisting of scavenged elements ratioed to Mn and Fe. However, ratioed data expand the geographic area of specific anomalies. Cd and Zn consistently show strong correlations with concretionary Mn-Fe oxides, but their concentrations in the oxides do not generally show as much contrast between anomalous and background localities as do Cu, Mo, and Pb. These latter elements are strongly scavenged where rocks are mineralized. ?? 1976.

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. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multiple free-radical scavenging (MULTIS) capacity in cattle serum.

PubMed

Sueishi, Yoshimi; Kamogawa, Erisa; Kimura, Anna; Kitahara, Go; Satoh, Hiroyuki; Asanuma, Taketoshi; Oowada, Shigeru

2017-01-01

Multiple free-radical scavenging (MULTIS) activity in cattle and human sera was evaluated with electron spin resonance spectroscopy. Scavenging rates against six active species, namely hydroxyl radical, superoxide anion, alkoxyl radical, alkylperoxyl radical, methyl radical, and singlet oxygen were quantified. The difference in the electron spin resonance signal intensity in the presence and absence of the serum was converted into the scavenging rates. Comparative MULTIS measurements were made in sera from eight beef cattle, three fetal calves and fifteen healthy human volunteers. Further, we determined the MULTIS value of albumin, the most abundant component in serum. MULTIS values in cattle sera indicated higher scavenging activity against most free radical species tested than human sera. In particular, cattle serum scavenging activities against superoxide and methyl radical were higher than human serum by 2.6 and 3.7 fold, respectively. In cattle serum, albumin appears to play a dominant role in MULTIS activity, but in human serum that is not the case. Previous data indicated that the abundance of uric acid in bovine blood is nearly 80% less than humans; however, this difference does not explain the deviation in MULTIS profile.

Free radical scavenging abilities of polypeptide from Chlamys farreri

NASA Astrophysics Data System (ADS)

Han, Zhiwu; Chu, Xiao; Liu, Chengjuan; Wang, Yuejun; Mi, Sun; Wang, Chunbo

2006-09-01

We investigated the radical scavenging effect and antioxidation property of polypeptide extracted from Chlamys farreri (PCF) in vitro using chemiluminescence and electron spin resonance (ESR) methods. We examined the scavenging effects of PCF on superoxide anions (O{2/-}), hydroxyl radicals (OH·), peroxynitrite (ONOO-) and the inhibiting capacity of PCF on peroxidation of linoleic acid. Our experiment suggested that PCF could scavenge oxygen free radicals including superoxide anions (O{2/-}) (IC50=0.3 mg/ml), hydroxyl radicals (OH·) (IC50=0.2 μg/ml) generated from the reaction systems and effectively inhibit the oxidative activity of ONOO- (IC50=0.2 mg/ml). At 1.25 mg/ml of PCF, the inhibition ratio on lipid peroxidation of linoleic acid was 43%. The scavenging effect of PCF on O{2/-}, OH· and ONOO- free radicals were stronger than those of vitamin C but less on lipid peroxidation of linoleic acid. Thus PCF could scavenge free radicals and inhibit the peroxidation of linoleic acid in vitro. It is an antioxidant from marine products and potential for industrial production in future.

Scavenging of radioactive soluble gases from inhomogeneous atmosphere by evaporating rain droplets.

PubMed

Elperin, Tov; Fominykh, Andrew; Krasovitov, Boris

2015-05-01

We analyze effects of inhomogeneous concentration and temperature distributions in the atmosphere, rain droplet evaporation and radioactive decay of soluble gases on the rate of trace gas scavenging by rain. We employ a one-dimensional model of precipitation scavenging of radioactive soluble gaseous pollutants that is valid for small gradients and non-uniform initial altitudinal distributions of temperature and concentration in the atmosphere. We assume that conditions of equilibrium evaporation of rain droplets are fulfilled. It is demonstrated that transient altitudinal distribution of concentration under the influence of rain is determined by the linear wave equation that describes propagation of a scavenging wave front. The obtained equation is solved by the method of characteristics. Scavenging coefficients are calculated for wet removal of gaseous iodine-131 and tritiated water vapor (HTO) for the exponential initial distribution of trace gases concentration in the atmosphere and linear temperature distribution. Theoretical predictions of the dependence of the magnitude of the scavenging coefficient on rain intensity for tritiated water vapor are in good agreement with the available atmospheric measurements. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

2016-01-14

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.

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

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.

Aerosol transport and wet scavenging in deep convective clouds: a case study and model evaluation using a multiple passive tracer analysis approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qing; Easter, Richard C.; Campuzano-Jost, Pedro

2015-08-20

The effect of wet scavenging on ambient aerosols in deep, continental convective clouds in the mid-latitudes is studied for a severe storm case in Oklahoma during the Deep Convective Clouds and Chemistry (DC3) field campaign. A new passive-tracer based transport analysis framework is developed to characterize the convective transport based on the vertical distribution of several slowly reacting and nearly insoluble trace gases. The passive gas concentration in the upper troposphere convective outflow results from a mixture of 47% from the lower level (0-3 km), 21% entrained from the upper troposphere, and 32% from mid-atmosphere based on observations. The transportmore » analysis framework is applied to aerosols to estimate aerosol transport and wet-scavenging efficiency. Observations yield high overall scavenging efficiencies of 81% and 68% for aerosol mass (Dp < 1μm) and aerosol number (0.03< Dp < 2.5μm), respectively. Little chemical selectivity to wet scavenging is seen among observed submicron sulfate (84%), organic (82%), and ammonium (80%) aerosols, while nitrate has a much lower scavenging efficiency of 57% likely due to the uptake of nitric acid. Observed larger size particles (0.15 - 2.5μm) are scavenged more efficiently (84%) than smaller particles (64%; 0.03 - 0.15μm). The storm is simulated using the chemistry version of the WRF model. Compared to the observation based analysis, the standard model underestimates the wet scavenging efficiency for both mass and number concentrations with low biases of 31% and 40%, respectively. Adding a new treatment of secondary activation significantly improves simulation results, so that the bias in scavenging efficiency in mass and number concentrations is reduced to <10%. This supports the hypothesis that secondary activation is an important process for wet removal of aerosols in deep convective storms.« less

Scavenging high-voltage copper wire, a hazardous petty larceny.

PubMed

Himel, H N; Ahn, L C; Jones, K C; Edlich, R F

1992-01-01

With the current emphasis on recycling and the establishment of markets for sale of used copper wire, scavenging of copper wire from old buildings and equipment has become common. Although scavenging without permission constitutes theft, a more significant risk to the perpetrator is the potential for electrical burn injury in attempting to remove "hot" wire. A severe high-voltage electrical burn injury sustained while attempting to scavenge wire from an old house is reported. The circumstances surrounding the injury, the clinical management of the case, and the long-term consequences to the patient are presented and discussed.

Earth-to-orbit propellant transportation overview

NASA Technical Reports Server (NTRS)

Fester, D.

1984-01-01

The transportation of large quantities of cryogenic propellants which are needed to support Space Station/OTV operation is discussed. Two ways to send propellants into space are: transporting them in dedicated tankers or scavenging unused STS propellant. Scavenging propellant, both with and without an aft cargo carrier system is examined. An average of two to four flights per year can be saved by scavenging and manifesting propellant as payload. Addition of an aft cargo carrier permits loading closer to maximum, reduces the required number of flights, and reduces the propellant available for scavenging. Sufficient propellant remains, however, for OTV needs.

Scavenging ratio of polycyclic aromatic compounds in rain and snow at the Athabasca oil sands region

NASA Astrophysics Data System (ADS)

Zhang, L.; Cheng, I.; Muir, D.; Charland, J.-P.

2014-07-01

Athabasca oil sands industry in northern Alberta, Canada is a possible source of polycyclic aromatic compounds (PACs). Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and dibenzothiophenes, in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during May 2011 to August 2012 were analyzed to generate a database of scavenging (or washout) ratios (Wt) for PACs scavenged by both snow and rain. Median precipitation and air concentrations of parent PAHs over the May 2011 to August 2012 period ranged from 0.3-184.9 (chrysene) ng L-1 and 0.01-3.9 (naphthalene) ng m-3, respectively, which were comparable to literature values. Higher concentrations in precipitation and air were observed for alkylated PAHs and dibenzothiophenes. The median precipitation and air concentrations were 11.3-646.7 (C3-fluoranthene/pyrene) ng L-1 and 0.21-16.9 (C3-naphthalene) ng m-3, respectively, for alkylated PAHs, and 8.5-530.5 (C4-dibenzothiophene) ng L-1 and 0.13-6.6 (C2-dibenzothiophene) ng m-3 for dibenzothiophenes and their alkylated derivatives. Median Wt over the measurement period were 6100-1.1 × 106 from snow scavenging and 350-2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations. But Wt for acenaphthylene in snow samples was 2-7 times higher. Some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(a)pyrene, dibenz(a,h)anthracene, and benzo(g,h,i)perylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14-20 times greater than gas-phase dominant PACs in snow samples and 7-20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging was ∼9 times greater than rain scavenging for particulate-phase dominant PACs and 4-9.6 times greater than rain scavenging for gas-phase dominant PACs. Gas-particle fractions of each PAC, particle size distributions of particulate-phase dominant PACs, and Henry's Law constant of gas-phase dominant PACs explained, to a large extent, the different Wt values among the different PACs and precipitation types. This study verified findings from a previous study of Wang et al. (2014) which suggested that snow scavenging is more efficient than rain scavenging of particles for equivalent precipitation amount, and also provided new knowledge on the scavenging of gas-phase PACs by snow and rain.

Rapid screening, separation, and detection of hydroxyl radical scavengers from total flavonoids of Ginkgo biloba leaves by chromatography combined with molecular devices.

PubMed

Wang, Jing; Zheng, Meizhu; Chen, Lina; Liu, Zhiqiang; Zhang, Yuchi; Liu, Chun-Ming; Liu, Shu

2016-11-01

Hydroxyl radicals are the most reactive free radical of human body, a strong contributor to tissue damage. In this study, liquid chromatography coupled to electrospray ionization mass spectrometry was applied to screen and identify hydroxyl radical scavengers from the total flavonoids of Ginkgo biloba leaves, and high-performance counter current chromatography was used to separate and isolate the active compounds. Furthermore, molecular devices were used to determine hydroxyl radical scavenging activities of the obtained hydroxyl radical scavengers and other flavonoids from G. biloba leaves. As a result, six compounds were screened as hydroxyl radical scavengers, but only three flavonoids, namely, rutin, cosmos glycosides and apigenin-7-O-Glu-4'-O-Rha, were isolated successfully from total flavonoids by high-performance counter current chromatography. The purities of the three obtained compounds were over 90%, respectively, as determined by liquid chromatography. Molecular devices with 96-well microplates evaluation indicated that the 50% scavenging concentration values of screened compounds were lower than that of other flavonoids, they performed greater hydroxyl radical scavenging activity, and the evaluation effects were consistent with the liquid chromatography with mass spectrometry screening results. Therefore, chromatography combined with molecular devices is a feasible and an efficient method for systematic screening, identification, isolation, and evaluation of bioactive components in mixture of botanical medicines. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Antioxidant ability and mechanism of rhizoma Atractylodes macrocephala.

PubMed

Li, Xican; Lin, Jian; Han, Weijuan; Mai, Wenqiong; Wang, Li; Li, Qiang; Lin, Miaofang; Bai, Mingsong; Zhang, Lishan; Chen, Dongfeng

2012-11-13

Rhizoma Atractylodes macrocephala (AM) has been used in Traditional Chinese Medicine (TCM) for about 2,000 years. In the study, we firstly determined the antioxidant levels of five AM extracts by •OH-scavenging, •O2−-scavenging, Fe2+-chelating, Cu2+-chelating, DPPH·-scavenging, and ABTS+·-scavenging assays. After measurement of the chemical contents in five AM extracts, we quantitatively analyzed the correlations between antioxidant levels and chemical contents. It was observed that total phenolics and total flavonoids had significant positive correlations with antioxidant levels (R = 0.685 and 0.479, respectively). In contrast, total sugars and total saponins presented lower correlations with antioxidant levels (R=−0.272 and 0.244, respectively). It means that antioxidant activity of AM should be attributed to total phenolics (including phenolic acids and flavonoids), and not total sugars and total saponins. Further analysis indicated that phenolic acids exhibited higher R values with radical-scavenging assays (R=0.32–1.00), while flavonoids showed higher R values with metal-chelating assays (R=0.86 and 0.90). In conclusion, AM exerts its antioxidant effect through metal-chelating, and radical-scavenging which is via donating hydrogen atom and donating electron. Its metal-chelating may result from flavonoids, while its radical-scavenging can be attributed to phenolic acids, especially caffeic acid, ferulic acid, and protocatechuic acid.

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…

75 FR 39790 - Airworthiness Directives; Airbus Model A330-200 and -300 Airplanes and Model A340-200, -300, -500...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-13

..., requiring repetitive inspections of the APU generator Scavenge filter element and filter housing and of the.... The new requirements include inspecting the APU generator scavenge oil filter element for contamination, the APU generator drain plug for contamination, and the APU generator scavenge filter housing for...

75 FR 55461 - Airworthiness Directives; Bombardier, Inc. Model DHC-8-200 and DHC-8-300 Series Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-13

..., preventing gravity feed. In the event of scavenge system failure, the collector tank fuel level can no longer... closed by the valve spring, preventing gravity feed. In the event of scavenge system failure, the... spring, preventing gravity feed. In the event of scavenge system failure, the collector tank fuel level...

OZONE-SCAVENGING REAGENTS SUITABLE FOR USE IN THE QUANTITATIVE DETERMINATION OF ALDEHYDES AS THE O-(2,3,4,5,6-PENTAFLUOROBENZYL)OXIMES BY GC-ECD

EPA Science Inventory

Previously, we reported interference due to several ozone-scavenging reagents (OSRs) in the quantitation of aldehydes using 0-(2,3,4,5,6-pentafluorobenzyl)oxylamine (PFBOA) in the analysis of ozonated waters. Scavenging ozone is essential if ozonation byproduct concentrations ar...

Computational study of the structure-free radical scavenging relationship of procyanidins.

PubMed

Mendoza-Wilson, Ana María; Castro-Arredondo, Sergio Ivan; Balandrán-Quintana, René Renato

2014-10-15

Procyanidins (PCs) are effective free radical scavengers, however, their antioxidant ability is variable because they have different degrees of polymerisation, are composed by distinct types of subunits and are very susceptible to changes in conformation. In this work the structure-free radical scavenging relationship of monomers, dimers and trimers of PCs was studied through the hydrogen atom transfer (HAT), sequential proton-loss electron-transfer (SPLET) and single electron transfer followed by proton transfer (SET-PT) mechanisms in aqueous phase, employing the Density Functional Theory (DFT) computational method. The structure-free radical scavenging relationship of PCs showed a very similar behaviour in HAT and SET-PT mechanisms, but very different in the SPLET mechanism. The structural factor that showed more effects on the ability of PCs to scavenge free radicals in aqueous phase was the conformation. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bilateral fractures of the coronoid processes: differential diagnosis of intra-oral gunshot trauma and scavenging using a sheep crania model.

PubMed

Puskas, Cathy M

2003-11-01

Approximately half of the skeleton of an adult male (minus the cranium) was found in a forested part of Greater Vancouver, Canada, in August 2000 by the Royal Canadian Mounted Police (RCMP). Authorities ruled the death as suicide. The only compelling signs of perimortem trauma were symmetrically fractured coronoid processes of the mandible, which can be attributed to a gunshot in the mouth. However, the remains had also been scavenged by canids, raising a problem in differential diagnosis. Could canid scavenging produce bilateral fracturing of the mandible indistinguishable from gunshot wounds to the mouth? We found that canid scavengers could not mimic the type of damage to the mandible caused by intra-oral gunshot wounding using a sheep model (n = 20). Bilateral fracturing of the coronoid processes was found to be characteristic of intra-oral gunshot wounding, while canid scavengers typically ignore this region of the mandible.

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

PubMed

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

2014-05-07

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.

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

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

PubMed

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

2012-04-01

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. In this study, we investigated the radical scavenging activity of A. melanocarpa fruit juice (AMFJ). 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. 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. The ESR measurements in this study showed a pronounced radical scavenging effect of AMFJ, an important mechanism of its antioxidant activity.

Some approximations for the wet and dry removal of particles and gases from the atmosphere

Treesearch

W. G. N. Slinn

1976-01-01

Semi-empirical formulae are presented which can be used to estimate precipitation scavenging and dry deposition of particles and gases. The precipitation scavenging formulae are appropriate both for in- and below-cloud scavenging and comparisons with data indicate the importance of accounting for aerosol particle growth by water vapor condensation and attachment of the...

Apoptotic and free radical scavenging properties of the methanolic extract of Gentianella alborosea.

PubMed

Acero, Nuria; Llinares, Francisco; Galán de Mera, Antonio; Oltra, Beatriz; Muñoz-Mingarro, Dolores

2006-09-01

Gentianella alborosea ("Hercampure") is a Peruvian species used in folk medicine for the treatment of a variety of health disorders. We tested the free radical scavenging (DPPH) and induction of apoptosis on a human uterus tumor cell line (HeLa) by its methanolic extract. The results showed a noticeable radical scavenging activity and a dose-dependent apoptotic effect.

Polyphenolic content and antioxidant activity of some wild Saudi Arabian Asteraceae plants.

PubMed

Shahat, Abdelaaty A; Ibrahim, Abeer Y; Elsaid, Mansour S

2014-07-01

To study the antioxidant properties of crude extract of different Asteraceae plants. The antioxidant properties of six extracts were evaluated using different antioxidant tests, including free radical scavenging, reducing power, metal chelation, superoxide anion radical scavenging, total antioxidant capacity and inhibition of lipid peroxidation activities. Picris cyanocarpa (P. cyanocarpa) and Anthemis deserti (A. deserti) had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger while Achillia fragrantissima (A. fragrantissima) and Artemissia monosperma (A. monosperma) were the most efficient as ion chelator (100% at 100, 200 and 400 μg/mL) A. fragrantissima and Rhantarium appoposum (R. appoposum) showed 100% inhibition on peroxidation of linoleic acid emulsion at 200 and 400 μg/mL, while butylatedhydroxy toluene and ascorbic acid showed 100 and 95% inhibition percentage at 400 μg/mL, respectively. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyl toluene and ascorbic acid. In most tests P. cyanocarpa and A. deserti had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Hydroxylated chalcones with dual properties: xanthine oxidase inhibitors and radical scavengers

PubMed Central

Hofmann, Emily; Webster, Jonathan; Do, Thuy; Kline, Reid; Snider, Lindsey; Hauser, Quintin; Higginbottom, Grace; Campbell, Austin; Ma, Lili; Paula, Stefan

2016-01-01

In this study, we evaluated the abilities of a series of chalcones to inhibit the activity of the enzyme xanthine oxidase (XO) and to scavenge radicals. 20 mono- and polyhydroxylated chalcone derivatives were synthesized by Claisen-Schmidt condensation reactions and then tested for inhibitory potency against XO, a known generator of reactive oxygen species (ROS). In parallel, the ability of the synthesized chalcones to scavenge a stable radical was determined. Structure-activity relationship analysis in conjunction with molecular docking indicated that the most active XO inhibitors carried a minimum of three hydroxyl groups. Moreover, the most effective radical scavengers had two neighboring hydroxyl groups on at least one of the two phenyl rings. Since it has been proposed previously that XO inhibition and radical scavenging could be useful properties for reduction of ROS-levels in tissue, we determined the chalcones’ effects to rescue neurons subjected to ROS-induced stress created by the addition of β-amyloid peptide. Best protection was provided by chalcones that combined good inhibitory potency with high radical scavenging ability in a single molecule, an observation that points to a potential therapeutic value of this compound class. PMID:26762836

In vitro evaluation of free radical scavenging activity of Codariocalyx motorius root extract.

PubMed

Chidambaram, Uma; Pachamuthu, Vanitha; Natarajan, Suganya; Elango, Bhakkiyalakshmi; Suriyanarayanan; Ramkumar, Kunga Mohan

2013-03-01

To determine the phenolic content in Codariocalyx motorius root extract and to evaluate its antioxidant properties using various in vitro assay systems. The antioxidant activity was evaluated based on scavenging of 1,1-diphenyl-2-picrylhydrazyl, hydroxyl radicals, superoxide anions, nitric oxide, hydrogen peroxide, peroxynitrite, reducing power and by inhibition of lipid peroxidation which was estimated in terms of thiobarbituric acid reactive substances. The root extract of the Codariocalyx motorius (C. motorius) exhibited potent total antioxidant activity that increased with increasing amount of extract concentration, which was compared with standard drug such as quercetin, butylated hydroxytoluene, tocopherol at different concentrations. The different concentrations of the extracts showed inhibition on lipid peroxidation. In addition, the extracts had effective reducing power, free radical scavenging, super oxide anion scavenging, nitric oxide scavenging, lipid peroxidation, and total phenolic content depending on concentration. High correlation between total phenolic contents and scavenging potential of different reactive oxygen species (r(2)=0.831-0.978) indicated the polyphenols as the main antioxidants. Codariocalyx motorius (C. motorius) root possess the highly active antioxidant substance which can be used for the treatment of oxidative stress-related diseases. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Online screening of nitric oxide scavengers in natural products using high performance liquid chromatography coupled with tandem diode array and fluorescence detection.

PubMed

Li, Dapeng; Wang, Ting; Guo, Yujie; Hu, Yuanjia; Yu, Boyang; Qi, Jin

2015-12-18

Nitric oxide (NO) is an important cellular signaling molecule with extensive physiological and pathophysiological effects. NO scavengers have the potential to treat inflammation, septic shock and other related diseases, and numerous examples have been chemically synthesized or isolated from natural products. The chemical diversity of natural products, however, means that a huge effort is necessary to efficiently screen and identify bioactive compounds, especially NO scavengers. In this article, we propose an effective analytical method to screen for NO scavengers in three natural products using an online system that couples high performance liquid chromatography with tandem diode array and fluorescence detection (HPLC-DAD-FLD). Eighteen compounds from radix of Scutellaria baicalensis Georgi and green tea displayed significant NO scavenging activity whereas components of Pueraria lobata (Willd.) Ohwi had no discernable activity. The structures of the active compounds were elucidated using Agilent Accurate-Mass Q-TOF LC/MS system. Preliminary analysis of structure-activity relationships indicated that, in flavonoids, a 2,3-double bond and a 3-H atom or a 3-OH group are essential for activity. In tannins, poly-hydroxyl groups are important for NO scavenging activity. Method validation indicated that the newly developed method is both reliable and repeatable. The online method that we present provides a simple, rapid and effective way to identify and characterize NO scavengers present in natural products. Copyright © 2015 Elsevier B.V. All rights reserved.

Evaluation of Antioxidant and Free Radical Scavenging Capacities of Polyphenolics from Pods of Caesalpinia pulcherrima

PubMed Central

Hsu, Feng-Lin; Huang, Wei-Jan; Wu, Tzu-Hua; Lee, Mei-Hsien; Chen, Lih-Chi; Lu, Hsiao-Jen; Hou, Wen-Chi; Lin, Mei-Hsiang

2012-01-01

Thirteen polyphenolics were isolated from fresh pods of Caesalpinia pulcherrima using various methods of column chromatography. The structures of these polyphenolics were elucidated as gallic acid (1), methyl gallate (2), 6-O-galloyl-d-glucoside (3), methyl 6-O-galloyl-β-d-glucoside (4), methyl 3,6-di-O-galloyl-α-d-glucopyranoside (5), gentisic acid 5-O-α-d-(6′-O-galloyl)glucopyranoside (6), guaiacylglycerol 4-O-β-d-(6′-O-galloyl)glucopyranoside (7), 3-methoxy-4-hydroxyphenol 1-O-β-d-(6′-O-galloyl) glucopyranoside (8), (+)-gallocatechin (9), (+)-catechin (10), (+)-gallocatechin 3-O-gallate (11), myricetin 3-rhamnoside (12), and ampelopsin (13). All isolated compounds were tested for their antioxidant activities in the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and peroxynitrite radicals scavenging assays. Among those compounds, 11, 12, and 2 exhibited the best DPPH-, hydroxyl-, and peroxynitrite radical-scavenging activities, respectively. Compound 7 is a new compound, and possesses better scavenging activities towards DPPH but has equivalent hydroxyl radical scavenging activity when compared to BHT. The paper is the first report on free radical scavenging properties of components of the fresh pods of Caesalpinia pulcherrima. The results obtained from the current study indicate that the free radical scavenging property of fresh pods of Caesalpinia pulcherrima may be one of the mechanisms by which this herbal medicine is effective in several free radical mediated diseases. PMID:22754350

Scavenging ratios of polycyclic aromatic compounds in rain and snow in the Athabasca oil sands region

NASA Astrophysics Data System (ADS)

Zhang, L.; Cheng, I.; Muir, D.; Charland, J.-P.

2015-02-01

The Athabasca oil sands industry in northern Alberta, Canada, is a possible source of polycyclic aromatic compounds (PACs). Monitored PACs, including polycyclic aromatic hydrocarbons (PAHs), alkylated PAHs, and dibenzothiophenes (DBTs), in precipitation and in air at three near-source sites in the Fort MacKay and Fort McMurray area during January 2011 to May 2012, were used to generate a database of scavenging ratios (Wt) for PACs scavenged by both snow and rain. Higher concentrations in precipitation and air were observed for alkylated PAHs and DBTs compared to the other PACs. The sums of the median precipitation concentrations over the period of data analyzed were 0.48 μ g L-1 for the 18 PAHs, 3.38 μ g L-1 for the 20 alkylated PAHs, and 0.94 μ g L-1 for the 5 DBTs. The sums of the median air concentrations for parent PAHs, alkylated PAHs, and DBTs were 8.37, 67.26, and 11.83 ng m-3, respectively. Median Wt over the measurement period were 6100 - 1.1 × 106 from snow scavenging and 350 - 2.3 × 105 from rain scavenging depending on the PAC species. Median Wt for parent PAHs were within the range of those observed at other urban and suburban locations, but Wt for acenaphthylene in snow samples were 2-7 times higher compared to other urban and suburban locations. Wt for some individual snow and rain samples exceeded literature values by a factor of 10. Wt for benzo(a)pyrene, dibenz(a,h)anthracene, and benzo(g,h,i)perylene in snow samples had reached 107, which is the maximum for PAH snow scavenging ratios reported in the literature. From the analysis of data subsets, Wt for particulate-phase dominant PACs were 14-20 times greater than gas-phase dominant PACs in snow samples and 7-20 times greater than gas-phase dominant PACs in rain samples. Wt from snow scavenging were ~ 9 times greater than from rain scavenging for particulate-phase dominant PACs and 4-9.6 times greater than from rain scavenging for gas-phase dominant PACs. Gas-particle fractions of each PAC, particle size distributions of particulate-phase dominant PACs, and the Henry's law constant of gas-phase dominant PACs explained, to a large extent, the different Wt values among the different PACs and precipitation types. The trend in Wt with increasing alkyl substitutions may be attributed to their physico-chemical properties, such as octanol-air and particle partition coefficients and subcooled vapor pressure, which increases gas-particle partitioning and, subsequently, the particulate mass fraction. This study verified findings from a previous study of Wang et al. (2014) that suggested that snow scavenging is more efficient than rain scavenging of particles for equivalent precipitation amounts, and also provided new knowledge of the scavenging of gas-phase PACs and alkylated PACs by snow and rain.

Whey protein film with oxygen scavenging function by incorporation of ascorbic acid.

PubMed

Janjarasskul, Theeranun; Tananuwong, Kanitha; Krochta, John M

2011-01-01

Residual O(2) in a package headspace can be removed by an O(2)-absorbing sachet, which can be harmful if swallowed by the consumer, or by a chemically-active plastic packaging film, which is difficult to recycle. An edible, O(2)-absorbing film would avoid these disadvantages. The objective of our research was to assess the O(2)-scavenging potential of an edible whey protein isolate (WPI) film incorporating ascorbic acid (AA). AA at 0.05, 0.1, or 0.2 M was added to 5% (w/w) heat-denatured WPI film-forming solutions with WPI : glycerol (Gly) ratio of 1: 1.00, 1: 0.80, or 1: 0.67. The pH of solutions was then adjusted to 3.5 (below pK(a1) of AA), to stabilize AA against oxidation, before film casting. The mechanical properties, O(2) permeabilities, and thermal transitions of films were measured. Activation of the O(2)-scavenging function of the AA-incorporated films was accomplished by adjustment of the films to pH ≥ 7. O(2)-scavenging ability of AA-incorporated WPI films was determined by measuring residual O(2) in the headspace of a high-barrier container. Incorporation of AA into WPI film decreased film tensile strength and further reduced O(2) permeability at each WPI : Gly ratio. AA-containing films adjusted to pH ≥ 7 demonstrated O(2) absorption proportional to AA content, consistent with theoretical O(2)-scavenging capacity. Thermal transition measurements indicated that AA was involved in WPI structural modification and decreased the degradation temperature of WPI-based film. The demonstrated O(2)-scavenging function, improved O(2) barrier and acceptable mechanical properties of AA-incorporated films indicate potential commercial usefulness. Ascorbic acid-incorporated whey protein film with oxygen scavenging function can be used to extend shelf lives of a wide variety of oxygen-sensitive products by eliminating headspace oxygen as well as oxygen permeating through the packaging wall over time. Edible oxygen-scavenger film has the advantages of avoiding both accidental consumption and nonrecyclability of conventional oxygen scavenger systems. © 2011 Institute of Food Technologists®

In vitro antioxidant and free radical scavenging activity of different parts of Tabebuia pallida growing in Bangladesh.

PubMed

Rahman, Md Mahbubur; Islam, Md Badrul; Biswas, Mohitosh; Khurshid Alam, A H M

2015-10-30

In humans, many diseases are associated with the accumulation of free radicals. Antioxidants can scavenge free radicals and minimize their impact. Therefore, the search for naturally occurring antioxidants of plant origin is imperative. Here, we aimed to investigate the antioxidant and free radical scavenging properties of methanolic extracts from Tabebuia pallida (T. pallida) stem bark (TPSB), root bark (TPRB), leaves (TPL), and flowers (TPF). The antioxidant and free radical scavenging activity were determined by several standard methods using spectrophotomer. Total phenolic and flavonoid contents were estimated using Folin-Ciocalteu reagent and aluminum chloride colorimetric assay methods, respectively. Among the extracts, TPL showed the highest total antioxidant capacity followed by TPRB, TPF, and TPSB. Based on DPPH and hydroxyl radical scavenging activity, TPL showed strong scavenging activity (91.05 ± 1.10 and 62.00 ± 0.57) with IC50 of 9.20 ± 0.28 and 46.00 ± 2.84 μg/mL, respectively when compared with standard BHT (IC50 of 7.00 ± 0.25 μg/mL) and CA (75.00 ± 0.14 μg/mL). These results suggest that TPL had the highest radical scavenging activity among the extractives that closely resembled the standard's. In lipid peroxidation inhibition assay, TPL exhibited the most potent inhibitory activity (83.18 ± 2.12 %) with IC50 of 12.00 ± 2.12 μg/mL, which closely resembled standard CA (IC50 of 10.50 ± 0.28 μg/mL). Also, the reducing capacity on ferrous ion was in the following order: TPL > TPRB > TF > TPSB. The phenolic and flavonoid contents of TPL were higher than other extractives. A positive correlation (p value <0.001) was observed between phenolic content and free radical (DPPH(·) and (·)OH) scavenging efficiencies and lipid peroxidation inhibition activity. Methanolic extract of T. pallida leaf is a potential source of natural antioxidants and serves as an effective free radical scavenger and/or inhibitor. Hence, T. pallida might be a good plant-based pharmaceutical product for several diseases caused by free radicals.

Novel hydroxyl radical scavenging antioxidant activity assay for water-soluble antioxidants using a modified CUPRAC method.

PubMed

Bektaşoğlu, Burcu; Esin Celik, Saliha; Ozyürek, Mustafa; Güçlü, Kubilay; Apak, Reşat

2006-07-07

Reactive oxygen species (ROS) such as superoxide anion, hydroxyl ((*)OH), peroxyl, and alkoxyl radicals may attack biological macromolecules giving rise to oxidative stress-originated diseases. Since (*)OH is very short-lived, secondary products resulting from (*)OH attack to various probes are measured. Although the measurement of aromatic hydroxylation with HPLC/electrochemical detection is more specific than the low-yield TBARS test, it requires sophisticated instrumentation. As a more convenient and less costly alternative, we used p-aminobenzoate, 2,4- and 3,5-dimethoxybenzoate probes for detecting hydroxyl radicals generated from an equivalent mixture of Fe(II)+EDTA with hydrogen peroxide. The produced hydroxyl radicals attacked both the probe and the water-soluble antioxidants in 37 degrees C-incubated solutions for 2h. The CUPRAC (i.e., our original method for total antioxidant capacity assay) absorbance of the ethylacetate extract due to the reduction of Cu(II)-neocuproine reagent by the hydroxylated probe decreased in the presence of (*)OH scavengers, the difference being proportional to the scavenging ability of the tested compound. A rate constant for the reaction of the scavenger with hydroxyl radical can be deduced from the inhibition of color formation. The second-order rate constants of the scavengers were determined with competition kinetics by means of a linear plot of A(0)/A as a function of C(scavenger)/C(probe), where A(0) and A are the CUPRAC absorbances of the system in the absence and presence of scavenger, respectively, and C is the molar concentration of relevant species. The 2,4- and 3,5-dimethoxybenzoates were the best probes in terms of linearity and sensitivity. Iodide, metabisulfite, hexacyanoferrate(II), thiourea, formate, and dimethyl sulfoxide were shown by the modified CUPRAC assay to be more effective scavengers than mannitol, glucose, lysine, and simple alcohols, as in the TBARS assay. The developed method is less lengthy, more specific, and of a higher yield than the classical TBARS assay. The hydroxyl radical scavenging rate constants of ascorbic acid, formate, and hexacyanoferrate(II) that caused interference in other assays could be easily found with the proposed procedure.

Pistachio (Pistacia vera L.) gum: a potent inhibitor of reactive oxygen species.

PubMed

Sehitoglu, M Hilal; Han, Hatice; Kalin, Pınar; Gülçin, İlhami; Ozkan, Ali; Aboul-Enein, Hassan Y

2015-04-01

In the present study, in order to evaluate antioxidant and radical scavenging properties of Pistachio gum (P-Gum), different bioanalytical methods such as DPPH(•) scavenging activity, DMPD(•+) radical scavenging activity, total antioxidant activity determination by ferric thiocyanate, reducing ability Fe(3+)-Fe(2+) transformation, Cuprac and FRAP assays, O2(•-) scavenging by riboflavin-methionine-illuminate system and ferrous ions (Fe(2+)) chelating activities by 2,2'-bipyridyl reagent were performed separately. P-Gum inhibited 54.2% linoleic acid peroxidation at 10 µg/ml concentration. On the other hand, BHA, BHT, α-tocopherol and trolox, pure antioxidant compounds, indicated inhibition of 80.3%, 73.5%, 36.2% and 72.0% on peroxidation of linoleic acid emulsion at the same concentration, respectively. In addition, all of sample had an effective DPPH(•), DMPD(•+) and O2(•-) scavenging, Fe(3+) reducing power by Fe(3+)-Fe(2+) transformation and FRAP assay, Cu(2+) reducing ability by Cuprac method and Fe(2+) chelating activities.

THE WATER-WATER CYCLE IN CHLOROPLASTS: Scavenging of Active Oxygens and Dissipation of Excess Photons.

PubMed

Asada, Kozi

1999-06-01

Photoreduction of dioxygen in photosystem I (PSI) of chloroplasts generates superoxide radicals as the primary product. In intact chloroplasts, the superoxide and the hydrogen peroxide produced via the disproportionation of superoxide are so rapidly scavenged at the site of their generation that the active oxygens do not inactivate the PSI complex, the stromal enzymes, or the scavenging system itself. The overall reaction for scavenging of active oxygens is the photoreduction of dioxygen to water via superoxide and hydrogen peroxide in PSI by the electrons derived from water in PSII, and the water-water cycle is proposed for these sequences. An overview is given of the molecular mechanism of the water-water cycle and microcompartmentalization of the enzymes participating in it. Whenever the water-water cycle operates properly for scavenging of active oxygens in chloroplasts, it also effectively dissipates excess excitation energy under environmental stress. The dual functions of the water-water cycle for protection from photoinihibition are discussed.

Active-oxygen scavenging activity of plant extracts.

PubMed

Masaki, H; Sakaki, S; Atsumi, T; Sakurai, H

1995-01-01

To find antioxidative compounds present in plants, 65 types of plant extract were tested using the neotetrazolium method for evidence of superoxide anion-scavenging effects and 7 plant extracts were selected for further investigation. The activity of active-oxygen scavengers such as superoxide anion radicals, hydroxyl radicals, singlet oxygens and lipid peroxides in the 7 plant extracts (Aeseclus hippocastanum L., Hamamelis virginiana L. Polygonum cuspidatum Sieb., Quercus robur L., Rosemarinous officinalis L., Salvia officinalis L. and Sanguisorba officinalis L.) was examined in detail by both ESR spin-trapping and malondialdehyde generation. Furthermore, the active-oxygen scavenging activity of these plant extracts was evaluated using a murine dermal fibroblast culture system. Both Aeseclus hippocastanum L. and Hamamelis virginia L. were found to have strong active-oxygen scavenging activity of and protective activity against cell damage induced by active oxygen. Both Aeseclus hippocastanum L. and Hamamelis virginiana L. are proposed as potent plant extracts with potential application as anti-aging or anti-wrinkle material for the skin.

Volcanic ash as an oceanic iron source and sink

NASA Astrophysics Data System (ADS)

Rogan, Nicholas; Achterberg, Eric P.; Le Moigne, Frédéric A. C.; Marsay, Chris M.; Tagliabue, Alessandro; Williams, Richard G.

2016-03-01

Volcanic ash deposition to the ocean forms a natural source of iron (Fe) to surface water microbial communities. Inputs of lithogenic material may also facilitate Fe removal through scavenging. Combining dissolved Fe (dFe) and thorium-234 observations alongside modeling, we investigate scavenging of Fe in the North Atlantic following the Eyjafjallajökull volcanic eruption. Under typical conditions biogenic particles dominate scavenging, whereas ash particles dominate during the eruption. The size of particles is important as smaller scavenging particles can become saturated with surface-associated ions. Model simulations indicate that ash deposition associated with Eyjafjallajökull likely led to net Fe removal. Our model suggests a threefold greater stimulation of biological activity if ash deposition had occurred later in the growing season when the region was Fe limited. The implications of ash particle scavenging, eruption timing, and particle saturation need to be considered when assessing the impact of ash deposition on the ocean Fe cycle and productivity.

Antioxidant properties of a radical-scavenging peptide purified from enzymatically prepared fish skin gelatin hydrolysate.

PubMed

Mendis, Eresha; Rajapakse, Niranjan; Kim, Se-Kwon

2005-02-09

Hoki (Johnius belengerii) skin gelatin was hydrolyzed with three commercial enzymes to identify radical-scavenging potencies of derived peptides. Peptides derived from tryptic hydrolysate exhibited the highest scavenging activities on superoxide, carbon-centered 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals assessed by ESR spectroscopy. Following consecutive chromatographic separations of tryptic hydroolysate, the peptide sequence His-Gly-Pro-Leu-Gly-Pro-Leu (797 Da) acted as a strong radical scavenger under studied conditions. Further, this peptide could act as an antioxidant against linoleic acid peroxidation and the activity was closer to the highly active synthetic antioxidant butylated hydroxytoluene (BHT). In addition, antioxidative enzyme levels in cultured human hepatoma cells were increased in the presence of this peptide and it was presumed to be the peptide involved in maintaining the redox balance in the cell environment. Present data indicate that free-radical-scavenging activities of hoki skin gelatin peptides substantially contribute to their antioxidant properties measured in different oxidative systems.

Comparison of scavenging capacities of vegetables by ORAC and EPR.

PubMed

Kameya, Hiromi; Watanabe, Jun; Takano-Ishikawa, Yuko; Todoriki, Setsuko

2014-02-15

Reactive oxygen species (ROS) are considered to be causative agents of many health problems. In spite of this, the radical-specific scavenging capacities of food samples have not been well studied. In the present work, we have developed an electron paramagnetic resonance (EPR) spin trapping method for analysis of the scavenging capacities of food samples for multiple ROS, utilising the same photolysis procedure for generating each type of radical. The optimal conditions for effective evaluation of hydroxyl, superoxide, and alkoxyl radical scavenging capacity were determined. Quantification of radical adducts was found to be highly reproducible, with variations of less than 4%. The optimised EPR spin trapping method was used to analyse the scavenging capacities of 54 different vegetable extracts for multiple radicals, and the results were compared with oxygen radical absorption capacity values. Good correlations between the two methods were observed for superoxide and alkoxyl radicals, but not for hydroxyl. Copyright © 2013 Elsevier Ltd. All rights reserved.

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

Immune Suppression by Dermal Application of JP-8 Jet Fuel

DTIC Science & Technology

2008-10-13

expressed the ROS scavengers, catalase or superoxide dismutase, ROS induction was significantly 4 STANDARD FORM 298 Back (Rev. 8/98) depressed ...Similarly, when keratinocytes that over-expressed the ROS scavengers were treated with JP-8, COX-2 expression was substantially depressed . We also...free radical scavengers, such as Vitamin C and N- acetylcysteine , we are blocking an early step in the pathway, ROS production. When we use parthenolide

Constraints from Airborne (210)Pb Observations on Aerosol Scavenging and Lifetime in a Global Chemical Transport Model

NASA Technical Reports Server (NTRS)

Zhang, Bo; Liu, Hongyu; Crawford, James H.; Fairlie, Duncan T.; Chen, Gao; Dibb, Jack E.; Shah, Viral; Sulprizio, Melissa P.; Yantosca, Robert M.

2016-01-01

Lead-210 distribution and lifetime in the atmosphere are not sensitive to ice in-cloud scavenging in convective updraft. Ice in-cloud scavenging in stratiform clouds reduce tropospheric (210)Pb lifetime by approximately 1 day and results in better agreements with observed surface observations and aircraft measured profiles. However, the process results in significant underestimate of (210)Pb in UT/LS.

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.

[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.

Free radical scavenging window of infertile patients with polycystic ovary syndrome: correlation with embryo quality.

PubMed

Huang, Bo; Li, Zhou; Ren, Xinling; Ai, Jihui; Zhu, Lixia; Jin, Lei

2017-06-01

The activity of free radicals in follicular fluid was related to ovarian responsiveness, in vitro fertilization (IVF), and embryo transfer success rate. However, studies analyzing the relationship between the free radical scavenging capacity and embryo quality of infertile women with polycystic ovarian syndrome (PCOS) were lacking. The aim of this study was to evaluate the relationship between the free radical scavenging window of women with PCOS and their embryo quality. The free radical scavenging capacity of follicular fluid from women with PCOS was determined by a,a-diphenyl-b-picrylhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzthiazoline-6-sulphonic acid) assay, superoxide radical, and reactive oxygen species (ROS) assay. In the DPPH and ROS assays, the follicular fluid from grades I and II embryos was significantly higher than the follicular fluid from grades III and IVembryos. The lower control limit of DPPH radical scavenging capacity and upper control limit of ROS level were 13.2% and 109.0 cps, respectively. The calculated lower control limit and upper control limit were further confirmed in the follicular fluid of embryos of all grades. These cut-off values of free radical scavenging activity of follicular fluid could assist embryologists in choosing the development of embryos in PCOS patients undergoing IVF.

Antioxidant activities of methanol extract of Sambucus ebulus L. flower.

PubMed

Ebrahimzadeh, M A; Nabavi, S F; Nabavi, S M

2009-03-01

In this study antioxidant activity of methanol extract of Sambucus ebulus L. flower was investigated employing various in vitro assay systems, i.e., DPPH and nitric oxide radical scavenging, hydrogen peroxide scavenging, reducing power, iron ion chelating power and linoleic acid. IC50 for DPPH radical-scavenging activity was 228 +/- 12 microg mL(-1). The extract showed very high activity in the reducing power assay that was comparable with positive control, vitamin C. The extract showed good nitric oxide-scavenging activity (IC50 = 309 +/- 14 microg mL(-1). It was found that antioxidant activity was dose dependent i.e., activity was increased with the increase of their concentrations. The extract showed very weak activity in iron ion chelating (IC50 = 1.3 +/- 0.07 mg mL(-1)). It is showed very good activity in scavenging of hydrogen'peroxide. IC50 for scavenging of extract was 59.5 +/- 3.3 mcirog mL(-1). The extracts exhibited no activity in linoleic acid model. The total phenolic content of flower was 56.3 +/- 2.81 mg gallic acid equivalent g(-1) of extract powder and total flavonoid content was 14.5 +/- 0.72 mg quercetin equivalent g(-1) of extract powder by reference to standard curve.

Multiple free-radical scavenging capacity in serum

PubMed Central

Oowada, Shigeru; Endo, Nobuyuki; Kameya, Hiromi; Shimmei, Masashi; Kotake, Yashige

2012-01-01

We have developed a method to determine serum scavenging-capacity profile against multiple free radical species, namely hydroxyl radical, superoxide radical, alkoxyl radical, alkylperoxyl radical, alkyl radical, and singlet oxygen. This method was applied to a cohort of chronic kidney disease patients. Each free radical species was produced with a common experimental procedure; i.e., uv/visible-light photolysis of free-radical precursor/sensitizer. The decrease in free-radical concentration by the presence of serum was quantified with electron spin resonance spin trapping method, from which the scavenging capacity was calculated. There was a significant capacity change in the disease group (n = 45) as compared with the healthy control group (n = 30). The percent values of disease’s scavenging capacity with respect to control group indicated statistically significant differences in all free-radical species except alkylperoxyl radical, i.e., hydroxyl radical, 73 ± 12% (p = 0.001); superoxide radical, 158 ± 50% (p = 0.001); alkoxyl radical, 121 ± 30% (p = 0.005); alkylperoxyl radical, 123 ± 32% (p>0.1); alkyl radical, 26 ± 14% (p = 0.001); and singlet oxygen, 57 ± 18% (p = 0.001). The scavenging capacity profile was illustrated using a radar chart, clearly demonstrating the characteristic change in the disease group. Although the cause of the scavenging capacity change by the disease state is not completely understood, the profile of multiple radical scavenging capacities may become a useful diagnostic tool. PMID:22962529

Carcasses of invasive species are predominantly utilized by invasive scavengers in an island ecosystem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abernethy, Erin F.; Turner, Kelsey L.; Beasley, James C.

Invasive species have significantly affected ecosystems, particularly islands, and species invasions continue with increasing globalization. Largely unstudied, the influence of invasive species on island ecosystem functions, especially scavenging and decomposition, could be substantive. Quantifying carcass utilization by different scavengers and shifts in community dynamics in the presence of invasive animals is of particular interest for understanding impacts on nutrient recycling. Invasive species could benefit greatly from carcass resources within highly invaded island ecosystems, through increased invasion success and population growth, subsequently exacerbating their impacts on native species. Here, we quantified how experimentally placed invasive amphibian, reptile, small mammal, and birdmore » carcasses were utilized by vertebrate and invertebrate scavengers on the Big Island of Hawai’i in three island habitats: a barren lava field, a vegetated lava field, and a rainforest. We used camera traps to record vertebrate scavengers removing carcasses and elapsed time until removal. We evaluated differences in cavenging between vertebrates and invertebrates and within the vertebrate community across different habitats and carcass types. Despite the small carcass sizes (<1 kg) used in this study, 55% of carcasses were removed by vertebrate scavengers, all invasive: mongoose, rodents, cats, pigs, and a common myna. Our data indicate that invasive vertebrate scavengers in this island ecosystem are highly efficient at assimilating a range of carrion resources across a variety of habitats. Carcasses of invasive animals could contribute substantially to energy budgets of other invasive vertebrate species. Finally, this may be a critical component contributing to successful invasions especially on islands and subsequent impacts on ecosystem function.« less

Carcasses of invasive species are predominantly utilized by invasive scavengers in an island ecosystem

DOE PAGES

Abernethy, Erin F.; Turner, Kelsey L.; Beasley, James C.; ...

2016-10-01

Invasive species have significantly affected ecosystems, particularly islands, and species invasions continue with increasing globalization. Largely unstudied, the influence of invasive species on island ecosystem functions, especially scavenging and decomposition, could be substantive. Quantifying carcass utilization by different scavengers and shifts in community dynamics in the presence of invasive animals is of particular interest for understanding impacts on nutrient recycling. Invasive species could benefit greatly from carcass resources within highly invaded island ecosystems, through increased invasion success and population growth, subsequently exacerbating their impacts on native species. Here, we quantified how experimentally placed invasive amphibian, reptile, small mammal, and birdmore » carcasses were utilized by vertebrate and invertebrate scavengers on the Big Island of Hawai’i in three island habitats: a barren lava field, a vegetated lava field, and a rainforest. We used camera traps to record vertebrate scavengers removing carcasses and elapsed time until removal. We evaluated differences in cavenging between vertebrates and invertebrates and within the vertebrate community across different habitats and carcass types. Despite the small carcass sizes (<1 kg) used in this study, 55% of carcasses were removed by vertebrate scavengers, all invasive: mongoose, rodents, cats, pigs, and a common myna. Our data indicate that invasive vertebrate scavengers in this island ecosystem are highly efficient at assimilating a range of carrion resources across a variety of habitats. Carcasses of invasive animals could contribute substantially to energy budgets of other invasive vertebrate species. Finally, this may be a critical component contributing to successful invasions especially on islands and subsequent impacts on ecosystem function.« less

The oxygen-centered radicals scavenging activity of sulfasalazine and its metabolites. A direct protection of the bowel.

PubMed

Prónai, L; Yukinobu, I; Láng, I; Fehér, J

1992-01-01

Oxygen-centered radicals, such as superoxide (O2-) and hydroxyl radicals (.OH) generated by phagocytes have been suggested to be involved in the pathogenesis of chronic inflammations of the bowel, such as Crohn's disease and colitis ulcerosa. Recently, sulfasalazine (SASP) and its metabolites have been reported to exert their effects as a direct scavenger of oxygen-centered radicals in the bowel. To scavenge oxygen-centered radicals in vivo, however, SASP and its metabolites have to react with O2- and/or .OH in vitro very rapidly, furthermore they have to reach an appropriate (possible millimolar) concentration range at the site of inflammation. To test this possibility, we investigated the direct O2- and .OH scavenging activity of SASP and its metabolites using the specific electron paramagnetic resonance/spin trapping method, and we compared the 50% inhibition rates of SASP and its metabolites with their known concentrations in the bowel and in the human plasma. It was found that SASP and its metabolites, such as 5-amino-salicylic acid (5-ASA), and acetyl-5-amino-salicylic acid (AC-5-ASA), but not sulfapyridine (SP) and acetyl-sulfapyridine (Ac-SP) have a direct O2- and .OH scavenging activity in vitro systems. Among the compounds, SASP and 5-ASA can reach a concentration which is appropriate to scavenge oxygen-centered radicals in the bowel but not in the human plasma. It was concluded that the in vivo antiinflammatory effects of SASP and its metabolites are, at least partly, due to the direct oxygen-centered scavenging activity of these drugs.

High throughput assay for evaluation of reactive carbonyl scavenging capacity.

PubMed

Vidal, N; Cavaille, J P; Graziani, F; Robin, M; Ouari, O; Pietri, S; Stocker, P

2014-01-01

Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

The effect of a Ta oxygen scavenger layer on HfO 2-based resistive switching behavior: Thermodynamic stability, electronic structure, and low-bias transport

DOE PAGES

Zhong, Xiaoliang; Rungger, Ivan; Zapol, Peter; ...

2016-02-15

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/HfO 2/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 themore » 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. Lastly, we show that the low-bias conductance of device on-states becomes much less sensitive to the spatial distribution of oxygen removed from the HfO 2 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.« less

A protocol for detecting and scavenging gas-phase free radicals in mainstream cigarette smoke.

PubMed

Yu, Long-Xi; Dzikovski, Boris G; Freed, Jack H

2012-01-02

Cigarette smoking is associated with human cancers. It has been reported that most of the lung cancer deaths are caused by cigarette smoking (5,6,7,12). Although tobacco tars and related products in the particle phase of cigarette smoke are major causes of carcinogenic and mutagenic related diseases, cigarette smoke contains significant amounts of free radicals that are also considered as an important group of carcinogens(9,10). Free radicals attack cell constituents by damaging protein structure, lipids and DNA sequences and increase the risks of developing various types of cancers. Inhaled radicals produce adducts that contribute to many of the negative health effects of tobacco smoke in the lung(3). Studies have been conducted to reduce free radicals in cigarette smoke to decrease risks of the smoking-induced damage. It has been reported that haemoglobin and heme-containing compounds could partially scavenge nitric oxide, reactive oxidants and carcinogenic volatile nitrosocompounds of cigarette smoke(4). A 'bio-filter' consisted of haemoglobin and activated carbon was used to scavenge the free radicals and to remove up to 90% of the free radicals from cigarette smoke(14). However, due to the cost-ineffectiveness, it has not been successfully commercialized. Another study showed good scavenging efficiency of shikonin, a component of Chinese herbal medicine(8). In the present study, we report a protocol for introducing common natural antioxidant extracts into the cigarette filter for scavenging gas phase free radicals in cigarette smoke and measurement of the scavenge effect on gas phase free radicals in mainstream cigarette smoke (MCS) using spin-trapping Electron Spin Resonance (ESR) Spectroscopy(1,2,14). We showed high scavenging capacity of lycopene and grape seed extract which could point to their future application in cigarette filters. An important advantage of these prospective scavengers is that they can be obtained in large quantities from byproducts of tomato or wine industry respectively(11,13).

Pre-recombination quenching of the radiation induced fluorescence as the approach to study kinetics of ion-molecular reactions

NASA Astrophysics Data System (ADS)

Borovkov, V. I.; Ivanishko, I. S.

2011-04-01

This study deals with the geminate ion recombination in the presence of bulk scavengers, that is the so-called scavenger problem, as well as with the effect of the scavenging reaction on the radiation-induced recombination fluorescence. Borovkov and Velizhanin (2004) have proposed a method to determine the rate constant of the bulk reaction between neutral scavengers and one of the geminate ions if the ion-molecular reaction prevented the formation of electronically excited states upon recombination involving a newly formed ion. If such pre-recombination quenching of the radiation-induced fluorescence took place, it manifested itself as a progressive decrease in the decay of the fluorescence intensity. The relative change in the fluorescence decay as caused by the scavengers was believed to be closely related to the kinetics of the scavenging reaction. The goal of the present study is to support this method, both computationally and experimentally because there are two factors, which cast doubt on the intuitively obvious approach to the scavenger problem: spatial correlations between the particles involved and the drift of the charged reagent in the electric field of its geminate partner. Computer simulation of geminate ions recombination with an explicit modeling of the motion trajectories of scavengers has been performed for media of low dielectric permittivity, i.e. for the maximal Coulomb interaction between the ions. The simulation has shown that upon continuous diffusion of the particles involved, the joint effect of the two above factors can be considered as insignificant with a high accuracy. Besides, it is concluded then that the method of pre-recombination quenching could be applied to study parallel and consecutive reactions where the yields of excited states in the reaction pathways are different with the use of very simple analytical relations of the formal chemical kinetics. The conclusion has been confirmed experimentally by the example of the reactions of electron transfer from the diphenylacetylene radical anion to dibromoethane and hexafluorobenzene in n-dodecane solutions.

High Throughput Immunomagnetic Scavenging Technique for ...

EPA Pesticide Factsheets

Journal Article This article describes a novel immunomagnetic scavenging (IMSc) technique for extracting cholinesterase inhibitors from aqueous matrixes using biological targeting and antibody-based extraction.

Increasing the volumetric efficiency of Diesel engines by intake pipes

NASA Technical Reports Server (NTRS)

List, Hans

1933-01-01

Development of a method for calculating the volumetric efficiency of piston engines with intake pipes. Application of this method to the scavenging pumps of two-stroke-cycle engines with crankcase scavenging and to four-stroke-cycle engines. The utility of the method is demonstrated by volumetric-efficiency tests of the two-stroke-cycle engines with crankcase scavenging. Its practical application to the calculation of intake pipes is illustrated by example.

Effects of ionic radius of redox-inactive bio-related metal ions on the radical-scavenging activity of flavonoids evaluated using photometric titration.

PubMed

Waki, Tsukasa; Kobayashi, Shigeki; Matsumoto, Ken-ichiro; Ozawa, Toshihiko; Kamada, Tadashi; Nakanishi, Ikuo

2013-10-28

Mg(2+) enhanced the scavenging activity of (+)-catechin and quercetin against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙), while Al(3+) decreased their activity. Such effects of Mg(2+) and Al(3+) were not observed for kaempferol. Na(+) and Ca(2+) with large ionic radii showed little effect on the DPPH˙-scavenging activity of these three flavonoids.

Expression of the macrophage scavenger receptor, a multifunctional lipoprotein receptor, in microglia associated with senile plaques in Alzheimer's disease.

PubMed Central

Christie, R. H.; Freeman, M.; Hyman, B. T.

1996-01-01

The macrophage scavenger receptor is a multifunctional receptor whose ligands include oxidized low density lipoprotein (LDL), as well as several other polyanionic macromolecules. Although the capacity of the receptor to bind modified LDL has implicated it in the process of atherosclerosis, its physiological role remains uncertain. We have examined human brain for expression of macrophage scavenger receptor as part of ongoing studies of lipoprotein receptors in the central nervous system. The receptor is expressed on microglia, but not on astrocytes, neurons, or vessel-associated structures. In Alzheimer disease, there is strong expression of the scavenger receptor in association with senile plaques. Images Figure 2 Figure 3 Figure 4 PMID:8579103

Scavenging energy from human motion with tubular dielectric polymer

NASA Astrophysics Data System (ADS)

Jean-Mistral, Claire; Basrour, Skandar

2010-04-01

Scavenging energy from human motion is a challenge to supply low consumption systems for sport or medical applications. A promising solution is to use electroactive polymers and especially dielectric polymers to scavenge mechanical energy during walk. In this paper, we present a tubular dielectric generator which is the first step toward an integration of these structures into textiles. For a 10cm length and under a strain of 100%, the structure is able to scavenge 1.5μJ for a poling voltage of 200V and up to 40μJ for a poling voltage of 1000V. A 30cm length structure is finally compared to our previous planar structure, and the power management module for those structures is discussed.

Effects of Wegener-Bergeron-Findeisen Process on Global Black Carbon Distribution

NASA Astrophysics Data System (ADS)

Qi, L.

2016-12-01

In mixed-phase clouds, the Wegener-Bergeron-Findeisen (WBF) process (ice crystals may grow while water drops evaporate, thereby releasing black carbon (BC) particles into the interstitial air) slows down wet scavenging of BC. Rimming (snowflakes fall and collect cloud water drops and the BC in them along their pathways), in contrast, results in more efficient wet scavenging. We systematically investigate the effects of WBF on BC scavenging efficiency, surface BCair, deposition flux, concentration in snow, and washout ratio using a global 3D chemical transport model. We differentiate riming- vs WBF-dominated in-cloud scavenging based on liquid water content and temperature. Specifically, we relate WBF to either temperature or ice mass fraction in mixed-phase clouds. We find that at Jungfraujoch, Switzerland and Abisko, Sweden, where WBF dominates, the discrepancies of simulated BC scavenging efficiency and washout ratio are significantly reduced (from a factor of 3 to 10% and from a factor of 4-5 to a factor of two). However, at Zeppelin, Norway, where riming dominates, simulation of BC scavenging efficiency, BCair, and washout ratio become worse (relative to observations) when WBF is included. There is thus an urgent need for extensive observations to distinguish and characterize riming- versus WBF-dominated aerosol scavenging in mixed-phase clouds and the associated BC scavenging efficiency. We find the reduction resulting from WBF to global BC scavenging efficiency varies substantially, from 8% in the tropics to 76% in the Arctic. The resulting annual mean BCair increases by up to 156% at high altitudes and at northern high latitudes. Overall, WBF halves the model-observation discrepancy (from -65% to -30%) of BCair across North America, Europe, China and the Arctic. Globally WBF increases BC burden from 0.22 to 0.29-0.35 mg m-2 yr-1, which partially explains the gap between observed and previous model simulated BC burdens over land (Bond et al., 2013). In addition, WBF significantly increases BC lifetime from 5.7 days to 8 days. We find that WBF decreases BCsnow at mid-latitudes (by 15%) but increases it in the Arctic (by 26%) while improving model comparisons with observations. In addition, WBF dramatically reduces the model-observation discrepancy of washout ratios in winter (from a factor of 16 to 4).

Free Radical Scavenging Properties of Annona squamosa

PubMed

Vikas, Biba; Akhil B, S; P, Remani; Sujathan, K

2017-10-26

Annona squamosa has extensively been used in the traditional and folkloric medicine and found to possess many biological activities. Different solvents, petroleum ether, chloroform, ethyl acetate and methanol extracts of Annona squamosa seeds (ASPE, ASCH, ASEA, ASME) have been used to prepare plant extracts. The present investigations dealt with the free radical scavenging activity of four extracts using various techniques such as total reducing power estimation, total phenolic count, 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical scavenging effect, evaluation of ABTS cation decolorisation capacity, FRAP assay, hdroxyl radical scavenging assay, super oxide assay and Nitric oxide radical scavenging assay of the extracts. The results showed that the four extracts of Annona squamosa showed significant reducing power in four extracts. The total phenolic contents in petroleum ether, chloroform, ethyl acetate, methanol extracts and positive control were 0.64±0.17, 0.54±0.27, 0.49±0.24, 0.57±0.22 and 0.66±0.33. The antioxidant capacity by ABTS assay of ASPE, ASCH, ASEA, ASME and positive control, trolox showed 77.75±0.5,73.25±1.7,78.5± 1.2 , 80 ± 0.8 μg/ml and 94.2 ± 0.9 respectively. The (50 % scavenging activity) SA50 of ASPE and ASCH, ASEA and ASME was found to be 34.4 μg/ml, 43.8 μg/ml 34.7 μg/m and 28.8 μg/ml respectively by DPPH assay. The percentage of hydroxyl radical scavenging increased with the increasing concentration of the extracts. ASPE, ASCH, ASEA and ASME showed superoxide radical scavenging activity, as indicated by their values 66 ± 0.5, 68 ± 1 ,63 ± 1 and 70 ± 0.5 μg/ml respectively compared to gallic acid which was 97 ± 0.5 μg/ml. The values for scavenging of nitric oxide for ASPE, ASCH, ASEA and ASME were 91.0 ± 1.0, 66.75 ± 0.5, 71.75 ± 1.1 and 75.75 ± 1.15 μg/ml while value for standard ascorbic acid was 91.0 ± 1.0 μg/ml. The results revealed strong antioxidants in four extracts may lead to the development of potent antioxidant agents from Annona squamosa seeds. Creative Commons Attribution License

Absorption rates and free radical scavenging values of vitamin C-lipid metabolites in human lymphoblastic cells.

PubMed

Weeks, Benjamin S; Perez, Pedro P

2007-10-01

In this study we investigated the cellular absorption rates, antioxidant and free radical scavenging activity of vitamin C-lipid metabolites. The absorption was measured in a human lymphoblastic cell line using a spectrophotometric technique. Cellular vitamin C levels in the human lymphoblastic H9 cell line were measured using the 2,4-dinitrophenylhydrazine spectrophotometric technique. Free radical scavenging activity of vitamin C-lipid metabolites was measured by the reduction of 1,1-diphenyl-2-picryl hydrazyl (DPPH) to 1,1-diphenyl-2-picryl hydrazine. Vitamin C-lipid metabolite scavenging of peroxyl radical oxygen reactive species (ORAC) was determined by fluorescence spectrophotometry. Compared to ascorbic acid (AA), calcium ascorbate (CaA), and calcium ascorbate-calcium threonate-dehydroascorbate (Ester-C), vitamin C-lipid metabolites (PureWay-C) were more rapidly absorbed by the H9 human T-lymphocytes. The vitamin C-lipid metabolites (PureWay-C) also reduced pesticide-induced T-lymphocyte aggregation by 84%, while calcium ascorbate-calcium threonate-dehydroascorbate (Ester-C) reduced aggregation by only 34%. The vitamin C-lipid metabolites (PureWay-C) demonstrated free radical scavenging activity of nearly 100% reduction of DPPH at 20 microg/ml and oxygen radical scavenging of over 1200 micro Trolox equivalents per gram. These data demonstrate that the vitamin C-lipid metabolites (PureWay-C) are more rapidly taken-up and absorbed by cells than other forms of vitamin C, including Ester-C. This increased rate of absorption correlates with an increased protection of the T-lymphocytes from pesticide toxicities. Further, vitamin C-lipid metabolites (PureWay-C) are a potent antioxidant and have significant free radical scavenging capabilities.

The Impact of Flight Hardware Scavenging on Space Logistics

NASA Technical Reports Server (NTRS)

Oeftering, Richard C.

2011-01-01

For a given fixed launch vehicle capacity the logistics payload delivered to the moon may be only roughly 20 percent of the payload delivered to the International Space Station (ISS). This is compounded by the much lower flight frequency to the moon and thus low availability of spares for maintenance. This implies that lunar hardware is much more scarce and more costly per kilogram than ISS and thus there is much more incentive to preserve hardware. The Constellation Lunar Surface System (LSS) program is considering ways of utilizing hardware scavenged from vehicles including the Altair lunar lander. In general, the hardware will have only had a matter of hours of operation yet there may be years of operational life remaining. By scavenging this hardware the program, in effect, is treating vehicle hardware as part of the payload. Flight hardware may provide logistics spares for system maintenance and reduce the overall logistics footprint. This hardware has a wide array of potential applications including expanding the power infrastructure, and exploiting in-situ resources. Scavenging can also be seen as a way of recovering the value of, literally, billions of dollars worth of hardware that would normally be discarded. Scavenging flight hardware adds operational complexity and steps must be taken to augment the crew s capability with robotics, capabilities embedded in flight hardware itself, and external processes. New embedded technologies are needed to make hardware more serviceable and scavengable. Process technologies are needed to extract hardware, evaluate hardware, reconfigure or repair hardware, and reintegrate it into new applications. This paper also illustrates how scavenging can be used to drive down the cost of the overall program by exploiting the intrinsic value of otherwise discarded flight hardware.

The scavenging of volatile anesthetic agents in the cardiovascular intensive care unit environment: a technical report.

PubMed

Pickworth, Thomas; Jerath, Angela; DeVine, Rita; Kherani, Nazmin; Wąsowicz, Marcin

2013-01-01

The use of volatile-based sedation within critical care environments has been limited by difficulties of drug administration and safety concerns over environment pollution and staff exposure in an intensive care unit (ICU) with no scavenging. The aim of this study was to develop a simple scavenging system to be used with the Anesthesia Conserving Device (AnaConDa(®)) and to determine whether or not ambient concentrations of residual anesthetic are within current acceptable limits. The scavenging system consists of two Deltasorb(®) canisters attached to the ICU ventilator in series. AnaConDa is a miniature vaporizer designed to provide volatile-based sedation within an ICU. The first ten patients recruited into a larger randomized trial assessing outcomes after elective coronary graft bypass surgery were sedated within the cardiac ICU using either isoflurane or sevoflurane. Sedation was guided by the Sedation Agitation Scale, resulting in an end-tidal minimum anesthetic concentration of volatile agent ranging from 0.1-0.3. At one hour post ICU admission, infrared photometric analysis was used to assess environmental contamination at four points along the ventilator circuit and scavenging system and around the patient's head. All measurements taken within the patient's room were below 1 part per million, which satisfies criteria for occupational exposure. This study shows that volatile agents can be administered safely within critical care settings using a simple scavenging system. Our scavenging system used in conjunction with the AnaConDa device reduced the concentration of environmental contamination to a level that is acceptable to Canadian standards and standards in most Western countries and thus conforms to international safety standards. The related clinical trial was registered at www.clinicaltrials.gov (NCT01151254).

The Effects of Scavenging on Waste Methoxyflurane Concentrations in Veterinary Operating Room Air

DTIC Science & Technology

1981-01-01

Afl-AO5 572 AIR FORCE OCCUPATIONAL AND ENVIRONMENTAL H4EALTH LAS -ETC F/S 6120 TIE EFFECTS OF SCAVENGING ON WASTE METHOXYFLURANE CONCENTRATIOH-ETC...REPRINT The Effects of Scavenging on Waste Methoxyflurane Concentrations in Veterinary Operating Room Air Approved for public release; distribution...Waste Methoxyflurane Fnal y t Concentrations ir Veterinary Operating Room Air, 6.PROMN _6._PERFORMIN oIG. REPORT NUMBER 7. AUTOR~s)B. CONTRACT OR GRANT

Free radical scavenging activity and neuroprotective potentials of D138, one Cu(II)/Zn(II) Schiff-base complex derived from N,N'-bis(2-hydroxynaphthylmethylidene)-1,3-propanediamine.

PubMed

Wang, Che; Cai, Zheng-Xu; You, Zhong-Lu; Guo, Hui-Shu; Shang, De-Jing; Wang, Xiao-Ling; Zhang, Liang; Ma, Li-Jie; Tan, Jun; Le, Wei-Dong; Li, Song

2014-09-01

There is increasing evidence that free radicals play an important role in neuronal damages induced by diabetes mellitus or cerebral ischemia insults. Antioxidants with free radical scavenging activities have been shown to be beneficial and neuroprotective for these pathological conditions. Here, we report free radical scavenging activity and neuroprotective potential of D138, one copper(II)/zinc(II) Schiff-base complex derived from N,N'-2(2-hydroxynaphthylmethylidene)-1,3-propanediamine. The data from three in vitro assays, 2,2-diphenyl-1-picrylhydrazyl assay, nitro blue tetrazolium assay and hydroxyl radical scavenging assay, indicated that D138 presented a potent free radical scavenging activity. The neuroprotective and antioxidative effects of D138 were further evaluated in vivo using bilateral common carotid artery occlusion (BCCAO) mouse model and streptozotocin (STZ) diabetic mouse model. Our results indicated that treatment of D138 significantly ameliorated the hippocampal neuronal damage and the oxidative stress levels in these animal models. Moreover, D138 also reversed the behavioral deficiencies induced by BCCAO or STZ, as assessed by Y-maze test and fear conditioning test. In conclusion, all these findings support that D138 exerts free radical scavenging and neuroprotective activities and has the potentials to be a potent therapeutic candidate for brain oxidative damage induced by cerebral ischemia or diabetes mellitus.

Free radical scavenging and COX-2 inhibition by simple colon metabolites of polyphenols: A theoretical approach.

PubMed

Amić, Ana; Marković, Zoran; Marković, Jasmina M Dimitrić; Jeremić, Svetlana; Lučić, Bono; Amić, Dragan

2016-12-01

Free radical scavenging and inhibitory potency against cyclooxygenase-2 (COX-2) by two abundant colon metabolites of polyphenols, i.e., 3-hydroxyphenylacetic acid (3-HPAA) and 4-hydroxyphenylpropionic acid (4-HPPA) were theoretically studied. Different free radical scavenging mechanisms are investigated in water and pentyl ethanoate as a solvent. By considering electronic properties of scavenged free radicals, hydrogen atom transfer (HAT) and sequential proton loss electron transfer (SPLET) mechanisms are found to be thermodynamically probable and competitive processes in both media. The Gibbs free energy change for reaction of inactivation of free radicals indicates 3-HPAA and 4-HPPA as potent scavengers. Their reactivity toward free radicals was predicted to decrease as follows: hydroxyl>alkoxyls>phenoxyl≈peroxyls>superoxide. Shown free radical scavenging potency of 3-HPAA and 4-HPPA along with their high μM concentration produced by microbial colon degradation of polyphenols could enable at least in situ inactivation of free radicals. Docking analysis with structural forms of 3-HPAA and 4-HPPA indicates dianionic ligands as potent inhibitors of COX-2, an inducible enzyme involved in colon carcinogenesis. Obtained results suggest that suppressing levels of free radicals and COX-2 could be achieved by 3-HPAA and 4-HPPA indicating that these compounds may contribute to reduced risk of colon cancer development. Copyright © 2016 Elsevier Ltd. All rights reserved.

Scavenging capacity of strawberry tree (Arbutus unedo L.) leaves on free radicals.

PubMed

Oliveira, Ivo; Coelho, Valentim; Baltasar, Raquel; Pereira, José Alberto; Baptista, Paula

2009-07-01

Despite strawberry tree (Arbutus unedo L.) leaves had a long use in traditional medicine due to its antiseptic, diuretic, astringent and depurative properties, the potential of their antioxidant activity are still lacking. Our study goals to assess the antioxidant and free radical scavenging potential of water, ethanol, methanol and diethyl ether extracts of A. unedo leaves. Total phenols content was achieved spectrophotometrically using Folin-Ciocalteau reagent with gallic acid as standard. Antioxidant activity was evaluated using three different methods: reducing power of iron (III)/ferricyanide complex assay, scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and scavenging effect on superoxide radicals by using the PMS-NADH-nitroblue tetrazolium system. Ethanol extracts of A. unedo leaves were the highest in reducing power (IC(50) 232.7 microg/mL) and DPPH scavenging effect (IC(50) 63.2 microg/mL) followed by water extracts (with IC(50) of 287.7 and 73.7 microg/mL, respectively); whereas diethyl ether extracts were the lowest. In the scavenging on superoxide radical assay, methanol extracts obtained the best results (IC(50) 6.9 microg/mL). For all the methods tested the antioxidant activity was concentration dependent. In accordance with antioxidant activity, highest total phenols content were found in ethanol, followed by water, methanol and diethyl ether extract. The results indicated that A. unedo leaves are a potential source of natural antioxidants.

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.

The preparation and antioxidant activity of glucosamine sulfate

NASA Astrophysics Data System (ADS)

Xing, Ronge; Liu, Song; Wang, Lin; Cai, Shengbao; Yu, Huahua; Feng, Jinhua; Li, Pengcheng

2009-05-01

Glucosamine sulfate was prepared from glucosamine hydrochloride that was produced by acidic hydrolysis of chitin by ion-exchange method. Optical rotation and elemental analysis characterized the degree of its purity. In addition, the antioxidant potency of chitosan derivative-glucosamine sulfate was investigated in various established in vitro systems, such as superoxide (O{2/-})/hydroxyl (·OH) radicals scavenging, reducing power, iron ion chelating. The following results are obtained: first, glucosamine sulfate had pronounced scavenging effect on superoxide radical. For example the O{2/-} scavenging activity of glucosamine sulfate was 92.11% at 0.8 mg/mL. Second, the ·OH scavenging activity of glucosamine sulfate was also strong, and was about 50% at 3.2 mg/mL. Third, the reducing power of glucosamine sulfate was more pronounced. The reducing power of glucosamine sulfate was 0.643 at 0.75 mg/mL. However, its potency for ferrous ion chelating was weak. Furthermore, except for ferrous ion chelating potency, the scavenging rate of radical and reducing power of glucosamine sulfate were concentration-dependent and increased with their increasing concentrations, but its ferrous ion chelating potency decreased with the increasing concentration. The multiple antioxidant activities of glucosamine sulfate were evidents of reducing power and superoxide/hydroxyl radicals scavenging ability. These in vitro results suggest the possibility that glucosamine sulfate could be used effectively as an ingredient in health or functional food, to alleviate oxidative stress.

[Comparison of waste anesthetic gases in operating rooms with or without an scavenging system in a Brazilian University Hospital].

PubMed

Braz, Leandro Gobbo; Braz, José Reinaldo Cerqueira; Cavalcante, Guilherme Aparecido Silva; Souza, Kátina Meneghetti; Lucio, Lorena Mendes de Carvalho; Braz, Mariana Gobbo

Occupational exposure to waste anesthetic gases in operating room (OR) without active scavenging system has been associated with adverse health effects. Thus, this study aimed to compare the trace concentrations of the inhaled anesthetics isoflurane and sevoflurane in OR with and without central scavenging system. Waste concentrations of isoflurane and sevoflurane were measured by infrared analyzer at different locations (near the respiratory area of the assistant nurse and anesthesiologist and near the anesthesia station) and at two times (30 and 120minutes after the start of surgery) in both OR types. All isoflurane and sevoflurane concentrations in unscavenged OR were higher than the US recommended limit (2 parts per million), regardless of the location and time evaluated. In scavenged OR, the average concentrations of isoflurane were within the limit of exposure, except for the measurements near the anesthesia station, regardless of the measurement times. For sevoflurane, concentrations exceeded the limit value at all measurement locations and at both times. The exposure to both anesthetics exceeded the international limit in unscavenged OR. In scavenged OR, the concentrations of sevoflurane, and to a lesser extent those of isoflurane, exceeded the recommended limit value. Thus, the OR scavenging system analyzed in the present study decreased the anesthetic concentrations, although not to the internationally recommended values. Copyright © 2017 Sociedade Brasileira de Anestesiologia. Publicado por Elsevier Editora Ltda. All rights reserved.

Novel Water Soluble Chitosan Derivatives with 1,2,3-Triazolium and Their Free Radical-Scavenging Activity

PubMed Central

Li, Qing; Sun, Xueqi; Gu, Guodong

2018-01-01

Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium charged units by associating “click reaction” with efficient 1,2,3-triazole quaternization were designed and synthesized. Their free radical-scavenging activity against three free radicals was tested. The inhibitory property and water solubility of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. It is hypothesized that triazole or triazolium groups enable the synthesized chitosan to possess obviously better radical-scavenging activity. Moreover, the scavenging activity against superoxide radical of chitosan derivatives with triazolium (IC50 < 0.01 mg mL−1) was more efficient than that of derivatives with triazole and Vitamin C. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical-scavenging assay, the same pattern were observed, which should be related to the triazolium grafted at the periphery of molecular chains. PMID:29597269

Novel Water Soluble Chitosan Derivatives with 1,2,3-Triazolium and Their Free Radical-Scavenging Activity.

PubMed

Li, Qing; Sun, Xueqi; Gu, Guodong; Guo, Zhanyong

2018-03-28

Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium charged units by associating "click reaction" with efficient 1,2,3-triazole quaternization were designed and synthesized. Their free radical-scavenging activity against three free radicals was tested. The inhibitory property and water solubility of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. It is hypothesized that triazole or triazolium groups enable the synthesized chitosan to possess obviously better radical-scavenging activity. Moreover, the scavenging activity against superoxide radical of chitosan derivatives with triazolium (IC 50 < 0.01 mg mL -1 ) was more efficient than that of derivatives with triazole and Vitamin C. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical-scavenging assay, the same pattern were observed, which should be related to the triazolium grafted at the periphery of molecular chains.

EVALUATION OF FREEZE DRIED ALOE VERA AND NOPAL CACTUS FOR POSSIBLE HEALTH TREATMENTS BY COMPARISON OF ANTIOXIDANT PROPERTIES AND FREE RADICAL INHIBITION.

PubMed

Rodriguez, Kenneth R; Jones, Anthony E; Belmont, Barbara

2014-01-01

The goal of this project was to characterize the antioxidant powers of lyophilized Aloe Vera ( Aloe barbadensis ) and Nopal Cactus (Opuntia ficus-indica) by quantifying the phenolics content and radical scavenging abilities of preparations derived from these plants. Extracts of these lyophylized succulents were assayed for phenolic compounds by the Folin Ciocalteau method and compared for free radical scavenging capability by the DPPH method. We found that even though the Aloe lyophilizate extract contained more phenolic content, the Nopal lyophilizate exhibited better free radical scavenging ability. Aloe Vera extract contained 0.278 g/L of phenolic content and exhibited 11.1% free radical inhibition, with a free radical scavenging rate constant of 0.177±0.015 min -1 . Nopal Cactus extract contained 0.174 g/L of phenolic content and exhibited 13.2% free radical inhibition, with a free radical scavenging rate constant of 0.155±0.009 min -1 . These results showed Nopal to have greater antioxidant potency than Aloe.

Screening of Potential Free Radicals Scavenger and Antibacterial Activities of Purwoceng (Pimpinella alpina Molk).

PubMed

Wahyuningrum, Retno; Utami, Pri Iswati; Dhiani, Binar Asrining; Kumalasari, Malikhah; Kusumawardani, Rizka Sari

2016-11-01

Purwoceng ( Pimpinella alpina Molk) is a traditional medicinal plant used for its aphrodisiac values. This plant was originated Dieng Plateu, Central Java, Indonesia. Purwoceng has been reported to contain steroid, flavonoids, glycoside, saponins, tannins, and phenolic. Based on secondary metabolite compounds of Purwoceng herbs, a research need to be done to determine the other potential free radicals scavenger and antibacterial activities of Purwoceng. The objectives of this research are to screen the potential free radicals scavenger activity of in vitro using DPPH (1,1 diphenyl-2-picryl-hydrazil) radicals and NO• (nitric oxide) radicals, and antibacterial activity of Purwoceng. The extraction is done by a maceration method with petroleum ether, ethyl acetate, and ethanol solvent, respectively. Free radicals scavenger test was performed using DPPH radicals and NO• radicals, while antibacterial activity screening was performed using agar diffusion test. The results showed that ethyl acetate extract of Purwoceng has free radical scavenger activity with IC50 53.07 ppm lower than butylated hydroxytoluene. Ethyl acetate extract and ethanol extract of Purwoceng have antibacterial activity against Staphyloccus aureus , Escherichia coli , and MG42 bacterial isolate.

EVALUATION OF FREEZE DRIED ALOE VERA AND NOPAL CACTUS FOR POSSIBLE HEALTH TREATMENTS BY COMPARISON OF ANTIOXIDANT PROPERTIES AND FREE RADICAL INHIBITION

PubMed Central

Jones, Anthony E.; Belmont, Barbara

2016-01-01

The goal of this project was to characterize the antioxidant powers of lyophilized Aloe Vera (Aloe barbadensis) and Nopal Cactus (Opuntia ficus-indica) by quantifying the phenolics content and radical scavenging abilities of preparations derived from these plants. Extracts of these lyophylized succulents were assayed for phenolic compounds by the Folin Ciocalteau method and compared for free radical scavenging capability by the DPPH method. We found that even though the Aloe lyophilizate extract contained more phenolic content, the Nopal lyophilizate exhibited better free radical scavenging ability. Aloe Vera extract contained 0.278 g/L of phenolic content and exhibited 11.1% free radical inhibition, with a free radical scavenging rate constant of 0.177±0.015 min−1. Nopal Cactus extract contained 0.174 g/L of phenolic content and exhibited 13.2% free radical inhibition, with a free radical scavenging rate constant of 0.155±0.009 min−1. These results showed Nopal to have greater antioxidant potency than Aloe. PMID:27284273

The antioxidant and radical scavenging activities of black pepper (Piper nigrum) seeds.

PubMed

Gülçin, Ilhami

2005-11-01

Water and ethanol crude extracts from black pepper (Piper nigrum) were investigated for their antioxidant and radical scavenging activities in six different assay, namely, total antioxidant activity, reducing power, 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, and metal chelating activities. Both water extract (WEBP) and ethanol extract (EEBP) of black pepper exhibited strong total antioxidant activity. The 75 microg/ml concentration of WEBP and EEBP showed 95.5% and 93.3% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, at the same concentration, standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and alpha-tocopherol exhibited 92.1%, 95.0%, and 70.4% inhibition on peroxidation of linoleic acid emulsion, respectively. Also, total phenolic content in both WEBP and EEBP were determined as gallic acid equivalents. The total phenolics content of water and ethanol extracts were determined by the Folin-Ciocalteu procedure and 54.3 and 42.8 microg gallic acid equivalent of phenols was detected in 1 mg WEBP and EEBP.

Effect of ultrafine grinding on physicochemical and antioxidant properties of dietary fiber from wine grape pomace.

PubMed

Zhu, Feng-Mei; Du, Bin; Li, Jun

2014-01-01

Wine grape pomace dietary fiber powders were prepared by superfine grinding, whose effects were investigated on the composition, functional and antioxidant properties of the wine grape pomace dietary fiber products. The results showed that superfine grinding could effectively pulverize the fiber particles to submicron scale. As particle size decrease, the functional properties (water-holding capacity, water-retention capacity, swelling capacity, oil-binding capacity, and nitrite ion absorption capacity) of wine grape pomace dietary fiber were significantly (p < 0.05) decreased and a redistribution of fiber components from insoluble to soluble fractions was observed. The antioxidant activities of wine grape pomace and dietary fiber before and after grinding were in terms of DPPH radical scavenging activity, ABTS diammonium salt radical scavenging activity, ferric reducing antioxidant power, and total phenolic content. Compared with dietary fiber before and after grinding, micronized insoluble dietary fiber showed increased ABTS radical scavenging activity, ferric reducing antioxidant power, and total phenolic content yet decreased DPPH radical scavenging activity. Positive correlations were detected between ABTS radical scavenging activity, ferric reducing antioxidant power, and total phenolic content.

Kinetic Reaction Mechanism of Sinapic Acid Scavenging NO2 and OH Radicals: A Theoretical Study

PubMed Central

Lu, Yang; Wang, AiHua; Shi, Peng; Zhang, Hui; Li, ZeSheng

2016-01-01

The mechanism and kinetics underlying reactions between the naturally-occurring antioxidant sinapic acid (SA) and the very damaging ·NO2 and ·OH were investigated through the density functional theory (DFT). Two most possible reaction mechanisms were studied: hydrogen atom transfer (HAT) and radical adduct formation (RAF). Different reaction channels of neutral and anionic sinapic acid (SA-) scavenging radicals in both atmosphere and water medium were traced independently, and the thermodynamic and kinetic parameters were calculated. We find the most active site of SA/SA- scavenging ·NO2 and ·OH is the –OH group in benzene ring by HAT mechanism, while the RAF mechanism for SA/SA- scavenging ·NO2 seems thermodynamically unfavorable. In water phase, at 298 K, the total rate constants of SA eliminating ·NO2 and ·OH are 1.30×108 and 9.20×109 M-1 S-1 respectively, indicating that sinapic acid is an efficient scavenger for both ·NO2 and ·OH. PMID:27622460

Isolation and Characterization of the 2,2'-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) Radical Cation-Scavenging Reaction Products of Arbutin.

PubMed

Tai, Akihiro; Ohno, Asako; Ito, Hideyuki

2016-09-28

Arbutin, a glucoside of hydroquinone, has shown strong 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation-scavenging activity, especially in reaction stoichiometry. This study investigated the reaction mechanism of arbutin against ABTS radical cation that caused high stoichiometry of arbutin in an ABTS radical cation-scavenging assay. HPLC analysis of the reaction mixture of arbutin and ABTS radical cation indicated the existence of two reaction products. The two reaction products were purified and identified to be a covalent adduct of arbutin with an ABTS degradation fragment and 3-ethyl-6-sulfonate benzothiazolone. A time-course study of the radical-scavenging reactions of arbutin and the two reaction products suggested that one molecule of arbutin scavenges three ABTS radical cation molecules to generate an arbutin-ABTS fragment adduct as a final reaction product. The results suggest that one molecule of arbutin reduced two ABTS radical cation molecules to ABTS and then cleaved the third ABTS radical cation molecule to generate two products, an arbutin-ABTS fragment adduct and 3-ethyl-6-sulfonate benzothiazolone.

New derivatives of 3,4-dihydroisoquinoline-3-carboxylic acid with free-radical scavenging, D-amino acid oxidase, acetylcholinesterase and butyrylcholinesterase inhibitory activity.

PubMed

Solecka, Jolanta; Guśpiel, Adam; Postek, Magdalena; Ziemska, Joanna; Kawęcki, Robert; Lęczycka, Katarzyna; Osior, Agnieszka; Pietrzak, Bartłomiej; Pypowski, Krzysztof; Wyrzykowska, Agata

2014-09-30

A series of 3,4-dihydroisoquinoline-3-carboxylic acid derivatives were synthesised and tested for their free-radical scavenging activity using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS·+), superoxide anion radical (O2·-) and nitric oxide radical (·NO) assays. We also studied d-amino acid oxidase (DAAO), acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) inhibitory activity. Almost each of newly synthesised compounds exhibited radical scavenging capabilities. Moreover, several compounds showed moderate inhibitory activities against DAAO, AChE and BuChE. Compounds with significant free-radical scavenging activity may be potential candidates for therapeutics used in oxidative-stress-related diseases.

Component analysis and free radicals scavenging activity of Cicer arietinum L. husk pectin.

PubMed

Urias-Orona, Vania; Huerta-Oros, Joselina; Carvajal-Millán, Elizabeth; Lizardi-Mendoza, Jaime; Rascón-Chu, Agustin; Gardea, Alfonso A

2010-10-11

A pectin (CAP) was extracted from the husk of Cicer arietinum L. Monosaccharide analysis of CAP revealed the dominance of galacturonic acid and smaller amounts of galactose, arabinose, rhamnose, glucose, xylose and mannose. Viscosimetric analysis showed that the intrinsic viscosity ([η]) and the molecular weight (MW) of CAP were 296 mL/g and 105 kDa, respectively. The degree of esterification (DE = 10%) was determined by FTIR spectroscopy. CAP exhibited a dose-dependent free radical scavenging activity, as shown by its DPPH radical inhibition. At 1.0 mg/mL CAP exhibited a scavenging rate of 29% on DPPH radicals. The evaluation of antioxidant activity suggested that CAP had good potential for DPPH radical scavenging activity and should be explored as a novel potential antioxidant.

Radical quenching by rosmarinic acid from Lavandula vera MM cell culture.

PubMed

Kovacheva, Elena; Georgiev, Milen; Pashova, Svetlana; Angelova, Maria; Ilieva, Mladenka

2006-01-01

This study was conducted to evaluate the radical scavenging capacities of extracts and preparations from a Lavandula vera MM plant cell culture with different rosmarinic acid content and to compare them with pure rosmarinic and caffeic acids as well. The methods, which were used are superoxide anion and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radicals scavenging assays. Results showed that extracts and preparations from Lavandula vera MM possess strong radical scavengers, as the best both radical scavengers appeared to be the fractions with enriched rosmarinic acid content, obtained after ethylacetate fractioning (47.7% inhibition of superoxide radicals and 14.2 microM 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid equivalents, respectively). These data reveal the possibilities for application of these preparations as antioxidants.

Amino acid composition and antioxidant capacity of Spanish honeys.

PubMed

Pérez, Rosa Ana; Iglesias, María Teresa; Pueyo, Encarnación; Gonzalez, Montserrat; de Lorenzo, Cristina

2007-01-24

The amino acid composition of 53 honey samples from Spain, consisting of 39 floral, 5 honeydew, and 9 blend honeys, has been determined. Physicochemical characteristics, polyphenolic content, amino acid composition, and estimation of the radical scavenging capacity against the stable free radical DPPH of the honey samples were analyzed. The resulting data have been statistically evaluated. The results showed that pH, acidity, net absorbance, electrical conductivity, and total polyphenolic contents of the honeys showed a strong correlation with the radical scavenging capacity. The correlation between the radical scavenging capacity of honey and amino acid contents was high with 18 of the 20 amino acids detected, with correlation values higher than those obtained for polyphenolic content. These results suggest that the amino acid composition of honey is an indicator of the sample's scavenging capacity.

Confrontational scavenging as a possible source for language and cooperation

PubMed Central

2011-01-01

The emergence of language and the high degree of cooperation found among humans seems to require more than a straightforward enhancement of primate traits. Some triggering episode unique to human ancestors was likely necessary. Here it is argued that confrontational scavenging was such an episode. Arguments for and against an established confrontational scavenging niche are discussed, as well as the probable effects of such a niche on language and co-operation. Finally, several possible directions for future research are suggested. PMID:21933413

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.

1,1-Diphenyl-2-picrylhydrazyl radical-scavenging compounds from soybean miso and antiproliferative activity of isoflavones from soybean miso toward the cancer cell lines.

PubMed

Hirota, A; Taki, S; Kawaii, S; Yano, M; Abe, N

2000-05-01

Guided by their DPPH radical-scavenging activity, nine compounds were isolated from soybean miso. Of these, 8-hydroxydaidzein, 8-hydroxygenistein and syringic acid had as high DPPH radical-scavenging activity as that of alpha-tocopherol. The antiproliferative activity of four of the isolated isoflavones toward three cancer cell lines was examined. 8-Hydroxygenistein showed the highest activity (IC50=5.2 microM) toward human promyelocytic leukemia cells (HL-60).

Virtual Scavenger Hunt: An AI-Powered Virtual Environment Designed for Training Individuals in Effective Teamwork, and Analyzing Cross-Cultural Behavior

DTIC Science & Technology

2009-03-20

involved the development of an environment within the Multiverse virtual world, oriented toward allowing individuals to acquire and reinforce skills via...PetBrain software G2: Creation of a scavenger hunt scenario in the Multiverse virtual world, in which humans and AIs can collaboratively play scavenger...carried out by Novamente LLC for AOARD during June 2008 ? February 2009. It involved the development of an environment within the Multiverse virtual world

Free radical-scavenging delta-lactones from Boletus calopus.

PubMed

Kim, Jin-Woo; Yoo, Ick-Dong; Kim, Won-Gon

2006-12-01

The methanol extracts from the fruiting body of the mushroom Boletus calopus showed free radical-scavenging activity. Bioactivity-guided fractionation of the methanol extracts led to a new hydroxylated calopin named calopin B, along with the known delta-lactones calopin and cyclocalopin A. The structure of the new calopin analogue was elucidated by spectroscopic methods. All compounds showed potent free radical-scavenging activity against superoxide, DPPH, and ABTS radicals with IC (50) values of 1.2 - 5.4 microg/mL.

Scavenging of long-lived radicals by (-)-epigallocatechin-3- O-gallate and simultaneous suppression of mutation in irradiated mammalian cells

NASA Astrophysics Data System (ADS)

Kumagai, Jun; Nakama, Mitsuo; Miyazaki, Tetsuo; Ise, Tamaki; Kodama, Seiji; Watanabe, Masami

2002-07-01

Effect of (-)-epigallocatechin-3- O-gallate (EGCg) on scavenging long-lived radicals and its biological significance were investigated using electron-spin-resonance spectroscopy and mutation assay in cultured human embryo cells. EGCg scavenged long-lived radicals in irradiated golden hamster embryo cells and albumin solution, and simultaneously reduced mutation frequency in the irradiated human embryo cells. These results indicate that long-lived radials are involved in the induction of mutation by radiation.

Forensically significant scavenging guilds in the southwest of Western Australia.

PubMed

O'Brien, R Christopher; Forbes, Shari L; Meyer, Jan; Dadour, Ian

2010-05-20

Estimation of time since death is an important factor in forensic investigations and the state of decomposition of a body is a prime basis for such estimations. The rate of decomposition is, however, affected by many environmental factors such as temperature, rainfall, and solar radiation as well as by indoor or outdoor location, covering and the type of surface the body is resting upon. Scavenging has the potential for major impact upon the rate of decomposition of a body, but there is little direct research upon its effect. The information that is available relates almost exclusively to North American and European contexts. The Australian faunal assemblage is unique in that it includes no native large predators or large detrivorous avians. This research investigates the animals that scavenge carcasses in natural outdoor settings in southern Western Australia and the factors which can affect each scavenger's activity. The research was conducted at four locations around Perth, Western Australia with different environmental conditions. Pig carcasses, acting as models for the human body, were positioned in an outdoor environment with no protection from scavengers or other environmental conditions. Twenty-four hour continuous time-lapse video capture was used to observe the pattern of visits of all animals to the carcasses. The time of day, length of feeding, material fed upon, area of feeding, and any movement of the carcass were recorded for each feeding event. Some species were observed to scavenge almost continually throughout the day and night. Insectivores visited the carcasses mostly during bloat and putrefaction; omnivores fed during all stages of decomposition and scavenging by carnivores, rare at any time, was most likely to occur during the early stages of decomposition. Avian species, which were the most prolific visitors to the carcasses in all locations, like reptiles, fed only during daylight hours. Only mammals and amphibians, which were seldom seen during diurnal hours, were nocturnal feeders. The combined effects of the whole guild of scavengers significantly accelerated the later stages of decomposition, especially in the cooler months of the year when natural decomposition was slowest.

Phytochemical investigations and antioxidant potential of roots of Leea macrophylla (Roxb.).

PubMed

Mahmud, Zobaer Al; Bachar, Sitesh C; Hasan, Choudhury Mahmood; Emran, Talha Bin; Qais, Nazmul; Uddin, Mir Muhammad Nasir

2017-07-06

Oleanolic acid (NZ-15), 7 α, 28-olean diol (NZ-38) and Stigmasterol (NZ-14) were isolated from the ethanolic extracts of the roots of Leea macrophylla (Family: Leeaceae) by using chromatographic analysis. This is the first report of isolation of these compounds from this plant. Their structures were constructed by spectroscopic analysis and by comparing the data with the published one. Subsequently the ethanolic extract was fractionated with two organic solvents and all the fractions were studied to evaluate their in vitro antioxidant property. The ethanolic extract was fractionated with two organic solvents and all the fractions were studied to evaluate their in vitro antioxidant property by DPPH free radical scavenging assay, superoxide anion radical scavenging assay, nitric oxide radical scavenging assay, and reducing power assay. In the DPPH free radical scavenging assay and superoxide radical scavenging assay, the ethyl acetate soluble fraction of ethanolic extract revealed the highest free radical scavenging activity with IC 50 value of 2.65 and 155.62 μg/ml, respectively as compared to standard ascorbic acid (IC 50 value of 5.8 and 99.66 μg/ml). Ethyl acetate fraction also possessed highest reducing power activity with an EC50 value of 15.27 μg/ml compared to ascorbic acid (EC 50 0.91 μg/ml). On the other hand, the carbon tetrachloride fraction exhibited most significant NO scavenging activity with IC 50 value of 277.8 μg/ml that was even higher than that of standard ascorbic acid (IC 50 value 356.04 μg/ml). In addition, the total phenolic contents of these extract and fractions were evaluated using Folin-Ciocalteu reagent and varied from 7.93 to 50.21 mg/g dry weight expressed as gallic acid equivalents (GAE). This study showed that different extracts of roots of L. macrophylla possess potential DPPH, superoxide, and NO free radical scavenging activities. The antioxidant activities of the plant extracts might be due to the presence of oleanolic acid, oleanolic acid derivative 7 α, 28-olean diol and stigmasterol.

Crank case scavenging of two-stroke-cycle engines

NASA Technical Reports Server (NTRS)

List, Hans

1929-01-01

This report presents the results of tests on two-stroke-cycle Diesel engines to determine the efficiency of the crank case scavenging pump. It was determined that efficiencies were between 95 and 100%.

Extensive screening for herbal extracts with potent antioxidant properties

PubMed Central

Niwano, Yoshimi; Saito, Keita; Yoshizaki, Fumihiko; Kohno, Masahiro; Ozawa, Toshihiko

2011-01-01

This paper summarizes our research for herbal extracts with potent antioxidant activity obtained from a large scale screening based on superoxide radical (O2•−) scavenging activity followed by characterization of antioxidant properties. Firstly, scavenging activity against O2•− was extensively screened from ethanol extracts of approximately 1000 kinds of herbs by applying an electron spin resonance (ESR)-spin trapping method, and we chose four edible herbal extracts with prominently potent ability to scavenge O2•−. They are the extracts from Punica granatum (Peel), Syzygium aromaticum (Bud), Mangifera indica (Kernel), and Phyllanthus emblica (Fruit). These extracts were further examined to determine if they also scavenge hydroxyl radical (•OH), by applying the ESR spin-trapping method, and if they have heat resistance as a desirable characteristic feature. Experiments with the Fenton reaction and photolysis of H2O2 induced by UV irradiation demonstrated that all four extracts have potent ability to directly scavenge •OH. Furthermore, the scavenging activities against O2•− and •OH of the extracts of P. granatum (peel), M. indica (kernel) and P. emblica (fruit) proved to be heat-resistant. The results of the review might give useful information when choosing a potent antioxidant as a foodstuff. For instance, the four herbal extracts chosen from extensive screening possess desirable antioxidant properties. In particular, the extracts of the aforementioned three herbs are expected to be suitable for food processing in which thermal devices are used, because of their heat resistance. PMID:21297917

Correlation among Singlet-Oxygen Quenching, Free-Radical Scavenging, and Excited-State Intramolecular-Proton-Transfer Activities in Hydroxyflavones, Anthocyanidins, and 1-Hydroxyanthraquinones.

PubMed

Nagaoka, Shin-Ichi; Bandoh, Yuki; Nagashima, Umpei; Ohara, Keishi

2017-10-26

Singlet-oxygen ( 1 O 2 ) quenching, free-radical scavenging, and excited-state intramolecular proton-transfer (ESIPT) activities of hydroxyflavones, anthocyanidins, and 1-hydroxyanthraquinones were studied by means of laser, stopped-flow, and steady-state spectroscopies. In hydroxyflavones and anthocyanidins, the 1 O 2 quenching activity positively correlates to the free-radical scavenging activity. The reason for this correlation can be understood by considering that an early step of each reaction involves electron transfer from the unfused phenyl ring (B-ring), which is singly bonded to the bicyclic chromen or chromenylium moiety (A- and C-rings). Substitution of an electron-donating OH group at B-ring enhances the electron transfer leading to activation of the 1 O 2 quenching and free-radical scavenging. In 3-hydroxyflavones, the OH substitution at B-ring reduces the activity of ESIPT within C-ring, which can be explained in terms of the nodal-plane model. As a result, the 1 O 2 quenching and free-radical scavenging activities negatively correlate to the ESIPT activity. A catechol structure at B-ring is another factor that enhances the free-radical scavenging in hydroxyflavones. In contrast to these hydroxyflavones, 1-hydroxyanthraquinones having an electron-donating OH substituent adjacent to the O-H---O═C moiety susceptible to ESIPT do not show a simple correlation between their 1 O 2 quenching and ESIPT activities, because the OH substitution modulates these reactions.

Nitric oxide scavengers differentially inhibit ammonia oxidation in ammonia-oxidizing archaea and bacteria.

PubMed

Sauder, Laura A; Ross, Ashley A; Neufeld, Josh D

2016-04-01

Differential inhibitors are important for measuring the relative contributions of microbial groups, such as ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), to biogeochemical processes in environmental samples. In particular, 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO) represents a nitric oxide scavenger used for the specific inhibition of AOA, implicating nitric oxide as an intermediate of thaumarchaeotal ammonia oxidation. This study investigated four alternative nitric oxide scavengers for their ability to differentially inhibit AOA and AOB in comparison to PTIO. Caffeic acid, curcumin, methylene blue hydrate and trolox were tested onNitrosopumilus maritimus, two unpublished AOA representatives (AOA-6f and AOA-G6) as well as the AOB representative Nitrosomonas europaea All four scavengers inhibited ammonia oxidation by AOA at lower concentrations than for AOB. In particular, differential inhibition of AOA and AOB by caffeic acid (100 μM) and methylene blue hydrate (3 μM) was comparable to carboxy-PTIO (100 μM) in pure and enrichment culture incubations. However, when added to aquarium sponge biofilm microcosms, both scavengers were unable to inhibit ammonia oxidation consistently, likely due to degradation of the inhibitors themselves. This study provides evidence that a variety of nitric oxide scavengers result in differential inhibition of ammonia oxidation in AOA and AOB, and provides support to the proposed role of nitric oxide as a key intermediate in the thaumarchaeotal ammonia oxidation pathway. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Antioxidant properties of ferulic acid and its related compounds.

PubMed

Kikuzaki, Hiroe; Hisamoto, Masashi; Hirose, Kanae; Akiyama, Kayo; Taniguchi, Hisaji

2002-03-27

Antioxidant activity of 24 ferulic acid related compounds together with 6 gallic acid related compounds was evaluated using several different physical systems as well as their radical scavenging activity. The radical scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) decreased in the order caffeic acid > sinapic acid > ferulic acid > ferulic acid esters > p-coumaric acid. In bulk methyl linoleate, test hydroxycinnamic acids and ferulic acid esters showed antioxidant activity in parallel with their radical scavenging activity. In an ethanol-buffer solution of linoleic acid, the activity of test compounds was not always associated with their radical scavenging activity. Ferulic acid was most effective among the tested phenolic acids. Esterification of ferulic acid resulted in increasing activity. The activity of alkyl ferulates was somewhat influenced by the chain length of alcohol moiety. When the inhibitory effects of alkyl ferulates against oxidation of liposome induced by AAPH were tested, hexyl, octyl, and 2-ethyl-1-hexyl ferulates were more active than the other alkyl ferulates. Furthermore, lauryl gallate is most effective among the tested alkyl gallates. These results indicated that not only the radical scavenging activity of antioxidants, but also their affinity with lipid substrates, might be important factors in their activity.

Supplanting ecosystem services provided by scavengers raises greenhouse gas emissions

NASA Astrophysics Data System (ADS)

Morales-Reyes, Zebensui; Pérez-García, Juan M.; Moleón, Marcos; Botella, Francisco; Carrete, Martina; Lazcano, Carolina; Moreno-Opo, Rubén; Margalida, Antoni; Donázar, José A.; Sánchez-Zapata, José A.

2015-01-01

Global warming due to human-induced increments in atmospheric concentrations of greenhouse gases (GHG) is one of the most debated topics among environmentalists and politicians worldwide. In this paper we assess a novel source of GHG emissions emerged following a controversial policy decision. After the outbreak of bovine spongiform encephalopathy in Europe, the sanitary regulation required that livestock carcasses were collected from farms and transformed or destroyed in authorised plants, contradicting not only the obligations of member states to conserve scavenger species but also generating unprecedented GHG emission. However, how much of this emission could be prevented in the return to traditional and natural scenario in which scavengers freely remove livestock carcasses is largely unknown. Here we show that, in Spain (home of 95% of European vultures), supplanting the natural removal of dead extensive livestock by scavengers with carcass collection and transport to intermediate and processing plants meant the emission of 77,344 metric tons of CO2 eq. to the atmosphere per year, in addition to annual payments of ca. $50 million to insurance companies. Thus, replacing the ecosystem services provided by scavengers has not only conservation costs, but also important and unnecessary environmental and economic costs.

Extraction and free radical scavenging activity of polysaccharide from 'Anji Baicha' (Camellia sinensis (L.) O. Kuntze).

PubMed

Zhang, Zhongshan; Wang, Xiaomei; Li, Jingfen; Wang, Guozhi; Mao, Genxiang

2016-03-01

In this study, the optimization of the extraction conditions of polysaccharide from 'Anji Baicha' (Camellia sinensis (L.) O. Kuntze) (AP) was investigated by response surface methodology (RSM). Three main independent variables (extraction temperature, time, ratio of water to raw material) were taken into consideration. And then the free radical scavenging activities of the sample were investigated including scavenging effects of superoxide and hydroxyl radicals. The RSM analysis showed good correspondence between experimental and predicted values.. The optimal condition to obtain the highest yield of AP was determined as follows: temperature 76.79 °C, time 2.48 h, ratio of water to material 22.53 mL/g. For the free radical scavenging activity, the IC50 values of Vc and AP were 7.78 and 83.25 μg/mL. And for the scavenging effect on hydroxyl radical, that of AP and Vc were 1.80 and 1.69 mg/mL. AP showed excellent antioxidant activity. This exhibited AP had a good potential for antioxidant. The purification and structure needs to be study in further. Copyright © 2015 Elsevier B.V. All rights reserved.

Serum Hydroxyl Radical Scavenging Capacity as Quantified with Iron-Free Hydroxyl Radical Source

PubMed Central

Endo, Nobuyuki; Oowada, Shigeru; Sueishi, Yoshimi; Shimmei, Masashi; Makino, Keisuke; Fujii, Hirotada; Kotake, Yashige

2009-01-01

We have developed a simple ESR spin trapping based method for hydroxyl (OH) radical scavenging-capacity determination, using iron-free OH radical source. Instead of the widely used Fenton reaction, a short (typically 5 seconds) in situ UV-photolysis of a dilute hydrogen peroxide aqueous solution was employed to generate reproducible amounts of OH radicals. ESR spin trapping was applied to quantify OH radicals; the decrease in the OH radical level due to the specimen’s scavenging activity was converted into the OH radical scavenging capacity (rate). The validity of the method was confirmed in pure antioxidants, and the agreement with the previous data was satisfactory. In the second half of this work, the new method was applied to the sera of chronic renal failure (CRF) patients. We show for the first time that after hemodialysis, OH radical scavenging capacity of the CRF serum was restored to the level of healthy control. This method is simple and rapid, and the low concentration hydrogen peroxide is the only chemical added to the system, that could eliminate the complexity of iron-involved Fenton reactions or the use of the pulse-radiolysis system. PMID:19794928

The effect of RU 486 and related compounds on cultured macrophage differentiation and function.

PubMed

Roberts, C P; Murphy, A A; Santanam, N; Parthasarathy, S

1996-08-01

Our purpose was to examine RU 486 and related compounds on macrophage scavenger receptors and cellular adhesion. THP-1 cells were activated with phorbol myristate acetate and treated with dexamethasone, levonorgestrel, and RU 486 alone or in combination. Scavenger receptor activity was determined by counting adhered cells. In addition, fluorescently labeled acetyl low density lipoprotein uptake was determined. Both dexamethasone and RU 486 significantly decreased activated macrophages (81% and 26% of control). Levonorgestrel stimulated adherent cells in activated monocytes (130% of control). RU 486 and dexamethasone were antagonistic when combined (p < 0.001). In contrast, dexamethasone could not overcome the stimulatory effect of levonorgestrel (p < 0.001). Fluorescent studies yielded similar results. RU 486 is a known antiglucocorticoid with novel antioxidant properties. Levonorgestrel has antiglucocorticoid but no antioxidant activity. Glucocorticoids decrease scavenger receptors and antioxidants regulate inflammatory cytokines. RU 486 antagonized the inhibitory effect of dexamethasone on scavenger receptors, whereas levonorgestrel was stimulatory. It is therapeutically important to up-regulate scavenger receptor activity by antiglucocorticoids in the peritoneal cavity of women with endometriosis. However, because these mechanisms also induce inflammatory cytokines, a balance of antioxidants and antiglucocorticoids may prove beneficial.

Antioxidant activity and oxidative stress protection of duck proteins hydrolysates in SK-N-SH cells.

PubMed

Guo, Yuxing; Pan, Daodong; Wu, Zhen; Zhao, Chuanchuan; Cao, Jinxuan

2013-02-26

Studies have found that natural antioxidants, which are free-radical scavengers, can reduce the risk of diseases caused by free radicals. This work investigated the antioxidant properties of duck proteins hydrolysates. The free-radical scavenging function of CP-1 (M(r) > 10 kDa), CP-2 (5 kDa < M(r) < 10 kDa) and CP-3 (M(r) < 5 kDa), obtained through ultrafiltration and gel filtration were evaluated. The results showed that the lower molecular weight fraction exhibited a stronger free-radical scavenging ability. The highest free-radical scavenging activity was detected in the fraction of p4 purified from CP-3 using Sephadex G-15 column chromatography. The 50% inhibitory value (IC(50)) of p4 for scavenging radicals of superoxide, hydroxyl and 1,1-diphenyl-2-pycrylhydrazyl (DPPH) were, respectively, 0.97 mg mL(-1), 0.84 mg mL(-1) and 1.84 mg mL(-1). Furthermore, the p4 fraction at a concentration of 10 μg mL(-1) increased cell viability from 84.8% to 94% under antioxidative stress in neuroblastoma SK-N-SH cells.

Scavenger and antioxidant properties of prenylflavones isolated from Artocarpus heterophyllus.

PubMed

Ko, F N; Cheng, Z J; Lin, C N; Teng, C M

1998-07-15

The antioxidant properties of prenylflavones, isolated from Artocarpus heterophyllus Lam., was evaluated in this study. Among them, artocarpine, artocarpetin, artocarpetin A, and cycloheterophyllin diacetate and peracetate had no effect on iron-induced lipid peroxidation in rat brain homogenate. They also did not scavenge the stable free radical 1,1-diphenyl-2-picrylhydrazyl. In contrast, cycloheterophyllin and artonins A and B inhibited iron-induced lipid peroxidation in rat brain homogenate and scavenged 1,1-diphenyl-2-picrylhydrazyl. They also scavenged peroxyl radicals and hydroxyl radicals that were generated by 2,2'-azobis(2-amidinopropane) dihydrochloride and the Fe3+-ascorbate-EDTA-H2O2 system, respectively. However, they did not inhibit xanthine oxidase activity or scavenge superoxide anion, hydrogen peroxide, carbon radical, or peroxyl radicals derived from 2,2'-azobis(2,4-dimethylvaleronitrile) in hexane. Moreover, cycloheterophyllin and artonins A and B inhibited copper-catalyzed oxidation of human low-density lipoprotein, as measured by fluorescence intensity, thiobarbituric acid-reactive substance and conjugated-diene formations and electrophoretic mobility. It is concluded that cycloheterophyllin and artonins A and B serve as powerful antioxidants against lipid peroxidation when biomembranes are exposed to oxygen radicals.

[Correlation Between Functional Groups and Radical Scavenging Activities of Acidic Polysaccharides from Dendrobium].

PubMed

Liao, Ying; Yuan, Wen-yu; Zheng, Wen-ke; Luo, Ao-xue; Fan, Yi-jun

2015-11-01

To compare the radical scavenging activity of five different acidic polysaccharides, and to find the correlation with the functional groups. Alkali extraction method and Stepwise ethanol precipitation method were used to extract and concentrate the five Dendrobium polysaccharides, and to determine the contents of sulfuric acid and uronic acid of each kind of acidic polysaccharides, and the scavenging activity to ABTS+ radical and hydroxyl radical. Functional group structures were examined by FTIR Spectrometer. Five kinds of Dendrobium polysaccharides had different ability of scavenging ABTS+ free radical and hydroxyl free radical. Moreover, the study had shown that five kinds of antioxidant activity of acidic polysaccharides had obvious correlation withuronic acid and sulfuric acid. The antioxidant activity of each sample was positively correlated with the content of uronic acid, and negatively correlated with the content of sulfuric acid. Sulfuric acid can inhibit the antioxidant activity of acidic polysaccharide but uronic acid can enhance the free radical scavenging activity. By analyzing the structure characteristics of five acidic polysaccharides, all samples have similar structures, however, Dendrobium denneanum, Dendrobium devonianum and Dendrobium officinale which had β configuration have higher antioxidant activity than Dendrobium nobile and Dendrobium fimbriatum which had a configuration.

Scavengers: A behind-the-scenes recycling battle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goff, J.A.

Though it may not garner a spotlight as the number-one issue facing the recycling industry, the theft of recyclables is a subtle and elusive vexation that is costing haulers and recyclers thousands of dollars each year. Scavenging is not a new dilemma for the industry. But aside from an occasional seminar on the topic, not much attention has been devoted to the problem, despite the fact that poaching deprives curbside programs of revenues that help offset operating costs. In some locations, losses due to scavenging have sabotaged the efficacy of curbside recycling as a whole.

Magnetic scavengers as carriers of analytes for flowing atmospheric pressure afterglow mass spectrometry (FAPA-MS).

PubMed

Cegłowski, Michał; Kurczewska, Joanna; Smoluch, Marek; Reszke, Edward; Silberring, Jerzy; Schroeder, Grzegorz

2015-09-07

In this paper, a procedure for the preconcentration and transport of mixtures of acids, bases, and drug components to a mass spectrometer using magnetic scavengers is presented. Flowing atmospheric pressure afterglow mass spectrometry (FAPA-MS) was used as an analytical method for identification of the compounds by thermal desorption from the scavengers. The proposed procedure is fast and cheap, and does not involve time-consuming purification steps. The developed methodology can be applied for trapping harmful substances in minute quantities, to transport them to specialized, remotely located laboratories.

Radical scavenger can scavenge lipid allyl radicals complexed with lipoxygenase at lower oxygen content.

PubMed

Koshiishi, Ichiro; Tsuchida, Kazunori; Takajo, Tokuko; Komatsu, Makiko

2006-04-15

Lipoxygenases have been proposed to be a possible factor that is responsible for the pathology of certain diseases, including ischaemic injury. In the peroxidation process of linoleic acid by lipoxygenase, the E,Z-linoleate allyl radical-lipoxygenase complex seems to be generated as an intermediate. In the present study, we evaluated whether E,Z-linoleate allyl radicals on the enzyme are scavenged by radical scavengers. Linoleic acid, the content of which was greater than the dissolved oxygen content, was treated with soya bean lipoxygenase-1 (ferric form) in the presence of radical scavenger, CmP (3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl). The reaction rate between oxygen and lipid allyl radical is comparatively faster than that between CmP and lipid allyl radical. Therefore a reaction between linoleate allyl radical and CmP was not observed while the dioxygenation of linoleic acid was ongoing. After the dissolved oxygen was depleted, CmP stoichiometrically trapped linoleate-allyl radicals. Accompanied by this one-electron redox reaction, the resulting ferrous lipoxygenase was re-oxidized to the ferric form by hydroperoxylinoleate. Through the adduct assay via LC (liquid chromatography)-MS/MS (tandem MS), four E,Z-linoleate allyl radical-CmP adducts corresponding to regio- and diastereo-isomers were detected in the linoleate/lipoxygenase system, whereas E,E-linoleate allyl radical-CmP adducts were not detected at all. If E,Z-linoleate allyl radical is liberated from the enzyme, the E/Z-isomer has to reach equilibrium with the thermodynamically favoured E/E-isomer. These data suggested that the E,Z-linoleate allyl radicals were not liberated from the active site of lipoxygenase before being trapped by CmP. Consequently, we concluded that the lipid allyl radicals complexed with lipoxygenase could be scavenged by radical scavengers at lower oxygen content.

Antioxidant activity of food constituents: an overview.

PubMed

Gülçin, İlhami

2012-03-01

Recently, there has been growing interest in research into the role of plant-derived antioxidants in food and human health. The beneficial influence of many foodstuffs and beverages including fruits, vegetables, tea, coffee, and cacao on human health has been recently recognized to originate from their antioxidant activity. For this purpose, the most commonly methods used in vitro determination of antioxidant capacity of food constituents are reviewed and presented. Also, the general chemistry underlying the assays in the present paper was clarified. Hence, this overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. In addition, the most important advantages and shortcomings of each method were detected and highlighted. The chemical principles of these methods are outlined and critically discussed. The chemical principles of methods of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS(·+)) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH(·)) radical scavenging, Fe(3+)-Fe(2+) transformation assay, ferric reducing antioxidant power (FRAP) assay, cupric ions (Cu(2+)) reducing power assay (Cuprac), Folin-Ciocalteu reducing capacity (FCR assay), peroxyl radical scavenging, superoxide anion radical (O (2) (·-)) scavenging, hydrogen peroxide (H(2)O(2)) scavenging, hydroxyl radical (OH(·)) scavenging, singlet oxygen ((1)O(2)) quenching assay and nitric oxide radical (NO(·)) scavenging assay are outlined and critically discussed. Also, the general antioxidant aspects of main food components were discussed by a number of methods which are currently used for detection of antioxidant properties food components. This review consists of two main sections. The first section is devoted to main components in the foodstuffs and beverages. The second general section is some definitions of the main antioxidant methods commonly used for determination of antioxidant activity of components in the foodstuffs and beverages. In addition, there are given some chemical and kinetic basis and technical details of the used methods.

Ocimum basilicum L.: phenolic profile and antioxidant-related activity.

PubMed

Dorman, H J Damien; Hiltunen, Raimo

2010-01-01

Ocimum basilicum L. leaf material was extracted by maceration with (80:20:1 v/v/v) methanol: water: acetic acid to produce a crude extract (CE), which was further fractionated by liquid-liquid extraction to isolate light petroleum (PE), ethyl acetate (EtOAc), n-butanol (n-BuOH) and H2O-soluble sub-fractions. The total phenol and flavonoid contents of the resulting samples were estimated using colorimetric-based methods, and their iron(III) reductive and free radical scavenging activities were determined in a battery of in vitro assays. The CE and sub-fractions contained phenolic compounds and flavonoids. The samples, except for PE, gave a positive result for the presence of flavones and flavonols; however, flavanones only appeared to be present in the CE. In iron(III) reduction, CE and n-BuOH were the most potent followed by EtOAc and H2O (statistically indistinguishable, p > 0.05). However, in the ferric reducing antioxidant power assay, H2O was the most potent followed by CE and EtOAc (statistically indistinguishable, p > 0.05) and n-BuOH and PE. In 1,1-diphenyl-2-picrylhydrazyl scavenging, all the samples, except PE, were effective against this reactive nitrogen species, with CE, EtOAc and n-BuOH being the most potent (statistically indistinguishable, p > 0.05). In alkylperoxyl scavenging, all the samples, except for PE, were effective against this reactive oxygen species (ROS). In superoxide anion scavenging, all the samples were capable of scavenging this ROS with CE being the most effective, followed by n-BuOH and H2O (statistically indistinguishable, p > 0.05) and EtOAc and PE. Similarly, in hydroxyl scavenging, all the samples were capable of scavenging this ROS with CE and n-BuOH being the most effective (statistically indistinguishable, p > 0.05) followed by EtOAc and H2O (statistically indistinguishable, p > 0.05) and PE.

Radical scavenger can scavenge lipid allyl radicals complexed with lipoxygenase at lower oxygen content

PubMed Central

Koshiishi, Ichiro; Tsuchida, Kazunori; Takajo, Tokuko; Komatsu, Makiko

2006-01-01

Lipoxygenases have been proposed to be a possible factor that is responsible for the pathology of certain diseases, including ischaemic injury. In the peroxidation process of linoleic acid by lipoxygenase, the E,Z-linoleate allyl radical–lipoxygenase complex seems to be generated as an intermediate. In the present study, we evaluated whether E,Z-linoleate allyl radicals on the enzyme are scavenged by radical scavengers. Linoleic acid, the content of which was greater than the dissolved oxygen content, was treated with soya bean lipoxygenase-1 (ferric form) in the presence of radical scavenger, CmP (3-carbamoyl-2,2,5,5-tetramethylpyrrolidine-N-oxyl). The reaction rate between oxygen and lipid allyl radical is comparatively faster than that between CmP and lipid allyl radical. Therefore a reaction between linoleate allyl radical and CmP was not observed while the dioxygenation of linoleic acid was ongoing. After the dissolved oxygen was depleted, CmP stoichiometrically trapped linoleate-allyl radicals. Accompanied by this one-electron redox reaction, the resulting ferrous lipoxygenase was re-oxidized to the ferric form by hydroperoxylinoleate. Through the adduct assay via LC (liquid chromatography)–MS/MS (tandem MS), four E,Z-linoleate allyl radical–CmP adducts corresponding to regio- and diastereo-isomers were detected in the linoleate/lipoxygenase system, whereas E,E-linoleate allyl radical–CmP adducts were not detected at all. If E,Z-linoleate allyl radical is liberated from the enzyme, the E/Z-isomer has to reach equilibrium with the thermodynamically favoured E/E-isomer. These data suggested that the E,Z-linoleate allyl radicals were not liberated from the active site of lipoxygenase before being trapped by CmP. Consequently, we concluded that the lipid allyl radicals complexed with lipoxygenase could be scavenged by radical scavengers at lower oxygen content. PMID:16396633

Tourism in protected areas: Disentangling road and traffic effects on intra-guild scavenging processes.

PubMed

Donázar, José Antonio; Ceballos, Olga; Cortés-Avizanda, Ainara

2018-07-15

The expansion of road networks and the increase in traffic have emerged in recent years as key threats to the conservation of biodiversity. This is particularly concerning in many protected areas because the increase of recreational activities requiring the use of vehicles. Effects of roads and traffic within guild scenarios and ecological processes remain however poorly known. Here we examined how road proximity and traffic intensity influence patterns of resource use in an Old-World avian scavenger guild living in a protected natural park in northern Spain. We experimentally placed 130 carcasses at different distances from a scenic road in the centre of the park. Vehicles were recorded by means of traffic counters which revealed that maximum numbers were reached during weekends and holidays and during the middle hours of the day. Avian scavenger attendance at carcasses was recorded by means of camera-traps. Obligated scavengers, Eurasian griffon (Gyps fulvus) and Egyptian vultures (Neophron percnopterus) were frequently observed (59.4% and 37.7% of the consumed carcasses) together with five other facultative scavenger species. We found that the richness (number of species) and the probability of consumption of the resource were reduced the smaller the distance to the road and in days with higher traffic intensity. The same factors affected the probability of presence of all the scavenger species. Moreover, some of them, notably griffon vultures, showed hourly patterns of carcass attendance suggesting avoidance of maximum traffic levels. Our results highlight that roads and traffic would trigger consequences on the structure and functioning of scavenger food webs, which may be particularly concerning in protected areas with remarkable levels of biodiversity. Future regulations at protected areas should couple both traffic and tourist affluence with wildlife conservation. In this way important ecological processes would be preserved while maintaining a good dissemination of natural values. Copyright © 2018 Elsevier B.V. All rights reserved.

Specific patterns of canine scavenging in indoor settings.

PubMed

Colard, Thomas; Delannoy, Yann; Naji, Stephan; Gosset, Didier; Hartnett, Kristen; Bécart, Anne

2015-03-01

Postmortem animal mutilations due to domestic dogs in isolated domestic deaths are taphonomic modifications regularly observed by forensic pathologists. They are rarely described in the literature; however, even though they present specific patterns. Through 41 cases, 10 at the forensic institute in Lille (France) and 31 at the New York City Office of Chief Medical Examiner (USA), plus 22 cases from the literature, specific locations and patterns of postmortem scavenging lesions are proposed. These lesions are mainly distributed in three locations: the face, especially the nose and the mouth (73.1%), the neck (43.1%), and the arm (shoulder/upper limb [29.2%], hand [26.8%]). We discuss the time span between death and scavenging, the consequences on identification, and comparison with outdoor settings. Outdoor scavenging lesions are mainly located on the trunk and limbs usually sparing the head, which strongly differs from indoor distribution and imply different animal motivations. © 2015 American Academy of Forensic Sciences.

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.

Determination of antioxidant activity of spices and their active principles by differential pulse voltammetry.

PubMed

Palma, Alberto; Ruiz Montoya, Mercedes; Arteaga, Jesús F; Rodríguez Mellado, Jose M

2014-01-22

The anodic oxidation of mercury in the presence of hydrogen peroxide in differential pulse voltammetry (DPV) was used to determine the antioxidant (AO) character of radical scavengers. Hydroperoxide radical is formed at the potentials of the oxidation peak on mercury electrodes, such radical reacting with the antioxidants in different extension. The parameter C10 (antioxidant concentration at which the peak area decreases by 10%) is used to measure the scavenging activity of the individual antioxidants. To establish the scavenging activity of antioxidant mixtures as a whole, the parameter, μ10 as the reverse of V10, V10 being the volume necessary to decrease the peak area in DPV by 10%, was selected. Higher μ10 values correspond to higher scavenging activity. The studies have been extended to aqueous extracts of some species. The results may be useful in explaining the effect of spices in vitro and in vivo studies.

Experimental Identification of Ultrafast Reverse Hole Transfer at the Interface of the Photoexcited Methanol/Graphitic Carbon Nitride System.

PubMed

Chen, Zongwei; Zhang, Qun; Luo, Yi

2018-05-04

An experimental scrutiny of the photoexcited hole dynamics in a prototypical system is presented in which hole-scavenging methanol molecules are chemisorbed on a graphitic carbon nitride (g-C 3 N 4 ) substrate. A set of comparison and control experiments by means of femtosecond time-resolved transient absorption (fs-TA) spectroscopy were conducted. The elusive reverse hole transfer (RHT) process was identified, which occurs on a timescale of a few hundred picoseconds. The critical role of interfacially chemisorbed methoxy (instead of methanol) as the dominant species responsible for hole scavenging was confirmed by a control experiment using protonated g-C 3 N 4 as the substrate. A hot-hole transfer effect was revealed by implementing different interband photoexcitation scenarios. The RHT rate is the key factor governing the hole-scavenging ability of different hole scavengers. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Combination of Antioxidants from Different Sources Could Offer Synergistic Benefits: A Case Study of Tea and Ginger Blend.

PubMed

Makanjuola, Solomon A; Enujiugha, Victor N; Omoba, Olufunmilayo S; Sanni, David M

2015-11-01

Tea and ginger are plants with high antioxidant potential. Combinations of antioxidants from different sources could also produce synergistic antioxidant effects. This study investigated the influence of solvent on antioxidant content of tea, ginger, and tea + ginger blends. Under the investigated extraction conditions, water was the most effective extraction solvent to maximise peroxide scavenging and iron chelating activity of tea, ginger, and their blends. Aqueous ethanol was the most effective solvent to maximise ABTS radical scavenging activity and ethanol was the best solvent to maximise DPPH radical scavenging activity. A good multivariate regression model that explains the relationship between the total flavonoid content of the extracts and their antioxidant activities was obtained (R2 and Q2 of 0.93 and 0.83, respectively). Extracts of tea-ginger blends exhibited synergistic effects in their ABTS and DPPH radical scavenging activity.

Lipoic acid and dihydrolipoic acid. A comprehensive theoretical study of their antioxidant activity supported by available experimental kinetic data.

PubMed

Castañeda-Arriaga, Romina; Alvarez-Idaboy, J Raul

2014-06-23

The free radical scavenging activity of lipoic acid (LA) and dihydrolipoic acid (DHLA) has been studied in nonpolar and aqueous solutions, using the density functional theory and several oxygen centered radicals. It was found that lipoic acid is capable of scavenging only very reactive radicals, while the dehydrogenated form is an excellent scavenger via a hydrogen transfer mechanism. The environment plays an important role in the free radical scavenging activity of DHLA because in water it is deprotonated, and this enhances its activity. In particular, the reaction rate constant of DHLA in water with an HOO(•) radical is close to the diffusion limit. This has been explained on the basis of the strong H-bonding interactions found in the transition state, which involve the carboxylate moiety, and it might have implications for other biological systems in which this group is present.

Bioimaging techniques for subcellular localization of plant hemoglobins and measurement of hemoglobin-dependent nitric oxide scavenging in planta.

PubMed

Hebelstrup, Kim H; Østergaard-Jensen, Erik; Hill, Robert D

2008-01-01

Plant hemoglobins are ubiquitous in all plant families. They are expressed at low levels in specific tissues. Several studies have established that plant hemoglobins are scavengers of nitric oxide (NO) and that varying the endogenous level of hemoglobin in plant cells negatively modulates bioactivity of NO generated under hypoxic conditions or during cellular signaling. Earlier methods for determination of hemoglobin-dependent scavenging in planta were based on measuring activity in whole plants or organs. Plant hemoglobins do not contain specific organelle localization signals; however, earlier reports on plant hemoglobin have demonstrated either cytosolic or nuclear localization, depending on the method or cell type investigated. We have developed two bioimaging techniques: one for visualization of hemoglobin-catalyzed scavenging of NO in specific cells and another for visualization of subcellular localization of green fluorescent protein-tagged plant hemoglobins in transformed Arabidopsis thaliana plants.

Killer whales and whaling: the scavenging hypothesis.

PubMed

Whitehead, Hal; Reeves, Randall

2005-12-22

Killer whales (Orcinus orca) frequently scavenged from the carcasses produced by whalers. This practice became especially prominent with large-scale mechanical whaling in the twentieth century, which provided temporally and spatially clustered floating carcasses associated with loud acoustic signals. The carcasses were often of species of large whale preferred by killer whales but that normally sink beyond their diving range. In the middle years of the twentieth century floating whaled carcasses were much more abundant than those resulting from natural mortality of whales, and we propose that scavenging killer whales multiplied through diet shifts and reproduction. During the 1970s the numbers of available carcasses fell dramatically with the cessation of most whaling (in contrast to a reasonably stable abundance of living whales), and the scavenging killer whales needed an alternative source of nutrition. Diet shifts may have triggered declines in other prey species, potentially affecting ecosystems, as well as increasing direct predation on living whales.

Medium-chain dehydrogenase/reductase and aldo-keto reductase scavenge reactive carbonyls in Synechocystis sp. PCC 6803.

PubMed

Shimakawa, Ginga; Kohara, Ayaka; Miyake, Chikahiro

2018-03-01

Reactive carbonyls (RCs), which are inevitably produced during respiratory and photosynthetic metabolism, have the potential to cause oxidative damage to photosynthetic organisms. Previously, we proposed a scavenging model for RCs in the cyanobacterium Synechocystis sp. PCC 6803 (S. 6803). In the current study, we constructed mutants deficient in the enzymes medium-chain dehydrogenase/reductase (ΔMDR) and aldo-keto reductase (ΔAKR) to investigate their contributions to RC scavenging in vivo. We found that treatment with the lipid-derived RC acrolein causes growth inhibition and promotes greater protein carbonylation in ΔMDR, compared with the wild-type and ΔAKR. In both ΔMDR and ΔAKR, photosynthesis is severely inhibited in the presence of acrolein. These results suggest that these enzymes function as part of the scavenging systems for RCs in S. 6803 in vivo. © 2018 Federation of European Biochemical Societies.

Composition, apparatus, and process, for sorption of gaseous compounds of group II-VII elements

DOEpatents

Tom, Glenn M.; McManus, James V.; Luxon, Bruce A.

1991-08-06

Scavenger compositions are disclosed, which have utility for effecting the sorptive removal of hazardous gases containing Group II-VII elements of the Periodic Table, such as are widely encountered in the manufacture of semiconducting materials and semiconductor devices. Gas sorption processes including the contacting of Group II-VII gaseous compounds with such scavenger compositions are likewise disclosed, together with critical space velocity contacting conditions pertaining thereto. Further described are gas contacting apparatus, including mesh structures which may be deployed in gas contacting vessels containing such scavenger compositions, to prevent solids from being introduced to or discharged from the contacting vessel in the gas stream undergoing treatment. A reticulate heat transfer structure also is disclosed, for dampening localized exothermic reaction fronts when gas mixtures comprising Group II-VII constituents are contacted with the scavenger compositions in bulk sorption contacting vessels according to the invention.

Preliminary assessment of free radical scavenging, thrombolytic and membrane stabilizing capabilities of organic fractions of Callistemon citrinus (Curtis.) skeels leaves.

PubMed

Ahmed, Farhana; Rahman, Mohammad Sharifur

2016-07-26

Callistemon citrinus (Curtis.) (Family- Myrtaceae) is a popular evergreen shrub in Bangladesh. In the present study, the leaves of this plant have been assessed comprehensively for free radical scavenging, thrombolytic and membrane stabilizing activities. The leaves were collected, powdered and extracted with methanol. The extract was then concentrated and successively fractionated into petroleum ether, carbon tetrachloride, chloroform and aqueous soluble fractions. The extractives were investigated for free radical scavenging, thrombolytic and membrane stabilizing activities. In case of 1,1 diphenyl-2-picrylhydrazyl (DPPH) and hydrogen peroxide radical scavenging assays, the crude methanol extract of the leaves showed the highest free radical scavenging activity among the tested materials including standard ascorbic acid (p = 0.0000). Besides, this extract was also found significantly rich (p = 0.0000) in phenolics and flavonoids compared to other organic fractions. In thrombolytic study, the petroleum ether fraction exhibited significantly stronger thrombolysis (p = 0.024) than other leaf extractives but was weaker than the standard streptokinase. In membrane stabilizing assay, the activity of chloroform fraction was similar to that of standard acetylsalicylic acid (p = 1.000) in hypotonic solution induced hemolysis. However, membrane stabilization activity of this chloroform fraction was found significantly stronger than that of the standard (p = 0.0000) in heat induced hemolysis. This study has revealed the medicinal capabilities of different organic fractions of C. citrinus displaying free radical scavenging, thrombolysis and membrane stabilizing antiinflammatory potentials. Further bioactivity guided isolation is required to obtain pharmacologically secondary metabolites.

Inhibition of platelet aggregation and in vitro free radical scavenging activity of dried fruiting bodies of Pleurotus eous.

PubMed

Suseem, S R; Saral, Mary

2015-07-01

To evaluate the ethyl acetate, methanol and aqueous extracts of dried fruiting bodies of Pleurotus eous for its anti-platelet activity on human volunteer's blood. And also to analyze the free radical scavenging property of the extracts of P.eous by using various in vitro models. Anti-platelet activity of dried fruiting bodies of P.eous was evaluated by in vitro model using blood platelets. Inhibition of platelet aggregation was monitored after pre-incubation of platelets with the crude extracts of mushroom P.eous. Antioxidant activities of extracts of P.eous were evaluated by different in vitro experiments, namely, 1, 1-diphenyl-2-picryl hydrazyl (DPPH), superoxide, hydroxyl radical and lipid peroxide radical models. Crude extracts of mushroom P.eous inhibited platelet aggregation dose-dependently which was induced by adenosine diphosphate (ADP). At a maximum concentration of 10 mg/mL, methanol extract effected 64.02% inhibition of lipid per-oxidation and 50.12% scavenging effect on superoxide anion radical. Aqueous extract of P.eous have shown 69.43% chelating ability on ferrous ions, 24.27% scavenging effect on hydroxyl radical and 49.57% scavenging effect on DPPH radical at 10 mg/mL. Increasing concentrations of the extract were found to cause progressively decreasing of the intensity of absorbance. Anti-platelet effects could be related in part to the polyphenolic compounds present in the extracts. Antioxidant activity results indicated the free radical scavenging property of the extracts of P.eous which might be due to the high content of phenolic compounds and flavonoids.

Isolation and characterisation of in vitro and cellular free radical scavenging peptides from corn peptide fractions.

PubMed

Wang, Liying; Ding, Long; Wang, Ying; Zhang, Yan; Liu, Jingbo

2015-02-16

Corn gluten meal, a corn processing industry by-product, is a good source for the preparation of bioactive peptides due to its special amino acid composition. In the present study, the in vitro and cellular free radical scavenging activities of corn peptide fractions (CPFs) were investigated. Results indicated that CPF1 (molecular weight less than 1 kDa) and CPF2 (molecular weight between 1 and 3 kDa) exhibited good hydroxyl radical, superoxide anion radical and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonicacid) diammonium salt (ABTS) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Meanwhile, the in vitro radical scavenging activity of CPF1 was slightly higher than that of CPF2. Both CPF1 and CPF2 also exhibited significant cytoprotective effects and intracellular reactive oxygen species scavenging activity in Caco-2 cells exposed to hydrogen peroxide (H2O2). The amino acid composition analysis revealed that the CPF were rich in hydrophobic amino acids, which comprised of more than 45% of total amino acids. An antioxidant peptide sequence of Tyr-Phe-Cys-Leu-Thr (YFCLT) was identified from CPF1 using matrix-assisted laser desorption/ionization time-of-flight/time-of-flight mass spectrometry (MALDI TOF/TOF MS). The YFCLT exhibited excellent ABTS radical scavenging activity with a 50% effective concentration (EC50) value of 37.63 µM, which was much lower than that of Trolox. In conclusion, corn gluten meal might be a good source to prepare antioxidant peptides.

Free radical scavenging injectable hydrogels for regenerative therapy.

PubMed

Komeri, Remya; Thankam, Finosh Gnanaprakasam; Muthu, Jayabalan

2017-02-01

Pathological free radicals generated from inflamed and infarcted cardiac tissues interferes natural tissue repair mechanisms. Hypoxic microenvironment at the injured zone of non-regenerating cardiac tissues hinders the therapeutic attempts including cell therapy. Here we report an injectable, cytocompatible, free radical scavenging synthetic hydrogel formulation for regenerative therapy. New hydrogel (PEAX-P) is prepared with D-xylitol-co-fumarate-co-poly ethylene adipate-co-PEG comaromer (PEAX) and PEGDiacrylate. PEAX-P hydrogel swells 4.9 times the initial weight and retains 100.07kPa Young modulus at equilibrium swelling, which is suitable for cardiac applications. PEAX-P hydrogel retains elastic nature even at 60% compressive strain, which is favorable to fit with the dynamic and elastic natural tissue counterparts. PEAX-P hydrogel scavenges 51% DPPH radical, 40% hydroxyl radicals 41% nitrate radicals with 31% reducing power. The presence of hydrogel protects 62% cardiomyoblast cells treated with stress inducing media at LD 50 concentration. The free hydroxyl groups in sugar alcohols of the comacromer influence the free radical scavenging. Comparatively, PEAX-P hydrogel based on xylitol evinces slightly lower scavenging characteristics than with previously reported PEAM-P hydrogel containing mannitol having more hydroxyl groups. The possible free radical scavenging mechanism of the present hydrogel relies on the free π electrons associated with uncrosslinked fumarate bonds, hydrogen atoms associated with sugar alcohols/PEG and radical dilution by free water in the matrix. Briefly, the present PEAX-P hydrogel is a potential injectable system for combined antioxidant and regenerative therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Phytochemical profile and free radical nitric oxide (NO) scavenging activity of Averrhoa bilimbi L. fruit extract.

PubMed

Suluvoy, Jagadish Kumar; Berlin Grace, V M

2017-05-01

Averrhoa bilimbi L. belongs to family Oxalidaceae. Traditionally, people use this plant (root, bark, leaves and fruits) for treating several illnesses include itches, boils, syphilis, whooping cough, hypertension, fever and inflammation. The aim of the study was to evaluate the nitric oxide (NO) scavenging activity and GC-MS analysis of A. bilimbi L. fruit extract. Averrhoa bilimbi L. fruits were collected for the preliminary phytochemical analysis, antioxidant scavenging activity and biologically important compounds were identified by GC-MS analysis. The preliminary phytochemicals, GC-MS, total phenolic content and NO scavenging activity of the plant were analysed. In the present investigation, the A. bilimbi L. fruit extract has major phytochemicals. Among the 151 compounds identified in GC-MS, 15 compounds are found to have diverse biological activity. We also observed that the A. bilimbi L. fruit extract has high level of total phenolic compounds at a concentration of 209.25 GAE mg/g. Presence of phenolic compound apparently explains the antioxidant activity of the plant. Antioxidant activity of A. bilimbi L. fruit extract is proven from its high level of NO scavenging activity of potent IC50 value of 108.10. From the above study, it is apparent that the A. bilimbi L. fruit extract is a rich source of phytochemicals (natural products) with biological activity. The GC-MS report on this fruit proves that natural products have pharmacologically and biologically active compounds. A high phenolic content is observed in our study. A. bilimbi L. fruit extract is also found to have NO scavenging activity in our study.

Phytochemical analysis with free radical scavenging, nitric oxide inhibition and antiproliferative activity of Sarcocephalus pobeguinii extracts.

PubMed

Mfotie Njoya, Emmanuel; Munvera, Aristide Mfifen; Mkounga, Pierre; Nkengfack, Augustin Ephrem; McGaw, Lyndy Joy

2017-04-04

Free radicals have been implicated in the pathogenesis of diverse metabolic disorders including cancer. Therefore, fighting against free radicals has become an important strategy in the prevention or treatment of such diseases, in addition to direct or indirect anticancer chemotherapy. Sarcocephalus pobeguinii has been used traditionally to treat various diseases in which excess production of free radicals is implicated, warranting investigation of its free radical scavenging, anticancer and anti-inflammatory activity. In the present study, extracts from leaves, fruits, roots and bark of Sarcocephalus pobeguinii were evaluated on four human cancer cell lines (MCF-7, HeLa, Caco-2 and A549 cells) and a non-cancerous cell line for their antiproliferative potential. The cells were incubated with the plant extracts for 48 h at 37 °C in a 5% CO 2 humidified environment and their cytotoxic effect was determined using the tetrazolium-based colorimetric (MTT) assay. The radical inhibition was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging techniques. The nitric oxide inhibitory activity was determined using LPS-activated RAW 264.7 macrophages. The correlation between radical scavenging capacity and antiproliferative activity was also analysed. The extract from leaves of Sarcocephalus pobeguinii (LSP) exhibited the highest cytotoxic effect on all four of the human cancer cell lines but with some cytotoxicity to the normal Vero cells. However, the LSP extract had the best selectivity index, ranging from 3.15 to 18.28. Also, antioxidant and anti-inflammatory assays indicated that the LSP extract had the highest radical scavenging capacity of all the extracts. A positive linear correlation was found between free radical scavenging ability and antiproliferative activity against the four cancer cell lines, with the highest correlation factor (R 2  = 0.9914) obtained between DPPH inhibition and antiproliferative activity against A549 cells. The high selectivity index of the Sarcocephalus pobeguinii leaf extract indicates the potential of using this extract in cancer therapy. Furthermore, the positive correlation between free radical scavenging and antiproliferative activity suggests that the radical scavenging capacity of extracts may contribute to a prediction of their anticancer property.

Antioxidant vitamins and enzymatic and synthetic oxygen-derived free radical scavengers in the prevention and treatment of cardiovascular disease.

PubMed

Nayak, D U; Karmen, C; Frishman, W H; Vakili, B A

2001-01-01

Oxygen-derived free radical formation can lead to cellular injury and death. Under normal situations, the human body has a free radical scavenger system (catalase, superoxide dismutase) that can detoxify free radicals. Antioxidant vitamins and enzymatic and synthetic oxygen-derived free radical scavengers have been used clinically to prevent the formation of oxidized LDL and to prevent reperfusion injury, which is often caused by free radicals. In this article, the pathogenesis of free radical production and cell injury are discussed, and therapeutic approaches for disease prevention are presented.

Evaluation of free radicals scavenging and immunity-modulatory activities of Purslane polysaccharides.

PubMed

YouGuo, Chen; ZongJi, Shen; XiaoPing, Chen

2009-12-01

In this study, antioxidant and immunity-modulatory activities of Purslane polysaccharide were estimated. The results revealed that in a dose-dependent manner, Purslane polysaccharides could significantly scavenge superoxide anion, 1,1-diphenyl-2-picrylhydrazyl (DPPH(-)), nitric oxide and hydroxyl radicals. Furthermore, the Purslane polysaccharides could still effectively inhibit the red blood cell (RBC) haemolysis, and increase spleen, thymocyte T and B lymphocyte proliferation, it could be concluded that Purslane polysaccharides could be of considerable preventive and therapeutic significance to some free radical associated health problems such as ovarian cancer, by scavenging accumulating free radicals and enhancing immunity functions.

A study of antioxidant potential of Perilladehyde

NASA Astrophysics Data System (ADS)

Malu, T. J.; Banerjee, Nitesh; Singh, Avinash Kumar; Kannadasan, S.; Ethiraj, K. R.

2017-11-01

The use of plants as food, medicine is credited to a biological property of their secondary metabolites. These naturally occurring secondary metabolites are found to have great importance in controlling the formation of free radicles. These antioxidants are capable to catch the free radicles present in the body and maintain its balance. Antioxidant activity and potency of Perillaldehyde using various in vitro biochemical assays were studied. The assay involves various levels of antioxidant action such as free radical scavenging activity through DPPH, reducing power determination, nitric oxide scavenging ability, metal chelation power, scavenging of hydrogen peroxide, membrane stabilizing activity, and lipid peroxidation study.

Boundary scavenging in the Pacific Ocean - A comparison of Be-10 and Pa-231

NASA Technical Reports Server (NTRS)

Anderson, R. F.; Lao, Y.; Broecker, W. S.; Trumbore, S. E.; Hofmann, H. J.

1990-01-01

Measurements of U, Th, Pa-231, and Be-10 concentrations were conducted in Holocene sediments from several sites representing open-ocean and ocean-margin environments in the Pacific Ocean. The results show that boundary scavenging plays a major role in the removal of Be-10 from the Pacific. Deposition of Be-10 is more than an order of magnitude greater at margin sites than at deep central Pacific sites, while Pa-231 is 4- to 5-fold greater at margin sites. The factors controling boundary scavenging of Pa and Be are discussed.

The effect of thermal and ultrasonic treatment on amino acid composition, radical scavenging and reducing potential of hydrolysates obtained from simulated gastrointestinal digestion of cowpea proteins.

PubMed

Quansah, Joycelyn K; Udenigwe, Chibuike C; Saalia, Firibu K; Yada, Rickey Y

2013-03-01

The effect of thermal and ultrasonic treatment of cowpea proteins (CP) on amino acid composition, radical scavenging and reducing potential of hydrolysates (CPH) obtained from in vitro simulated gastrointestinal digestion of CP was evaluated. Hydrolysis of native and treated CP with gastrointestinal pepsin and pancreatin yielded CPH that displayed antioxidant activities based on oxygen radical scavenging capacity (ORAC), ferric reducing antioxidant power (FRAP) and superoxide radical scavenging activity (SRSA). CPH derived from the treated CP yielded higher ORAC values than CPH from untreated proteins. However, lower significant FRAP and SRSA values were observed for these samples compared to untreated CPH (p < 0.05). Amino acid analysis indicated that CP processing decreased total sulphur-containing amino acids in the hydrolysates, particularly cysteine. The amount of cysteine appeared to be positively related to FRAP and SRSA values of CPH samples, but not ORAC. The results indicated that thermal and ultrasonic processing of CP can reduce the radical scavenging and reducing potential of the enzymatic hydrolysates possibly due to the decreased amounts of cysteine. Since the hydrolysates were generated with gastrointestinal enzymes, it is possible that the resulting compounds are produced to exert some health functions during normal consumption of cowpea.

A Targeted "Capture" and "Removal" Scavenger toward Multiple Pollutants for Water Remediation based on Molecular Recognition.

PubMed

Wang, Jie; Shen, Haijing; Hu, Xiaoxia; Li, Yan; Li, Zhihao; Xu, Jinfan; Song, Xiufeng; Zeng, Haibo; Yuan, Quan

2016-03-01

For the water remediation techniques based on adsorption, the long-standing contradictories between selectivity and multiple adsorbability, as well as between affinity and recyclability, have put it on weak defense amid more and more severe environment crisis. Here, a pollutant-targeting hydrogel scavenger is reported for water remediation with both high selectivity and multiple adsorbability for several pollutants, and with strong affinity and good recyclability through rationally integrating the advantages of multiple functional materials. In the scavenger, aptamers fold into binding pockets to accommodate the molecular structure of pollutants to afford perfect selectivity, and Janus nanoparticles with antibacterial function as well as anisotropic surfaces to immobilize multiple aptamers allow for simultaneously handling different kinds of pollutants. The scavenger exhibits high efficiencies in removing pollutants from water and it can be easily recycled for many times without significant loss of loading capacities. Moreover, the residual concentrations of each contaminant are well below the drinking water standards. Thermodynamic behavior of the adsorption process is investigated and the rate-controlling process is determined. Furthermore, a point of use device is constructed and it displays high efficiency in removing pollutants from environmental water. The scavenger exhibits great promise to be applied in the next generation of water purification systems.

Pedalium murex Linn (Pedaliaceae) fruits: a comparative antioxidant activity of its different fractions

PubMed Central

Patel, DK; Kumar, R; Prasad, SK; Hemalatha, S

2011-01-01

Objective To examine the antioxidant activity and total phenolic content of different solvent fractions of Pedalium murex (P. murex) Linn fruits (Family: Pedaliaceae) as well as the correlation between the total antioxidant capacity and total phenolic content. Methods In the present study, the antioxidant activities of P. murex were evaluated using six in-vitro assays, namely total antioxidant assay, DPPH assay, reducing power, nitric oxide scavenging, hydrogen peroxide scavenging and deoxyribose scavenging assays, and total phenol contents were also investigated. Results The ethyl acetate (EA) fraction was found to have high levels of phenolic content (298.72±2.09 mg GAE/g). The EA fraction exhibit higher total antioxidant capacity, higher percentage of DPPH radical scavenging activity (135.11±2.95µg/mL), nitric oxide (200.57±4.51µg/mL), hydrogen peroxide (217.91±6.12 µg/mL), deoxyribose (250.01±4.68µg/mL) and higher reducing power. Correlation coefficient (r2=0.914) was found to be significant between total phenolic content and total antioxidant activity. Conclusions In general, the results indicate that the EA fractions are rich in phenolic antioxidants with potent free radical scavenging activity implying their importance to human health. PMID:23569800

The Nitrite-Scavenging Properties of Catechol, Resorcinol, and Hydroquinone: A Comparative Study on Their Nitration and Nitrosation Reactions.

PubMed

Lu, Yunhao; Dong, Yanzuo; Li, Xueli; He, Qiang

2016-10-14

The nitration and nitrosation reactions of catechol, resorcinol, and hydroquinone (0.05 mmol/L) with sodium nitrite (0.05 mmol/L) at pH 3 and 37 °C were studied by using liquid chromatography and mass spectrometry (LC-MS) and atom charge analysis, which was aimed to provide chemical insight into the nitrite-scavenging behavior of polyphenols. The 3 benzenediols showed different mechanisms to scavenge nitrite due to their differences in hydroxyl position. Catechol was nitrated with 1 NO 2 group at the hydroxyl oxygen, and resorcinol was nitrosated with 2 NO groups at the C 2 and C 4 (or C 6 ) positions of the benzene ring. Hydroquinone could scavenge nitrite through both nitration and nitrosation mechanisms. The nitrated hydroquinone had 1 NO 2 group at the hydroxyl oxygen in the molecule, while the nitrosated 1 containing 2 NO groups at the benzene ring might have 3 structure probabilities. The results may provide a structure-activity understanding on the nitrite-scavenging property of polyphenols, so as to promote their application in the food industry for the removal of possibly toxic nitrites found in many vegetables and often in processed meat products. © 2016 Institute of Food Technologists®.

Studies on the development of functional powder from citrus peel.

PubMed

Kang, H J; Chawla, S P; Jo, C; Kwon, J H; Byun, M W

2006-03-01

The suitability of citrus peels, generated as a by-product of the juice industry, as a source of antioxidants was investigated. Citrus peel powder was prepared by lyophilizing 70% ethanol extract from citrus peels. Extraction was carried out at room temperature (20 degrees C) for 72 h. The extract was subjected to gamma-irradiation treatment (20 kGy). The aqueous solutions of citrus peel powder were examined for color characteristics and antioxidant potential in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, beta-carotene bleaching and nitrite scavenging activities. There were significant changes in Hunter color values due to irradiation. The a*- and b*-values decreased due to radiation treatment. DPPH radical scavenging, beta-carotene bleaching and nitrite scavenging activities were not affected by irradiation treatment. Nitrite scavenging activity was the highest in the extract at pH 1.2 followed by pH 4.2 and 6.0. These functional properties of the aqueous solution were found to be stable in heat treatment. It could significantly improve oxidative stability of lipids in fish meat system. Based on these results there may be opportunities to use citrus peel powder as a functional component in the food processing industry with gamma irradiation treatment improving its color characteristics without adversely influencing the functional properties.

Radical-scavenging-linked antioxidant activities of extracts from black chokeberry and blueberry cultivated in Korea.

PubMed

Hwang, Seok Joon; Yoon, Won Byong; Lee, Ok-Hwan; Cha, Seung Ju; Kim, Jong Dai

2014-03-01

The objective of this study was to investigate the radical-scavenging-linked antioxidant properties of the extracts from black chokeberry and blueberry cultivated in Korea. The 70% ethanol extracts were prepared from black chokeberry and blueberry, and evaluated for total phenolic content, total flavonoid content, total proanthocyanidin content, and antioxidative activities, using various in vitro assays, such as DPPH(2,2-diphenyl-1-picrylhydrazyl), ABTS(2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulphonic acid)) radical-scavenging activity, FRAP(ferric-reducing antioxidant power) and reducing power. The major phenolic compounds, including cyanidin-3-galactoside, cyanidin-3-arabinoside, neochlorogenic acid, procyanidin B1, were analysed by HPLC with a photodiode array detector. Results showed that total phenol, flavonoid and proanthocyanidin contents of black chokeberry extract were higher than those of blueberry extract. In addition, black chokeberry extract exhibited higher free radical-scavenging activity and reducing power than did blueberry extract. Cyanidin-3-galactoside was identified as a major phenolic compound, with considerable content in black chokeberry, that correlated with its higher antioxidant and radical-scavenging effects. These results suggest that black chokeberry extracts could be considered as a good source of natural antioxidants and functional food ingredients. Copyright © 2013 Elsevier Ltd. All rights reserved.

Post-hypoxic cellular disintegration in glycine-preserved renal tubules is attenuated by hydroxyl radical scavengers and iron chelators.

PubMed

Moussavian, Mohammed R; Slotta, Jan E; Kollmar, Otto; Menger, Michael D; Gronow, Gernot; Schilling, Martin K

2008-05-01

Cellular stress during reoxygenation is a common phenomenon in solid organ transplantation and is characterized by production of reactive oxygen species. Herein, we studied in isolated tubular segments of rat kidney cortex the impact of oxygen radical scavengers and an iron chelator on post-hypoxic recovery. Tubules, suspended in Ringer's solution containing 5 mM glycine, underwent 30 min hypoxia and 60 min reoxygenation. Untreated tubules served as controls. Hypoxia-reoxygenation injury was measured by membrane leakage, lipid peroxidation and cellular functions. In hypoxia-reoxygenated-isolated tubular segments, protective effects of different scavengers and of the iron chelator deferoxamine on hypoxia-reoxygenation injury were analyzed. Scavengers protected isolated tubular segments from hypoxia-reoxygenation-induced cellular disintegration and dysfunction. Deferoxamine was found to exert the most distinct protection. It was further found to exert a dose-dependent protection on hypoxia-reoxygenation damage in isolated tubular segments, which was critically mediated by chelating tissue and bond iron. Our data demonstrate that radical scavengers effectively protect from hypoxia-reoxygenation injury in isolated tubular segments and that the iron chelator deferoxamine is especially a potent inhibitor of iron ion-mediated hypoxia-reoxygenation damage. Thus, inclusion of this iron chelator in organ storage solutions might improve post-transplant organ function and protect from reperfusion injury.

Evaluation of antitumor, immunomodulatory and free radical scavenging effects of a new herbal prescription seaweed complex preparation

NASA Astrophysics Data System (ADS)

Liu, Xin; Shao, Changlun; Kong, Wenwen; Fang, Yuchun; Wang, Changyun

2013-09-01

Seaweed Complex Preparation (SCP) is a clinical traditional Chinese medicine preparation which is composed of seven traditional Chinese herbs, and it has been used for treatment of lung cancer, liver cancer and digestive cancer. However, little information is available about the pharmacodynamic basis. The antitumor, immunomodulatory and free radical scavenging effects of SCP were evaluated in this study. Transplanted tumor in vivo method was used to determine the antitumor effect. The effects on splenocyte proliferation and phagocytosis of macrophages in tumor-bearing mice were measured by the MTT method and the phagocytizing cock red blood cell (CRBC) method respectively. The scavenging activities of SCP on DPPH and hydroxyl radicals in vitro were investigated. It was found that the medium-dose and high-dose of SCP could significantly inhibit the growth of transplanted hepatic tumor of murine hepatocarcinoma cell line H22, and promote proliferation of splenocytes and phagocytosis of macrophages. SCP possessed noticeable scavenging activities on DPPH and hydroxyl radicals. The antitumor effects of SCP might be achieved by improving immune system and scavenging free radicals, which is in accordance with the viewpoint of traditional Chinese medicine in promoting the body resistance and eliminating pathogenic factors for cancer treatment.

Scavenging rate ecoassay: a potential indicator of estuary condition.

PubMed

Porter, Augustine G; Scanes, Peter R

2015-01-01

Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress.

Donor-Control of Scavenging Food Webs at the Land-Ocean Interface.

PubMed

Schlacher, Thomas A; Strydom, Simone; Connolly, Rod M; Schoeman, David

2013-01-01

Food webs near the interface of adjacent ecosystems are potentially subsidised by the flux of organic matter across system boundaries. Such subsidies, including carrion of marine provenance, are predicted to be instrumental on open-coast sandy shores where in situ productivity is low and boundaries are long and highly permeable to imports from the sea. We tested the effect of carrion supply on the structure of consumer dynamics in a beach-dune system using broad-scale, repeated additions of carcasses at the strandline of an exposed beach in eastern Australia. Carrion inputs increased the abundance of large invertebrate scavengers (ghost crabs, Ocypode spp.), a numerical response most strongly expressed by the largest size-class in the population, and likely due to aggregative behaviour in the short term. Consumption of carrion at the beach-dune interface was rapid and efficient, driven overwhelmingly by facultative avian scavengers. This guild of vertebrate scavengers comprises several species of birds of prey (sea eagles, kites), crows and gulls, which reacted strongly to concentrations of fish carrion, creating hotspots of intense scavenging activity along the shoreline. Detection of carrion effects at several trophic levels suggests that feeding links arising from carcasses shape the architecture and dynamics of food webs at the land-ocean interface.

Rare earth element scavenging in seawater

NASA Astrophysics Data System (ADS)

Byrne, Robert H.; Kim, Ki-Hyun

1990-10-01

Examinations of rare earth element (REE) adsorption in seawater, using a variety of surface-types, indicated that, for most surfaces, light rare earth elements (LREEs) are preferentially adsorbed compared to the heavy rare earths (HREEs). Exceptions to this behavior were observed only for silica phases (glass surfaces, acid-cleaned diatomaceous earth, and synthetic SiO 2). The affinity of the rare earths for surfaces can be strongly affected by thin organic coatings. Glass surfaces which acquired an organic coating through immersion in Tampa Bay exhibited adsorptive behavior typical of organic-rich, rather than glass, surfaces. Models of rare earth distributions between seawater and carboxylate-rich surfaces indicate that scavenging processes which involve such surfaces should exhibit a strong dependence on pH and carbonate complexation. Scavenging models involving carboxylate surfaces produce relative REE abundance patterns in good general agreement with observed shale-normalized REE abundances in seawater. Scavenging by carboxylate-rich surfaces should produce HREE enrichments in seawater relative to the LREEs and may produce enrichments of lanthanum relative to its immediate trivalent neighbors. Due to the origin of distribution coefficients as a difference between REE solution complexation (which increases strongly with atomic number) and surface complexation (which apparently also increases with atomic number) the relative solution abundance patterns of the REEs produced by scavenging reactions can be quite complex.

Variations of Antioxidant Properties and NO Scavenging Abilities during Fermentation of Tea

PubMed Central

Xu, Yang; Zhao, Hang; Zhang, Min; Li, Chun-Jie; Lin, Xue-Zhen; Sheng, Jun; Shi, Wei

2011-01-01

Tea is known as one of the most popular beverages in the world, which is believed to be beneficial for health. The main components in tea will change a lot depending on the different processes of fermentation, and thus the effects of different teas on human health may differ. The aim of this study is to explore the varied abilities of reactive oxygen species (ROS) and nitric oxide (NO) scavenging during the fermentation of tea. In this study, we conducted the in vitro experiments which involved some reaction systems indicating the abilities of scavenging ROS and NO. We also investigated the effects of tea and their components (catechins, theabrownins, caffeine) on the intracellular levels of ROS and NO, using Raw 264.7 cells as the model. We found that regardless of whether it was out of cell system or in Raw 264.7 cells, the abilities of scavenging ROS would decrease during the fermentation of tea. Further, the post-fermented pu-erh tea showed the best effect on inhibiting the lipopolysaccharide (LPS)-induced production of NO. These findings indicated that the fermentation process caused a change of the components which might be due to the changes of their antioxidant properties and NO scavenging abilities. PMID:21845097

Energy scavenging strain absorber: application to kinetic dielectric elastomer generator

NASA Astrophysics Data System (ADS)

Jean-Mistral, C.; Beaune, M.; Vu-Cong, T.; Sylvestre, A.

2014-03-01

Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human's wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.

Surveillance for transmissible spongiform encephalopathy in scavengers of white-tailed deer carcasses in the chronic wasting disease area of wisconsin

USGS Publications Warehouse

Jennelle, C.S.; Samuel, M.D.; Nolden, C.A.; Keane, D.P.; Barr, D.J.; Johnson, Chad; Vanderloo, J.P.; Aiken, Judd M.; Hamir, A.N.; Hoover, E.A.

2009-01-01

Chronic wasting disease (CWD), a class of neurodegenerative transmissible spongiform encephalopathies (TSE) occurring in cervids, is found in a number of states and provinces across North America. Misfolded prions, the infectious agents of CWD, are deposited in the environment via carcass remains and excreta, and pose a threat of cross-species transmission. In this study tissues were tested from 812 representative mammalian scavengers, collected in the CWD-affected area of Wisconsin, for TSE infection using the IDEXX HerdChek enzyme-linked immunosorbent assay (ELISA). Only four of the collected mammals tested positive using the ELISA, but these were negative when tested by Western blot. While our sample sizes permitted high probabilities of detecting TSE assuming 1% population prevalence in several common scavengers (93%, 87%, and 87% for raccoons, opossums, and coyotes, respectively), insufficient sample sizes for other species precluded similar conclusions. One cannot rule out successful cross-species TSE transmission to scavengers, but the results suggest that such transmission is not frequent in the CWD-affected area of Wisconsin. The need for further surveillance of scavenger species, especially those known to be susceptible to TSE (e.g., cat, American mink, raccoon), is highlighted in both a field and laboratory setting.

Radical-scavenging activity, protective effect against lipid peroxidation and mineral contents of monofloral Cuban honeys.

PubMed

Alvarez-Suarez, José M; Giampieri, Francesca; Damiani, Elisabetta; Astolfi, Paola; Fattorini, Daniele; Regoli, Francesco; Quiles, José L; Battino, Maurizio

2012-03-01

Several monofloral Cuban honeys were analyzed to determine their free radical-scavenging activity and from this the total antioxidant content was estimated. The protective effect against lipid peroxidation in an in vitro model of rat liver homogenates was evaluated and, lastly, the mineral content of the honeys, which can be related to the maintenance of intracellular oxidative balance, was determined. The scavenging capacities against hydroxyl and superoxide radicals were determined using the spin-trapping technique and the hypoxanthine/xanthine oxidase assay, respectively. Lipid peroxidation was evaluated through the production of TBARS and hydroperoxides. All honeys tested showed potential antioxidant activity with Linen vine displaying the highest scavenging capacity towards the DPPH, hydroxyl and superoxide radicals, while the least efficient was Christmas vine honey. Honeys also inhibited, in a concentration-dependent mode, lipid peroxidation in rat liver homogenates, with Linen vine resulting the best while the least effective was Christmas vine honey. The ability to scavenge free radicals and protect against lipid peroxidation may contribute to the ability of certain Cuban honeys to help in preventing/reducing some inflammatory diseases in which oxidative stress is involved. A total of eight minerals were identified and quantified as follows: cadmium, chromium, copper, nickel, iron, manganese, lead, and zinc. Minerals found in higher concentrations were iron, zinc and manganese.

Ameliorative effect of alkaloid extract of Cyclea peltata (Poir.) Hook. f. & Thoms. roots (ACP) on APAP/CCl4 induced liver toxicity in Wistar rats and in vitro free radical scavenging property.

PubMed

Shine, Varghese Jancy; Latha, Panikamparambil Gopalakrishnan; Suja, Somasekharan Nair Rajam; Anuja, Gangadharan Indira; Raj, Gopan; Rajasekharan, Sreedharan Nair

2014-02-01

To evaluate the hepatoprotective and antioxidant properties of alkaloid extract of Cyclea peltata (C. peltata) against paracetamol/carbon tetra chloride induced liver damage in Wistar rats. In vivo paracetamol/carbon tetrachloride induced liver damage in Wistar rats, in vitro free radical scavenging studies, HPTLC estimation of tetrandrine and direct analysis in real time- mass spectrometry of alkaloid extract of C. peltata were used for the validation. The results showed that pretreatment with alkaloid extract of C. peltata caused significant reduction of serum glutamate pyruvate transaminase, serum glutamate oxaloacetate transaminase, serum alkaline phosphatase, serum cholesterol, liver malondialdehyde levels. The reduced glutathione, catalase, superoxide dismutase levels in liver were increased with alkaloid extract of C. peltata treatment. These results were almost comparable to silymarin and normal control. Histopathological studies also substantiated the biochemical findings. The in vitro hydroxyl, superoxide and DPPH scavenging study of alkaloid extract of C. peltata showed significant free radical scavenging property. The hepatoprotective property of alkaloid extract of C. peltata against paracetamol/carbon tetrachloride may be due the synergistic action of alkaloids especially tetrandrine, fangchinoline through free radical scavenging and thus preventing oxidative stress.

Inhibitory effect of antioxidant-rich marinades on the formation of heterocyclic aromatic amines in pan-fried beef.

PubMed

Viegas, Olga; Amaro, L Filipe; Ferreira, Isabel M P L V O; Pinho, Olívia

2012-06-20

The inhibitory effect of antioxidant-rich marinades containing beer and white wine (with/without alcohol) alone or mixed with herbs commonly used as meat flavoring (garlic, ginger, thyme, rosemary, and red chili pepper) on the formation of heterocyclic aromatic amines (HAs) in pan-fried beef was studied. Radical-scavenging activity was evaluated by DPPH assay, before the addition of meat to the marinade (T0) and after 4 h of meat marinating (T4). At T0, wine with herbs possessed the highest scavenging activity (73.5%), followed by wine (72.5%), dealcoholized wine with herbs (53.4%), beer and herbs (41.7%), dealcoholized wine (39.6%), and beer (25.9%). At T4, a decrease in the radical-scavenging activity of all marinades was observed, although with a similar radical-scavenging profile. All of the six marinades under the study reduced the total amount of HAs, keeping meat with good overall sensory quality. Beer marinades were more efficient than white wine marinades, and the addition of herbs provided a superior inhibitory effect, reducing around 90% of HAs. No correlation was observed between radical-scavenging activity of marinades and total or individual HAs formation. Herbs explained around 30% of inhibition of PhIP formation, whereas alcohol increased PhIP formation.

Donor-Control of Scavenging Food Webs at the Land-Ocean Interface

PubMed Central

Schlacher, Thomas A.; Strydom, Simone; Connolly, Rod M.; Schoeman, David

2013-01-01

Food webs near the interface of adjacent ecosystems are potentially subsidised by the flux of organic matter across system boundaries. Such subsidies, including carrion of marine provenance, are predicted to be instrumental on open-coast sandy shores where in situ productivity is low and boundaries are long and highly permeable to imports from the sea. We tested the effect of carrion supply on the structure of consumer dynamics in a beach-dune system using broad-scale, repeated additions of carcasses at the strandline of an exposed beach in eastern Australia. Carrion inputs increased the abundance of large invertebrate scavengers (ghost crabs, Ocypode spp.), a numerical response most strongly expressed by the largest size-class in the population, and likely due to aggregative behaviour in the short term. Consumption of carrion at the beach-dune interface was rapid and efficient, driven overwhelmingly by facultative avian scavengers. This guild of vertebrate scavengers comprises several species of birds of prey (sea eagles, kites), crows and gulls, which reacted strongly to concentrations of fish carrion, creating hotspots of intense scavenging activity along the shoreline. Detection of carrion effects at several trophic levels suggests that feeding links arising from carcasses shape the architecture and dynamics of food webs at the land-ocean interface. PMID:23826379

Antioxidant effects of herbal therapies used by patients with inflammatory bowel disease: an in vitro study.

PubMed

Langmead, L; Dawson, C; Hawkins, C; Banna, N; Loo, S; Rampton, D S

2002-02-01

Herbal remedies used by patients for treatment of inflammatory bowel disease include slippery elm, fenugreek, devil's claw, Mexican yam, tormentil and wei tong ning, a traditional Chinese medicine. Reactive oxygen metabolites produced by inflamed colonic mucosa may be pathogenic. Aminosalicylates (5-ASA) are antioxidant and other such agents could be therapeutic. To assess the antioxidant effects of herbal remedies in cell-free oxidant-generating systems and inflamed human colorectal biopsies. Luminol-enhanced chemiluminescence in a xanthine/xanthine oxidase cell-free system was used to detect superoxide scavenging by herbs and 5-ASA, and fluorimetry to define peroxyl radical scavenging using a phycoerythrin degradation assay. Chemiluminescence was used to detect herbal effects on generation of oxygen radicals by mucosal biopsies from patients with active ulcerative colitis. Like 5-ASA, all herbs, except fenugreek, scavenged superoxide dose-dependently. All materials tested scavenged peroxyl dose-dependently. Oxygen radical release from biopsies was reduced after incubation in all herbs except Mexican yam, and by 5-ASA. All six herbal remedies have antioxidant effects. Fenugreek is not a superoxide scavenger, while Mexican yam did not inhibit radical generation by inflamed biopsies. Slippery elm, fenugreek, devil's claw, tormentil and wei tong ning merit formal evaluation as novel therapies in inflammatory bowel disease.

A New Wet Deposition Module in SILAM Chemical Transport Model

NASA Astrophysics Data System (ADS)

Kouznetsov, R.; Sofiev, M.

2013-12-01

The System for Integrated modeLling of Atmopsheric coMposition SILAM (http://silam.fmi.fi/) is a CTM model of FMI air-quality research unit. SILAM is used for research, operational and emergency-response assessments and forecasting of the atmospheric composition within the scope of European and Finnish national projects. Characteristic scales of the SILAM applications vary from -mesoscale (grid spacing 1 km) up to the globe with characteristic resolution of 1 degree. Till recently, a simple approach based on scavenging coefficients and their species-dependent scaling was used in SILAM. Due to the lack of information on the vertical structure of precipitation in older meteorological datasets, it was prescribed. The new scheme uses a mechanistic description of the scavenging process and utilizes the vertical profiles of cloud water content. A simple model for dissociation of H2SO3 accounts for saturation of SO2 scavenging. As the vertical profiles of precipitation rates are rarely available from meteorological models, they are reconstructed from the profiles of cloud water and surface precipitation fields. The rain/snow increment in a 3D model grid cell is taken as a fraction of surface precipitation intensity equal to the cell's fraction of total cloud water column. The phase of precipitation (liquid/solid) is a function of air temperature. The fall speed is derived from the size of water drops given by a function of rain/snow intensity. In-cloud scavenging is considered as an equilibrium process: . the concentrations in cloud water are assumed to be in equilibrium with ambient air. The sub-cloud scavenging is driven by the precipitation that comes from above the cell. The scavenging by a single droplet is considered as a two-way equilibration process of in-water and in-air concentrations, controlled by the hydrometeors size, cross-section and a time the droplet falls through a cell, effective solubility and amount of already dissolved pollutant. The solubility for most species is given by their effective Henry factors as functions of temperature. An exception is SO2 since the in-water amount of [S(IV)] is not a linear function of SO2 partial pressure in the air. The effective Henry factor for SO2 is then calculated from a dissociation equation after all other species in a cell are processed and their in-water concentrations are known. The new scheme results in substantially more realistic vertical patterns for scavenging. The consideration of equilibration rather than one-way scavenging allows modelling the vertical redistribution of pollutants by precipitation. The scheme provides a simple and well-grounded means to account for saturation of scavenging for SO2.

Reward Your Students with an Online Scavenger Hunt!

ERIC Educational Resources Information Center

Board, Keith

2013-01-01

Do you have a class of students who do excellent work and whom you would like to give an enjoyable reward? Try an "Internet scavenger hunt" for a fun and educational change of pace! This article shares how to run the activity.

Recent Findings in EPA’s Lead Scavengers Evaluation

EPA Science Inventory

In response to continued concerns about the concentrations of 1,2-dibromoethane (EDB) in ground water from spills of leaded gasoline, OUST formed a Lead Scavengers Team with assistance from ASTSWMO. ASTSWMO and EPA Regions solicited participation from state agencies. Analysis w...

Leucine-rich Repeats of Bacterial Surface Proteins Serve as Common Pattern Recognition Motifs of Human Scavenger Receptor gp340*

PubMed Central

Loimaranta, Vuokko; Hytönen, Jukka; Pulliainen, Arto T.; Sharma, Ashu; Tenovuo, Jorma; Strömberg, Nicklas; Finne, Jukka

2009-01-01

Scavenger receptors are innate immune molecules recognizing and inducing the clearance of non-host as well as modified host molecules. To recognize a wide pattern of invading microbes, many scavenger receptors bind to common pathogen-associated molecular patterns, such as lipopolysaccharides and lipoteichoic acids. Similarly, the gp340/DMBT1 protein, a member of the human scavenger receptor cysteine-rich protein family, displays a wide ligand repertoire. The peptide motif VEVLXXXXW derived from its scavenger receptor cysteine-rich domains is involved in some of these interactions, but most of the recognition mechanisms are unknown. In this study, we used mass spectrometry sequencing, gene inactivation, and recombinant proteins to identify Streptococcus pyogenes protein Spy0843 as a recognition receptor of gp340. Antibodies against Spy0843 are shown to protect against S. pyogenes infection, but no function or host receptor have been identified for the protein. Spy0843 belongs to the leucine-rich repeat (Lrr) family of eukaryotic and prokaryotic proteins. Experiments with truncated forms of the recombinant proteins confirmed that the Lrr region is needed in the binding of Spy0843 to gp340. The same motif of two other Lrr proteins, LrrG from the Gram-positive S. agalactiae and BspA from the Gram-negative Tannerella forsythia, also mediated binding to gp340. Moreover, inhibition of Spy0843 binding occurred with peptides containing the VEVLXXXXW motif, but also peptides devoid of the XXXXW motif inhibited binding of Lrr proteins. These results thus suggest that the conserved Lrr motif in bacterial proteins serves as a novel pattern recognition motif for unique core peptides of human scavenger receptor gp340. PMID:19465482

Scavenging of black carbon in mixed phase clouds at the high alpine site Jungfraujoch

NASA Astrophysics Data System (ADS)

Cozic, J.; Verheggen, B.; Mertes, S.; Connolly, P.; Bower, K.; Petzold, A.; Baltensperger, U.; Weingartner, E.

2007-04-01

The scavenging of black carbon (BC) in liquid and mixed phase clouds was investigated during intensive experiments in winter 2004, summer 2004 and winter 2005 at the high alpine research station Jungfraujoch (3580 m a.s.l., Switzerland). Aerosol residuals were sampled behind two well characterized inlets; a total inlet which collected cloud particles (droplets and ice particles) as well as interstitial (unactivated) aerosol particles; an interstitial inlet which collected only interstitial aerosol particles. BC concentrations were measured behind each of these inlets along with the submicrometer aerosol number size distribution, from which a volume concentration was derived. These measurements were complemented by in-situ measurements of cloud microphysical parameters. BC was found to be scavenged into the condensed phase to the same extent as the bulk aerosol, which suggests that BC was covered with soluble material through aging processes, rendering it more hygroscopic. The scavenged fraction of BC (FScav,BC), defined as the fraction of BC that is incorporated into cloud droplets and ice crystals, decreases with increasing cloud ice mass fraction (IMF) from FScav,BC=60% in liquid phase clouds to FScav,BC~5-10% in mixed-phase clouds with IMF>0.2. This can be explained by the evaporation of liquid droplets in the presence of ice crystals (Wegener-Bergeron-Findeisen process), releasing BC containing cloud condensation nuclei back into the interstitial phase. In liquid clouds, the scavenged BC fraction is found to decrease with decreasing cloud liquid water content. The scavenged BC fraction is also found to decrease with increasing BC mass concentration since there is an increased competition for the available water vapour.

Scavenging of black carbon in mixed phase clouds at the high alpine site Jungfraujoch

NASA Astrophysics Data System (ADS)

Cozic, J.; Verheggen, B.; Mertes, S.; Connolly, P.; Bower, K.; Petzold, A.; Baltensperger, U.; Weingartner, E.

2006-11-01

The scavenging of black carbon (BC) in liquid and mixed phase clouds was investigated during intensive experiments in winter 2004, summer 2004 and winter 2005 at the high alpine research station Jungfraujoch (3580 m a.s.l., Switzerland). Aerosol residuals were sampled behind two well characterized inlets; a total inlet which collected cloud particles (drops and ice particles) as well as interstitial aerosol particles; an interstitial inlet which collected only interstitial (unactivated) aerosol particles. BC concentrations were measured behind each of these inlets along with the submicrometer aerosol number size distribution, from which a volume concentration was derived. These measurements were complemented by in-situ measurements of cloud microphysical parameters. BC was found to be scavenged into the cloud phase to the same extent as the bulk aerosol, which suggests that BC was covered with soluble material through aging processes, rendering it more hygroscopic. The scavenged fraction of BC (FScav,BC), defined as the fraction of BC that is incorporated into cloud droplets and ice crystals, decreases with increasing cloud ice mass fraction (IMF) from FScav,BC=60% in liquid phase clouds to FScav,BC~10% in mixed-phase clouds with IMF>0.2. This is explained by the evaporation of liquid droplets in the presence of ice crystals (Wegener-Bergeron-Findeisen process), releasing BC containing cloud condensation nuclei back into the interstitial phase. In liquid clouds, the scavenged BC fraction is found to decrease with decreasing cloud liquid water content. The scavenged BC fraction is also found to decrease with increasing BC mass concentration since there is an increased competition for the available water vapour.

High risk of lead contamination for scavengers in an area with high moose hunting success.

PubMed

Legagneux, Pierre; Suffice, Pauline; Messier, Jean-Sébastien; Lelievre, Frédérick; Tremblay, Junior A; Maisonneuve, Charles; Saint-Louis, Richard; Bêty, Joël

2014-01-01

Top predators and scavengers are vulnerable to pollutants, particularly those accumulated along the food chain. Lead accumulation can induce severe disorders and alter survival both in mammals (including humans) and in birds. A potential source of lead poisoning in wild animals, and especially in scavengers, results from the consumption of ammunition residues in the tissues of big game killed by hunters. For two consecutive years we quantified the level lead exposure in individuals of a sentinel scavenger species, the common raven (Corvus corax), captured during the moose (Alces alces) hunting season in eastern Quebec, Canada. The source of the lead contamination was also determined using stable isotope analyses. Finally, we identified the different scavenger species that could potentially be exposed to lead by installing automatic cameras targeting moose gut piles. Blood lead concentration in ravens increased over time, indicating lead accumulation over the moose-hunting season. Using a contamination threshold of 100 µg x L(-1), more than 50% of individuals were lead-contaminated during the moose hunting period. Lead concentration was twice as high in one year compared to the other, matching the number of rifle-shot moose in the area. Non-contaminated birds exhibited no ammunition isotope signatures. The isotope signature of the lead detected in contaminated ravens tended towards the signature from lead ammunition. We also found that black bears (Ursus americanus), golden eagles and bald eagles (Aquila chrysaetos and Haliaeetus leucocephalus, two species of conservation concern) scavenged heavily on moose viscera left by hunters. Our unequivocal results agree with other studies and further motivate the use of non-toxic ammunition for big game hunting.

Depth zonation and bathymetric trends of deep-sea megafaunal scavengers of the Hawaiian Islands

NASA Astrophysics Data System (ADS)

Yeh, John; Drazen, Jeffrey C.

2009-02-01

The deep sea has been shown to exhibit strong depth zonation in species composition and abundance. Examination of these patterns can offer ecological insight into how organisms adapt and respond to changing environmental parameters that co-occur with depth. Here we provide the first tropical study on bathymetric zonation and other depth-related trends (size, abundance, and species richness) spanning shelf to abyssal depths of scavenging megafauna. Baited time-lapse free-vehicle cameras were used to examine the deep-sea benthic and demersal scavenging communities of the Hawaiian Islands, an area for which the biology and ecology have remained poorly studied below 2000 m. Twenty-two deployments ranging in depth from 250 to 4783 m yielded 37 taxa attracted to bait, including the first known occurrence of the family Zoarcidae in the Hawaiian Islands. Cluster analysis of Bray-Curtis similarity of species peak abundance ( nmax) revealed four main faunal zones (250-500, 1000, 1500-3000, and ⩾4000 m) with significant separation (ANOSIM, global R=0.907, p=0.001) between designated depth groups. A major faunal break was identified at the 500-1000 m transition where species turnover was greatest, coinciding with the location of the local oxygen minimum zone. Dominance in species assemblage shifted from decapod crustaceans to teleosts moving from shallow to deeper faunal zones. Significant size differences in total length with depth were found for two of the four fish species examined. A logarithmic decline was observed in scavenger relative abundance with depth. Evidence of interaction between scavenging species was also noted between Synaphobranchus affinis and Neolithodes sp. (competition) and Histiobranchus sp. and aristeid shrimp (predation), suggesting that interactions between scavengers could influence indices of abundance generated from baited camera data.

The single-particle mixing state and cloud scavenging of black carbon: a case study at a high-altitude mountain site in southern China

NASA Astrophysics Data System (ADS)

Zhang, Guohua; Lin, Qinhao; Peng, Long; Bi, Xinhui; Chen, Duohong; Li, Mei; Li, Lei; Brechtel, Fred J.; Chen, Jianxin; Yan, Weijun; Wang, Xinming; Peng, Ping'an; Sheng, Guoying; Zhou, Zhen

2017-12-01

In the present study, a ground-based counterflow virtual impactor (GCVI) was used to sample cloud droplet residual (cloud RES) particles, while a parallel PM2.5 inlet was used to sample cloud-free or cloud interstitial (cloud INT) particles. The mixing state of black carbon (BC)-containing particles and the mass concentrations of BC in the cloud-free, RES and INT particles were investigated using a single-particle aerosol mass spectrometer (SPAMS) and two aethalometers, respectively, at a mountain site (1690 m a. s. l. ) in southern China. The measured BC-containing particles were extensively internally mixed with sulfate and were scavenged into cloud droplets (with number fractions of 0.05-0.45) to a similar (or slightly lower) extent as all the measured particles (0.07-0.6) over the measured size range of 0.1-1.6 µm. The results indicate the preferential activation of larger particles and/or that the production of secondary compositions shifts the BC-containing particles towards larger sizes. BC-containing particles with an abundance of both sulfate and organics were scavenged less than those with sulfate but limited organics, implying the importance of the mixing state on the incorporation of BC-containing particles into cloud droplets. The mass scavenging efficiency of BC with an average of 33 % was similar for different cloud events independent of the air mass. This is the first time that both the mixing state and cloud scavenging of BC in China have been reported. Our results would improve the knowledge on the concentration, mixing state, and cloud scavenging of BC in the free troposphere.

Hydroxyl radical scavenging assay of phenolics and flavonoids with a modified cupric reducing antioxidant capacity (CUPRAC) method using catalase for hydrogen peroxide degradation.

PubMed

Ozyürek, Mustafa; Bektaşoğlu, Burcu; Güçlü, Kubilay; Apak, Reşat

2008-06-02

Hydroxyl radicals (OH) generated in the human body may play an important role in tissue injury at sites of inflammation in oxidative stress-originated diseases. As a more convenient, efficient, and less costly alternative to HPLC/electrochemical detection techniques and to the nonspecific, low-yield deoxyribose (TBARS) test, we used a salicylate probe for detecting OH generated by the reaction of iron(II)-EDTA complex with H(2)O(2). The produced hydroxyl radicals attack both the salicylate probe and the hydroxyl radical scavengers that are incubated in solution for 10 min. Added radical scavengers compete with salicylate for the OH produced, and diminish chromophore formation from Cu(II)-neocuproine. At the end of the incubation period, the reaction was stopped by adding catalase. With the aid of this reaction, a kinetic approach was adopted to assess the hydroxyl radical scavenging properties of polyphenolics, flavonoids and other compounds (e.g., ascorbic acid, glucose, mannitol). A second-order rate constant for the reaction of the scavenger with OH could be deduced from the inhibition of colour formation due to the salicylate probe. In addition to phenolics and flavonoids, five kinds of herbs were evaluated for their OH scavenging activity using the developed method. The modified CUPRAC (cupric ion reducing antioxidant capacity) assay proved to be efficient for ascorbic acid, gallic acid and chlorogenic acid, for which the deoxyribose assay test is basically nonresponsive. An important contribution of this developed assay is the inhibition of the Fenton reaction with catalase degradation of hydrogen peroxide so that the remaining H(2)O(2) would neither give a CUPRAC absorbance nor involve in redox cycling of phenolic antioxidants, enabling the rapid assay of polyphenolics.

High Risk of Lead Contamination for Scavengers in an Area with High Moose Hunting Success

PubMed Central

Legagneux, Pierre; Suffice, Pauline; Messier, Jean-Sébastien; Lelievre, Frédérick; Tremblay, Junior A.; Maisonneuve, Charles; Saint-Louis, Richard; Bêty, Joël

2014-01-01

Top predators and scavengers are vulnerable to pollutants, particularly those accumulated along the food chain. Lead accumulation can induce severe disorders and alter survival both in mammals (including humans) and in birds. A potential source of lead poisoning in wild animals, and especially in scavengers, results from the consumption of ammunition residues in the tissues of big game killed by hunters. For two consecutive years we quantified the level lead exposure in individuals of a sentinel scavenger species, the common raven (Corvus corax), captured during the moose (Alces alces) hunting season in eastern Quebec, Canada. The source of the lead contamination was also determined using stable isotope analyses. Finally, we identified the different scavenger species that could potentially be exposed to lead by installing automatic cameras targeting moose gut piles. Blood lead concentration in ravens increased over time, indicating lead accumulation over the moose-hunting season. Using a contamination threshold of 100 µg.L−1, more than 50% of individuals were lead-contaminated during the moose hunting period. Lead concentration was twice as high in one year compared to the other, matching the number of rifle-shot moose in the area. Non-contaminated birds exhibited no ammunition isotope signatures. The isotope signature of the lead detected in contaminated ravens tended towards the signature from lead ammunition. We also found that black bears (Ursus americanus), golden eagles and bald eagles (Aquila chrysaetos and Haliaeetus leucocephalus, two species of conservation concern) scavenged heavily on moose viscera left by hunters. Our unequivocal results agree with other studies and further motivate the use of non-toxic ammunition for big game hunting. PMID:25389754

Evaluation of antioxidant potential of essential oils of some commonly used Indian spices in in vitro models and in food supplements enriched with omega-6 and omega-3 fatty acids.

PubMed

Bag, Anwesa; Chattopadhyay, Rabi Ranjan

2018-01-01

The aim of this study was to evaluate and compare the antioxidant potential of essential oils of some commonly used Indian spices (black pepper, cinnamon, clove, coriander and cumin) in various in vitro models and in food supplements enriched with omega-6 and omega-3 fatty acids. In vitro antioxidant potential was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and Fe 2+ ion-chelating methods and lipid oxidation stabilisation potential was evaluated in bulk soybean oil-fish oil mixture and their oil-in-water emulsions using peroxide value (PV), p-anisidine value (p-AV) and total oxidation value as indicators of oxidation. Combination effects using DPPH radical scavenging and Briggs-Rauscher oscillating reaction methods were also evaluated. Test essential oils showed varying degrees of radical scavenging and Fe 2+ ion-chelating efficacy. Clove and coriander oils showed significantly higher (P < 0.05) radical scavenging and Fe 2+ ion-chelating potential over other tested essential oils as well as BHT and ∞-tocopherol. The anti-lipid peroxidative potential of test essential oils was found in the following decreasing order: clove > coriander > BHT > cinnamon > α-tocopherol > cumin > black pepper. Furthermore, clove and coriander oils showed synergistic antioxidant activity in combination both in DPPH radical scavenging and Briggs-Rauscher oscillating reaction methods whereas other possible combinations showed additive effects. Strong radical scavenging and Fe 2+ -chelating as well as anti-lipid peroxidative activities of clove and coriander oils provide evidence that clove and coriander oils may serve as a potential source of natural antioxidants for retarding lipid oxidation of food supplements enriched with omega-6 and omega-3 fatty acids.

Survey of energy harvesting and energy scavenging approaches for on-site powering of wireless sensor- and microinstrument-networks

NASA Astrophysics Data System (ADS)

Lee, D.; Dulai, G.; Karanassios, Vassili

2013-05-01

Energy (or power) harvesting can be defined as the gathering and either storing or immediately using energy "freely" available in a local environment. Examples include harvesting energy from obvious sources such as photon-fluxes (e.g., solar), or wind or water waves, or from unusual sources such as naturally occurring pH differences. Energy scavenging can be defined as gathering and storing or immediately re-using energy that has been discarded, for instance, waste heat from air conditioning units, from in-door lights or from everyday actions such as walking or from body-heat. Although the power levels that can be harvested or scavenged are typically low (e.g., from nWatt/cm2 to mWatt/cm2), the key motivation is to harvest or to scavenge energy for a wide variety of applications. Example applications include powering devices in remote weather stations, or wireless Bluetooth headsets, or wearable computing devices or for sensor networks for health and bio-medical applications. Beyond sensors and sensor networks, there is a need to power compete systems, such as portable and energy-autonomous chemical analysis microinstruments for use on-site. A portable microinstrument is one that offers the same functionality as a large one but one that has at least one critical component in the micrometer regime. This paper surveys continuous or discontinuous energy harvesting and energy scavenging approaches (with particular emphasis on sensor and microinstrument networks) and it discusses current trends. It also briefly explores potential future directions, for example, for nature-inspired (e.g., photosynthesis), for human-power driven (e.g., for biomedical applications, or for wearable sensor networks) or for nanotechnology-enabled energy harvesting and energy scavenging approaches.

Single- and double-strand break formation in DNA irradiated in aqueous solution: dependence on dose and OH radical scavenger concentration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siddiqi, M.A.; Bothe, E.

The yields of single- and double-strand breaks (SSB and DSB) in calf thymus DNA, after /sup 60/Co gamma irradiation in dilute aqueous solution, have been determined via molecular weight measurements using a low-angle laser light scattering technique. The irradiations were administered to N/sub 2/O-containing solutions of DNA in the absence and presence of oxygen and with different concentrations of the OH radical scavengers phenol, tertiary butanol, and methanol. OH radicals were found to produce SSB linearly with dose with a G value of 55 nmol J-1 and 54 nmol J-1 in deoxygenated and oxygenated solutions, respectively. DSB were formed accordingmore » to a linear-quadratic dose relationship and the G value of linearly formed DSB were GDSB alpha(r.t.) = 3.5 nmol J-1 in deoxygenated and 3.2 nmol J-1 in oxygenated solution. The ratio of GSSB/GDSB alpha(r.t.) = gamma of 19 +/- 6 was independent of the scavenger concentration in the case of tertiary butanol and methanol-containing solutions. GDSB alpha(r.t.) is interpreted to result from a radical site transferred from a sugar moiety of the cleaved strand to the complementary intact strand. This process of radical transfer and subsequent cleavage of the second strand occurs with a probability of about 6 +/- 2% in the presence of oxygen at all scavenger concentrations studied. These data on scavenging capacity on GDSB alpha(r.t.) suggest that the double-strand breakage produced via radical transfer remains higher than that resulting from direct effect, up to scavenging capacities of about 10(9) s-1.« less

Characterization of the radical-scavenging reaction of 2-O-substituted ascorbic acid derivatives, AA-2G, AA-2P, and AA-2S: a kinetic and stoichiometric study.

PubMed

Takebayashi, Jun; Tai, Akihiro; Gohda, Eiichi; Yamamoto, Itaru

2006-04-01

The aim of this study was to characterize the antioxidant activity of three ascorbic acid (AA) derivatives O-substituted at the C-2 position of AA: ascorbic acid 2-glucoside (AA-2G), ascorbic acid 2-phosphate (AA-2P), and ascorbic acid 2-sulfate (AA-2S). The radical-scavenging activities of these AA derivatives and some common low molecular-weight antioxidants such as uric acid or glutathione against 1,1-diphenyl-picrylhydrazyl (DPPH) radical, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS+), or galvinoxyl radical were kinetically and stoichiometrically evaluated under pH-controlled conditions. Those AA derivatives slowly and continuously reacted with DPPH radical and ABTS+, but not with galvinoxyl radical. They effectively reacted with DPPH radical under acidic conditions and with ABTS+ under neutral conditions. In contrast, AA immediately quenched all species of radicals tested at all pH values investigated. The reactivity of Trolox, a water-soluble vitamin E analogue, was comparable to that of AA in terms of kinetics and stoichiometrics. Uric acid and glutathione exhibited long-lasting radical-scavenging activity against these radicals under certain pH conditions. The radical-scavenging profiles of AA derivatives were closer to those of uric acid and glutathione rather than to that of AA. The number of radicals scavenged by one molecule of AA derivatives, uric acid, or glutathione was equal to or greater than that by AA or Trolox under the appropriate conditions. These data suggest the potential usage of AA derivatives as radical scavengers.

Updates on the EPA Study of Lead Scavengers (EDB and DCA)

EPA Science Inventory

In response to continued concerns about the concentrations of 1,2-dibromoethane (EDB) in ground water from spills of leaded gasoline, OUST formed a Lead Scavengers Team with assistance from ASTSWMO. ASTSWMO and EPA Regions solicited participation from state agencies. Analysis w...

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…

Body Size as a Driver of Scavenging in Theropod Dinosaurs.

PubMed

Kane, Adam; Healy, Kevin; Ruxton, Graeme D; Jackson, Andrew L

2016-06-01

Theropod dinosaurs dominated Earth's terrestrial ecosystem as a diverse group of predators for more than 160 million years, yet little is known about their foraging ecology. Maintaining a balanced energy budget presented a major challenge for therapods, which ranged from the chicken-sized Microraptor up to the whale-sized Giganotosaurus, in the face of intense competition and the demands of ontogenetic growth. Facultative scavenging, a behavior present in almost all modern predators, may have been important in supplementing energetically expensive lifestyles. By using agent-based models based on the allometric relationship between size and foraging behaviors, we show that theropods between 27 and 1,044 kg would have gained a significant energetic advantage over individuals at both the small and large extremes of theropod body mass through their scavenging efficiency. These results were robust to rate of competition, primary productivity, and detection distance. Our models demonstrate the potential importance of facultative scavenging in theropods and the role of body size in defining its prevalence in Mesozoic terrestrial systems.

Radical scavenging activity and LC-MS metabolic profiling of petals, stamens, and flowers of Crocus sativus L.

PubMed

Montoro, Paola; Maldini, Mariateresa; Luciani, Leonilda; Tuberoso, Carlo I G; Congiu, Francesca; Pizza, Cosimo

2012-08-01

Radical scavenging activities of Crocus sativus petals, stamens and entire flowers, which are waste products in the production of the spice saffron, by employing ABTS radical scavenging method, were determined. At the same time, the metabolic profiles of different extract (obtained by petals, stamens and flowers) were obtained by LC-ESI-IT MS (liquid chromatography coupled with electrospray mass spectrometry equipped with Ion Trap analyser). LC-ESI-MS is a techniques largely used nowadays for qualitative fingerprint of herbal extracts and particularly for phenolic compounds. To compare the different extracts under an analytical point of view a specific method for qualitative LC-MS analysis was developed. The high variety of glycosylated flavonoids found in the metabolic profiles could give value to C. sativus petals, stamens and entire flowers. Waste products obtained during saffron production, could represent an interesting source of phenolic compounds, with respect to the high variety of compounds and their free radical scavenging activity. © 2012 Institute of Food Technologists®

How is edaravone effective against acute ischemic stroke and amyotrophic lateral sclerosis?

PubMed Central

Watanabe, Kazutoshi; Tanaka, Masahiko; Yuki, Satoshi; Hirai, Manabu; Yamamoto, Yorihiro

2018-01-01

Edaravone is a low-molecular-weight antioxidant drug targeting peroxyl radicals among many types of reactive oxygen species. Because of its amphiphilicity, it scavenges both lipid- and water-soluble peroxyl radicals by donating an electron to the radical. Thus, it inhibits the oxidation of lipids by scavenging chain-initiating water-soluble peroxyl radicals and chain-carrying lipid peroxyl radicals. In 2001, it was approved in Japan as a drug to treat acute-phase cerebral infarction, and then in 2015 it was approved for amyotrophic lateral sclerosis (ALS). In 2017, the U.S. Food and Drug Administration also approved edaravone for treatment of patients with ALS. Its mechanism of action was inferred to be scavenging of peroxynitrite. In this review, we focus on the radical-scavenging characteristics of edaravone in comparison with some other antioxidants that have been studied in clinical trials, and we summarize its pharmacological action and clinical efficacy in patients with acute cerebral infarction and ALS. PMID:29371752

Application of chitooligosaccharides as antioxidants in beer to improve the flavour stability by protecting against beer staling during storage.

PubMed

Yang, Fan; Luan, Bo; Sun, Zhen; Yang, Chao; Yu, Zhimin; Li, Xianzhen

2017-02-01

To improve beer flavour stability by adding chitooligosaccharides that prevent formation of staling compounds and also scavenge radicals in stale beer. Chitooligosaccharides, at 0.001-0.01%, inhibited the formation of staling compounds in forced aged beer. The formation of 5-hydroxymethylfurfural, trans-2-nonenal and phenylacetaldehyde were decreased by 105, 360 and 27%, respectively, when compared with those in stale beer without chitooligosaccharide addition. The capability of chitooligosaccharides to prevent staling compound formation depended on their molecular size (2 or 3 kDa). The DPPH/hydroxyl radical scavenging activity in fresh beer significantly lower than that in forced aged beer in the presence of chitooligosaccharides. When compared with stale beer without added chitooligosaccharides, the radical scavenging activity could be increased by adding chitooligosaccharides to forced aged beer. Chitooligosaccharides play an active part in the prevention of beer flavour deterioration by inhibiting the formation of staling compounds and increasing radical scavenging activity.

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.

Impact of sampling parameters on the radical scavenging potential of olive (Olea europaea L.) leaves.

PubMed

Papoti, Vassiliki T; Tsimidou, Maria Z

2009-05-13

The impact of sampling parameters, that is, cultivar, leaf age, and sampling date, on the radical scavenging potential of olive leaf extracts was examined via the DPPH(*) and other assays. Total phenol content was estimated colorimetrically and by fluorometry, whereas phenol composition was assessed by RP-HPLC coupled with diode array, fluorometric, and MS detection systems. Oleuropein was not always the major leaf constituent. Considerable differences noted in individual phenol levels (hydroxytyrosol, oleuropein and other secoiridoids, verbascoside, and flavonoids) among samples were not reflected either in the total phenol content or in the radical scavenging potential of the extracts. It can be suggested that olive leaf is a robust source of radical scavengers throughout the year and that differentiation in the levels of individual components depends rather on sampling period than on cultivar or age. The latter does not present predictable regularity. Exploitation of all types of leaves expected in an olive tree shoot for the extraction of bioactive compounds is feasible.

Selection for Growth Performance in Broiler Chickens Associates with Less Diet Flexibility

PubMed Central

Pauwels, Jana; Coopman, Frank; Cools, An; Michiels, Joris; Fremaut, Dirk; De Smet, Stefaan; Janssens, Geert P. J.

2015-01-01

Global competition for high standard feed-food resources between man and livestock, such as industrial broilers, is a concerning problem. In addition, the low productivity of scavenger chickens in developing countries leaves much to be desired. Changing the ingredients, and therefore, the nutrient composition of feed intake by commercial fed as well as scavenger chickens seems like an obvious solution. In this study, the ability of four broiler chicken breeds to perform on a commercial versus a scavenger diet was tested. The four broiler breeds differed genetically in growth potential. A significant (P < 0.01) negative effect of the scavenger diet on the bodyweight of the fast growing breeds was found and this effect decreased with decreasing growth rate in the other breeds. These differences in bodyweight gain could not be explained by differences in nutrient digestibility but were caused by the lack of ability of the fast growing breeds to increase their feed intake sufficiently. PMID:26042600

A comparative assessment of antioxidant properties, total phenolic content of einkorn, wheat, barley and their malts.

PubMed

Fogarasi, Attila-Levente; Kun, Szilárd; Tankó, Gabriella; Stefanovits-Bányai, Eva; Hegyesné-Vecseri, Beáta

2015-01-15

Two einkorn wheat, one barley, three optional winter cultivation wheat and five winter cultivation wheat samples harvested in Hungary in 2011, and their malts were evaluated for their DPPH radical and ABTS radical cation scavenging activity, ferric reduction capacity (FRAP) and total phenolic content (TPC). All einkorn and barley samples exhibited significant antioxidant activities determined by DPPH and ABTS radical scavenging activities. The einkorn samples show higher polyphenol content than the other wheat samples. In all cases the barley sample had the highest antioxidant potential and polyphenol content. The einkorn malts had high DPPH and ABTS radical cation scavenging activities, but the phenolic content was lower against wheat samples. There was significant difference between the antioxidant potential of optional and winter cultivation wheat samples except on ABTS scavenging activities. Einkorn wheat is potentially a new raw material to produce organic beer that might have beneficial effects with its increased antioxidant potential. Copyright © 2014 Elsevier Ltd. All rights reserved.

Numerical Study on the Improvement of Oil Return Structure in Aero-Engine Bearing Chambers

NASA Astrophysics Data System (ADS)

Jingyu, Zhao; Yaguo, Lyv; Zhenxia, Liu; Guozhe, Ren

2018-03-01

Numerical study has been carried out to improve the unreasonable oil film accumulation and oil return effect of the bearing chamber. Ramp sump and eccentricity sump offtake structures are designed and improved, and oil-gas two-phase flow calculation model based on CLSVOF (coupled level set and volume of fluid) method is proposed. Based on the grid-independent analysis and verifying the rationality of numerical data, oil-gas movement mechanism and oil return characteristics for different scavenge offtakes are calculated and analyzed. Results show that both the ramp sump and eccentricity sump offtake structures have favorable effects on improving the local oil distribution such as recirculation and stripping, etc. at low rotation speeds and alleviating the rapid decline of scavenge efficiency at high rotation speeds. Meanwhile, the air shear force is the main reason for the rapid decline of scavenge efficiency, while the design of oil return sump makes for the oil discharge from the scavenge offtake, and the deeper the sump depth is, the better.

Homogenate-assisted Vacuum-powered Bubble Extraction of Moso Bamboo Flavonoids for On-line Scavenging Free Radical Capacity Analysis.

PubMed

Sun, Yinnan; Yang, Kui; Cao, Qin; Sun, Jinde; Xia, Yu; Wang, Yinhang; Li, Wei; Ma, Chunhui; Liu, Shouxin

2017-07-11

A homogenate-assisted vacuum-powered bubble extraction (HVBE) method using ethanol was applied for extraction of flavonoids from Phyllostachys pubescens (P. pubescens) leaves. The mechanisms of homogenate-assisted extraction and vacuum-powered bubble generation were discussed in detail. Furthermore, a method for the rapid determination of flavonoids by HPLC was established. HVBE followed by HPLC was successfully applied for the extraction and quantification of four flavonoids in P. pubescens , including orientin, isoorientin, vitexin, and isovitexin. This method provides a fast and effective means for the preparation and determination of plant active components. Moreover, the on-line antioxidant capacity, including scavenging positive ion and negative ion free radical capacity of different fractions from the bamboo flavonoid extract was evaluated. Results showed that the scavenging DPPH ˙ free radical capacity of vitexin and isovitexin was larger than that of isoorientin and orientin. On the contrary, the scavenging ABTS⁺ ˙ free radical capacity of isoorientin and orientin was larger than that of vitexin and isovitexin.

Controlling chromium slag pollution utilising scavengers: a case of Shandong Province, China.

PubMed

Liu, Changhao; Côté, Raymond P

2015-04-01

The problem of chromium slag pollution is a great challenge for China. It is now an urgent task for China to take effective measures to eliminate chromium slag pollution. This article examines the case of the treatment of chromium slag in Shandong Province and explores how chromium slag pollution can be eliminated in Shandong Province. It shows that the chromium slag stockpiled by the chemical plants was successfully utilised by local steel companies, who act as 'scavenger companies'. The driving mechanism, seeking a potential 'scavenger company' within the local region and the role of the local government on the case of Shandong Province are discussed. This article concludes that local steel companies can be utilised to effectively and efficiently treat the chromium slag while benefiting the steel companies. The local governments need to play multiple roles in solving the problem of chromium slag pollution. Seeking and identifying 'scavenger companies' within a region could be an important approach to reducing pollution within the region. © The Author(s) 2015.

Relationship between the lipophilicity of gallic acid n-alquil esters' derivatives and both myeloperoxidase activity and HOCl scavenging.

PubMed

Rosso, Rober; Vieira, Tiago O; Leal, Paulo C; Nunes, Ricardo J; Yunes, Rosendo A; Creczynski-Pasa, Tânia B

2006-09-15

The gallic acid and several n-alkyl gallates, with the same number of hydroxyl substituents, varying only in the side carbonic chain length, with respective lipophilicity defined through the C log P, were studied. It evidenced the structure-activity relationship of the myeloperoxidase activity inhibition and the hypochlorous acid scavenger property, as well as its low toxicity in rat hepatic tissue. The gallates with C log P below 3.0 (compounds 2-7) were more active against the enzyme activity, what means that the addition of 1-6 carbons (C log P between 0.92 and 2.92) at the side chain increased approximately 50% the gallic acid effect. However, a relationship between the HOCl scavenging capability and the lipophilicity was not observed. With these results it is possible to suggest that the gallates protect the HOCl targets through two mechanisms: inhibiting its production by the enzyme and scavenging the reactive specie.

Analysis of a piezoelectric bimorph plate with a central-attached mass as an energy harvester.

PubMed

Jiang, Shunong; Hu, Yuantai

2007-07-01

This article analyzes the performance of a piezoelectric energy harvester in the flexural mode for scavenging ambient vibration energy. The energy harvester consists of a piezoelectric bimorph plate with a central-attached mass. The linear piezoelectricity theory is applied to evaluate the performance dependence upon the physical and geometrical parameters of the model bimorph plate. The analytical solution for the flexural motion of the piezoelectric bimorph plate energy harvester shows that the output power density increases initially, reaches a maximum, then decreases monotonically with the increasing load impedance, which is normalized by a parameter that is a simple combination of the physical and geometrical parameters of the scavenging structure, the bimorph plate, and the frequency of the ambient vibration, underscoring the importance for the load circuit to have the impedance desirable by the scavenging structure. The numerical results illustrate the considerably enhanced performances by adjusting the physical and geometrical parameters of the scavenging structure.

Scavenging of peroxynitrite by phycocyanin and phycocyanobilin from Spirulina platensis: protection against oxidative damage to DNA.

PubMed

Bhat, V B; Madyastha, K M

2001-07-13

Peroxynitrite (ONOO(-)) is known to inactivate important cellular targets and also mediate oxidative damage in DNA. The present study has demonstrated that phycocyanin, a biliprotein from spirulina platensis and its chromophore, phycocyanobilin (PCB), efficiently scavenge ONOO(-), a potent physiological inorganic toxin. Scavenging of ONOO(-) by phycocyanin and PCB was established by studying their interaction with ONOO(-) and quantified by using competition kinetics of pyrogallol red bleaching assay. The relative antioxidant ratio and IC(50) value clearly indicate that phycocyanin is a more efficient ONOO(-) scavenger than PCB. The present study has also shown that PCB significantly inhibits the ONOO(-)-mediated single-strand breaks in supercoiled plasmid DNA in a dose-dependent manner with an IC(50) value of 2.9 +/- 0.6 microM. These results suggest that phycocyanin, has the ability to inhibit the ONOO(-)-mediated deleterious biological effects and hence has the potential to be used as a therapeutic agent. Copyright 2001 Academic Press.

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.

2,4,6-Trichlorophenylhydrazine Schiff bases as DPPH radical and super oxide anion scavengers.

PubMed

Khan, Khalid Mohammed; Shah, Zarbad; Ahmad, Viqar Uddin; Khan, Momin; Taha, Muhammad; Rahim, Fazal; Ali, Sajjad; Ambreen, Nida; Perveen, Shahnaz; Choudhary, M Iqbal; Voelter, Wolfgang

2012-05-01

Syntheses of thirty 2,4,6-trichlorophenylhydrazine Schiff bases 1-30 were carried out and evaluated for their in vitro DPPH radical and super oxide anion scavenging activities. Compounds 1-30 have shown a varying degree of DPPH radical scavenging activity and their IC50 values range between 4.05-369.30 µM. The compounds 17, 28, 18, 14, 8, 15, 12, 2, 29, and 7 exhibited IC50 values ranging between 4.05±0.06-24.42±0.86 µM which are superior to standard n-propylgallate (IC50=30.12±0.27 µM). Selected compounds have shown a varying degree of superoxide anion radical scavenger activity and their IC50 values range between 91.23-406.90 µM. The compounds 28, 8, 17, 15, and 14, showed IC50 values between 91.23±1.2-105.31±2.29 µM which are superior to standard n-propylgallate (IC50=106.34±1.6 µM).

Space Transportatioin System (STS) propellant scavenging system study. Volume 3: Cost and work breakdown structure-dictionary

NASA Technical Reports Server (NTRS)

1985-01-01

Fundamentally, the volumes of the oxidizer and fuel propellant scavenged from the orbiter and external tank determine the size and weight of the scavenging system. The optimization of system dimensions and weights is stimulated by the requirement to minimize the use of partial length of the orbiter payload bay. Thus, the cost estimates begin with weights established for the optimum design. Both the design, development, test, and evaluation and theoretical first unit hardware production costs are estimated from parametric cost weight scaling relations for four subsystems. For cryogenic propellants, the widely differing characteristics of the oxidizer and the fuel lead to two separate tank subsystems, in addition to the electrical and instrumentation subsystems. Hardwares costs also involve quantity, as an independent variable, since the number of production scavenging systems is not firm. For storable propellants, since the tankage volume of the oxidizer and fuel are equal, the hardware production costs for developing these systems are lower than for cryogenic propellants.

Total phenolic, total flavonoid content, and antioxidant capacity of the leaves of Meyna spinosa Roxb., an Indian medicinal plant.

PubMed

Sen, Saikat; De, Biplab; Devanna, N; Chakraborty, Raja

2013-03-01

The objective of the present study was to determine the total phenolic and total flavonoid contents, and to evaluate the antioxidant potential of different leaf extracts of Meyna spinosa Roxb. ex Link, a traditional medicinal plant of India. Free radical scavenging and antioxidant potential of the methanol, ethyl acetate, and petroleum ether extracts of Meyna spinosa leaves were investigated using several in vitro and ex vivo assays, including the 2, 2-diphenyl-picrylhydrazyl radical scavenging, superoxide anion scavenging, hydroxyl radical scavenging, nitric oxide radical scavenging, hydrogen peroxide scavenging activity, metal chelating assay, and reducing power ability method. Total antioxidant activity of the extracts was estimated by the ferric thiocyanate method. Inhibition assay of lipid peroxidation and oxidative hemolysis were also performed to confirm the protective effect of the extracts. Total phenolic and total flavonoid contents of the extracts were estimated using standard chemical assay procedures. Methanol extracts showed the highest polyphenolic content and possessed the better antioxidant activity than the other two extracts. Total phenolic and total flavonoid contents in the methanol extract were (90.08 ± 0.44) mg gallic acid equivalents/g and (58.50 ± 0.09) mg quercetin equivalents/g, respectively. The IC50 of the methanol extract in the DPPH(·), superoxide anion, hydroxyl radical, nitric oxide radical, hydrogen peroxide scavenging activity and metal chelating assays were (16.4 ± 0.41), (35.9 ± 0.19), (24.1 ± 0.33), (23.7 ± 0.09), (126.8 ± 2.92), and (117.2 ± 1.01) μg·mL(-1), respectively. The methanol extract showed potent reducing power ability, total antioxidant activity, and significantly inhibit lipid peroxidation and oxidative hemolysis which was similar to that of standards. The results indicated a direct correlation between the antioxidant activity and the polyphenolic content of the extracts, which may the foremost contributors to the antioxidant activity of the plant. The present study confirmed that the methanol extract of Meyna spinosa leaves is a potential source of natural antioxidants. Copyright © 2013 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Occupational exposure to nitrous oxide - the role of scavenging and ventilation systems in reducing the exposure level in operating rooms.

PubMed

Krajewski, Wojciech; Kucharska, Malgorzata; Wesolowski, Wiktor; Stetkiewicz, Jan; Wronska-Nofer, Teresa

2007-03-01

The aim of this study was to assess the level of occupational exposure to nitrous oxide (N(2)O) in operating rooms (ORs), as related to different ventilation and scavenging systems used to remove waste anaesthetic gases from the work environment. The monitoring of N(2)O in the air covered 35 ORs in 10 hospitals equipped with different systems for ventilation and anaesthetic scavenging. The examined systems included: natural ventilation with supplementary fresh air provided by a pressure ventilation system (up to 6 air changes/h); pressure and exhaust ventilation systems equipped with ventilation units supplying fresh air to and discharging contaminated air outside the working area (more than 10 air changes/h); complete air-conditioning system with laminar air flow (more than 15 air changes/h). The measurements were carried out during surgical procedures (general anaesthesia induced intravenously and maintained with inhaled N(2)O and sevofluran delivered through cuffed endotracheal tubes) with connected or disconnected air scavenging. Air was collected from the breathing zone of operating personnel continuously through the whole time of anaesthesia to Tedlar((R)) bags, and N(2)O concentrations in air samples were analyzed by adsorption gas chromatography/mass spectrometry. N(2)O levels in excess of the occupational exposure limit (OEL) value of 180mg/m(3) were registered in all ORs equipped with ventilation systems alone. The OEL value was exceeded several times in rooms with natural ventilation plus supplementary pressure ventilations and twice or less in those with pressure/exhaust ventilation systems or air conditioning. N(2)O levels below or within the OEL value were observed in rooms where the system of air conditioning or pressure/exhaust ventilation was combined with scavenging systems. Systems combining natural/pressure ventilation with scavenging were inadequate to maintain N(2)O concentration below the OEL value. Air conditioning and an efficient pressure/exhaust ventilation (above 12 air exchanges/h) together with efficient active scavenging systems are sufficient to sustain N(2)O exposure in ORs at levels below or within the OEL value of 180mg/m(3).

Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection

PubMed Central

Mishra, Om P.; Popov, Anatoliy V.; Pietrofesa, Ralph A.; Christofidou-Solomidou, Melpo

2017-01-01

Background Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. Methods The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3′-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3′-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton 1H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO− and radiation. Purine base chlorination by ClO− and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Results: Chloride anions (Cl−) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by 1H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO− or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO− generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl•) and dichloro radical anions (Cl2−•)), which were trapped by SDG and its structural analog dopamine. Conclusion We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged ACS and prevented ACS-induced DNA damage and chlorination of 2-aminopurine. This study identified a novel and unique mechanism of SDG radioprotection, through ACS scavenging, and supports the potential usefulness of SDG as a radioprotector and mitigator for radiation exposure as part of cancer therapy or accidental exposure. PMID:27261092

Gamma-irradiation produces active chlorine species (ACS) in physiological solutions: Secoisolariciresinol diglucoside (SDG) scavenges ACS - A novel mechanism of DNA radioprotection.

PubMed

Mishra, Om P; Popov, Anatoliy V; Pietrofesa, Ralph A; Christofidou-Solomidou, Melpo

2016-09-01

Secoisolariciresinol diglucoside (SDG), the main lignan in whole grain flaxseed, is a potent antioxidant and free radical scavenger with known radioprotective properties. However, the exact mechanism of SDG radioprotection is not well understood. The current study identified a novel mechanism of DNA radioprotection by SDG in physiological solutions by scavenging active chlorine species (ACS) and reducing chlorinated nucleobases. The ACS scavenging activity of SDG was determined using two highly specific fluoroprobes: hypochlorite-specific 3'-(p-aminophenyl) fluorescein (APF) and hydroxyl radical-sensitive 3'-(p-hydroxyphenyl) fluorescein (HPF). Dopamine, an SDG structural analog, was used for proton (1)H NMR studies to trap primary ACS radicals. Taurine N-chlorination was determined to demonstrate radiation-induced generation of hypochlorite, a secondary ACS. DNA protection was assessed by determining the extent of DNA fragmentation and plasmid DNA relaxation following exposure to ClO(-) and radiation. Purine base chlorination by ClO(-) and γ-radiation was determined by using 2-aminopurine (2-AP), a fluorescent analog of 6-aminopurine. Chloride anions (Cl(-)) consumed >90% of hydroxyl radicals in physiological solutions produced by γ-radiation resulting in ACS formation, which was detected by (1)H NMR. Importantly, SDG scavenged hypochlorite- and γ-radiation-induced ACS. In addition, SDG blunted ACS-induced fragmentation of calf thymus DNA and plasmid DNA relaxation. SDG treatment before or after ACS exposure decreased the ClO(-) or γ-radiation-induced chlorination of 2-AP. Exposure to γ-radiation resulted in increased taurine chlorination, indicative of ClO(-) generation. NMR studies revealed formation of primary ACS radicals (chlorine atoms (Cl) and dichloro radical anions (Cl2¯)), which were trapped by SDG and its structural analog dopamine. We demonstrate that γ-radiation induces the generation of ACS in physiological solutions. SDG treatment scavenged ACS and prevented ACS-induced DNA damage and chlorination of 2-aminopurine. This study identified a novel and unique mechanism of SDG radioprotection, through ACS scavenging, and supports the potential usefulness of SDG as a radioprotector and mitigator for radiation exposure as part of cancer therapy or accidental exposure. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Screening of various botanical extracts for antioxidant activity using DPPH free radical method.

PubMed

Waqas, Muhammad Khurram; Saqib, Najam-Us; Rashid, Saeed-Ur; Shah, Pervaiz Akhtar; Akhtar, Naveed; Murtaza, Ghulam

2013-01-01

Aiming at the exploration of herbal use by society, crude extracts of the seeds of some commonly used medicinal plants (Vitis vinifera, Tamarindus indica and Glycin max) were screened for their free radical scavenging properties using ascorbic acid as standard antioxidant. Free radical scavenging activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical. The overall antioxidant activity of grape seeds (Vitis vinifera) was the strongest, followed in descending order by soybean (Glycin max) and tamarind (Tamarindus indica). The seeds extract of Vitis vinifera, Glycin max and Tamarindus indica showed 85.61%, 83.45% and 79.26%, DPPH scavenging activity respectively.

Cytokine Decoy and Scavenger Receptors as Key Regulators of Immunity and Inflammation

PubMed Central

Bonecchi, Raffaella; Garlanda, Cecilia; Mantovani, Alberto; Riva, Federica

2017-01-01

IL-1R2 was the first decoy receptor to be described. Subsequently receptors which act as pure decoys or scavengers or trigger dampening of cytokine signaling have been described for cytokines and chemokines. Here we review the current understanding of the mode of action and significance in pathology of the chemokine atypical receptor ACKR2, the IL-1 decoy receptor IL-1R2 and the atypical IL-1 receptor family IL-1R8. Decoy and scavenger receptors with no or atypical signaling have emerged as a general strategy conserved in evolution to tune the action of cytokines, chemokines and growth factors. PMID:27498604

Analysis of Ethyl Acetate Extract of Enzymatic Hydrolysate from High Purity Oleuropein and DPPH Radical Scavenging Capacity

NASA Astrophysics Data System (ADS)

Yuan, Jiaojiao; Li, Bing; Qin, Frank G. F.; Tu, Junling

2018-01-01

High purify oleuropein (81.04% OL) was hydrolyzed by hemicellulase and phenols was existed in the ethyl acetate extract of enzymatic hydrolysate (EAE). The results presented that there were hydroxytyrosol (HT), tyrosol, caffeic acid, 3,4-dihydroxybenzoic acid, 3,4-dihydroxy phenylacetic acid in EAE by HPLC, and HT content was 19.36%. Antioxidant activities (DPPH radical scavenging capacity) were all added as the samples concentration increased, and dose-effect relationships also existed. HT possessed the highest DPPH radical scavenging capacity, followed by Vc, and eugenol, OL, caffeic acid, 3,4-dihydroxy phenylacetic acid and 3,4-dihydroxybenzoic acid.

Selective heterogeneous acid catalyzed esterification of N-terminal sulfyhdryl fatty acids

USDA-ARS?s Scientific Manuscript database

Our interest in thiol fatty acids lies in their antioxidative, free radical scavenging, and metal ion scavenging capabilities as applied to cosmeceutical and skin care formulations. The retail market is filled with products containing the disulfide-containing free fatty acid, lipoic acid. These pr...

98. LEAD SCAVENGER CELLS, LOOKING NORTHEAST. NOTE VSHAPED LAUNDER TO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

98. LEAD SCAVENGER CELLS, LOOKING NORTHEAST. NOTE V-SHAPED LAUNDER TO COLLECT CONCENTRATE FROTH THAT SPILLED OVER WIER ALONG EDGE OF CELLS. EACH ELECTRIC MOTOR TURNED AGITATORS IN TWO CELLS VIA BELT DRIVES. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

Education can improve the negative perception of a threatened long-lived scavenging bird, the Andean condor

PubMed Central

Cailly Arnulphi, Verónica B.; Lambertucci, Sergio A.

2017-01-01

Human-wildlife conflicts currently represent one of the main conservation problems for wildlife species around the world. Vultures have serious conservation concerns, many of which are related to people's adverse perception about them due to the belief that they prey on livestock. Our aim was to assess local perception and the factors influencing people's perception of the largest scavenging bird in South America, the Andean condor. For this, we interviewed 112 people from Valle Fértil, San Juan province, a rural area of central west Argentina. Overall, people in the area mostly have an elementary education, and their most important activity is livestock rearing. The results showed that, in general, most people perceive the Andean condor as an injurious species and, in fact, some people recognize that they still kill condors. We identified two major factors that affect this perception, the education level of villagers and their relationship with livestock ranching. Our study suggests that conservation of condors and other similar scavengers depends on education programs designed to change the negative perception people have about them. Such programs should be particularly focused on ranchers since they are the ones who have the worst perception of these scavengers. We suggest that highlighting the central ecological role of scavengers and recovering their cultural value would be fundamental to reverse their persecution and their negative perception by people. PMID:28950019

Contrasting Boundary Scavenging in two Eastern Boundary Current Regimes

NASA Astrophysics Data System (ADS)

Anderson, R. F.; Fleisher, M. Q.; Pavia, F. J.; Vivancos, S. M.; Lu, Y.; Zhang, P.; Cheng, H.; Edwards, R. L.

2016-02-01

We use data from two US GEOTRACES expeditions to compare boundary scavenging intensity in two eastern boundary current systems: the Canary Current off Mauritania and the Humboldt Current off Peru. Boundary scavenging refers to the enhanced removal of trace elements from the ocean by sorption to sinking particles in regions of greater than average particle abundance. Both regimes experience high rates of biological productivity and generation of biogenic particles, with rates of productivity potentially a little greater off Peru, whereas dust fluxes are an order of magnitude greater off NW Africa (see presentation by Vivancos et al., this meeting). Despite greater productivity off Peru, we find greater intensity of scavenging off NW Africa as measured by the residence time of dissolved 230Th integrated from the surface to a depth of 2500 m (10-11 years off NW Africa vs. 15-17 years off Peru). Dissolved 231Pa/230Th ratios off NW Africa (Hayes et al., Deep Sea Res.-II 116 (2015) 29-41) are nearly twice the values observed off Peru. We attribute this difference to the well-known tendency for lithogenic phases (dust) to strongly fractionate in favor of Th uptake during scavenging and removal, leaving the dissolved phase enriched in Pa. This behavior needs to be considered when interpreting sedimentary 231Pa/230Th ratios as a paleo proxy.

Using Scavenger Hunts to Familiarize Students with Scientific Journal Articles.

PubMed

Lijek, Rebeccah S; Fankhauser, Sarah C

2016-03-01

Primary scientific literature can be difficult to navigate for anyone unfamiliar with its foreign, formal structure. We sought to create a fun, easy learning tool to help familiarize students of all ages with the structure of a scientific article. Our main learning objective was for the student to realize that science writing is formulaic-that specific information is found in predictable locations within an article-and that, with an understanding of the formula, anyone can comfortably navigate any journal article and accurately predict what to expect to find in each section. To this end, we designed a Journal Article Scavenger Hunt that requires the user to find and identify a series of commonplace features of a primary research article. The scavenger hunt activity is quick and easy to implement, and is adaptable to various ages and settings, including the classroom, lab, and at outreach events. The questions in the scavenger hunt can be scaled in difficulty and specificity to suit the instructor's needs. Over many years of using this activity, we have received positive feedback from students of all ages, from elementary school students to lay adult-learners as well as science teachers themselves. By making the unknown seem predictable and approachable, the scavenger hunt helps a variety of audiences feel more comfortable with science and more confident in their ability to engage directly with the scientific literature. Journal of Microbiology & Biology Education.

2,4,8-trihydroxybicyclo [3.2.1]octan-3-one scavenges free radicals and protects against xenobiotic-induced cytotoxicity.

PubMed

Srivastava, Anup; Jagan Mohan Rao, L; Shivanandappa, T

2012-03-01

Currently, there is a great deal of interest in the study of natural compounds with free-radical-scavenging activity because of their potential role in maintaining human health and preventing diseases. In this paper, we report the antioxidant and cytoprotective properties of 2,4,8-trihydroxybicyclo [3.2.1]octan-3-one (TBO) isolated from the aqueous extract of Decalepis hamiltonii roots. Our results show that TBO is a potent scavenger of superoxide (O(2)·-), hydroxyl (·OH), nitric oxide (·NO) and lipid peroxide (LOO·) - physiologically relevant free radicals with IC(50) values in nmolar (42-281) range. TBO also exhibited concentration-dependent secondary antioxidant activities such as reducing power, metal-chelating activity and inhibition of protein carbonylation. Further, TBO at nmolar concentration prevented CuSO(4)-induced human LDL oxidation. Apart from the in vitro free-radical-scavenging activity, TBO demonstrated cytoprotective activity in primary hepatocytes and Ehrlich ascites tumour (EAT) cells against oxidative-stress-inducing xenobiotics. The mechanism of cytoprotective action involved maintaining the intracellular glutathione (GSH), scavenging of reactive oxygen species (ROS) and inhibiting lipid peroxidation (LPO). Based on the results, it is suggested that TBO is a novel bioactive molecule with implications in both prevention and amelioration of diseases involving oxidative stress as well as in the general well-being.

Scavenging Rate Ecoassay: A Potential Indicator of Estuary Condition

PubMed Central

Porter, Augustine G.; Scanes, Peter R.

2015-01-01

Monitoring of estuary condition is essential due to the highly productive and often intensely impacted nature of these ecosystems. Assessment of the physico-chemical condition of estuaries is expensive and difficult due to naturally fluctuating water quality and biota. Assessing the vigour of ecosystem processes is an alternative method with potential to overcome much of the variability associated with physico-chemical measures. Indicators of estuary condition should have small spatial and temporal variability, have a predictable response to perturbation and be ecologically relevant. Here, we present tests of the first criterion, the spatio-temporal variability of a potential ecoassay measuring the rate of scavenging in estuaries. We hypothesised that the proposed scavenging ecoassay would not vary significantly among A) sites in an estuary, B) trips separated by weeks, or C) days in a trip. Because not all habitats are present in all estuaries, this test was undertaken in two habitats. When conducted over bare substrate there were occasional significant differences, but no discernible patterns, within levels of the experiment. When conducted over vegetated substrate, days within a trip did not vary significantly, but later trips experienced greater scavenging. This scavenging ecoassay shows potential as a tool for assessing the condition of estuarine ecosystems, and further exploration of this protocol is warranted by implementation in estuaries across a gradient of anthropogenic stress. PMID:26024225

Chemical Composition and Antioxidant Properties of Juniper Berry (Juniperus communis L.) Essential Oil. Action of the Essential Oil on the Antioxidant Protection of Saccharomyces cerevisiae Model Organism

PubMed Central

Höferl, Martina; Stoilova, Ivanka; Schmidt, Erich; Wanner, Jürgen; Jirovetz, Leopold; Trifonova, Dora; Krastev, Lutsian; Krastanov, Albert

2014-01-01

The essential oil of juniper berries (Juniperus communis L., Cupressaceae) is traditionally used for medicinal and flavoring purposes. As elucidated by gas chromatography/flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS methods), the juniper berry oil from Bulgaria is largely comprised of monoterpene hydrocarbons such as α-pinene (51.4%), myrcene (8.3%), sabinene (5.8%), limonene (5.1%) and β-pinene (5.0%). The antioxidant capacity of the essential oil was evaluated in vitro by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging, 2,2-azino-bis-3-ethylbenzothiazoline-6 sulfonic acid (ABTS) radical cation scavenging, hydroxyl radical (ОН•) scavenging and chelating capacity, superoxide radical (•O2−) scavenging and xanthine oxidase inhibitory effects, hydrogen peroxide scavenging. The antioxidant activity of the oil attributable to electron transfer made juniper berry essential oil a strong antioxidant, whereas the antioxidant activity attributable to hydrogen atom transfer was lower. Lipid peroxidation inhibition by the essential oil in both stages, i.e., hydroperoxide formation and malondialdehyde formation, was less efficient than the inhibition by butylated hydroxytoluene (BHT). In vivo studies confirmed these effects of the oil which created the possibility of blocking the oxidation processes in yeast cells by increasing activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). PMID:26784665

Chemical Composition and Antioxidant Properties of Juniper Berry (Juniperus communis L.) Essential Oil. Action of the Essential Oil on the Antioxidant Protection of Saccharomyces cerevisiae Model Organism.

PubMed

Höferl, Martina; Stoilova, Ivanka; Schmidt, Erich; Wanner, Jürgen; Jirovetz, Leopold; Trifonova, Dora; Krastev, Lutsian; Krastanov, Albert

2014-02-24

The essential oil of juniper berries (Juniperus communis L., Cupressaceae) is traditionally used for medicinal and flavoring purposes. As elucidated by gas chromatography/flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS methods), the juniper berry oil from Bulgaria is largely comprised of monoterpene hydrocarbons such as α-pinene (51.4%), myrcene (8.3%), sabinene (5.8%), limonene (5.1%) and β-pinene (5.0%). The antioxidant capacity of the essential oil was evaluated in vitro by 2,2-Diphenyl-1-picrylhydrazyl (DPPH) scavenging, 2,2-azino-bis-3-ethylbenzothiazoline-6 sulfonic acid (ABTS) radical cation scavenging, hydroxyl radical (ОН(•)) scavenging and chelating capacity, superoxide radical ((•)O₂(-)) scavenging and xanthine oxidase inhibitory effects, hydrogen peroxide scavenging. The antioxidant activity of the oil attributable to electron transfer made juniper berry essential oil a strong antioxidant, whereas the antioxidant activity attributable to hydrogen atom transfer was lower. Lipid peroxidation inhibition by the essential oil in both stages, i.e., hydroperoxide formation and malondialdehyde formation, was less efficient than the inhibition by butylated hydroxytoluene (BHT). In vivo studies confirmed these effects of the oil which created the possibility of blocking the oxidation processes in yeast cells by increasing activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx).

Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

PubMed Central

Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce A.; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K.

2015-01-01

Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. PMID:26606755

In vitro and in vivo antioxidant potentials of an ethanolic extract of Ganoderma lucidum in rat mammary carcinogenesis.

PubMed

Deepalakshmi, K; Mirunalini, S; Krishnaveni, M; Arulmozhi, V

2013-11-01

Considering the importance of diet in the prevention of cellular damage caused by reactive oxygen species which has been implicated for several diseases, this present study was undertaken to evaluate the in vitro and in vivo antioxidant potential of the ethanolic extract of the fruiting bodies of Ganoderma lucidum on 7, 12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinogenesis in Sprague Dawley rats. Ganoderma lucidum extract was tested for in vitro antioxidant and radical scavenging assays, such as (ABTS(+)) radical cation decolorization assay, DPPH radical scavenging, hydroxyl radical, and superoxide radical scavenging assays. The in vivo antioxidant potentials were analyzed by SOD, CAT, and GPx in plasma, mammary, and liver tissues. In all the in vitro antioxidant and radical scavenging assays the extract exhibited good scavenging activity. In vivo enzymatic antioxidant levels, such as SOD, CAT, and GPx were decreased in DMBA-induced animals. Moreover, pretreatment with G. lucidum (500 mg · kg(-1) bw) to DMBA-induced animals significantly (P < 0.05) increased the levels of SOD, CAT, and GPx in plasma, mammary, and liver tissues compared to DMBA induced animals. From these findings, it is suggested that G. lucidum extract could be considered as a potential source of natural antioxidants and can be used as an effective chemopreventive agent against mammary cancer. Copyright © 2013 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Nitric oxide signals ROS scavenger-mediated enhancement of PAL activity in nitrogen-deficient Matricaria chamomilla roots: side effects of scavengers.

PubMed

Kovácik, Jozef; Klejdus, Borivoj; Backor, Martin

2009-06-15

Owing to the abundance of phenolic metabolites in plant tissue, their accumulation represents an important tool for stress protection. However, the regulation of phenolic metabolism is still poorly known. The regulatory role of reactive oxygen species (ROS) in the activity of phenylalanine ammonia-lyase (PAL) in nitrogen (N)-deficient chamomile roots treated for 24 h was studied using three ROS scavengers [dithiothreitol (DTT), salicylhydroxamic acid, and sodium benzoate]. Scavengers decreased the level of hydrogen peroxide and/or superoxide (and up-regulated ascorbate/guaiacol peroxidase and glutathione reductase), but, surprisingly, stimulated PAL activity. This up-regulation was correlated with increases in nitric oxide (NO) content, total soluble phenols, selected phenolic acids, and, partially, lignin (being expressed the most in DTT-exposed roots). We therefore tested the hypothesis that NO may be involved in these changes. Application of 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) decreased PAL activity and the accumulation of soluble phenols in all treatments. Exogenous H(2)O(2) and NO also stimulated PAL activity and the accumulation of phenols. We conclude that NO, in addition to hydrogen peroxide, may regulate PAL activity during N deficiency. The anomalous effect of PTIO on NO content and possible mechanism of ROS scavenger-evoked NO increases in light of the current knowledge are also discussed.

NO Dioxygenase Activity in Hemoglobins Is Ubiquitous In Vitro, but Limited by Reduction In Vivo

PubMed Central

Smagghe, Benoit J.; Trent, James T.; Hargrove, Mark S.

2008-01-01

Genomics has produced hundreds of new hemoglobin sequences with examples in nearly every living organism. Structural and biochemical characterizations of many recombinant proteins reveal reactions, like oxygen binding and NO dioxygenation, that appear general to the hemoglobin superfamily regardless of whether they are related to physiological function. Despite considerable attention to “hexacoordinate” hemoglobins, which are found in nearly every plant and animal, no clear physiological role(s) has been assigned to them in any species. One popular and relevant hypothesis for their function is protection against NO. Here we have tested a comprehensive representation of hexacoordinate hemoglobins from plants (rice hemoglobin), animals (neuroglobin and cytoglobin), and bacteria (Synechocystis hemoglobin) for their abilities to scavenge NO compared to myoglobin. Our experiments include in vitro comparisons of NO dioxygenation, ferric NO binding, NO-induced reduction, NO scavenging with an artificial reduction system, and the ability to substitute for a known NO scavenger (flavohemoglobin) in E. coli. We conclude that none of these tests reveal any distinguishing predisposition toward a role in NO scavenging for the hxHbs, but that any hemoglobin could likely serve this role in the presence of a mechanism for heme iron re-reduction. Hence, future research to test the role of Hbs in NO scavenging would benefit more from the identification of cognate reductases than from in vitro analysis of NO and O2 binding. PMID:18446211

Antioxidant activity profiling by spectrophotometric methods of aqueous methanolic extracts of Helichrysum stoechas subsp. rupestre and Phagnalon saxatile subsp. saxatile.

PubMed

Haddouchi, Farah; Chaouche, Tarik Mohammed; Ksouri, Riadh; Medini, Faten; Sekkal, Fatima Zohra; Benmansour, Abdelhafid

2014-06-01

The aqueous methanolic extracts of two plants from Algeria, Helichrysum stoechas subsp. rupestre and Phagnalon saxatile subsp. saxatile, were investigated for their antioxidant activity. Total phenolics, flavonoids, and tannins were determined by spectrophotometric techniques. In vitro antioxidant and radical scavenging profiling was determined by spectrophotometric methods, through: Total antioxidant capacity, and radical scavenging effects by the DPPH and ABTS methods, reducing and chelating power, and blanching inhibition of the β-carotene. All of the extracts showed interesting antioxidant and radical scavenging activity. The highest contents in phenolics, tannins, and the highest total antioxidant capacity as gallic acid equivalents of 97.5 ± 0.33 mg GAE/g DW was obtained for the flowers of H. stoechas subsp. rupestre extract in the phosphomolybdenum assay. An extract of the leafy stems of P. saxatile subsp. saxatile revealed the highest content of flavonoids, and the highest antioxidant activity by the radical scavenging and β-carotene assays when compared with standards. The best activity was by the scavenging radical DPPH with an IC50 value of 5.65 ± 0.10 μg·mL(-1). The studied medicinal plants could provide scientific evidence for some traditional uses in the treatment of diseases related to the production of reactive oxygen species (ROS) and oxidative stress. Copyright © 2014 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Oxygen radical absorbance capacity (ORAC) of cyclodextrin-solubilized flavonoids, resveratrol and astaxanthin as measured with the ORAC-EPR method

PubMed Central

Sueishi, Yoshimi; Ishikawa, Misa; Yoshioka, Daisuke; Endoh, Nobuyuki; Oowada, Shigeru; Shimmei, Masashi; Fujii, Hirotada; Kotake, Yashige

2012-01-01

Recently, we proposed an oxygen radical absorbance capacity method that directly quantifies the antioxidant’s scavenging capacity against free radicals and evaluated the radical scavenging abilities for water soluble antioxidant compounds. In this study, we determined the radical scavenging abilities of lipophilic antioxidants which were solubilized by cyclodextrin in water. Commonly employed fluorescence-based method measures the antioxidant’s protection capability for the fluorescent probe, while we directly quantify free-radical level using electron paramagnetic resonance spin trapping technique. In addition, the spin trapping-based method adopted controlled UV-photolysis of azo-initiator for free radical generation, but in fluorescence-based method, thermal decomposition of azo-initiator was utilized. We determined the radical scavenging abilities of seven well-known lipophilic antioxidants (five flavonoids, resveratrol and astaxanthin), using methylated β-cyclodextrin as a solubilizer. The results indicated that the agreement between spin trapping-based and fluorescence-based values was only fair partly because of a large variation in the previous fluorescence-based data. Typical radical scavenging abilities in trolox equivalent unit are: catechin 0.96; epicatechin 0.94; epigallocatechin gallate 1.3; kaempferol 0.37; myricetin 3.2; resveratrol 0.64; and astaxanthin 0.28, indicating that myricetin possesses the highest antioxidant capacity among the compounds tested. We sorted out the possible causes of the deviation between the two methods. PMID:22448093

Oxygen radical absorbance capacity (ORAC) of cyclodextrin-solubilized flavonoids, resveratrol and astaxanthin as measured with the ORAC-EPR method.

PubMed

Sueishi, Yoshimi; Ishikawa, Misa; Yoshioka, Daisuke; Endoh, Nobuyuki; Oowada, Shigeru; Shimmei, Masashi; Fujii, Hirotada; Kotake, Yashige

2012-03-01

Recently, we proposed an oxygen radical absorbance capacity method that directly quantifies the antioxidant's scavenging capacity against free radicals and evaluated the radical scavenging abilities for water soluble antioxidant compounds. In this study, we determined the radical scavenging abilities of lipophilic antioxidants which were solubilized by cyclodextrin in water. Commonly employed fluorescence-based method measures the antioxidant's protection capability for the fluorescent probe, while we directly quantify free-radical level using electron paramagnetic resonance spin trapping technique. In addition, the spin trapping-based method adopted controlled UV-photolysis of azo-initiator for free radical generation, but in fluorescence-based method, thermal decomposition of azo-initiator was utilized. We determined the radical scavenging abilities of seven well-known lipophilic antioxidants (five flavonoids, resveratrol and astaxanthin), using methylated β-cyclodextrin as a solubilizer. The results indicated that the agreement between spin trapping-based and fluorescence-based values was only fair partly because of a large variation in the previous fluorescence-based data. Typical radical scavenging abilities in trolox equivalent unit are: catechin 0.96; epicatechin 0.94; epigallocatechin gallate 1.3; kaempferol 0.37; myricetin 3.2; resveratrol 0.64; and astaxanthin 0.28, indicating that myricetin possesses the highest antioxidant capacity among the compounds tested. We sorted out the possible causes of the deviation between the two methods.

Quantitative studies on structure-DPPH• scavenging activity relationships of food phenolic acids.

PubMed

Jing, Pu; Zhao, Shu-Juan; Jian, Wen-Jie; Qian, Bing-Jun; Dong, Ying; Pang, Jie

2012-11-01

Phenolic acids are potent antioxidants, yet the quantitative structure-activity relationships of phenolic acids remain unclear. The purpose of this study was to establish 3D-QSAR models able to predict phenolic acids with high DPPH• scavenging activity and understand their structure-activity relationships. The model has been established by using a training set of compounds with cross-validated q2 = 0.638/0.855, non-cross-validated r2 = 0.984/0.986, standard error of estimate = 0.236/0.216, and F = 139.126/208.320 for the best CoMFA/CoMSIA models. The predictive ability of the models was validated with the correlation coefficient r2(pred) = 0.971/0.996 (>0.6) for each model. Additionally, the contour map results suggested that structural characteristics of phenolics acids favorable for the high DPPH• scavenging activity might include: (1) bulky and/or electron-donating substituent groups on the phenol ring; (2) electron-donating groups at the meta-position and/or hydrophobic groups at the meta-/ortho-position; (3) hydrogen-bond donor/electron-donating groups at the ortho-position. The results have been confirmed based on structural analyses of phenolic acids and their DPPH• scavenging data from eight recent publications. The findings may provide deeper insight into the antioxidant mechanisms and provide useful information for selecting phenolic acids for free radical scavenging properties.

Toward a more physical representation of precipitation scavenging in global chemistry models: cloud overlap and ice physics and their impact on tropospheric ozone

NASA Astrophysics Data System (ADS)

Neu, J. L.; Prather, M. J.

2011-08-01

Uptake and removal of soluble trace gases and aerosols by precipitation represents a major uncertainty in the processes that control the vertical distribution of atmospheric trace species. Model representations of precipitation scavenging vary greatly in their complexity, and most are divorced from the physics of precipitation formation and transformation. Here, we describe a new large-scale precipitation scavenging algorithm, developed for the UCI chemistry-transport model (UCI-CTM), that represents a step toward a more physical treatment of scavenging through improvements in the formulation of the removal in sub-gridscale cloudy and ambient environments and their overlap within the column as well as ice phase uptake of soluble species. The UCI algorithm doubles the lifetime of HNO3 in the upper troposphere relative to a scheme with commonly made assumptions about cloud overlap and ice uptake, and provides better agreement with HNO3 observations. We find that the process of ice phase scavenging of HNO3 is a critical component of the tropospheric O3 budget, but that differences in the formulation of ice phase removal, while generating large relative differences in HNO3 abundance, have little impact on NOx and O3. The O3 budget is much more sensitive to the lifetime of HNO4, highlighting the need for better understanding of its interactions with ice and for additional observational constraints.

Toward a more physical representation of precipitation scavenging in global chemistry models: cloud overlap and ice physics and their impact on tropospheric ozone

NASA Astrophysics Data System (ADS)

Neu, J. L.; Prather, M. J.

2012-04-01

Uptake and removal of soluble trace gases and aerosols by precipitation represents a major uncertainty in the processes that control the vertical distribution of atmospheric trace species. Model representations of precipitation scavenging vary greatly in their complexity, and most are divorced from the physics of precipitation formation and transformation. Here, we describe a new large-scale precipitation scavenging algorithm, developed for the UCI chemistry-transport model (UCI-CTM), that represents a step toward a more physical treatment of scavenging through improvements in the formulation of the removal in sub-gridscale cloudy and ambient environments and their overlap within the column as well as ice phase uptake of soluble species. The UCI algorithm doubles the lifetime of HNO3 in the upper troposphere relative to a scheme with commonly used fractional cloud cover assumptions and ice uptake determined by Henry's Law and provides better agreement with HNO3 observations. We find that the process of ice phase scavenging of HNO3 is a critical component of the tropospheric O3 budget, but that NOx and O3 mixing ratios are relatively insensitive to large differences in the removal rate. Ozone abundances are much more sensitive to the lifetime of HNO4, highlighting the need for better understanding of its interactions with ice and for additional observational constraints.

Optimization of free radical scavenging capacity and pH of Hylocereus polyrhizus peel by Response Surface Methodology

NASA Astrophysics Data System (ADS)

Putranto, A. W.; Dewi, S. R.; Puspitasari, Y.; Nuriah, F. A.

2018-03-01

Red dragon fruit (Hylocereus polyrhizus) peel, a by-product of juice processing, contains a high antioxidant that can be used for nutraceuticals. Hence, it is important to extract and investigate its antioxidant stability. The aim of this study was to optimize the free radical scavenging capacity and pH of H. polyrhizus peel extract using Central Composite Design (CCD) under Response Surface Methodology (RSM). The extraction of H. polyrhizus peel was done by using green-Pulsed Electric Field (PEF)-assisted extraction method. Factors optimized were electric field strength (kV/cm) and extraction time (seconds). The result showed that the correlation between responses (free radical-scavenging capacity and pH) and two factors was quadratic model. The optimum conditions was obtained at the electric field strength of 3.96 kV/cm, and treatment time of 31.9 seconds. Under these conditions, the actual free radical-scavenging capacity and pH were 75.86 ± 0.2 % and 4.8, respectively. The verification model showed that the actual values are in accordance with the predicted values, and have error rate values of free radical-scavenging capacity and pH responses were 0.1% and 3.98%, respectively. We suggest to extract the H. polyrhizus peel using a green and non-thermal extraction technology, PEF-assisted extraction, for research, food applications and nutraceuticals industry.

Brain neuroprotection by scavenging blood glutamate.

PubMed

Zlotnik, Alexander; Gurevich, Boris; Tkachov, Sergei; Maoz, Ilana; Shapira, Yoram; Teichberg, Vivian I

2007-01-01

Excess glutamate in brain fluids characterizes acute brain insults such as traumatic brain injury and stroke. Its removal could prevent the glutamate excitotoxicity that causes long-lasting neurological deficits. As blood glutamate scavenging has been demonstrated to increase the efflux of excess glutamate from brain into blood, we tested the prediction that oxaloacetate-mediated blood glutamate scavenging causes neuroprotection in a pathological situation such as closed head injury (CHI), in which there is a well established deleterious increase of glutamate in brain fluids. We observed highly significant improvements of the neurological status of rats submitted to CHI following an intravenous treatment with 1 mmol oxaloacetate/100 g rat weight which decreases blood glutamate levels by 40%. No detectable therapeutic effect was obtained when rats were treated IV with 1 mmol oxaloacetate together with 1 mmol glutamate/100 g rat. The treatment with 0.005 mmol/100 g rat oxaloacetate was no more effective than saline but when it was combined with the intravenous administration of 0.14 nmol/100 g of recombinant glutamate-oxaloacetate transaminase, recovery was almost complete. Oxaloacetate provided neuroprotection when administered before CHI or at 60 min post CHI but not at 120 min post CHI. Since neurological recovery from CHI was highly correlated with the decrease of blood glutamate levels (r=0.89, P=0.001), we conclude that blood glutamate scavenging affords brain neuroprotection Blood glutamate scavenging may open now new therapeutic options.

The Use of Large Valve Overlap in Scavenging a Supercharged Spark-ignition Engine Using Fuel Injection

NASA Technical Reports Server (NTRS)

Schey, Oscar W; Young, Alfred W

1932-01-01

This investigation was conducted to determine the effect of more complete scavenging on the full throttle power and the fuel consumption of a four-stroke-cycle engine. The NACA single-cylinder universal test engine equipped with both a fuel-injection system and a carburetor was used. The engine was scavenged by using a large valve overlap and maintaining a pressure in the inlet manifold of 2 inches of mercury above atmospheric. The maximum valve overlap used was 112 degrees. Tests were conducted for a range of compression ratios from 5.5 to 8.5. Except for variable speed tests, all tests were conducted at an engine speed of 1,500 r.p.m. The results of the tests show that the clearance volume of an engine can be scavenged by using a large valve overlap and about 2 to 5 inches of mercury pressure difference between the inlet and exhaust valve. With a fuel-injection system when the clearance volume was scavenged, a b.m.e.p. of over 185 pounds per square inch and a fuel consumption of 9.45 pound per brake horsepower per hour were obtained with a 6.5 compression ratio. An increase of approximately 10 pounds per square inch b.m.e.p. was obtained with a fuel-injection system over that with a carburetor.

Potential Ambient Energy-Harvesting Sources and Techniques

ERIC Educational Resources Information Center

Yildiz, Faruk

2009-01-01

Ambient energy harvesting is also known as energy scavenging or power harvesting, and it is the process where energy is obtained from the environment. A variety of techniques are available for energy scavenging, including solar and wind powers, ocean waves, piezoelectricity, thermoelectricity, and physical motions. For example, some systems…

Solvated Electrons in Organic Chemistry Laboratory

ERIC Educational Resources Information Center

Ilich, Predrag-Peter; McCormick, Kathleen R.; Atkins, Adam D.; Mell, Geoffrey J.; Flaherty, Timothy J.; Bruck, Martin J.; Goodrich, Heather A.; Hefel, Aaron L.; Juranic, Nenad; Seleem, Suzanne

2010-01-01

A novel experiment is described in which solvated electrons in liquid ammonia reduce a benzyl alcohol carbon without affecting the aromatic ring. The reductive activity of solvated electrons can be partially or completely quenched through the addition of electron scavengers to the reaction mixture. The effectiveness of these scavengers was found…

Variation in bird-window collision mortality and scavenging rates within an urban landscape

EPA Science Inventory

Annual avian mortality from collisions with windows and buildings is estimated to range from a million to a billion birds in the United States alone. However, estimates of mortality based on carcass counts suffer from bias due to imperfect detection and carcass scavenging. We stu...

Wanted dead or alive: scavenging versus predation by three insect predators

USDA-ARS?s Scientific Manuscript database

Many generalist insect predators may engage in facultative scavenging. If an apparent predator frequently consumes dead prey instead of live prey then the biological control services provided by that predator may be overestimated. The use of unique protein markers on live and dead prey of the same s...

Dependence on solute concentration of the efficiency of scavenging of electrons in recombining geminate ion pairs

NASA Astrophysics Data System (ADS)

Tweeten, David W.; Lee, Kaidee; Lipsky, Sanford

The fluorescence from solutions of hexafluorobenzene in cyclopentane, 2,2,4-trimethylpentane, 2,2-dimethylbutane and tetramethylsilane irradiated with β-particles has been studied as a function of the hexafluorobenzene concentration from c = 10 -3-10 -1 M. The data are analyzed to permit extraction of geminate ion-pair scavenging probability p†. This is found to have a dependence on c entirely similar to what has previously been reported for p† extracted from quenching of solvent fluorescence by perfluorocarbon scavengers, i.e. p† = (α c) 0.7/[1 + (α c) 0.7]. The difference between these results and that for p† obtained via measurement of chemical product formation is discussed.

GST ( phi) gene from Macrophyte Lemna minor is involved in cadmium exposure responses

NASA Astrophysics Data System (ADS)

Chen, Shihua; Chen, Xin; Dou, Weihong; Wang, Liang; Yin, Haibo; Guo, Shanli

2016-03-01

Reactive oxygen species (ROS) scavengers, including ascorbate peroxidase, superoxide dismutase, catalase and peroxidase, are the most commonly used biomarkers in assessing an organisms' response to many biotic and abiotic stresses. In this study, we cloned an 866 bp GST ( phi) gene in Lemna minor and investigated its characteristics, expression and enzymatic activities under 75 μmol/L cadmium concentrations in comparison with other ROS scavengers. GST ( phi) gene expression patterns were similar to those of other scavengers of ROS. This suggests that GST ( phi) might be involved in responding to heavy metal (cadmium) stress and that its expression level could be used as a bio-indicator in monitoring cadmium pollution.

STS propellant scavenging systems study. Part 2, volume 1: Executive summary and study results

NASA Technical Reports Server (NTRS)

Williams, Frank L.

1987-01-01

The major objective of the STS Propellant Scavenging Study is to define the hardware, operations, and life cycle costs for recovery of unused Space Transportation System propellants. Earlier phases were concerned exclusively with the recovery of cryogenic propellants from the main propulsion system of the manned STS. The phase of the study covered by this report (Part II Extension) modified the objectives to include cryogenic propellants delivered to orbit by the unmanned cargo vehicle. The Part II Extension had the following objectives: (1) predict OTV propellant requirements from 1995 to 2010; investigate scavenging/transport tank reuse; determine optimum tank sizing and arrangement; and develop hardware concepts for tanks.

Hunting for Knowledge: Using a Scavenger Hunt to Orient Graduate Veterinary Students

ERIC Educational Resources Information Center

Pike, Caitlin; Alpi, Kristine M.

2015-01-01

Active participation in orientation is hoped to increase understanding and use of library resources and services beyond the effect of tours or welcome lectures. Timed scavenger hunts have been used to orient undergraduate and medical students to academic libraries. This report describes the planning, execution, and evaluation of an untimed…

Is the scavenger receptor MARCO a new immune checkpoint?

PubMed

Arredouani, Mohamed S

2014-11-01

Whereas macrophages use the scavenger receptor MARCO primarily in antimicrobial immunity by interacting with both exogenous and endogenous environments, in dendritic cells (DCs) MARCO is believed to pleiotropically link innate to adaptive immunity. MARCO exerts a significant modulatory effect on TLR-induced DC activation, thus offering novel avenues in cancer immunotherapy.

In vitro antioxidant activity of polysaccharide from Gardenia jasminoides ellis

USGS Publications Warehouse

Fan, Y.; Ge, Z.; Luo, A.

2011-01-01

A water-soluble polysaccharide, GP, was isolated from Gardenia jasminoides Ellis through hot water extraction followed by ethanol precipitation. The in vitro free radicals scavenging tests exhibited that GP has significant scavenging abilities especially for ABTS, DPPH, and hydroxyl radicals, which suggests that the polysaccharide GP is a novel antioxidant. ?? 2011 Academic Journals.

Blueberry diet protect against atherosclerosis in apoE-deficient mice by inhibiting scavenger receptor expression

USDA-ARS?s Scientific Manuscript database

Atherosclerosis is an inflammatory process that leads to the onset of cardiovascular disease. The scavenger receptor-mediated uptake of oxLDL by macrophages leads to foam cell formation, which is an initial event in the formation of atherosclerotic fatty streak lesions. In this report, the mechanism...

Adaptation of Staphylococcus aureus to Airway Environments in Patients With Cystic Fibrosis by Upregulation of Superoxide Dismutase M and Iron-Scavenging Proteins.

PubMed

Treffon, Janina; Block, Desiree; Moche, Martin; Reiss, Swantje; Fuchs, Stephan; Engelmann, Susanne; Becher, Dörte; Langhanki, Lars; Mellmann, Alexander; Peters, Georg; Kahl, Barbara C

2018-04-11

Adaptation of S. aureus to the hostile environment of CF airways resulted in changed abundance of proteins involved in energy metabolism, cellular processes, transport and binding, but most importantly in an iron-scavenging phenotype and increased activity of superoxide dismutase M.

A Cloud-Based Scavenger Hunt: Orienting Undergraduates to ACS National Meetings

ERIC Educational Resources Information Center

Kubasik, Matthew A.; Van Dyke, Aaron R.; Harper-Leatherman, Amanda S.; Miecznikowski, John R.; Steffen, L. Kraig; Smith-Carpenter, Jillian

2016-01-01

American Chemical Society (ACS) National Meetings are valuable for the development of undergraduate researchers but can be overwhelming for first-time attendees. To orient and engage students with the range of offerings at an ACS meeting, we developed a cloud-based scavenger hunt. Using their mobile devices, teams of undergraduates…

Effects of P25 TiO2 Nanoparticles on the Free Radical-Scavenging Ability of Antioxidants upon Their Exposure to Simulated Sunlight.

PubMed

Li, Meng; Chong, Yu; Fu, Peter P; Xia, Qingsu; Croley, Timothy R; Lo, Y Martin; Yin, Jun-Jie

2017-11-15

Although nanosized ingredients, including TiO 2 nanoparticles (NPs), can be found in a wide range of consumer products, little is known about the effects these particles have on other active compounds in product matrices. These NPs can interact with reactive oxygen species (ROS), potentially disrupting or canceling the benefits expected from antioxidants. We used electron spin resonance spectrometry to assess changes in the antioxidant capacities of six dietary antioxidants (ascorbic acid, α-tocopherol, glutathione, cysteine, epicatechin, and epicatechin gallate) during exposure to P25 TiO 2 and/or simulated sunlight. Specifically, we determined the ability of these antioxidants to scavenge 1-diphenyl-2-picryl-hydrazyl radical, superoxide radical, and hydroxyl radical. Exposure to simulated sunlight alone did not lead to noticeable changes in radical-scavenging abilities; however, in combination with P25 TiO 2 NPs, the scavenging abilities of most antioxidants were weakened. We found glutathione to be the most resistant to treatment with sunlight and NPs among these six antioxidants.

Assessment of antioxidant activity of cane brown sugars by ABTS and DPPH radical scavenging assays: determination of their polyphenolic and volatile constituents.

PubMed

Payet, Bertrand; Shum Cheong Sing, Alain; Smadja, Jacqueline

2005-12-28

Seven cane brown sugars (four from La Réunion, two from Mauritius, and one from France) were investigated for their polyphenol content and volatile composition in relation to their free radical scavenging capacity determined by ABTS and DPPH assays. The thin layer coated on the sugar crystal was extracted by Soxhlet extractor with dichloromethane. The volatile compounds of brown sugars were studied by GC-MS, and 43 compounds were identified. The total phenolic content of brown sugars was determined according to the Folin-Ciocalteu method. Phenolic compounds were quantified in the brown sugar extracts by LC-UV-ESI-MS. Brown sugar aqueous solutions exhibited weak free radical scavenging activity in the DPPH assay and higher antioxidant activity in the ABTS assay at relatively high concentration. The brown sugar extracts showed interesting free radical scavenging properties despite the low concentration of phenolic and volatile compounds. Sugar is a common foodstuff traditionally used for its sweetening properties, which might be accompanied by antioxidant properties arising from molecules (polyphenols, Maillard products) other than sucrose of the cane brown sugars.

[Comparative studies on scavenging DPPH free radicals activity of flavone C-glycosides from different parts of Dendrobium officinale].

PubMed

Zhou, Guifen; Lv, Guiyuan

2012-06-01

To study the scavenging DPPH free radicals activity of flavone C-glycosides from different parts of Dendrobium officinale. The types and contents of flavonoids from different parts of D. officinale were analyzed by TLC and HPLC. The antioxidant effect was tested by scavenging DPPH free radicals activity. The stems, leaves and flowers contained the same type of flavone C-A glycosides and 8 common peaks were identified. The content of flavone C-A glycosides was significantly different. The content of flavone C-glycosides in leaves and flowers was higher than that in stems. The flavonoid in roots was less. Stems contained naringenin, which was not identified in root, leave and flower. Both stems and leaves had antioxidant capacity of eliminating DPPH free radicals, of which scavenging DPPH free radicals activity of leaves was better than stems. Considering the content of flavonoid and antioxidant activity leave and flower of D. officinale may substitute stems. The study provides a preliminary basis for the development and utilization of leave and flower of D. officinale.

Hypoxic and Ras-transformed cells support growth by scavenging unsaturated fatty acids from lysophospholipids

PubMed Central

Kamphorst, Jurre J.; Cross, Justin R.; Fan, Jing; de Stanchina, Elisa; Mathew, Robin; White, Eileen P.; Thompson, Craig B.; Rabinowitz, Joshua D.

2013-01-01

Cancer cell growth requires fatty acids to replicate cellular membranes. The kinase Akt is known to up-regulate fatty acid synthesis and desaturation, which is carried out by the oxygen-consuming enzyme stearoyl-CoA desaturase (SCD)1. We used 13C tracers and lipidomics to probe fatty acid metabolism, including desaturation, as a function of oncogene expression and oxygen availability. During hypoxia, flux from glucose to acetyl-CoA decreases, and the fractional contribution of glutamine to fatty acid synthesis increases. In addition, we find that hypoxic cells bypass de novo lipogenesis, and thus, both the need for acetyl-CoA and the oxygen-dependent SCD1-reaction, by scavenging serum fatty acids. The preferred substrates for scavenging are phospholipids with one fatty acid tail (lysophospholipids). Hypoxic reprogramming of de novo lipogenesis can be reproduced in normoxic cells by Ras activation. This renders Ras-driven cells, both in culture and in allografts, resistant to SCD1 inhibition. Thus, a mechanism by which oncogenic Ras confers metabolic robustness is through lipid scavenging. PMID:23671091

Rainfall-aerosol relationships explained by wet scavenging and humidity

NASA Astrophysics Data System (ADS)

Grandey, Benjamin S.; Gururaj, Anisha; Stier, Philip; Wagner, Till M.

2014-08-01

Relationships between precipitation rate and aerosol optical depth, the extinction of light by aerosol in an atmospheric column, have been observed in satellite-retrieved data. What are the reasons for these precipitation-aerosol relationships? We investigate relationships between convective precipitation rate (Rconv) and aerosol optical depth (τtot) using the ECHAM5-HAM aerosol-climate model. We show that negative Rconv-τtot relationships arise due to wet scavenging of aerosol. The apparent lack of negative Rconv-τtot relationships in satellite-retrieved data is likely because the satellite data do not sample wet scavenging events. When convective wet scavenging is excluded in the model, we find positive Rconv-τtot relationships in regions where convective precipitation is the dominant form of model precipitation. The spatial distribution of these relationships is in good agreement with satellite-based results. We further demonstrate that a substantial component of these positive relationships arises due to covariation with large-scale relative humidity. Although the interpretation of precipitation-aerosol relationships remains a challenging question, we suggest that progress can be made through a synergy between observations and models.

The roles of ROS production-scavenging system in Lasiodiplodia theobromae (Pat.) Griff. & Maubl.-induced pericarp browning and disease development of harvested longan fruit.

PubMed

Sun, Junzheng; Lin, Hetong; Zhang, Shen; Lin, Yifen; Wang, Hui; Lin, Mengshi; Hung, Yen-Con; Chen, Yihui

2018-05-01

Effects of Lasiodiplodia theobromae on reactive oxygen species (ROS) production-scavenging system during L. theobromae-induced pericarp browning and disease development of harvested "Fuyan" longans were investigated. Compared with control longans, L. theobromae-inoculated longans exhibited higher pericarp browning index and fruit disease index, higher pericarp O 2 - generation rate and MDA content. Moreover, L. theobromae infection also resulted in lower contents of pericarp AsA and GSH, lower levels of pericarp DPPH radical scavenging ability and reducing power. Additionally, L. theobromae infection decreased the activities of pericarp SOD, CAT and APX from day 2 to day 5. These findings suggested that L. theobromae-induced pericarp browning and disease development of harvested longans might be due to reduction of ROS scavenging ability and increase in ROS production, which might stimulate membrane lipid peroxidation, disrupt cellular membrane structure, and cause the loss of cellular compartmentalization and disease resistance, in turn, resulting in pericarp browning and disease development. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protective effect of Rehmannia glutinosa on the cisplatin-induced damage of HEI-OC1 auditory cells through scavenging free radicals.

PubMed

Yu, Hyeon-Hee; Seo, Se-Jeong; Kim, Yeon-Hwa; Lee, Hae-Youn; Park, Rae-Kil; So, Hong-Seob; Jang, Seon Ll; You, Yong-Ouk

2006-10-11

The steamed root of Rehmannia glutinosa has been used in traditional Oriental Medicine for treatment of inner ear diseases, such as tinnitus and hearing loss. In the present study, we showed that the ethanol extract of steamed roots of Rehmannia glutinosa (SRG) protected HEI-OC1 auditory cells from cisplatin cytotoxicity in a dose-dependent fashion. In addition, to investigate the protection mechanism of SRG on cisplatin cytotoxicity towards HEI-OC1, we measured the effects of SRG on lipid peroxidation of cisplatin treated cells as well as scavenging activities against superoxide radical, hydroxyl radical, hydrogen peroxide, and DPPH radical. SRG (5-100 microg/ml) had protective effect against the cisplatin-induced HEI-OC1 cell damage and reduced lipid peroxidation in a dose-dependent manner. Furthermore, SRG showed strong scavenging activity against superoxide radical, hydroxyl radical, hydrogen peroxide, and DPPH radical. These results indicate that SRG protects cisplatin-induced HEI-OC1 cell damage through inhibition of lipid peroxidation and scavenging activities of free radials.

Effect of lactobacillus strains on phenolic profile, color attributes and antioxidant activities of lactic-acid-fermented mulberry juice.

PubMed

Kwaw, Emmanuel; Ma, Yongkun; Tchabo, William; Apaliya, Maurice Tibiru; Wu, Meng; Sackey, Augustina Sackle; Xiao, Lulu; Tahir, Haroon Elrasheid

2018-06-01

This study was conducted to investigate the effect of lactic acid bacteria (LAB) strains on color properties, phenolic profile and antioxidant activities of mulberry juice. Mulberry juice was separately fermented at 37 °C for 36 h using Lactobacillus plantarum, Lactobacillus acidophilus and Lactobacillus paracasei. The results showed that lactic acid fermentation impacted on the color of the juice. Moreover, the study demonstrated that LABs impacted on the phenolic profile of the juice. Syringic acid, cyanidin-3-O-rutinoside and quercetin were the predominant phenolic acid, anthocyanin and flavonol respectively in the lactic-acid-fermented mulberry juice. The degree of radical scavenging activity was species-specific with the L. plantarum fermented juice having the highest radical scavenging activities. The correlation analysis demonstrated that flavonols and anthocyanins were mostly responsible for the increased in 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) scavenging activity while phenolic acids and flavonols were responsible for 2,2-diphenyl-1-picrylhydrazyl scavenging activity and reducing power capacity of the fermented juice. Copyright © 2018 Elsevier Ltd. All rights reserved.

Energy scavenging sources for biomedical sensors.

PubMed

Romero, E; Warrington, R O; Neuman, M R

2009-09-01

Energy scavenging has increasingly become an interesting option for powering electronic devices because of the almost infinite lifetime and the non-dependence on fuels for energy generation. Moreover, the rise of wireless technologies promises new applications in medical monitoring systems, but these still face limitations due to battery lifetime and size. A trade-off of these two factors has typically governed the size, useful life and capabilities of an autonomous system. Energy generation from sources such as motion, light and temperature gradients has been established as commercially viable alternatives to batteries for human-powered flashlights, solar calculators, radio receivers and thermal-powered wristwatches, among others. Research on energy harvesting from human activities has also addressed the feasibility of powering wearable or implantable systems. Biomedical sensors can take advantage of human-based activities as the energy source for energy scavengers. This review describes the state of the art of energy scavenging technologies for powering sensors and instrumentation of physiological variables. After a short description of the human power and the energy generation limits, the different transduction mechanisms, recent developments and challenges faced are reviewed and discussed.

Antioxidant activity of selected plant species; potential new sources of natural antioxidants.

PubMed

Nićiforović, N; Mihailović, V; Masković, P; Solujić, S; Stojković, A; Pavlović Muratspahić, D

2010-11-01

The aim of this study was to examine six plants from Serbia for their potential antioxidant activity. Therefore, six antioxidant activity assays were carried out, including: total antioxidant capacity, DPPH free-radical scavenging, the inhibitory activity toward lipid peroxidation, Fe(3+)- reducing power, Fe(2+)- chelating ability and hydroxyl radical scavenging activity. Total phenolic and flavonoid contents were also determined for each alcoholic extract. Cotinus coggygria extract contained the highest amount of total phenols (413mg GAE /g dry extract), while the highest proportion of flavonoids was found in the Echium vulgare methanol extract (105 mg RU/g). Cotinus coggygria and Halacsya sendtneri alcoholic extracts showed the highest total antioxidant capacity (313 and 231 mg AA/g dry extract), as well as DPPH free-radical scavenging (IC(50)=9 and 99 μg/ml), inhibitory activity toward lipid peroxidation (IC(50)=3 and 17 μg/ml) and reducing power. Whereas, the greatest hydroxyl radical scavenging activity, as well as ferrous ion chelating ability showed Echium vulgare, Echium rubrum and Halacsya sendtneri. Copyright © 2010 Elsevier Ltd. All rights reserved.

Extracts, Anthocyanins and Procyanidins from Aronia melanocarpa as Radical Scavengers and Enzyme Inhibitors

PubMed Central

Bräunlich, Marie; Slimestad, Rune; Wangensteen, Helle; Brede, Cato; Malterud, Karl E.; Barsett, Hilde

2013-01-01

Extracts, subfractions, isolated anthocyanins and isolated procyanidins B2, B5 and C1 from the berries and bark of Aronia melanocarpa were investigated for their antioxidant and enzyme inhibitory activities. Four different bioassays were used, namely scavenging of the diphenylpicrylhydrazyl (DPPH) radical, inhibition of 15-lipoxygenase (15-LO), inhibition of xanthine oxidase (XO) and inhibition of α-glucosidase. Among the anthocyanins, cyanidin 3-arabinoside possessed the strongest and cyanidin 3-xyloside the weakest radical scavenging and enzyme inhibitory activity. These effects seem to be influenced by the sugar units linked to the anthocyanidin. Subfractions enriched in procyanidins were found to be potent α-glucosidase inhibitors; they possessed high radical scavenging properties, strong inhibitory activity towards 15-LO and moderate inhibitory activity towards XO. Trimeric procyanidin C1 showed higher activity in the biological assays compared to the dimeric procyanidins B2 and B5. This study suggests that different polyphenolic compounds of A. melanocarpa can have beneficial effects in reducing blood glucose levels due to inhibition of α-glucosidase and may have a potential to alleviate oxidative stress. PMID:23459328

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

Role of scavenger receptors in the pathophysiology of chronic liver diseases.

PubMed

Armengol, Carolina; Bartolí, Ramon; Sanjurjo, Lucía; Serra, Isabel; Amézaga, Núria; Sala, Margarita; Sarrias, Maria-Rosa

2013-01-01

Scavenger receptors comprise a large family of structurally diverse proteins that are involved in many homeostatic functions. They recognize a wide range of ligands, from pathogen-associated molecular patterns (PAMPs) to endogenous, as well as modified host-derived molecules (DAMPs). The liver deals with blood micro-organisms and DAMPs released from injured organs, thus performing vital metabolic and clearance functions that require the uptake of nutrients and toxins. Many liver cell types, including hepatocytes and Kupffer cells, express scavenger receptors that play key roles in hepatitis C virus entry, lipid uptake, and macrophage activation, among others. Chronic liver disease causes high morbidity and mortality worldwide. Hepatitis virus infection, alcohol abuse, and non-alcoholic fatty liver are the main etiologies associated with this disease. In this context, continuous inflammation as a result of liver damage leads to hepatic fibrosis, which frequently brings about cirrhosis and ultimately hepatocellular carcinoma. In this review, we will summarize the role of scavenger receptors in the pathophysiology of chronic liver diseases. We will also emphasize their potential as biomarkers of advanced liver disease, including cirrhosis and cancer.

Extracts, anthocyanins and procyanidins from Aronia melanocarpa as radical scavengers and enzyme inhibitors.

PubMed

Bräunlich, Marie; Slimestad, Rune; Wangensteen, Helle; Brede, Cato; Malterud, Karl E; Barsett, Hilde

2013-03-04

Extracts, subfractions, isolated anthocyanins and isolated procyanidins B2, B5 and C1 from the berries and bark of Aronia melanocarpa were investigated for their antioxidant and enzyme inhibitory activities. Four different bioassays were used, namely scavenging of the diphenylpicrylhydrazyl (DPPH) radical, inhibition of 15-lipoxygenase (15-LO), inhibition of xanthine oxidase (XO) and inhibition of α-glucosidase. Among the anthocyanins, cyanidin 3-arabinoside possessed the strongest and cyanidin 3-xyloside the weakest radical scavenging and enzyme inhibitory activity. These effects seem to be influenced by the sugar units linked to the anthocyanidin. Subfractions enriched in procyanidins were found to be potent α-glucosidase inhibitors; they possessed high radical scavenging properties, strong inhibitory activity towards 15-LO and moderate inhibitory activity towards XO. Trimeric procyanidin C1 showed higher activity in the biological assays compared to the dimeric procyanidins B2 and B5. This study suggests that different polyphenolic compounds of A. melanocarpa can have beneficial effects in reducing blood glucose levels due to inhibition of α-glucosidase and may have a potential to alleviate oxidative stress.

Evaluation of the Nitric Oxide and Nitrite Scavenging Capability, N-Nitrosamine Formation Inhibitory Activity, and Optimization of Ultrasound-Assisted Aqueous Two-Phase System Extraction of Total Saponins from Coreopsis tinctoria Flowering Tops by Response Surface Methodology.

PubMed

Luo, Ruiling; Yao, Xincheng; Liu, Xieying; Zhang, Yushang; Ying, Xue

2018-03-01

Coreopsis tinctoria flowering tops (CTFs) is a popular health product as herbal tea or as a traditional medicinal herb that is rich in saponins and exerts substantial biological activity. In this study, an ultrasound-assisted aqueous two-phase system (ATPS) was utilized to extract total saponins from CTFs and optimize the extraction process by response surface methodology. Moreover, the nitric oxide and nitrite scavenging capability, and N-nitrosamine formation inhibitory activity of total saponins were evaluated. Results showed that the optimal conditions for total saponins were 37.76% (w/w) ammonium sulfate and 35.62% (w/w) ethanol in ATPS coupled with ultrasonic-assisted extraction. Under the optimal conditions, the maximum yield of total saponins of 33.4 g/kg can be obtained from the CTFs raw material. The nitric oxide radical scavenging, nitrite scavenging, and N-nitrosamine inhibitory activities (SC 50 ) were 287.92 ± 7.42, 191.63 ± 7.69, and 1787.4 ± 51.26 μg/mL, respectively. The total saponins has a certain nitric oxide and nitrite scavenging capability, and N-nitrosamine formation inhibitory activity in vitro. Given these activities, research on saponins from CTFs provides profound and lasting implications for the novel applications of C. tinctoria.

The removal of particle-reactive radionuclides in shallow water: Bottom scavenging versus particle settling of iodine-131 and beryllium-7.

PubMed

Montenero, Michael P; Dilbone, Elizabeth K; Waples, James T

2017-10-01

In pelagic waters, the removal of particle-reactive radionuclides is controlled by nuclide sorption to particles and subsequent settling by gravity. However, in shallow nearshore waters, the dominant mechanism of nuclide scavenging is not so clear. Understanding how particle-reactive radionuclides are scavenged from the water column is critical if these tracers are to be used as proxies of particle flux in shallow aquatic systems. In this study, we present evidence that the removal of particle-reactive radionuclides in nearshore and turbulent waters is primarily controlled by bottom scavenging. Specifically, we measured both water column and bottom sediment activities of sewage-sourced iodine-131 ( 131 I, t ½ = 8.02 days) and atmospherically-sourced beryllium-7 ( 7 Be, t ½ = 53.3 days) in a semi-enclosed harbor. We show that the water column 7 Be/ 131 I flux ratio that is required to sustain observed harbor bottom inventories of both nuclides is incongruent with 7 Be/ 131 I activity ratios on water column particles, and (2) 131 I and 7 Be derived mass fluxes of particulate matter to the harbor bottom are in concordance with each other and independently made estimates of river sediment loading to the harbor only when bottom scavenging of both particle-bound and dissolved (<0.7 μm) nuclide fractions are considered. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determination of antioxidant activity of Hibiscus sabdariffa and Croton caudatus in Saccharomyces cerevisiae model system.

PubMed

Subhaswaraj, Pattnaik; Sowmya, M; Bhavana, V; Dyavaiah, Madhu; Siddhardha, Busi

2017-08-01

From ancient times, plants and plant derived products are exploited as a prominent source of folkloric medicines with tremendous therapeutic potential for an array of health disorders. In the present study, ethanolic leaf extract of Hibiscus sabdariffa and Croton caudatus were evaluated for free radical scavenging activity in Saccharomyces cerevisiae model system. H. sabdariffa and C. caudatus showed tremendous DPPH free radical scavenging potential with an IC 50 value of 184.88 and 305.39 µg/mL respectively at a concentration of 500 µg/mL. The ethanolic leaf extract of H. sabdariffa and C. caudatus also showed significant hydoxyl radical scavenging and total antioxidant activity. Ascorbic acid was used as positive control. The in vitro antioxidant activity was further supported by in vivo studies using radical scavenging mechanism in S. cerevisiae wild type and its isogenic deletion strains sod1∆ and tsa1∆ . The mutant yeast cells substantially scavenged the stress generated by H 2 O 2 when supplemented with ethanolic leaf extract of H. sabdariffa and C. caudatus as evident from spot assays followed by fluorescence assay (DCF-DA) using fluorescence microscopic and intensity studies. H. sabdariffa and C.caudatus significantly neutralize the ROS level in yeast mutants with concomitant decrease in fluorescence intensity as compared to the untreated yeast cells. The results suggested the efficacy of H. sabdariffa and C. caudatus as potent antioxidants in yeast system and thus their futuristic applications in therapeutics.

Effect of ultraviolet irradiation on free radical scavenging activity of immunosuppressants used in lung transplantation and comparative electron paramagnetic resonance study of kinetics of their interactions with model free radicals.

PubMed

Stanjek-Cichoracka, A; Żegleń, S; Ramos, P; Pilawa, B; Wojarski, J

2018-06-01

The immunosuppressive drugs used in solid organ transplantation or autoimmunological processes were studied by electron paramagnetic resonance (EPR) spectroscopy to estimate their free radical scavenging activity. The interactions of immunosuppressants with free radicals were examined by an X-band (9.3 GHz) EPR spectroscopy and a model of DPPH free radicals. The EPR spectra of DPPH and DPPH interacting with individual drugs were compared. Kinetic studies were performed, and the effect of ultraviolet (UV) irradiation on the free radical scavenging activity of the tested drugs was determined. The free radical scavenging activity of non-irradiated drugs decreased in the order: rapamycin > mycophenolate mofetil > ciclosporin > tacrolimus. UV irradiation increased the free radical scavenging activity of all the tested immunosuppressive drugs, and the effect was highest for tacrolimus. For the non-irradiated samples, the speed of free radical interactions decreased in the order: ciclosporin > tacrolimus > mycophenolate mofetil > rapamycin. UV irradiation only slightly affected the speed of interactions of the immunosuppressive drugs with the model DPPH free radicals. Electron paramagnetic resonance spectroscopy is useful for obtaining information on interactions of immunosuppressive drugs with free radicals. We hypothesized that the long-term immunosuppressive effects of these drugs after transplantation or during autoimmune disorders may be mediated by anti-inflammatory action in addition to the known receptor/cell cycle inhibition. © 2018 John Wiley & Sons Ltd.

Theoretical simulations on the antioxidant mechanism of naturally occurring flavonoid: A DFT approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Praveena, R.; Sadasivam, K.

Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are found to be toxic, hence non-carcinogenic naturally occurring radical scavengers especially flavonoids have gained considerable importance in the past two decades. In the present investigation, the radical scavenging activity of C-glycosyl flavonoids is evaluated using theoretical approach which could broaden its scope in therapeutic applications. Gas and solvent phase studies of structural and molecular characteristics of C-glycosyl flavonoid, isovitexin is investigated through hydrogen atom transfer mechanism (HAT), Electron transfer-proton transfer (ET–PT) and Sequential proton loss electron transfer (SPLET) by Density functional theory (DFT) using hybrid parameters. The computedmore » values of the adiabatic ionization potential, electron affinity, hardness, softness, electronegativity and electrophilic index indicate that isovitexin possess good radical scavenging activity. The behavior of different –OH groups in polyphenolic compounds is assessed by considering electronic effects of the neighbouring groups and the overall geometry of molecule which in turn helps in analyzing the antioxidant capacity of the polyphenolic molecule. The studies indicate that the H–atom abstraction from 4’–OH site is preferred during the radical scavenging process. From Mulliken spin density analysis and FMOs, B–ring is found to be more delocalized center and capable of electron donation. Comparison of antioxidant activity of vitexin and isovitexin leads to the conclusion that isovitexin acts as a better radical scavenger. This is an evidence for the importance of position of glucose unit in the flavonoid.« less

A PELAGIC OUTBREAK OF AVIAN CHOLERA IN NORTH AMERICAN GULLS: SCAVENGING AS A PRIMARY MECHANISM FOR TRANSMISSION?

PubMed

Wille, Michelle; McBurney, Scott; Robertson, Gregory J; Wilhelm, Sabina I; Blehert, David S; Soos, Catherine; Dunphy, Ron; Whitney, Hugh

2016-10-01

Avian cholera, caused by the bacterium Pasteurella multocida , is an endemic disease globally, often causing annual epizootics in North American wild bird populations with thousands of mortalities. From December 2006 to March 2007, an avian cholera outbreak caused mortality in marine birds off the coast of Atlantic Canada, largely centered 300-400 km off the coast of the island of Newfoundland. Scavenging gulls ( Larus spp.) were the primary species detected; however, mortality was also identified in Black-legged Kittiwakes ( Rissa tridactyla ) and one Common Raven ( Corvus corax ), a nonmarine species. The most common gross necropsy findings in the birds with confirmed avian cholera were acute fibrinous and necrotizing lesions affecting the spleen, air sacs, and pericardium, and nonspecific hepatomegaly and splenomegaly. The etiologic agent, P. multocida serotype 1, was recovered from 77 of 136 carcasses examined, and confirmed or probable avian cholera was diagnosed in 85 cases. Mortality observed in scavenging gull species was disproportionately high relative to their abundance, particularly when compared to nonscavenging species. The presence of feather shafts in the ventricular lumen of the majority of larid carcasses diagnosed with avian cholera suggests scavenging of birds that died from avian cholera as a major mode of transmission. This documentation of an outbreak of avian cholera in a North American pelagic environment affecting primarily scavenging gulls indicates that offshore marine environments may be a component of avian cholera dynamics.

Scavenging of black carbon in Chilean coastal fogs.

PubMed

Heintzenberg, Jost; Cereceda-Balic, Francisco; Vidal, Victor; Leck, Caroline

2016-01-15

In November/December 2013 a pilot experiment on aerosol/fog interaction was conducted on a coastal hill in the suburbs of Valparaíso, Chile. Passages of garúa fog were monitored with continuous recordings of a soot photometer and an optical aerosol spectrometer. An optical fog sensor and an automatic weather station provided meteorological data with which the aerosol could be classified. High-resolution back trajectories added meteorological information. From filter samples, optical and chemical aerosol information was derived. Scavenging coefficients of black carbon (BC) and measured particulate mass below 1 μm diameter (PM1) were estimated with three approaches. Averaging over all fog periods of the campaign yielded a scavenging coefficient of only 6% for BC and 40% for PM1. Dividing the data into four 90°-wind sectors gave scavenging factors for BC ranging from 13% over the Valparaíso, Viña del Mar conurbation to 50% in the marine sector (180°-270°). The third, and independent approach was achieved with two pairs of chemical aerosol samples taken inside and outside fogs, which yielded a scavenging coefficient of 25% for BC and 70% for nonseasalt sulfate. Whereas fogs occurred rather infrequently in the beginning of the campaign highly regular daily fog cycles appeared towards the end of the experiment, which allowed the calculation of typical diurnal cycles of the aerosol in relation to a fog passage. Copyright © 2015 Elsevier B.V. All rights reserved.

A pelagic outbreak of avian cholera in North American gulls: Scavenging as a primary mechanism for transmission?

USGS Publications Warehouse

Wille, Michelle; McBurney, Scott; Robertson, Gregory J.; Wilhelm, Sabine; Blehert, David; Soos, Catherine; Dunphy, Ron; Whitney, Hugh

2016-01-01

Avian cholera, caused by the bacterium Pasteurella multocida, is an endemic disease globally, often causing annual epizootics in North American wild bird populations with thousands of mortalities. From December 2006 to March 2007, an avian cholera outbreak caused mortality in marine birds off the coast of Atlantic Canada, largely centered 300–400 km off the coast of the island of Newfoundland. Scavenging gulls (Larus spp.) were the primary species detected; however, mortality was also identified in Black-legged Kittiwakes (Rissa tridactyla) and one Common Raven (Corvus corax), a nonmarine species. The most common gross necropsy findings in the birds with confirmed avian cholera were acute fibrinous and necrotizing lesions affecting the spleen, air sacs, and pericardium, and nonspecific hepatomegaly and splenomegaly. The etiologic agent, P. multocida serotype 1, was recovered from 77 of 136 carcasses examined, and confirmed or probable avian cholera was diagnosed in 85 cases. Mortality observed in scavenging gull species was disproportionately high relative to their abundance, particularly when compared to nonscavenging species. The presence of feather shafts in the ventricular lumen of the majority of larid carcasses diagnosed with avian cholera suggests scavenging of birds that died from avian cholera as a major mode of transmission. This documentation of an outbreak of avian cholera in a North American pelagic environment affecting primarily scavenging gulls indicates that offshore marine environments may be a component of avian cholera dynamics.

HBOC vasoactivity: interplay between nitric oxide scavenging and capacity to generate bioactive nitric oxide species.

PubMed

Cabrales, Pedro; Friedman, Joel M

2013-06-10

Despite many advances in blood substitute research, the development of materials that are effective in maintaining blood volume and oxygen delivery remains a priority for emergency care and trauma. Clinical trials on hemoglobin (Hb)-based oxygen carriers (HBOCs) have not provided information on the mechanism of toxicity, although all commercial formulations have safety concerns. Specifically, it is important to reconcile the different hypotheses of Hb toxicity, such as nitric oxide (NO) depletion and oxidative reactions, to provide a coherent molecular basis for designing a safe HBOC. HBOCs with different sizes often exhibit differences in the degree of HBOC-induced vasoactivity. This has been attributed to differences in the degree of NO scavenging and in the extent of Hb extravasation. Additionally, it is appears that Hb can undergo reactions that compensate for NO scavenging by generating bioactive forms of NO. Engineering modifications to enhance bioactive NO production can result in diminished oxygen delivery by virtue of increased oxygen affinity. This strategy can prevent the HBOC from fulfilling the intended goal on preserving oxygenation; however, the NO production effects will increase perfusion and oxygen transport. Hb modifications influence NO scavenging and the capacity of certain HBOCs to compensate for NO scavenging through nitrite-mediated reactions that generate bioactive NO. Based on the current understanding of these NO-related factors, possible synthetic strategies are presented that address how HBOC formulations can be prepared that: (i) effectively deliver oxygen, (ii) maintain tissue perfusion, and (iii) limit/reverse underlying inflammation within the vasculature.

Antioxidative and in vitro antiproliferative activity of Arctium lappa root extracts

PubMed Central

2011-01-01

Background Arctium lappa, known as burdock, is widely used in popular medicine for hypertension, gout, hepatitis and other inflammatory disorders. Pharmacological studies indicated that burdock roots have hepatoprotective, anti-inflammatory, free radical scavenging and antiproliferative activities. The aim of this study was to evaluate total phenolic content, radical scavenging activity by DPPH and in vitro antiproliferative activity of different A. lappa root extracts. Methods Hot and room temperature dichloromethanic, ethanolic and aqueous extracts; hydroethanolic and total aqueous extract of A. lappa roots were investigated regarding radical scavenging activity by DPPH, total phenolic content by Folin-Ciocalteau method and antiproliferative in vitro activity was evaluated in human cancer cell lines. The hydroethanolic extract analyzed by high-resolution electrospray ionization mass spectroscopy. Results Higher radical scavenging activity was found for the hydroethanolic extract. The higher phenolic contents were found for the dichloromethane, obtained both by Soxhlet and maceration extraction and hydroethanolic extracts. The HRESI-MS demonstrated the presence of arctigenin, quercetin, chlorogenic acid and caffeic acid compounds, which were identified by comparison with previous data. The dichloromethane extracts were the only extracts that exhibited activity against cancer cell lines, especially for K562, MCF-7 and 786-0 cell lines. Conclusions The hydroethanolic extracts exhibited the strongest free radical scavenging activity, while the highest phenolic content was observed in Soxhlet extraction. Moreover, the dichloromethanic extracts showed selective antiproliferative activity against K562, MCF-7 and 786-0 human cancer cell lines. PMID:21429215

Antioxidative and in vitro antiproliferative activity of Arctium lappa root extracts.

PubMed

Predes, Fabricia S; Ruiz, Ana L T G; Carvalho, João E; Foglio, Mary A; Dolder, Heidi

2011-03-23

Arctium lappa, known as burdock, is widely used in popular medicine for hypertension, gout, hepatitis and other inflammatory disorders. Pharmacological studies indicated that burdock roots have hepatoprotective, anti-inflammatory, free radical scavenging and antiproliferative activities. The aim of this study was to evaluate total phenolic content, radical scavenging activity by DPPH and in vitro antiproliferative activity of different A. lappa root extracts. Hot and room temperature dichloromethanic, ethanolic and aqueous extracts; hydroethanolic and total aqueous extract of A. lappa roots were investigated regarding radical scavenging activity by DPPH, total phenolic content by Folin-Ciocalteau method and antiproliferative in vitro activity was evaluated in human cancer cell lines. The hydroethanolic extract analyzed by high-resolution electrospray ionization mass spectroscopy. Higher radical scavenging activity was found for the hydroethanolic extract. The higher phenolic contents were found for the dichloromethane, obtained both by Soxhlet and maceration extraction and hydroethanolic extracts. The HRESI-MS demonstrated the presence of arctigenin, quercetin, chlorogenic acid and caffeic acid compounds, which were identified by comparison with previous data. The dichloromethane extracts were the only extracts that exhibited activity against cancer cell lines, especially for K562, MCF-7 and 786-0 cell lines. The hydroethanolic extracts exhibited the strongest free radical scavenging activity, while the highest phenolic content was observed in Soxhlet extraction. Moreover, the dichloromethanic extracts showed selective antiproliferative activity against K562, MCF-7 and 786-0 human cancer cell lines. © 2011 Predes et al; licensee BioMed Central Ltd.

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

Assessment of the Antioxidant and Reactive Oxygen Species Scavenging Activity of Methanolic Extract of Caesalpinia crista Leaf

PubMed Central

Mandal, Sourav; Hazra, Bibhabasu; Sarkar, Rhitajit; Biswas, Santanu; Mandal, Nripendranath

2011-01-01

“Oxidative stress” is initiated by reactive oxygen species (ROS), which are responsible for majority of the diseases. However, antioxidants with ROS scavenging ability may have great relevance in the prevention of oxidative stress. The present study was undertaken, using a 70% methanolic extract of Caesalpinia crista leaves, to examine different in vitro tests in diversified fields including total antioxidant activity, scavenging activities for various ROS, iron chelating activity and phenolic and flavonoid contents. Total antioxidant activity was evaluated as trolox equivalent antioxidant capacity value of 0.546 ± 0.014. The extract was investigated for different ROS scavenging activities and IC50 values were found to be 0.44 ± 0.1 mg/ml, 24.9 ± 0.98 μg/ml, 33.72 ± 0.85 μg/ml, 61.13 ± 3.24 μg/mL and 170.51 ± 4.68 μg/mL for hydroxyl, superoxide, nitric oxide, singlet oxygen and hypochlorous acid, respectively; however, no significant results were obtained in scavenging of hydrogen peroxide and peroxynitrite anion. The extract was found to be a potent iron chelator with IC50 = 279.85 ± 4.72 μg/mL. The plant extract (100 mg) yielded 50.23 ± 0.003 mg/mL gallic acid equivalent phenolic content and 106.83 ± 0.0003 mg/mL quercetin equivalent flavonoid content. In the in vivo experiments, the extract treatment showed significant increase in the level of superoxide dismutase, catalase, glutathione-S-transferase and reduced glutathione. In a word, it may be concluded that 70% methanol extract of C. crista leaves acts as an antioxidant and ROS scavenger; which may be due to the presence of phenolic and flavonoid compounds. PMID:19596746

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

Microbial ice nucleators scavenged from the atmosphere during simulated rain events

NASA Astrophysics Data System (ADS)

Hanlon, Regina; Powers, Craig; Failor, Kevin; Monteil, Caroline L.; Vinatzer, Boris A.; Schmale, David G.

2017-08-01

Rain and snow collected at ground level have been found to contain biological ice nucleators. These ice nucleators have been proposed to have originated in clouds, where they may have participated in the formation of precipitation via ice phase nucleation. We conducted a series of field experiments to test the hypothesis that at least some of the microbial ice nucleators (prokaryotes and eukaryotes) present in rain may not originate in clouds but instead be scavenged from the lower atmosphere by rainfall. Thirty-three simulated rain events were conducted over four months off the side of the Smart Road Bridge in Blacksburg, VA, USA. In each event, sterile water was dispensed over the side of the bridge and recovered in sterile containers in an open fallow agricultural field below (a distance of ∼55 m). Microbes scavenged from the simulated rain events were cultured and their ice nucleation activity was examined. Putative microbial ice nucleators were cultured from 94% (31/33) of the simulated rain events, and represented 1.5% (121/8331) of the total colonies assayed. Putative ice nucleators were subjected to additional droplet freezing assays, and those confirmed through these repeated assays represented 0.4% (34/8331) of the total. Mean CFUs scavenged by simulated rain ranged from 2 to 267 CFUs/mL. Scavenged ice nucleators belong to a number of taxa including the bacterial genera Pseudomonas, Pantoea, and Xanthomonas, and the fungal genera Fusarium, Humicola, and Mortierella. An ice-nucleating strain of the fungal genus Penicillium was also recovered from a volumetric air sampler at the study site. This work expands our knowledge of the scavenging properties of rainfall, and suggests that at least some ice nucleators in natural precipitation events may have been scrubbed from the atmosphere during rainfall, and thus are not likely to be involved in precipitation.

Phytochemical analysis and free radical scavenging activity of medicinal plants Gnidia glauca and Dioscorea bulbifera.

PubMed

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 × 10(6) and 1.72 × 10(6), respectively. Similarly, methanol extract of G. glauca flower and ethyl acetate extract of D. bulbifera bulb with second order rate constants of 4.48 × 10(6) and 4.46 × 10(6) 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.

Comparative study of the antioxidant and reactive oxygen species scavenging properties in the extracts of the fruits of Terminalia chebula, Terminalia belerica and Emblica officinalis

PubMed Central

2010-01-01

Background Cellular damage caused by reactive oxygen species (ROS) has been implicated in several diseases, and hence natural antioxidants have significant importance in human health. The present study was carried out to evaluate the in vitro antioxidant and reactive oxygen species scavenging activities of Terminalia chebula, Terminalia belerica and Emblica officinalis fruit extracts. Methods The 70% methanol extracts were studied for in vitro total antioxidant activity along with phenolic and flavonoid contents and reducing power. Scavenging ability of the extracts for radicals like DPPH, hydroxyl, superoxide, nitric oxide, hydrogen peroxide, peroxynitrite, singlet oxygen, hypochlorous acid were also performed to determine the potential of the extracts. Results The ability of the extracts of the fruits in exhibiting their antioxative properties follow the order T. chebula >E. officinalis >T. belerica. The same order is followed in their flavonoid content, whereas in case of phenolic content it becomes E. officinalis >T. belerica >T. chebula. In the studies of free radicals' scavenging, where the activities of the plant extracts were inversely proportional to their IC50 values, T. chebula and E. officinalis were found to be taking leading role with the orders of T. chebula >E. officinalis >T. belerica for superoxide and nitric oxide, and E. officinalis >T. belerica >T. chebula for DPPH and peroxynitrite radicals. Miscellaneous results were observed in the scavenging of other radicals by the plant extracts, viz., T. chebula >T. belerica >E. officinalis for hydroxyl, T. belerica >T. chebula >E. officinalis for singlet oxygen and T. belerica >E. officinalis >T. chebula for hypochlorous acid. In a whole, the studied fruit extracts showed quite good efficacy in their antioxidant and radical scavenging abilities, compared to the standards. Conclusions The evidences as can be concluded from the study of the 70% methanol extract of the fruits of Terminalia chebula, Terminalia belerica and Emblica officinalis, imposes the fact that they might be useful as potent sources of natural antioxidant. PMID:20462461

Detection and scavenging of hydroxyl radical via D-phenylalanine hydroxylation in human fluids.

PubMed

Biondi, Roberto; Brancorsini, Stefano; Poli, Giulia; Egidi, Maria Giulia; Capodicasa, Enrico; Bottiglieri, Livio; Gerli, Sandro; Brillo, Eleonora; Renzo, Gian Carlo Di; Cretoiu, Dragos; Micu, Romeo; Suciu, Nicolae

2018-05-01

Hydroxyl radical (.OH) is highly reactive, and therefore very short-lived. Finding new means to accurately detect .OH, and testing the ability of known .OH scavengers to neutralize them in human biological fluids would leverage our ability to more effectively counter oxidative (.OH) stress-mediated damage in human diseases. To achieve this, we pursued the evaluation of secondary products resulting from .OH attack, using a detection system based on Fenton reaction-mediated D-phenylalanine (D-Phe) hydroxylation. This reaction in turn generates o-tyrosine (o-tyr), m-tyrosine (m-tyr) and p-tyrosine (p-tyr). Here, these isomers were separated by HPLC, equipped with fluorescence detectors due to the natural fluorescence of these hydrotyrosines. By extension, we found that, adding radical scavengers competed with D-Phe on .OH attack, thus allowing to determine the .OH quenching capacity of a given compound expressed as inhibition ratio percent (IR%). Using a kinetic approach, we then tested the .OH scavenging capacity (OHSC) of well-known antioxidant molecules. In a test tube, N,N'-dimethylthiourea (DMTU) was the most efficient scavenger as compared to Trolox and N-Acethyl-L-cysteine, with NAC being the less effective. OHSC assay was then applied to biological fluid samples as seminal plasma, human serum from normal subjects and patients undergoing hemodialysis (HD), colostrum and human breast milk from mothers that received daily doses of 30g of chocolate (70% cocoa) during pregnancy. We found that a daily administration of dark chocolate during pregnancy almost doubled OHSC levels in breast milk (1.88 ± 0.12 times, p < 0.01). Furthermore, HD treatment determined a significant reduction of serum OHSC concentration (54.63 ± 2.82%, p < 0.001). Our results provide evidence that Fenton reaction-mediated D-Phe hydroxylation is a suitable method for routine and non-invasive evaluation of .OH detection and its scavenging in human biological fluids. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

Microbial ice nucleators are scavenged from the atmosphere during artificial rain events

NASA Astrophysics Data System (ADS)

Hanlon, Regina; Powers, Craig; Failor, Kevin; Vinatzer, Boris; Schmale, David

2016-04-01

Some microorganisms associated with rain may catalyze the nucleation of ice crystals at significantly warmer temperatures than would normally be required for ice formation, suggesting that they may play an important role in the onset of precipitation. Rain samples collected near the surface of the earth contain an array of microbial ice nucleators, but the little is known about their source(s) and life history. We conducted a series of field experiments to test the hypothesis that microbial ice nucleators are scavenged from the atmosphere by rainfall. Thirty three artificial rain events were conducted over four months (Nov 2014, Dec 2014, April 2015, and June 2015) off the side of the Smart Road Bridge in Blacksburg, VA, USA. In each event, sterile water was dispensed over the side of the bridge and recovered in sterile containers following gravitational settling from the bridge to an open fallow agricultural field below (a distance of ~55m). Microbes scavenged from the artificial rain events were cultured on six different types of agar media (R2A, TSA, CA; +/-cycloheximide), and the ice nucleation activity was examined for colonies cultured from the different media types. Mean CFUs scavenged by artificial rain ranged from 2 to 267 CFUs/mL. Microbial ice nucleators were cultured from 94% (31/33) of the simulated rain events, and represented 1.4% (121/8871) of the total number of colonies assayed. This percentage is similar to the percentage of culturable microbial ice nucleators occurring in about half of the natural rain events studied in Blacksburg, VA. Sequence-assisted identification of the repeatable microbial ice nucleators that were scavenged from the atmosphere showed a number of unique prokaryotic and eukaryotic taxa. This work expands our knowledge of the scavenging properties of rainfall, and suggests that at least some ice nucleators in natural precipitation events may have been scrubbed from the atmosphere during rainfall, and thus are not likely to be involved in the onset of precipitation.

Scavenging of ice-nucleating microorganisms from the atmosphere by artificial rain events

NASA Astrophysics Data System (ADS)

Hanlon, Regina; Powers, Craig; Failor, Kevin; Vinatzer, Boris; Schmale, David

2015-04-01

Little is known about how microorganisms are scavenged from the atmosphere during rainfall. Microorganisms are abundant and diverse in rain (precipitation) collected near the surface of the earth. Some of these rain-associated microorganisms produce proteins that catalyze the nucleation of ice crystals at significantly warmer temperatures than would normally be required for ice formation, suggesting that they may play important roles in weather, including the onset of precipitation. We conducted a series of field experiments to test the hypothesis that ice-nucleating microorganisms are scavenged from the atmosphere by rainfall. Thirteen artificial rain events were conducted off the side of the Smart Road Bridge in Blacksburg, VA, USA. In each event, sterile water was dispensed over the side of the bridge (simulated rainfall), and recovered in sterile containers following gravitational settling from the side of the bridge to an open fallow agricultural field below (a distance of ~55m from the release site to the collection site). Microbes scavenged from the artificial rain events were cultured on six different types of agar media (R2A, TSA, CA; +/- cycloheximide) and the ice nucleation activity was examined for colonies cultured from the different media types. Mean CFUs scavenged by artificial rain ranged from 83 to 196 CFUs/mL across all six media types. Ice-nucleating microorganisms were recovered from 85% (11/13) of the simulated rain events, and represented about 1% of the total number of colonies assayed from each event. Strikingly, this percentage is nearly identical to the percentage of culturable ice-nucleating microorganisms occurring in about half of the natural rain events studied to date in Blacksburg, Virginia. This work expands our knowledge of the scavenging properties of rain, and suggests that at least some ice nucleators in natural precipitation events may have been stripped from the atmosphere during rainfall, thus negating their potential role in the onset of precipitation.

Hepatoprotective, antinociceptive and antioxidant activities of cimetidine, ranitidine and famotidine as histamine H2 receptor antagonists.

PubMed

Ahmadi, Amirhossein; Ebrahimzadeh, Mohammad Ali; Ahmad-Ashrafi, Saeb; Karami, Mohammad; Mahdavi, Mohammad Reza; Saravi, Seyed Soheil Saeedi

2011-02-01

The antioxidant, antinociceptive and hepatoprotective effects of H(2) receptor blockers were examined with different experimental models. Antioxidant activities were determined by employing various in vitro assay systems such as 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical-scavenging activity assays, reducing power determination assays, nitric oxide-scavenging activity assays and hydrogen peroxide-scavenging activity assays. Antinociceptive effects were determined using the hot plate test in mice. The hepatoprotective effects of cimetidine, ranitidine and famotidine against hepatotoxicity induced by carbon tetrachloride (CCl(4) ) were determined by measuring the levels of serum enzymes alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) activities in mice. We found that the IC(50) values of cimetidine, ranitidine and famotidine on DPPH radical-scavenging activity were 671±28, 538±21 and 955±43 μg/mL, respectively. Famotidine showed very strong nitric oxide-scavenging activity. All three compounds showed very weak hydrogen peroxide-scavenging activity. Moreover, the compounds did not exhibit any reducing power activity until concentrations of 1.6 mg/mL. All compounds also showed a dose-dependent and marked analgesic activity in mice relative to controls. Pretreatment of mice with cimetidine, ranitidine or famotidine for three consecutive days reduced CCl(4)-induced hepatotoxicity in mice. Treatment with 200 mg/kg ranitidine reduced AST, AST and ALP serum levels, while 200 and 40 mg/kg of cimetidine and famotidine, respectively, reduced AST and ALP serum levels. H(2) blockers exhibited varying levels of antioxidant activities in various assays. Our results indicate that the antioxidant activities of H(2) blockers have an analgesic activity and protective effect on CCl(4)-induced hepatotoxicity in mice. These effects were greater with ranitidine than with the other compounds. © 2010 The Authors Fundamental and Clinical Pharmacology © 2010 Société Française de Pharmacologie et de Thérapeutique.

Natural products isolated from Tetragonula carbonaria cerumen modulate free radical-scavenging and 5-lipoxygenase activities in vitro.

PubMed

Hamilton, Karina D; Brooks, Peter R; Ogbourne, Steven M; Russell, Fraser D

2017-04-26

Propolis and cerumen are plant-derived products found in honeybees and stingless bees, respectively. Although propolis is an ancient folk medicine, the bioactivities of cerumen obtained from Australian native stingless bees (Tetragonula carbonaria) have not been widely studied. Therefore, we investigated selected anti-oxidant and anti-inflammatory properties of T. carbonaria cerumen. A methanolic extract was prepared from the combined cerumen of 40 T. carbonaria hives, and HPLC was used to screen for chemical constituents that scavenged 2,2-azobis(2-methylpropionamidine) dihydrochloride (AAPH). The ability of cerumen extracts to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) and to interfere with leukotriene B 4 (LTB 4 ) production in ionomycin-stimulated human neutrophils was also examined. The extract dose-dependently scavenged DPPH (EC 50  = 27.0 ± 2.3 μg/mL); and inhibited the 5-lipoxygenase (5-LOX)-mediated oxidation of linoleic acid (IC 50  = 67.1 ± 9.6 μg/mL). Pre-treatment of isolated human neutrophils with the methanolic cerumen extract additionally inhibited the ionomycin-stimulated production of LTB 4 from these cells (IC 50  = 13.3 ± 5.3 μg/mL). Following multi-solvent extraction, the free radical-scavenging and 5-LOX-inhibiting activities of the initial cerumen extract were retained in a polar, methanol-water extract, which contained gallic acid and a range of flavonone and phenolic natural products. The findings identify free radical scavenging activity, and interference by extracts of T. carbonaria cerumen in 5-LOX-LTB 4 signaling. Further investigation is needed to determine whether the extracts will provide therapeutic benefits for medical conditions in which oxidative stress and inflammation are implicated, including cardiovascular disease and impaired wound healing.

Antioxidant Potential and Wound Healing Activity of Biosurfactant Produced by Acinetobacter junii B6.

PubMed

Ohadi, Mandana; Forootanfar, Hamid; Rahimi, Hamid Reza; Jafari, Elham; Shakibaie, Mojtaba; Eslaminejad, Touba; Dehghannoudeh, Gholamreza

2017-01-01

Recently, the development of a safe bioactive material with antioxidant properties, which can improve healing activity are focusing. Biosurfactants are very famous for their antimicrobial and free radical scavenging activities. Thereof, the main aim of the present study was to investigate the antioxidant and wound healing activity of the lipopeptide biosurfactant (LBS) produced by Acinetobacter junii B6. DPPH radical scavenging activities and FRAP assays were used to measure the antioxidant properties. For evaluation of the wound healing activity, 36 rats (previously wounded in depilated thoracic region) were randomly distributed into six groups and chromatic, wound contraction, and histopathological feature were examined. The assessment levels of reactive oxygen species (ROS) after LBS exposure were determined using malondialdehyde (MDA), hydrogen peroxide (H2O2), and glutathione (GSH) assay kits. DPPH assay showed notable scavenging activities at the corresponding concentrations with IC50 value of 0.7 mg/ml. The reductive potency of the LBS showed lower performance at low concentration, while exhibited a remarkable increase at higher concentration. The best histopathological remission was achieved following treatment by 5 mg/ml of the LBS. Scar wounds at day 13 showed the lowest lesion sizes, increased re-epithelialization, hair follicle detection, and decreased amounts of neutrophilic inflammation, immaturity of the wound bed, erythema, edema, capillary, and retention of necrotic tissue. Results from MDA, H2O2, and GSH levels of the treated sample confirmed the scavenging property of the bacterial derived LBS through ROS. It could be concluded that the pharmaceutical formula encourages the wound healing because of its notable antioxidant capacity. • DPPH and FRAP assays showed notable scavenging activity. • MDA, H2O2, and GSH; confirmed the scavenging property of the derived biosurfactant through ROS. • Synthesized formula encourages the healing of the wound because of its antioxidant capacity. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Antioxidant activities and phenolic contents of three red seaweeds (Division: Rhodophyta) harvested from the Gulf of Mannar of Peninsular India.

PubMed

Chakraborty, Kajal; Joseph, Deepu; Praveen, Nammunayathuputhenkotta Krishnankartha

2015-04-01

The antioxidant activities of methanol extract and its solvent fractions (n-hexane, dichloromethane and ethyl acetate) of three red seaweeds (Hypnea musciformis, H. valentiae, and Jania rubens) collected from the Gulf of Mannar of South eastern coast of India were evaluated, using different in vitro systems, viz., DPPH, ABTS, HO radical scavenging activities, H2O2 scavenging ability, Fe(2+) ion chelating ability and reducing potential. Folin-Ciocalteu method was used to determine the total phenolic content of the extracts/fractions, and the results were expressed as mg of gallic acid equivalent (GAE)/g of the seaweed extracts/fractions. Thiobarbituric acid-reactive substances (TBARS) inhibition assay was employed to assess the ability of the seaweed extracts/fractions to inhibit lipid oxidation. Ethyl acetate (EtOAc) fractions of H. musciformis exhibited significantly higher total phenolic content (205.5 mg GAE/g), DPPH· scavenging activity (IC50 0.6 mg/mL), ABTS(.+) scavenging activity (IC50 0.51 μg/mL), Fe(2+) chelating ability (IC50 0.70 mg/mL), H2O2 scavenging activity (IC50 0.39 mg/mL), reducing ability (Abs700 nm 1.46) and lipid peroxidation inhibitory ability (2.71 MDAEC/kg) (P < 0.05) compared to its n-hexane, DCM fractions, crude MeOH extract and MeOH extracts/fractions of H. valentiae and J. rubens. DCM fraction of J. rubens showed significantly higher hydroxyl radical scavenging activity (IC50 0.55 mg/mL) compared with H. musciformis and H. valentiae (P < 0.05). This study indicated the potential use of red seaweeds, in particular, H. musciformis as candidate species to be used as food supplement for increasing the shelf-life of food industry, and candidates in combating carcinogenesis and inflammatory diseases.

Loading of free radicals on the functional graphene combined with liquid chromatography-tandem mass spectrometry screening method for the detection of radical-scavenging natural antioxidants.

PubMed

Wang, Guoying; Shi, Gaofeng; Chen, Xuefu; Chen, Fuwen; Yao, Ruixing; Wang, Zhenju

2013-11-13

A novel free radical reaction combined with liquid chromatography electrospray ionization tandem mass spectrometry (FRR-LC-PDA-ESI/APCI-MS/MS) screening method was developed for the detection and identification of radical-scavenging natural antioxidants. Functionalized graphene was prepared by chemical method for loading free radicals (superoxide radical, peroxyl radical and PAHs free radical). Separation was performed with and without a preliminary exposure of the sample to specific free radicals on the functionalized graphene, which can facilitate reaction kinetics (charge transfers) between free radicals and potential antioxidants. The difference in chromatographic peak areas is used to identify potential antioxidants. The structure of the antioxidants in one sample (Swertia chirayita) is identified using MS/MS and comparison with standards. Thirteen compounds were found to possess potential antioxidant activity, and their free radical-scavenging capacities were investigated. The thirteen compounds were identified as 1,3,5-trihydroxyxanthone-8-O-β-D-glucopyranoside (PD1), norswertianin (PD2), 1,3,5,8-tetrahydroxyxanthone (PD3), 3, 3', 4', 5, 8-penta hydroxyflavone-6-β-D-glucopyranosiduronic acid-6'-pentopyranose-7-O-glucopyranoside (PD4), 1,5,8-trihydroxy-3-methoxyxanthone (PD5), swertiamarin (PS1), 2-C-β-D-glucopyranosyl-1,3,7-trihydroxylxanthone (PS2), 1,3,7-trihydroxylxanthone-8-O-β-D-glucopyranoside (PL1), 1,3,8-trihydroxyl xanthone-5-O-β-D-glucopyranoside (PL2), 1,3,7-trihydroxy-8-methoxyxanthone (PL3), 1,2,3-trihydroxy-7,8-dimethoxyxanthone (PL4), 1,8-dihydroxy-2,6-dimethoxy xanthone (PL5) and 1,3,5,8-tetramethoxydecussatin (PL6). The reactivity and SC50 values of those compounds were investigated, respectively. PD4 showed the strongest capability for scavenging PAHs free radical; PL4 showed prominent scavenging capacities in the lipid peroxidation processes; it was found that all components in S. chirayita exhibited weak reactivity in the superoxide radical scavenging capacity. The use of the free radical reaction screening method based on LC-PDA-ESI/APCI-MS/MS would provide a new approach for rapid detection and identification of radical-scavenging natural antioxidants from complex matrices. Copyright © 2013 Elsevier B.V. All rights reserved.

Chemical constituents and free radical scavenging activity of corn pollen collected from Apis mellifera hives compared to floral corn pollen at Nan, Thailand.

PubMed

Chantarudee, Atip; Phuwapraisirisan, Preecha; Kimura, Kiyoshi; Okuyama, Masayuki; Mori, Haruhide; Kimura, Atsuo; Chanchao, Chanpen

2012-04-18

Bee pollen is composed of floral pollen mixed with nectar and bee secretion that is collected by foraging honey (Apis sp.) and stingless bees. It is rich in nutrients, such as sugars, proteins, lipids, vitamins and flavonoids, and has been ascribed antiproliferative, anti-allergenic, anti-angiogenic and free radical scavenging activities. This research aimed at a preliminary investigation of the chemical constituents and free radical scavenging activity in A. mellifera bee pollen. Bee pollen was directly collected from A. mellifera colonies in Nan province, Thailand, in June, 2010, whilst floral corn (Zea mays L.) pollen was collected from the nearby corn fields. The pollen was then sequentially extracted with methanol, dichloromethane (DCM) and hexane, and each crude extract was tested for free radical scavenging activity using the DPPH assay, evaluating the percentage scavenging activity and the effective concentration at 50% (EC50). The most active crude fraction from the bee pollen was then further enriched for bioactive components by silica gel 60 quick and adsorption or Sephadex LH-20 size exclusion chromatography. The purity of all fractions in each step was observed by thin layer chromatography and the bioactivity assessed by the DPPH assay. The chemical structures of the most active fractions were analyzed by nuclear magnetic resonance. The crude DCM extract of both the bee corn pollen and floral corn pollen provided the highest active free radical scavenging activity of the three solvent extracts, but it was significantly (over 28-fold) higher in the bee corn pollen (EC(50) = 7.42 ± 0.12 μg/ml), than the floral corn pollen (EC(50) = 212 ± 13.6% μg/ml). After fractionation to homogeneity, the phenolic hydroquinone and the flavone 7-O-R-apigenin were found as the minor and major bioactive compounds, respectively. Bee corn pollen contained a reasonably diverse array of nutritional components, including biotin (56.7 μg/100 g), invert sugar (19.9 g/100 g), vitamin A and β carotene (1.53 mg/100 g). Bee pollen derived from corn (Z. mays), a non-toxic or edible plant, provided a better free radical scavenging activity than floral corn pollen.

Chemical constituents and free radical scavenging activity of corn pollen collected from Apis mellifera hives compared to floral corn pollen at Nan, Thailand

PubMed Central

2012-01-01

Background Bee pollen is composed of floral pollen mixed with nectar and bee secretion that is collected by foraging honey (Apis sp.) and stingless bees. It is rich in nutrients, such as sugars, proteins, lipids, vitamins and flavonoids, and has been ascribed antiproliferative, anti-allergenic, anti-angiogenic and free radical scavenging activities. This research aimed at a preliminary investigation of the chemical constituents and free radical scavenging activity in A. mellifera bee pollen. Methods Bee pollen was directly collected from A. mellifera colonies in Nan province, Thailand, in June, 2010, whilst floral corn (Zea mays L.) pollen was collected from the nearby corn fields. The pollen was then sequentially extracted with methanol, dichloromethane (DCM) and hexane, and each crude extract was tested for free radical scavenging activity using the DPPH assay, evaluating the percentage scavenging activity and the effective concentration at 50% (EC50). The most active crude fraction from the bee pollen was then further enriched for bioactive components by silica gel 60 quick and adsorption or Sephadex LH-20 size exclusion chromatography. The purity of all fractions in each step was observed by thin layer chromatography and the bioactivity assessed by the DPPH assay. The chemical structures of the most active fractions were analyzed by nuclear magnetic resonance. Results The crude DCM extract of both the bee corn pollen and floral corn pollen provided the highest active free radical scavenging activity of the three solvent extracts, but it was significantly (over 28-fold) higher in the bee corn pollen (EC50 = 7.42 ± 0.12 μg/ml), than the floral corn pollen (EC50 = 212 ± 13.6% μg/ml). After fractionation to homogeneity, the phenolic hydroquinone and the flavone 7-O-R-apigenin were found as the minor and major bioactive compounds, respectively. Bee corn pollen contained a reasonably diverse array of nutritional components, including biotin (56.7 μg/100 g), invert sugar (19.9 g/100 g), vitamin A and β carotene (1.53 mg/100 g). Conclusions Bee pollen derived from corn (Z. mays), a non-toxic or edible plant, provided a better free radical scavenging activity than floral corn pollen. PMID:22513008

New insights into cycling of 231Pa and 230Th in the Atlantic Ocean

NASA Astrophysics Data System (ADS)

Rempfer, Johannes; Stocker, Thomas F.; Joos, Fortunat; Lippold, Jörg; Jaccard, Samuel L.

2017-06-01

We use the Bern3D model of intermediate complexity to examine the marine cycle of isotopes 231Pa and 230Th and the relationship between the particle-bound ratio Pap /Thp and changes in the formation of the North Atlantic Deep Water (NADW). Model parameters describing reversible scavenging of isotopes by organic particles, opal, calcite and resuspended sediments were systematically varied and alternative sink parametrisations explored. It proves difficult to simultaneously achieve a good agreement with observations of dissolved and particle-associated concentrations of 231Pa and 230Th (Pad, Thd, Pap, Thp) as well as the particle-bound ratio Pap /Thp within the classical concept of reversible scavenging alone. Agreement between simulated and observed Pad, Thd and estimates of mean ocean residence times is improved by taking into account simplified representations of additional sinks at the sea floor (bottom scavenging) and at continental boundaries (boundary scavenging). We also find improved agreement between model and data by increasing lateral advection, in particular for Pad. These results point to the importance of sink processes that act in addition to reversible scavenging to shape the steady state distribution of 231Pa and, to a lesser degree, of 230Th. In transient experiments in which the strength of the Atlantic meridional overturning circulation (AMOC) is periodically turned on and off, we find a strong statistical relationship between variations in AMOC strength and Pap /Thp at great depths in the Northwest Atlantic region. These conclusions are robust across the range of sink parametrisations, that are consistent with estimates in the mean ocean residence time of 231Pa and 230Th. Our results indicate that the relationship between Pap /Thp and AMOC-strength may not be fundamentally affected by uncertainties in sink processes, at least on the large spatial and temporal scale considered here, and support the idea that changes in Pap /Thp in sediments of the Northwest Atlantic are indicative of changes in AMOC strength. Taking into account our simplified approach, our results indicate that the relationship between Pap /Thp and AMOC-strength in the deep Northwest Atlantic is not affected by boundary scavenging or bottom scavenging. Our results thus support the idea that changes in Pap /Thp in sediments of the Northwest Atlantic are indicative of changes in AMOC strength.

Effects of the Wegener-Bergeron-Findeisen process on global black carbon distribution

NASA Astrophysics Data System (ADS)

Qi, Ling; Li, Qinbin; He, Cenlin; Wang, Xin; Huang, Jianping

2017-06-01

We systematically investigate the effects of Wegener-Bergeron-Findeisen process (hereafter WBF) on black carbon (BC) scavenging efficiency, surface BCair, deposition flux, concentration in snow (BCsnow, ng g-1), and washout ratio using a global 3-D chemical transport model (GEOS-Chem). We differentiate riming- versus WBF-dominated in-cloud scavenging based on liquid water content (LWC) and temperature. Specifically, we implement an implied WBF parameterization using either temperature or ice mass fraction (IMF) in mixed-phase clouds based on field measurements. We find that at Jungfraujoch, Switzerland, and Abisko, Sweden, where WBF dominates in-cloud scavenging, including the WBF effect strongly reduces the discrepancies of simulated BC scavenging efficiency and washout ratio against observations (from a factor of 3 to 10 % and from a factor of 4-5 to a factor of 2). However, at Zeppelin, Norway, where riming dominates, simulation of BC scavenging efficiency, BCair, and washout ratio become worse (relative to observations) when WBF is included. There is thus an urgent need for extensive observations to distinguish and characterize riming- versus WBF-dominated aerosol scavenging in mixed-phase clouds and the associated BC scavenging efficiency. Our model results show that including the WBF effect lowers global BC scavenging efficiency, with a higher reduction at higher latitudes (8 % in the tropics and up to 76 % in the Arctic). The resulting annual mean BCair increases by up to 156 % at high altitudes and at northern high latitudes because of lower temperature and higher IMF. Overall, WBF halves the model-observation discrepancy (from -65 to -30 %) of BCair across North America, Europe, China and the Arctic. Globally WBF increases BC burden from 0.22 to 0.29-0.35 mg m-2 yr-1, which partially explains the gap between observed and previous model-simulated BC burdens over land. In addition, WBF significantly increases BC lifetime from 5.7 to ˜ 8 days. Additionally, WBF results in a significant redistribution of BC deposition in source and remote regions. Specifically, it lowers BC wet deposition (by 37-63 % at northern mid-latitudes and by 21-29 % in the Arctic), while it increases dry deposition (by 3-16 % at mid-latitudes and by 81-159 % in the Arctic). The resulting total BC deposition is lower at mid-latitudes (by 12-34 %) but higher in the Arctic (by 2-29 %). We find that WBF decreases BCsnow at mid-latitudes (by ˜ 15 %) but increases it in the Arctic (by 26 %) while improving model comparisons with observations. In addition, WBF dramatically reduces the model-observation discrepancy of washout ratios in winter (from a factor of 16 to 4). The remaining discrepancies in BCair, BCsnow and BC washout ratios suggest that in-cloud removal in mixed-phased clouds is likely still excessive over land.

Uncertainty associated with convective wet removal of entrained aerosols in a global climate model

NASA Astrophysics Data System (ADS)

Croft, B.; Pierce, J. R.; Martin, R. V.; Hoose, C.; Lohmann, U.

2012-11-01

The uncertainties associated with the wet removal of aerosols entrained above convective cloud bases are investigated in a global aerosol-climate model (ECHAM5-HAM) under a set of limiting assumptions for the wet removal of the entrained aerosols. The limiting assumptions for the wet removal of entrained aerosols are negligible scavenging and vigorous scavenging (either through activation, with size-dependent impaction scavenging, or with the prescribed fractions of the standard model). To facilitate this process-based study, an explicit representation of cloud-droplet-borne and ice-crystal-borne aerosol mass and number, for the purpose of wet removal, is introduced into the ECHAM5-HAM model. This replaces and is compared with the prescribed cloud-droplet-borne and ice-crystal-borne aerosol fraction scavenging scheme of the standard model. A 20% to 35% uncertainty in simulated global, annual mean aerosol mass burdens and optical depth (AOD) is attributed to different assumptions for the wet removal of aerosols entrained above convective cloud bases. Assumptions about the removal of aerosols entrained above convective cloud bases control modeled upper tropospheric aerosol concentrations by as much as one order of magnitude. Simulated aerosols entrained above convective cloud bases contribute 20% to 50% of modeled global, annual mean aerosol mass convective wet deposition (about 5% to 10% of the total dry and wet deposition), depending on the aerosol species, when including wet scavenging of those entrained aerosols (either by activation, size-dependent impaction, or with the prescribed fraction scheme). Among the simulations, the prescribed fraction and size-dependent impaction schemes yield the largest global, annual mean aerosol mass convective wet deposition (by about two-fold). However, the prescribed fraction scheme has more vigorous convective mixed-phase wet removal (by two to five-fold relative to the size-dependent impaction scheme) since nearly all entrained accumulation and coarse mode aerosols are assumed to be cloud-droplet borne or ice-crystal borne, and evaporation due to the Bergeron-Findeisen process is neglected. The simulated convective wet scavenging of entrained accumulation and coarse mode aerosols has feedbacks on new particle formation and the number of Aitken mode aerosols, which control stratiform and convective cloud droplet number concentrations and yield precipitation changes in the ECHAM5-HAM model. However, the geographic distribution of aerosol annual mean convective wet deposition change in the model is driven by changes to the assumptions regarding the scavenging of aerosols entrained above cloud bases rather than by precipitation changes, except for sea salt deposition in the tropics. Uncertainty in the seasonal, regional cycles of AOD due to assumptions about entrained aerosol wet scavenging is similar in magnitude to the estimated error in the AOD retrievals. The uncertainty in aerosol concentrations, burdens, and AOD attributed to different assumptions for the wet scavenging of aerosols entrained above convective cloud bases in a global model motivates the ongoing need to better understand and model the activation and impaction processes that aerosols undergo after entrainment into convective updrafts.

Lowbush blueberries inhibit scavenger receptors CD36 and SR-A expression and attenuate foam cell formation in ApoE-deficient mice

USDA-ARS?s Scientific Manuscript database

Blueberries have recently been reported to reduce atherosclerotic lesion progression in apoE deficient (apoE-/-) mice. However, the underlying mechanisms are not fully understood. The objective of this study was to determine whether blueberries altered scavenger receptors expression and foam cell fo...

Nature or Nurture? Gender Roles Scavenger Hunt

ERIC Educational Resources Information Center

Whalen, Shannon; Maurer-Starks, Suanne

2008-01-01

The examination of gender roles and stereotypes and their subsequent impact on sexual behavior is a concept for discussion in many sex education courses in college and sex education units in high school. This analysis often leads to a discussion of the impact of nature vs. nurture on gender roles. The gender roles scavenger hunt is an interactive…

Occurrence of antibodies to Toxoplasma gondii in the scavenging black vultures (Coragyps atratus) from Brazil

USDA-ARS?s Scientific Manuscript database

This is the first report of Toxoplasma gondii infection in black vultures (Coragyps atratus) that are are obligate scavenging birds found throughout the American continent. Serum samples from 121 wild black vultures captured in urban areas of the city of São Paulo, SP, Brazil, were tested for the pr...

Dynamical properties of a prey-predator-scavenger model with quadratic harvesting

NASA Astrophysics Data System (ADS)

Gupta, R. P.; Chandra, Peeyush

2017-08-01

In this paper, we propose and analyze an extended model for the prey-predator-scavenger in presence of harvesting to study the effects of harvesting of predator as well as scavenger. The positivity, boundedness and persistence conditions are derived for the proposed model. The model undergoes a Hopf-bifurcation around the co-existing equilibrium point. It is also observed that the model is capable of exhibiting period doubling route to chaos. It is pointed out that a suitable amount of harvesting of predator can control the chaotic dynamics and make the system stable. An extensive numerical simulation is performed to validate the analytic findings. The associated control problem for the proposed model has been analyzed for optimal harvesting.

Effect of Organic Oxygen Scavenger on Performance of Pyrrole as Corrosion Inhibitor

NASA Astrophysics Data System (ADS)

Kassim, E. S. Mohd; Ibrahim, I. M.; Jai, J.; So’aib, M. S.; Zamanhuri, N. Ahmad; Husin, H.; Hashim, M. A.

2018-05-01

Abstract.The inhibitory effect of pyrrole in the presence of methyl ethyl ketoxime (MEKO) and erythorbic acid (EA) on the corrosion of carbon steel in static of condition 3.5 wt% NaCl solution were studied using Linear Polarization Resistance (LPR) method. Experimental results found that the inhibition effect of pyrrole increased with the increase of oxygen scavenger concentration.The inhibition efficiency was observed to be about 67% after addition of erythorbic acid (EA) into saline solution containing 100 ppm of pyrrole compared by adding MEKO which recorded about 59%. The addition of oxygen scavenger could reducing the corrosion rate of carbon steel by reacting with dissolved oxygen in the solution and thus further to protect metal surface.

The elevation effect on water-soluble polysaccharides and DPPH free radical scavenging activity of Ganoderma lucidum K

NASA Astrophysics Data System (ADS)

Darsih, C.; Apriyana, W.; Nur Hayati, S.; Taufika Rosyida, V.; Hernawan; Dewi Poeloengasih, C.

2017-02-01

Water soluble polysaccharide is one of the important phytochemical in Ganoderma lucidum K. Phytochemicals in the plants, microorganisms, and plants were affected by internal and external factors. The objective of the research was to evaluate the effect of elevation on the water-soluble polysaccharides and its DPPH radical scavenging activity. We found that the water-polysaccharides in mushroom from Godean (elevation <100 mamsl) (35.28 ± 0.31%) higher than Kaliurang (elevation 800 mamsl) (25.17 ± 1.85%). The DPPH free radical scavenging activity of Ganoderma lucidum K from Godean (IC50 11.5 ± 0.29 mg/mL) higher than Kaliurang (IC50 14.4 ± 0.27%).

Antioxidant activity of beta-blockers: an effect mediated by scavenging reactive oxygen and nitrogen species?

PubMed

Gomes, Ana; Costa, David; Lima, José L F C; Fernandes, Eduarda

2006-07-01

The therapeutic effects of beta-blockers are normally explained by their capacity to block the beta-adrenoceptors, however, some of the beneficial cardiovascular effects shown by this group of compounds have already been associated with the antioxidant properties that some of them seem to possess. The beta-blockers atenolol, labetalol, metoprolol, pindolol, propranolol, sotalol, timolol, and carvedilol were tested for their putative scavenging activity for ROS (O(2)(-), H(2)O(2), HO(.), HOCl, and ROO(.)) and RNS ((.)NO and ONOO(-)). Some of the studied compounds are effective ROS and/or RNS scavengers, these effects being possibly useful in preventing oxidative damage verified in hypertension as well as in other cardiovascular diseases that frequently emerge in association with oxidative stress.

FDSOI 28nm performances study for RF energy scavenging

NASA Astrophysics Data System (ADS)

Rochefeuille, E.; Alicalapa, F.; Douyère, A.; Vuong, T. P.

2018-03-01

This paper presents a study on an integrated technology: Fully-Depleted-Silicon-On-Insulator (FDSOI) at a 28nm node. FDSOI results are compared to another technology: Complementary-Metal-Oxide-Semiconductor (CMOS) 350nm. The aim of this work was to demonstrate the advantages of using FDSOI technology in RF energy scavenging applications. Characteristics of transistors are pointed out and results showed an improved 22%-output voltage gain for a series rectifier and a 13%-output voltage gain for a Dickson charge pump in FDSOI technology compared to CMOS, for an input voltage and power of 0.5 V and 0 dBm respectively. Those results allowed to prove that FDSOI 28nm is a better technology choice for energy scavenging and low-power applications.

Conductive Fabric-Based Stretchable Hybridized Nanogenerator for Scavenging Biomechanical Energy.

PubMed

Zhang, Kewei; Wang, Zhong Lin; Yang, Ya

2016-04-26

We demonstrate a stretchable hybridized nanogenerator based on a highly conductive fabric of glass fibers/silver nanowires/polydimethylsiloxane. Including a triboelectric nanogenerator and an electromagnetic generator, the hybridized nanogenerator can deliver output voltage/current signals from stretchable movements by both triboelectrification and electromagnetic induction, maximizing the efficiency of energy scavenging from one motion. Compared to the individual energy-harvesting units, the hybridized nanogenerator has a better charging performance, where a 47 μF capacitor can be charged to 2.8 V in only 16 s. The hybridized nanogenerator can be integrated with a bus grip for scavenging wasted biomechanical energy from human body movements to solve the power source issue of some electric devices in the pure electric bus.

Antioxidant Potential and DNA Damage Protection by the Slate Grey Saddle Mushroom, Helvella lacunosa (Ascomycetes), from Kashmir Himalaya (India).

PubMed

Shameem, Nowsheen; Kamili, Azra N; Ahmad, Mushtaq; Masoodi, F A; Parray, Javid A

2016-01-01

This study pertains to the radical scavenging potential of and DNA protection by Helvella lacunosa, an edible mushroom from Kashmir Himalaya (India). Different solvents, on the basis of their polarities, were used to extract all solvent-soluble bioactive compounds. Seven different antioxidant methods were also used to determine extensive radical scavenging activity. The mushroom ethanol extract and butanol extract showed effective scavenging activity of radicals at 95% and 89%, respectively. At 800 µg/mg, the ethanol extract was potent enough to protect DNA from degradation by hydroxyl radicals. It is evident from these findings that the presence of antioxidant substances signifies the use of H. lacunosa as food in the mountainous valleys of the Himalayan region.

[In vitro studies on antioxidant and antimicrobial activities of polysaccharide from Lycoris aurea].

PubMed

Ru, Qiao-Mei; Pei, Zhen-Ming; Zheng, Hai-Lei

2008-10-01

To study the preliminary antioxidant and antimicrobial activities of polysaccharide extracted from Lycoris aurea. The scavenging activities of the polysaccharide in vitro on superoxide radical (O2-*), hydroxyl radical (*OH), alkyl radical (R*) and hydrogen peroxide (H2O2) were investigated by modified chemical systems. Meanwhile, the antimicrobial activities were tested using paper-discagar diffusion method. In general, the antioxidant activities of the polysaccharide were lower compared with Vc. However, the scavenging effects to *OH and H2O2 were parallel to Vc. Meanwhile, polysaccharide from Lycoris aurea had strong antimicrobial activities against Micrococcus luteus, Bacillus pumilus and Staphylococcus aureus. The polysaccharide extracted from L. aurea can scavenge *OH and H2O2 effectively and inhibit Gram-positive bacterias.

Scavenging flow velocity in small two-strokes at high engine speed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ekenberg, M.; Johansson, B.

1995-12-31

2D-LDV-measurements were made on the flow from one transfer channel into the cylinder in a small two-stroke SI engine. The LDV measuring volume was located just outside the transfer port. The engine was a carburetted piston-ported crankcase compression chainsaw engine and it was run with wide open throttle at 9000 RPM. The muffler was removed to enable access into the cylinder. No additional seeding was used; the fuel and/or oil was not entirely vaporized as it entered the cylinder. Very high velocities ({approximately}275 m/s) were detected in the beginning of the scavenging phase. The horizontal velocity was, during the wholemore » scavenging phase, higher than the vertical.« less

Free radical scavenging actions of three Trifolium species in the protection of blood plasma antioxidant capacity in vitro.

PubMed

Kolodziejczyk-Czepas, Joanna; Nowak, Pawel; Moniuszko-Szajwaj, Barbara; Kowalska, Iwona; Stochmal, Anna

2015-01-01

Three clover [Trifolium L. (Leguminosae)] species were selected on the basis of data from traditional medicine, phytochemical profiles, and agricultural significance. The in vitro evaluations of free radical scavenging properties, ferric reducing abilities, and antioxidant effects of extracts from T. pratense L. (crude extract and phenolic fraction), T. pallidum L., and T. scabrum L. (phenolic fractions) were performed. Activities of the Trifolium extracts were determined at their final concentrations of 1.5-50 µg/ml. Free radical scavenging properties of methanol extract solutions were estimated by the reduction of DPPH(•) and ABTS(•) radicals. Measurements of the total antioxidant capacity (TAC) were carried out to assess the antioxidant activities of the extracts in human blood plasma under conditions of oxidative stress, induced by 200 μM peroxynitrite. The phenolic fraction of T. pratense displayed the strongest ABTS(•) and DPPH(•) radical scavenging effects (EC50 value of 21.69 and 12.27 µg/ml, respectively). The EC50 value for T. pallidum extract attained 29.77 and 30.06 µg/ml. The two remaining extracts were less potent scavengers (EC50 value higher than 50 µg/ml). Similar differences were obtained during evaluation of the ferric reducing abilities. Analysis of antioxidant properties of the extracts in blood plasma did not provide such evident differences in their actions, however, it indicated that the T. pratense phenolic fraction displayed the strongest effect. The examined Trifolium extracts partly protected blood plasma and enhanced its non-enzymatic antioxidant defense against harmful action of peroxynitrite in vitro.

Biological activity of clovers - free radical scavenging ability and antioxidant action of six Trifolium species.

PubMed

Kolodziejczyk-Czepas, Joanna; Nowak, Pawel; Kowalska, Iwona; Stochmal, Anna

2014-10-01

Clovers were chosen on the basis of traditional medicine recommendations, agricultural value, or available information on their promising chemical profiles. This study evaluates and compares free radical scavenging and antioxidant properties of six clover species: Trifolium alexandrinum L. (Leguminosae), Trifolium fragiferum L., Trifolium hybridum L., Trifolium incarnatum L., Trifolium resupinatum var. majus Boiss., and Trifolium resupinatum var. resupinatum L. Free radical scavenging activity of the extracts (1.5-50 µg/ml) was estimated by reduction of 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic) acid (ABTS(•)) radicals. The Trifolium extract effects on total antioxidant capacity of blood plasma were determined by the reduction of ABTS(•+) and DPPH(•) radicals, as well as with the use of the ferric reducing ability of plasma (FRAP) assay. The UPLC analysis of chemical profiles of the examined extracts showed the presence of three or four groups of phenolic substances, including phenolic acids, clovamides, isoflavones, and other flavonoids. The measurements of free radical scavenging and ferric reducing ability of the examined clover extracts revealed the strongest effect for T. alexandrinum. Furthermore, antioxidant activity assays in human plasma have shown protective effects of all extracts against peroxynitrite-induced reduction of total antioxidant capacity. Trifolium plants may be a rich source of bioactive substances with antioxidant properties. The examined extracts displayed free radical scavenging action and partly protected blood plasma against peroxynitrite-induced oxidative stress; however, the beneficial effects of T. alexandrinum and T. incarnatum seem to be slightly higher.

Inhibition effects of flavonoids on 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline formation and alkoxy radical scavenging capabilities of flavonoids in a model system.

PubMed

Shao, Zeping; Han, Zhonghui; Zhang, Jinhui; Zhang, Yan; Wang, Shuo

2018-06-01

Heterocyclic aromatic amines (HAAs) have been considered as carcinogenic and mutagenic chemicals generated during thermal processing of protein-rich foods that can be inhibited by some flavonoids. Free radical scavenging is a major characteristic of flavonoids. The half-maximal inhibitory concentration (IC 50 ) values of nine flavonoids were determined by evaluating their capacity to inhibit 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx) formation in a model system. The results of the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) test validated that MeIQx and 7,8-DiMeIQx formed via a free radical pathway. Electron spin resonance (ESR) spectroscopic analysis with spin trapping (α-(4-pyridyl N-oxide)-N-tert-butylnitrone (POBN) spin adduct, a N  = 15.2 G and a H  = 2.7 G) revealed that an alkoxy radical was the generated intermediate. The scavenging capacities of the nine flavonoids on alkoxy radicals were then evaluated based on the ESR spectra of the POBN spin adducts. The weak correlation between the alkoxy radical scavenging capacities and IC 50 of the flavonoids suggested that their inhibitory activity against MeIQx and 7,8-DiMeIQx formation operates by a more complex mechanism than simply scavenging alkoxy radicals. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Structural characteristics for superoxide anion radical scavenging and productive activities of green tea polyphenols including proanthocyanidin dimers.

PubMed

Sato, Masashi; Toyazaki, Hajime; Yoshioka, Yu; Yokoi, Nobutoshi; Yamasaki, Toru

2010-01-01

The purpose of this paper is to report structural characteristics for superoxide anion radical (O(2(-))) scavenging and productive activities of green tea polyphenols. (-)-Epicatechin 3-O-gallate (5), (-)-epigallocatechin (6), (-)-epigallocatechin 3-O-gallate (7), (+)-gallocatechin-(4alpha-->8')-epigallocatechin (8), and (-)-epigallocatechin-(2beta-->O-->7', 4beta-->8')-epicatechin 3'-O-gallate (9) were isolated from the tea plant Camellia sinensis L. (+)-Epigallocatechin-(2beta-->O-->7, 4beta-->8')-epicatechin (10) was prepared by hydrolyzing 9. The polyphenols, as well as commercially available pyrogallol (1), methyl gallate (2), (+)-catechin (3), (-)-epicatechin (4), and the flavonol myricetin (11), produced O(2(-)) in descending order 1, 6 asymptotically equal to11 asymptotically equal to8, 7, 10, 2 asymptotically equal to9, 5 asymptotically equal to4. In the polyphenols with the pyrogallol-type B-ring and/or galloyl group, electron-withdrawing substituents (carbonyl and ketal carbons) and/or intramolecular hydrogen bonding constituted structural characteristics against the autoxidation reaction. The O(2(-))-productive activity partially counteracted O(2(-))-scavenging activity. However, such structural characteristics appeared to enhance the scavenging activity, accordingly the polyphenols in effect served as O(2(-))-scavengers in descending order 9 asymptotically equal to7, 2, 11, 8, 10, 3 asymptotically equal to4. On the other hand, 6, having no such structural characteristic, acted as a O(2(-))-generator, as well as 1. Further assessments covering tannins (e.g., A-type proanthocyanidin dimer 9) are needed to identify which green tea polyphenols are the most desirable chemopreventive agents.

A case study of aerosol scavenging in a biomass burning plume over eastern Canada during the 2011 BORTAS field experiment

NASA Astrophysics Data System (ADS)

Franklin, J. E.; Drummond, J. R.; Griffin, D.; Pierce, J. R.; Waugh, D. L.; Palmer, P. I.; Parrington, M.; Lee, J. D.; Lewis, A. C.; Rickard, A. R.; Taylor, J. W.; Allan, J. D.; Coe, H.; Walker, K. A.; Chisholm, L.; Duck, T. J.; Hopper, J. T.; Blanchard, Y.; Gibson, M. D.; Curry, K. R.; Sakamoto, K. M.; Lesins, G.; Dan, L.; Kliever, J.; Saha, A.

2014-08-01

We present measurements of a long-range smoke transport event recorded on 20-21 July 2011 over Halifax, Nova Scotia, Canada, during the Quantifying the impact of BOReal forest fires on Tropospheric oxidants over the Atlantic using Aircraft and Satellites (BORTAS-B) campaign. Ground-based Fourier transform spectrometers and photometers detected air masses associated with large wildland fires burning in eastern Manitoba and western Ontario. We investigate a plume with high trace gas amounts but low amounts of particles that preceded and overlapped at the Halifax site with a second plume with high trace gas loadings and significant amounts of particulate material. We show that the first plume experienced a meteorological scavenging event, but the second plume had not been similarly scavenged. This points to the necessity to account carefully for the plume history when considering long-range transport since simultaneous or near-simultaneous times of arrival are not necessarily indicative of either similar trajectories or meteorological history. We investigate the origin of the scavenged plume, and the possibility of an aerosol wet deposition event occurring in the plume ~ 24 h prior to the measurements over Halifax. The region of lofting and scavenging is only monitored on an intermittent basis by the present observing network, and thus we must consider many different pieces of evidence in an effort to understand the early dynamics of the plume. Through this discussion we also demonstrate the value of having many simultaneous remote-sensing measurements in order to understand the physical and chemical behaviour of biomass burning plumes.

Parameterization of aerosol scavenging due to atmospheric ionization under varying relative humidity

NASA Astrophysics Data System (ADS)

Zhang, Liang; Tinsley, Brian A.

2017-05-01

Simulations and parameterizations of the modulation of aerosol scavenging by electric charges on particles and droplets for different relative humidities have been made for 3 μm radii droplets and a wide range of particle radii. For droplets and particles with opposite-sign charges, the attractive Coulomb force increases the collision rate coefficients above values due to other forces. With same-sign charges, the repulsive Coulomb force decreases the rate coefficients, and the short-range attractive image forces become important. The phoretic forces are attractive for relative humidity less than 100% and repulsive for relative humidity greater than 100% and have increasing overall effect for particle radii up to about 1 μm. There is an analytic solution for rate coefficients if only inverse square forces are present, but due to the presence of image forces, and for larger particles the intercept, weight, and the flow around the particle affecting the droplet trajectory, the simulated results usually depart far from the analytic solution. We give simple empirical parameterization formulas for some cases and more complex parameterizations for more exact fits to the simulated results. The results can be used in cloud models with growing droplets, as in updrafts, as well as with evaporating droplets in downdrafts. There is considered to be little scavenging of uncharged ice-forming nuclei in updrafts, but with charged ice-forming nuclei it is possible for scavenging in updrafts in cold clouds to produce contact ice nucleation. Scavenging in updrafts below the freezing level produces immersion nuclei that promote enhanced freezing as droplets rise above it.

Rapid scavenging of jellyfish carcasses reveals the importance of gelatinous material to deep-sea food webs.

PubMed

Sweetman, Andrew K; Smith, Craig R; Dale, Trine; Jones, Daniel O B

2014-12-07

Jellyfish blooms are common in many oceans, and anthropogenic changes appear to have increased their magnitude in some regions. Although mass falls of jellyfish carcasses have been observed recently at the deep seafloor, the dense necrophage aggregations and rapid consumption rates typical for vertebrate carrion have not been documented. This has led to a paradigm of limited energy transfer to higher trophic levels at jelly falls relative to vertebrate organic falls. We show from baited camera deployments in the Norwegian deep sea that dense aggregations of deep-sea scavengers (more than 1000 animals at peak densities) can rapidly form at jellyfish baits and consume entire jellyfish carcasses in 2.5 h. We also show that scavenging rates on jellyfish are not significantly different from fish carrion of similar mass, and reveal that scavenging communities typical for the NE Atlantic bathyal zone, including the Atlantic hagfish, galatheid crabs, decapod shrimp and lyssianasid amphipods, consume both types of carcasses. These rapid jellyfish carrion consumption rates suggest that the contribution of gelatinous material to organic fluxes may be seriously underestimated in some regions, because jelly falls may disappear much more rapidly than previously thought. Our results also demonstrate that the energy contained in gelatinous carrion can be efficiently incorporated into large numbers of deep-sea scavengers and food webs, lessening the expected impacts (e.g. smothering of the seafloor) of enhanced jellyfish production on deep-sea ecosystems and pelagic-benthic coupling. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Blood glutamate scavengers prolong the survival of rats and mice with brain-implanted gliomas.

PubMed

Ruban, Angela; Berkutzki, Tamara; Cooper, Itzik; Mohar, Boaz; Teichberg, Vivian I

2012-12-01

L-Glutamate (Glu) plays a crucial role in the growth of malignant gliomas. We have established the feasibility of accelerating a naturally occurring brain to-blood Glu efflux by decreasing blood Glu levels with intravenous oxaloacetate, the respective Glu co-substrate of the blood resident enzyme humane glutamate–oxaloacetate transaminase(hGOT). We wished to demonstrate that blood Glu scavenging provides neuroprotection in the case of glioma.We now describe the neuroprotective effects of blood Glu scavenging in a fatal condition such as brain-implanted C6 glioma in rats and brain-implanted human U87 MG glioma in nude mice. Rat (C-6) or human (U87) glioma cells were grafted stereotactically in the brain of rats or mice. After development of tumors, the animals were drinking oxaloacetate with or without injections of hGOT. In addition, mice were treated with combination treatment, which included drinking oxaloacetate with intracutaneous injections of hGOT and intraperitoneal injection of Temozolomide. Animals drinking oxaloacetate with or without injections of hGOT displayed a smaller tumor volume, reduced invasiveness and prolonged survival than control animals drinking saline. These effects were significantly enhanced by Temozolomide in mice, which increased survival by 237%. This is the first demonstration of blood Glu scavenging in brain cancer, and because of its safety, is likely to be of clinical significance for the future treatment of human gliomas. As we demonstrated, the blood glutamate scavenging treatment in combination with TMZ could be a good candidate or as an alternative treatment to the patients that do not respond to TMZ.

Case study of a solid-waste-scavenger community with respect to health and environment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kungskulniti, Nipapun.

1991-01-01

This study was an investigation of a solid waste scavenger community at the On-Nooch Dump Site in Bangkok, Thailand. The purpose was to identify the dimensions of the public health conditions of solid waste scavengers and their community. Cross-sectional field surveys and measurements were undertaken to characterize the distribution and magnitude of health-related problems and environmental conditions. Scavengers were found to be exposed to hazardous conditions due to the waste materials at the dump site. Cuts and punctures from sharp materials were the most common complaints among scavengers. Health symptoms like headache, diarrhea, respiratory illness, skin diseases and back painmore » were also reported. There was a high prevalence of childhood respiratory illness especially among those children of households where cigarette smoking was present. Children had poor nutritional status and were commonly infected by intestinal protozoa and helminths. An appreciable proportion of adult respondents was below the normal range for lung function performance. Seroprevalence of HBV infection was found to be high among male respondents in addition to six respondents that had possible HIV infections. The quality of the community water supply was low. Air pollution measurements showed acceptable ambient air levels except for particulate levels (TSP and RSP). Levels of indoor, outdoor, and personal exposure NO{sub 2} were found to be similar. Data for an inner-city project apartment community named Din-Dang were also collected for comparison. A priority rating index and recommendations for public health condition improvements were presented.« less

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.

Hydrogen scavengers

DOEpatents

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.

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.

A New Perspective on an Old Problem, Natural Attenuation of the Lead Scavengers EDB and DCA in Ground Water

EPA Science Inventory

Tetra-ethyl lead was widely used in leaded automobile gasoline from 1923 until 1987. To prevent lead deposits from fouling the engine, 1,2-dibromoethane (EDB) and 1,2-dichloroethane (1,2-DCA) were added to the gasoline to act as lead scavengers. If leaded gasoline is spilled to...

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

USDA-ARS?s Scientific Manuscript database

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...

Rare variant in scavenger receptor BI raises HDL cholesterol and increases risk of coronary heart disease

USDA-ARS?s Scientific Manuscript database

Scavenger receptor BI (SR-BI) is the major receptor for high-density lipoprotein (HDL) cholesterol (HDL-C). In humans, high amounts of HDL-C in plasma are associated with a lower risk of coronary heart disease (CHD). Mice that have depleted Scarb1 (SR-BI knockout mice) have markedly elevated HDL-C l...

75 FR 49375 - Airworthiness Directives; The Boeing Company Model 777-200LR and -300ER Series Airplanes Equipped...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-13

... scavenge tube on the turbine rear frame of the engine for damage, and replacement if necessary. This AD... scavenge tube on the turbine rear frame of the engine and the bolt on the aft cowl insulation blanket of...: Federal eRulemaking Portal: Go to http://www.regulations.gov . Follow the instructions for submitting...

RESEARCH NOTE: INTERFERENCES DUE TO OZONE-SCAVENGING REAGENTS IN THE GC-ECD DETERMINATION OF ALDEHYDES AND KETONS AS THE O-(2,3,4,5,6-PENTAFLUOROBENZYL)OXIMES

EPA Science Inventory

Six potential ozone-scavenging reagents were tested for possible interference in the GC-ECD determination of aldehydes and ketones after derivatization with O-(2,3,4,5,6-pentafluorobenzyl)oxylamine (PFBOA). All six-nitrite, cynaide, methanoate (formate), indigo-55'-disulfonate d...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Taehoon; Jung, Yong Chan; Seong, Sejong

The metal gate electrodes of Ni, W, and Pt have been investigated for their scavenging effect: a reduction of the GeO{sub x} interfacial layer (IL) between HfO{sub 2} dielectric and Ge substrate in metal/HfO{sub 2}/GeO{sub x}/Ge capacitors. All the capacitors were fabricated using the same process except for the material used in the metal electrodes. Capacitance-voltage measurements, scanning transmission electron microscopy, and electron energy loss spectroscopy were conducted to confirm the scavenging of GeO{sub x} IL. Interestingly, these metals are observed to remotely scavenge the interfacial layer, reducing its thickness in the order of Ni, W, and then Pt. Themore » capacitance equivalent thickness of these capacitors with Ni, W, and Pt electrodes are evaluated to be 2.7 nm, 3.0 nm, and 3.5 nm, and each final remnant physical thickness of GeO{sub x} IL layer is 1.1 nm 1.4 nm, and 1.9 nm, respectively. It is suggested that the scavenging effect induced by the metal electrodes is related to the concentration of oxygen vacancies generated by oxidation reaction at the metal/HfO{sub 2} interface.« less

Anti-inflammatory, cyclooxygenase (COX)-2, COX-1 inhibitory, and free radical scavenging effects of Rumex nepalensis.

PubMed

Gautam, Raju; Karkhile, Kailas V; Bhutani, Kamlesh K; Jachak, Sanjay M

2010-10-01

Evaluation of the topical anti-inflammatory activity of chloroform and ethyl acetate extracts of RUMEX NEPALENSIS roots in a TPA-induced acute inflammation mouse model demonstrated a significant reduction in ear edema. The extracts were further tested on purified enzymes for COX-1 and COX-2 inhibition to elucidate their mechanism of action, and a strong inhibition was observed. Six anthraquinones and two naphthalene derivatives were isolated from the ethyl acetate extract. Among the isolated compounds, emodin was found to be a potent inhibitor with slight selectivity towards COX-2, and nepodin exhibited selectivity towards COX-1. Emodin, endocrocin, and nepodin also exhibited significant topical anti-inflammatory activity in mice. Interestingly, nepodin showed better radical scavenging activity than trolox and ascorbic acid against DPPH and ABTS radicals. The strong radical scavenging activity of chloroform and ethyl acetate extracts could be explained by the presence of nepodin as well as by the high phenolic content of the ethyl acetate extract. Thus, the anti-inflammatory effect of R. NEPALENSIS roots was assumed to be mediated through COX inhibition by anthraquinones and naphthalene derivatives and through the radical scavenging activities of naphthalene derivatives. © Georg Thieme Verlag KG Stuttgart · New York.

The efficacy of edaravone (radicut), a free radical scavenger, for cardiovascular disease.

PubMed

Kikuchi, Kiyoshi; Tancharoen, Salunya; Takeshige, Nobuyuki; Yoshitomi, Munetake; Morioka, Motohiro; Murai, Yoshinaka; Tanaka, Eiichiro

2013-07-04

Edaravone was originally developed as a potent free radical scavenger, and has been widely used to treat acute ischemic stroke in Japan since 2001. Free radicals play an important role in the pathogenesis of a variety of diseases, such as cardiovascular diseases and stroke. Therefore, free radicals may be targets for therapeutic intervention in these diseases. Edaravone shows protective effects on ischemic insults and inflammation in the heart, vessel, and brain in experimental studies. As well as scavenging free radicals, edaravone has anti-apoptotic, anti-necrotic, and anti-cytokine effects in cardiovascular diseases and stroke. Edaravone has preventive effects on myocardial injury following ischemia and reperfusion in patients with acute myocardial infarction. Edaravone may represent a new therapeutic intervention for endothelial dysfunction in the setting of atherosclerosis, heart failure, diabetes, or hypertension, because these diseases result from oxidative stress and/or cytokine-induced apoptosis. This review evaluates the potential of edaravone for treatment of cardiovascular disease, and covers clinical and experimental studies conducted between 1984 and 2013. We propose that edaravone, which scavenges free radicals, may offer a novel option for treatment of cardiovascular diseases. However, additional clinical studies are necessary to verify the efficacy of edaravone.

Edaravone, a potent free radical scavenger, reacts with peroxynitrite to produce predominantly 4-NO-edaravone.

PubMed

Fujisawa, Akio; Yamamoto, Yorihiro

2016-05-01

3-Methyl-1-phenyl-2-pyrazolin-5-one (edaravone) is used in clinical treatment of acute brain infarction to rescue the penumbra, based on its ability to prevent lipid peroxidation by scavenging lipid peroxyl radicals. Here, we show that edaravone also reacts with peroxynitrite to yield 4-NO-edaravone as the major product and 4-NO2-edaravone as a minor product. We observed little formation of 3-methyl-1-phenyl-2-pyrazolin-4,5-dione (4-oxoedaravone) and its hydrate, 2-oxo-3-(phenylhydrazono)butanoic acid, which are the major free radical-induced oxidation products of edaravone, suggesting that free radicals are not involved in the reaction with peroxynitrite. The reaction of peroxynitrite with edaravone is approximately 30-fold greater than with uric acid, a physiological peroxynitrite scavenger (reaction rate k = 1.5 × 10 (4)  M(-1) s(-1) vs. 480 M(-1) s(-1)). These results suggest that edaravone functions therapeutically as a scavenger of peroxynitrite as well as lipid peroxyl radicals, which is consistent with a report that edaravone treatment reduced levels of 3-nitrotyrosine in the cerebrospinal fluid of patients with amyotrophic lateral sclerosis.

The Efficacy of Edaravone (Radicut), a Free Radical Scavenger, for Cardiovascular Disease

PubMed Central

Kikuchi, Kiyoshi; Tancharoen, Salunya; Takeshige, Nobuyuki; Yoshitomi, Munetake; Morioka, Motohiro; Murai, Yoshinaka; Tanaka, Eiichiro

2013-01-01

Edaravone was originally developed as a potent free radical scavenger, and has been widely used to treat acute ischemic stroke in Japan since 2001. Free radicals play an important role in the pathogenesis of a variety of diseases, such as cardiovascular diseases and stroke. Therefore, free radicals may be targets for therapeutic intervention in these diseases. Edaravone shows protective effects on ischemic insults and inflammation in the heart, vessel, and brain in experimental studies. As well as scavenging free radicals, edaravone has anti-apoptotic, anti-necrotic, and anti-cytokine effects in cardiovascular diseases and stroke. Edaravone has preventive effects on myocardial injury following ischemia and reperfusion in patients with acute myocardial infarction. Edaravone may represent a new therapeutic intervention for endothelial dysfunction in the setting of atherosclerosis, heart failure, diabetes, or hypertension, because these diseases result from oxidative stress and/or cytokine-induced apoptosis. This review evaluates the potential of edaravone for treatment of cardiovascular disease, and covers clinical and experimental studies conducted between 1984 and 2013. We propose that edaravone, which scavenges free radicals, may offer a novel option for treatment of cardiovascular diseases. However, additional clinical studies are necessary to verify the efficacy of edaravone. PMID:23880849

Computational Studies of Free Radical-Scavenging Properties of Phenolic Compounds

PubMed Central

Alov, Petko; Tsakovska, Ivanka; Pajeva, Ilza

2015-01-01

For more than half a century free radical-induced alterations at cellular and organ levels have been investigated as a probable underlying mechanism of a number of adverse health conditions. Consequently, significant research efforts have been spent for discovering more effective and potent antioxidants / free radical scavengers for treatment of these adverse conditions. Being by far the most used antioxidants among natural and synthetic compounds, mono- and polyphenols have been the focus of both experimental and computational research on mechanisms of free radical scavenging. Quantum chemical studies have provided a significant amount of data on mechanisms of reactions between phenolic compounds and free radicals outlining a number of properties with a key role for the radical scavenging activity and capacity of phenolics. The obtained quantum chemical parameters together with other molecular descriptors have been used in quantitative structure-activity relationship (QSAR) analyses for the design of new more effective phenolic antioxidants and for identification of the most useful natural antioxidant phenolics. This review aims at presenting the state of the art in quantum chemical and QSAR studies of phenolic antioxidants and at analysing the trends observed in the field in the last decade. PMID:25547098

BPIC: A novel anti-tumor lead capable of inhibiting inflammation and scavenging free radicals.

PubMed

Li, Shan; Wang, Yuji; Zhao, Ming; Wu, Jianhui; Peng, Shiqi

2015-03-01

Inflammation has a critical role in the tumor progression, free radical damage can worse the status of patients in cancer condition. The anti-cancer agents capable of inhibiting inflammation and scavenging free radicals attract a lot of our interest. Aimed at the discovery of such anti-tumor agent, a novel intercalator, benzyl 1-[4-hydroxy-3-(methoxycarbonyl)-phenyl-9H-pyrido[3,4-b]indole-3-carboxylate (BPIC) was presented. The docking investigation of BPIC and doxorubicin towards the DNA (PDB ID: 1NAB) gave equal score and similar feature. The anti-proliferation assay of 8 cancer cells identified S180 cells had equal sensitivity to BPIC and doxorubicin. The anti-tumor assay defined the efficacy of BPIC been 2 folds higher than that of doxorubicin. At 1μmol/kg of dose BPIC effectively inhibited xylene-induced ear edema and decreased the plasma TNF-α and IL-8 of the mice. BPIC scavenged ∙OH, ∙O2(-) and NO free radicals in a concentration dependent manner and NO free radicals had the highest sensitivity. BPIC could be a novel anti-tumor lead capable of simultaneously inhibiting inflammation and scavenging free radicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Study of scavenging activity of sorghum pigment to hydroxyl free radicals by fluorimetry].

PubMed

Zhang, Hai-rong; Wang, Wen-yan

2007-03-01

A natural product, sorghum pigment, consists of a number of important flavonoid derivatives, occurrs on the seed capsules or in the stems of many sorghums, and is widely applied in different fields of food, cosmetic and dyeing industries, It is important for scavenging hydroxyl free radicals and protection of human healthiness. Scavenging capacities of hydroxyl free radicals with sodium nitrite, quercetin and sorghum pigment were comparatively researched by fluorimetry, and the model of hydroxyl free radicals produced is based on the reaction of Cu2+ -catalyzed oxidation of ascorbic acid in the presence of hydrogen peroxide. The hydroxyl radicals react with benzoic acid, forming a fluorescent product, and the fluorescence intensity was determined by the concentration of hydroxybenzoic acid. The experimental results show that the sodium nitrite, quercetin and sorghum pigment have a quantity-effect relationship for scavenging hydroxyl free radicals, and sodium nitrite and quercetin in comparison with sorghum pigment have high antioxidant capacity. Finally, the quenching mechanisms were explored with sodium nitrite, sorghum pigment, and quercetin respectively. The sorghum pigment and sodium nitrite feature a dynamic quenching processes, while quercetin shows a static quenching processes. A reference method was provided for reasonable exploitation and utilization of sorghum pigment.

Traditional Uighur Medicine Karapxa decoction, inhibits liver xanthine oxidase and reduces serum uric acid concentrations in hyperuricemic mice and scavenges free radicals in vitro.

PubMed

Amat, Nurmuhammat; Umar, Anwar; Hoxur, Parida; Anaydulla, Mihrigul; Imam, Guzalnur; Aziz, Ranagul; Upur, Halmurat; Kijjoa, Anake; Moore, Nicholas

2015-04-25

Karapxa decoction (KD) is a Traditional Uighur Medicine used for hepatitis, cholecystitis, gastralgia, oedema, gout and arthralgia. Because of its purported effect in gout, its effects were tested in hyperuricemic mice models induced by yeast extract paste or potassium oxonate, as well as its capacity to scavenge free radicals in vitro. Hyperuricemia was induced in mice by yeast extract paste or potassium oxonate. KD was given orally for 14 days at 200, 400 and 800 mg/kg/day, with Allopurinol 10 mg/kg/day as positive control. Serum uric acid (UA), and liver xanthine oxidase activity (XO) were measured. Scavenging activity of KD on 1, 1-diphenyl-2-picrylhydrazyl radicals (DPP•), nitric oxide (•NO), superoxide (O2•-), efficiency against lipid peroxidation, and XO inhibition were determined in vitro. KD inhibited liver XO activity and reduced serum uric acid in hyperuricemic mice. KD also showed noticeable antioxidant activity, scavenging free radicals (DPP•, •NO and O2•-). It was effective against lipid peroxidation and inhibited XO in vitro. This study supports the traditional use of Karapxa decoction to treat hyperuricemia and gout.

Pueraria thunbergiana inhibits cisplatin-induced damage of HEI-OC1 auditory cells through scavenging free radicals.

PubMed

Yu, Hyeon-Hee; Jung, Su-Young; Shin, Mee-Kyung; Park, Raekil; So, Hong-Seob; You, Yong-Ouk

2010-06-01

The radix of Pueraria thunbergiana (P. thunbergiana) is traditionally prescribed to attenuate the clinical manifestation of inner ear dysfunction and various clinical situations including fevers, gastrointestinal disorders, skin problems, migraine headaches, lowering cholesterol, and treating chronic alcoholism in oriental medicine. In the present study, we examined the protective effect of ethanol extract of the radix of P. thunbergiana (RPT) on cisplatin-induced damage of HEI-OC1 auditory hair cells. When the cells were cultured in the medium containing 5-100 microg/mL of RPT, RPT showed protective effect against the cisplatin-induced HEI-OC1 cell damage. We also measured the effects of RPT on lipid peroxidation of cisplatin-treated cells as well as scavenging activities against superoxide radical, hydroxyl radical, hydrogen peroxide, and DPPH radical. RPT reduced cisplatin-induced lipid peroxidation in a dose-dependent manner. Furthermore, RPT showed strong scavenging activity against superoxide radical, hydroxyl radical, hydrogen peroxide, and DPPH radical. These results indicate that RPT protects cisplatin-induced HEI-OC1 cell damage through inhibition of lipid peroxidation and scavenging activities of free radials. (c) 2009 John Wiley & Sons, Ltd.

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.

Phenolic acid composition and antioxidant properties of Malaysian honeys.

PubMed

Khalil, M I; Alam, N; Moniruzzaman, M; Sulaiman, S A; Gan, S H

2011-08-01

The phenolic acid and flavonoid contents of Malaysian Tualang, Gelam, and Borneo tropical honeys were compared to those of Manuka honey. Ferric reducing/antioxidant power assay (FRAP) and the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical-scavenging activities were also quantified. All honey extracts exhibited high phenolic contents (15.21 ± 0.51- 42.23 ± 0.64 mg/kg), flavonoid contents (11.52 ± 0.27- 25.31 ± 0.37 mg/kg), FRAP values (892.15 ± 4.97- 363.38 ± 10.57 μM Fe[II]/kg), and high IC₅₀ of DPPH radical-scavenging activities (5.24 ± 0.40- 17.51 ± 0.51 mg/mL). Total of 6 phenolic acids (gallic, syringic, benzoic, trans-cinnamic, p-coumaric, and caffeic acids) and 5 flavonoids (catechin, kaempferol, naringenin, luteolin, and apigenin) were identified. Among the Malaysian honey samples, Tualang honey had the highest contents of phenolics, and flavonoids, and DPPH radical-scavenging activities. We conclude that among Malaysian honey samples, Tualang honey is the richest in phenolic acids, and flavonoid compounds, which have strong free radical-scavenging activities. © 2011 Institute of Food Technologists®

Comparison of taurine, GABA, Glu, and Asp as scavengers of malondialdehyde in vitro and in vivo

NASA Astrophysics Data System (ADS)

Deng, Yan; Wang, Wei; Yu, Pingfeng; Xi, Zhijiang; Xu, Lijian; Li, Xiaolong; He, Nongyue

2013-04-01

The purpose of this study is to determine if amino acid neurotransmitters such as gamma-aminobutyric acid (GABA), taurine, glutamate (Glu), and aspartate (Asp) can scavenge activated carbonyl toxicants. In vitro, direct reaction between malondialdehyde (MDA) and amino acids was researched using different analytical methods. The results indicated that scavenging activated carbonyl function of taurine and GABA is very strong and that of Glu and Asp is very weak in pathophysiological situations. The results provided perspective into the reaction mechanism of taurine and GABA as targets of activated carbonyl such as MDA in protecting nerve terminals. In vivo, we studied the effect of taurine and GABA as antioxidants by detecting MDA concentration and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities. It was shown that MDA concentration was decreased significantly, and the activities of SOD and GSH-Px were increased significantly in the cerebral cortex and hippocampus of acute epileptic state rats, after the administration of taurine and GABA. The results indicated that the peripherally administered taurine and GABA can scavenge free radicals and protect the tissue against activated carbonyl in vivo and in vitro.

An ethanol extract derived from Bonnemaisonia hamifera scavenges ultraviolet B (UVB) radiation-induced reactive oxygen species and attenuates UVB-induced cell damage in human keratinocytes.

PubMed

Piao, Mei Jing; Hyun, Yu Jae; Cho, Suk Ju; Kang, Hee Kyoung; Yoo, Eun Sook; Koh, Young Sang; Lee, Nam Ho; Ko, Mi Hee; Hyun, Jin Won

2012-12-14

The present study investigated the photoprotective properties of an ethanol extract derived from the red alga Bonnemaisonia hamifera against ultraviolet B (UVB)-induced cell damage in human HaCaT keratinocytes. The Bonnemaisonia hamifera ethanol extract (BHE) scavenged the superoxide anion generated by the xanthine/xanthine oxidase system and the hydroxyl radical generated by the Fenton reaction (FeSO₄ + H₂O₂), both of which were detected by using electron spin resonance spectrometry. In addition, BHE exhibited scavenging activity against the 1,1-diphenyl-2-picrylhydrazyl radical and intracellular reactive oxygen species (ROS) that were induced by either hydrogen peroxide or UVB radiation. BHE reduced UVB-induced apoptosis, as shown by decreased apoptotic body formation and DNA fragmentation. BHE also attenuated DNA damage and the elevated levels of 8-isoprostane and protein carbonyls resulting from UVB-mediated oxidative stress. Furthermore, BHE absorbed electromagnetic radiation in the UVB range (280-320 nm). These results suggest that BHE protects human HaCaT keratinocytes against UVB-induced oxidative damage by scavenging ROS and absorbing UVB photons, thereby reducing injury to cellular components.

Shape similarities and differences in the skulls of scavenging raptors.

PubMed

Guangdi, S I; Dong, Yiyi; Ma, Yujun; Zhang, Zihui

2015-04-01

Feeding adaptations are a conspicuous feature of avian evolution. Bill and cranial shape as well as the jaw muscles are closely related to diet choice and feeding behaviors. Diurnal raptors of Falconiformes exhibit a wide range of foraging behaviors and prey preferences, and are assigned to seven dietary groups in this study. Skulls of 156 species are compared from the dorsal, lateral and ventral views, by using geometric morphometric techniques with those landmarks capturing as much information as possible on the overall shape of cranium, bill, orbits, nostrils and attachment area for different jaw muscles. The morphometric data showed that the skull shape of scavengers differ significantly from other raptors, primarily because of different feeding adaptations. As a result of convergent evolution, different scavengers share generalized common morphology, possessing relatively slender and lower skulls, longer bills, smaller and more sideward orbits, and more caudally positioned quadrates. Significant phylogenetic signals suggested that phylogeny also played important role in shape variation within scavengers. New World vultures can be distinguished by their large nostrils, narrow crania and small orbits; Caracaras typically show large palatines, crania and orbits, as well as short, deep and sharp bill.

Comparison of Antioxidant Activities of Melanin Fractions from Chestnut Shell.

PubMed

Yao, Zeng-Yu; Qi, Jian-Hua

2016-04-22

Chestnut shell melanin can be used as a colorant and antioxidant, and fractionated into three fractions (Fr. 1, Fr. 2, and Fr. 3) with different physicochemical properties. Antioxidant activities of the fractions were comparatively evaluated for the first time. The fractions exhibited different antioxidative potential in different evaluation systems. Fr. 1, which is only soluble in alkaline water, had the strongest peroxidation inhibition and superoxide anion scavenging activity; Fr. 2, which is soluble in alkaline water and hydrophilic organic solvents but insoluble in neutral and acidic water, had the greatest power to chelate ferrous ions; and Fr. 3, which is soluble both in hydrophilic organic solvents and in water at any pH conditions, had the greatest hydroxyl (·OH) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH·) radicals scavenging abilities, reducing power, and phenolic content. The pigment fractions were superior to butylated hydroxytolune (BHT) in ·OH and DPPH· scavenging and to ethylene diamine tetraacetic acid (EDTA) in the Fe(2+)-chelation. They were inferior to BHT in peroxidation inhibition and O₂·(-) scavenging and reducing power. However, BHT is a synthetic antioxidant and cannot play the colorant role. The melanin fractions might be used as effective biological antioxidant colorants.

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

Water fraction of edible medicinal fern Stenochlaena palustris is a potent α-glucosidase inhibitor with concurrent antioxidant activity.

PubMed

Chai, Tsun-Thai; Kwek, Meng-Tee; Ong, Hean-Chooi; Wong, Fai-Chu

2015-11-01

This study aimed to isolate a potent antiglucosidase and antioxidant fraction from Stenochlaena palustris. Extraction was performed with hexane, chloroform, ethyl acetate, methanol, and water. Antiglucosidase, 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging and ferric reducing antioxidant power (FRAP) assays found methanol extract (ME) to be the most active. Water fraction (WF) of ME was a stronger α-glucosidase inhibitor (EC50 2.9 μg/mL) than quercetin, with weak antiamylase activity. WF was a competitive α-glucosidase inhibitor. DPPH scavenging activity of WF (EC50 7.7 μg/mL) was weaker than quercetin. WF (EC50 364 μg/mL) was a stronger hydrogen peroxide scavenger than gallic acid (EC50 838 μg/mL) and was equally strong as quercetin in scavenging superoxide. WF possessed moderate copper chelating activity. WF was enriched in total phenolics (TP) and hydroxycinnamic acids (THC). TP correlated with antioxidant activity (R(2) > 0.76). Only THC correlated with antiglucosidase activity (R(2) = 0.86). Overall, WF demonstrated concurrent, potent antiglucosidase and antioxidant activities. Copyright © 2015 Elsevier Ltd. All rights reserved.

Involvement of specific macrophage-lineage cells surrounding arterioles in barrier and scavenger function in brain cortex.

PubMed Central

Mato, M; Ookawara, S; Sakamoto, A; Aikawa, E; Ogawa, T; Mitsuhashi, U; Masuzawa, T; Suzuki, H; Honda, M; Yazaki, Y; Watanabe, E; Luoma, J; Yla-Herttuala, S; Fraser, I; Gordon, S; Kodama, T

1996-01-01

The transport of solutes between blood and brain is regulated by a specific barrier. Capillary endothelial cells of brain are known to mediate barrier function and facilitate transport. Here we report that specific cells surrounding arterioles, known as Mato's fluorescent granular perithelial (FGP) cells or perivascular microglial cells, contribute to the barrier function. Immunohistochemical and in situ hybridization studies indicate that, in normal brain cortex, type I and type II macrophage scavenger receptors are expressed only in FGP/perivascular microglial cells, and surface markers of macrophage lineage are also detected on them. These cells mediate the uptake of macromolecules, including modified low density lipoprotein, horseradish peroxidase, and ferritin injected either into the blood or into the cerebral ventricles. Accumulation of scavenged materials with aging or after the administration of a high-fat diet results in the formation of honeycomb-like foam cells and the narrowing of the lumen of arterioles in the brain cortex. These results indicate involvement of FGP/perivascular microglial cells in the barrier and scavenger functions in the central nervous system. Images Fig. 1 Fig. 2 Fig. 4 Fig. 5 Fig. 6 PMID:8622926

Protection of cadmium chloride induced DNA damage by Lamiaceae plants

PubMed Central

Thirugnanasampandan, Ramaraj; Jayakumar, Rajarajeswaran

2011-01-01

Objective To analyze the total phenolic content, DNA protecting and radical scavenging activity of ethanolic leaf extracts of three Lamiaceae plants, i.e. Anisomelos malabarica (A. malabarica), Leucas aspera (L. aspera) and Ocimum basilicum (O. basilicum). Methods The total polyphenols and flavonoids were analyzed in the ethanolic leaf extracts of the lamiaceae plants. To determine the DNA protecting activity, various concentrations of the plant extracts were prepared and treated on cultured HepG2 human lung cancer cells. The pretreated cells were exposed to H2O2 to induce DNA damage through oxidative stress. Comet assay was done and the tail length of individual comets was measured. Nitric oxide and superoxide anion scavenging activities of lamiaceae plants were analyzed. Results Among the three plant extracts, the highest amount of total phenolic content was found in O. basilicum (189.33 mg/g), whereas A. malabarica showed high levels of flavonoids (10.66 mg/g). O. basilicum also showed high levels of DNA protecting (85%) and radical scavenging activity. Conclusions The results of this study shows that bioactive phenols present in lamiaceae plants may prevent carcinogenesis through scavenging free radicals and inhibiting DNA damage. PMID:23569799

Estimating Carcass Persistence and Scavenging Bias in a Human Influenced Landscape

USGS Publications Warehouse

Flint, Paul L.; Lance, Ellen W.; Sowl, Kristine M.; Donnelly, Tyrone F.

2010-01-01

We examined variation in persistence rates of waterfowl carcasses placed along a series of transects in tundra habitats in western Alaska. This study was designed to assess the effects of existing tower structures and was replicated with separate trials in winter, summer and fall as both the resident avian population and the suite of potential scavengers varied seasonally. Carcass persistence rates were uniformly low, with <50% of carcasses persisting for more than a day on average. Persistence rate varied by carcass age, carcass size, among transects and was lowest in the fall and highest in the summer. We found little support for models where persistence varied in relation to the presence of tower structures. We interpret this as evidence that scavengers were not habituated to searching for carcasses near these structures. Our data demonstrate that only a small fraction of bird carcasses are likely to persist between searches, and if not appropriately accounted for, scavenging bias could significantly influence bird mortality estimates. The variation that we documented suggests that persistence rates should not be extrapolated among tower locations or across time periods as the variation in carcass persistence will result in biased estimates of total bird strike mortality.

Cobalt(II) ion as a promoter of hydroxyl radical and possible 'crypto-hydroxyl' radical formation under physiological conditions. Differential effects of hydroxyl radical scavengers.

PubMed

Moorhouse, C P; Halliwell, B; Grootveld, M; Gutteridge, J M

1985-12-13

Co(II) ions react with hydrogen peroxide under physiological conditions to form a 'reactive species' that can hydroxylate aromatic compounds (phenol and salicylate) and degrade deoxyribose to thiobarbituric-acid-reactive material. Catalase decreases the formation of this species but superoxide dismutase or low concentrations of ascorbic acid have little effect. EDTA, present in excess over the Co(II), can accelerate deoxyribose degradation and aromatic hydroxylation. In the presence of EDTA, deoxyribose degradation by the reactive species is inhibited competitively by scavengers of the hydroxyl radical (.OH), their effectiveness being related to their second-order rate constants for reaction with .OH. In the absence of EDTA the scavengers inhibit only at much higher concentrations and their order of effectiveness is changed. It is suggested that, in the presence of EDTA, hydroxyl radical is formed 'in free solution' and attacks deoxyribose or an aromatic molecule. In the absence of EDTA, .OH radical is formed in a 'site-specific' manner and is difficult to intercept by .OH scavengers. The relationship of these results to the proposed 'crypto .OH' radical is discussed.

Extracts and Constituents of Rubus chingii with 1,1-Diphenyl-2-picrylhydrazyl (DPPH) Free Radical Scavenging Activity

PubMed Central

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 IC50 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 IC50 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

Scavenging nucleic acid debris to combat autoimmunity and infectious disease

NASA Astrophysics Data System (ADS)

Holl, Eda K.; Shumansky, Kara L.; Borst, Luke B.; Burnette, Angela D.; Sample, Christopher J.; Ramsburg, Elizabeth A.; Sullenger, Bruce A.

2016-08-01

Nucleic acid-containing debris released from dead and dying cells can be recognized as damage-associated molecular patterns (DAMPs) or pattern-associated molecular patterns (PAMPs) by the innate immune system. Inappropriate activation of the innate immune response can engender pathological inflammation and autoimmune disease. To combat such diseases, major efforts have been made to therapeutically target the pattern recognition receptors (PRRs) such as the Toll-like receptors (TLRs) that recognize such DAMPs and PAMPs, or the downstream effector molecules they engender, to limit inflammation. Unfortunately, such strategies can limit the ability of the immune system to combat infection. Previously, we demonstrated that nucleic acid-binding polymers can act as molecular scavengers and limit the ability of artificial nucleic acid ligands to activate PRRs. Herein, we demonstrate that nucleic acid scavengers (NASs) can limit pathological inflammation and nucleic acid-associated autoimmunity in lupus-prone mice. Moreover, we observe that such NASs do not limit an animal’s ability to combat viral infection, but rather their administration improves survival when animals are challenged with lethal doses of influenza. These results indicate that molecules that scavenge extracellular nucleic acid debris represent potentially safer agents to control pathological inflammation associated with a wide range of autoimmune and infectious diseases.

Lightweight two-stroke cycle aircraft diesel engine technology enablement program, volume 1

NASA Technical Reports Server (NTRS)

Freen, P. D.; Berenyi, S. G.; Brouwers, A. P.; Moynihan, M. E.

1985-01-01

An experimental Single Cylinder Test Engine Program is conducted to confirm the analytically projected performance of a two-stroke cycle diesel engine for aircraft applications. The test engine delivered 78kW indicated power from 1007cc displacement, operating at 3500 RPM on Schnuerle loop scavenged two-stroke cycle. Testing confirms the ability of a proposed 4-cylinder version of such an engine to reach the target power at altitude, in a highly turbocharged configuration. The experimental program defines all necessary parameters to permit design of a multicylinder engine for eventual flight applications; including injection system requirement, turbocharging, heat rejection, breathing, scavenging, and structural requirements. The multicylinder engine concept is configured to operate with an augmented turbocharger, but with no primary scavenge blower. The test program is oriented to provide a balanced turbocharger compressor to turbine power balance without an auxiliary scavenging system. Engine cylinder heat rejection to the ambient air has been significantly reduced and the minimum overall turbocharger efficiency required is within the range of commercially available turbochargers. Analytical studies and finite element modeling is made of insulated configurations of the engines - including both ceramic and metallic versions. A second generation test engine is designed based on current test results.

Free radical scavengers and antioxidants from Lemongrass (Cymbopogon citratus (DC.) Stapf.).

PubMed

Cheel, José; Theoduloz, Cristina; Rodríguez, Jaime; Schmeda-Hirschmann, Guillermo

2005-04-06

Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 microg/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 microg/mL and were inactive toward the XO at 50 microg/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2' '-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC(50): 9-10 microM) and inhibited lipid peroxidation by 70% at 100 microg/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC(50) values of 68.8 and 54.2 microM, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 microg/mL.

Protective effects of polysaccharides from Psidium guajava leaves against oxidative stresses.

PubMed

Kim, Seo-Young; Kim, Eun-A; Kim, Young-Sun; Yu, Seok-Kyu; Choi, Changyong; Lee, Jung-Suk; Kim, Yong-Tae; Nah, Jae-Woon; Jeon, You-Jin

2016-10-01

The aim of this study was to analyze antioxidant properties of a polysaccharide isolated from Psidium guajava leaves (PS-PGL) in vitro including its radical scavenging activities and protective effects against damage to cells as well as in vivo in zebrafish. The water extract of P. guajava leaves (WE-PGL) and PS-PGL showed strong radical scavenging effects in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, and alkyl radical. Compared to WE-PGL, PS-PGL enhanced all scavenging activities and in particular strongly scavenged the hydroxyl radical (50% inhibitory concentration [IC50], 0.02mg/mL). In addition, PS-PGL exerted a protective effect against hydrogen peroxide-induced oxidative stress and against toxicity to Vero cells. Furthermore, in vivo experiments using zebrafish embryos indicated that treatment with hydrogen peroxide decreased the survival rate and heart-beating rate of zebrafish embryos, whereas these problems were reduced by PS-PGL treatment. Moreover, PS-PGL inhibited hydrogen peroxide-induced reactive oxygen species (ROS) production, lipid peroxidation, and cell death. Taken together, these results suggest that PS-PGL may be useful as a beneficial antioxidant material in the food and cosmetic industries. Copyright © 2016 Elsevier B.V. All rights reserved.

Ethylene formation from methionine as a method to evaluate oxygen free radical scavenging and metal inactivation by cosmetics.

PubMed

Galey, J B; Millecamps, F; Nguyen, Q L

1991-04-01

Synopsis It has been proposed that oxygen free radicals are involved in skin aging. This paper describes a new method for the evaluation of oxygen free radical scavenging by cosmetic products. It is based on the measurement, by gas chromatography, of ethylene produced during the oxidation of methionine by the hydroxyl radical. OH. is produced by an iron catalyzed superoxide-driven Fenton reaction in which superoxide is obtained by photochemical oxygen reduction. The cosmetic is applied, together with methionine, riboflavine, NADH, FeCl(3) and EDTA, on a glass microfibre filter and submitted to UVA exposure through a quartz cell. Ethylene is then measured from aliquots of the atmosphere inside the cell. Catalase or Desferal completely inhibits ethylene production. SOD or high concentrations of hydroxyl radical scavengers (Mannitol, DMSO etc.) afford a partial protection. Thus the efficiency of O(2) (-)., H(2)O(2) and OH. scavengers and iron chelators can be measured. The main advantage of this test is that it is performed in conditions which simulate skin during UV exposure (e.g. air and UV exposed thin layer). Furthermore, as it is non-invasive, it can also be applied to human skin in vivo.

Computational studies of free radical-scavenging properties of phenolic compounds.

PubMed

Alov, Petko; Tsakovska, Ivanka; Pajeva, Ilza

2015-01-01

For more than half a century free radical-induced alterations at cellular and organ levels have been investigated as a probable underlying mechanism of a number of adverse health conditions. Consequently, significant research efforts have been spent for discovering more effective and potent antioxidants / free radical scavengers for treatment of these adverse conditions. Being by far the most used antioxidants among natural and synthetic compounds, mono- and polyphenols have been the focus of both experimental and computational research on mechanisms of free radical scavenging. Quantum chemical studies have provided a significant amount of data on mechanisms of reactions between phenolic compounds and free radicals outlining a number of properties with a key role for the radical scavenging activity and capacity of phenolics. The obtained quantum chemical parameters together with other molecular descriptors have been used in quantitative structure-activity relationship (QSAR) analyses for the design of new more effective phenolic antioxidants and for identification of the most useful natural antioxidant phenolics. This review aims at presenting the state of the art in quantum chemical and QSAR studies of phenolic antioxidants and at analysing the trends observed in the field in the last decade.

Antioxidant property of aerial parts and root of Phyllanthus fraternus Webster, an important medicinal plant.

PubMed

Upadhyay, Richa; Chaurasia, Jitendra Kumar; Tiwari, Kavindra Nath; Singh, Karuna

2014-01-01

In present study free radical scavenging potential of aerial parts and root of Phyllanthus fraternus was investigated. Extraction was done in water and ethanol. Total antioxidant capacity was measured by DPPH free radical scavenging method; ethanolic extract of aerial part was most potent in activity with 50% inhibition at 258 μg/mL concentration. Lipid peroxidation (LPO) was measured in terms of thiobarbituric acid-reactive substances (TBARS) by using egg-yolk homogenates as lipid-rich media with EC₅₀ of aerial part (ethanolic) 1522 μg/mL which was found to be most active. Superoxide (SO) radical scavenging activity was measured using riboflavin-light-nitroblue tetrazolium assay. Ethanolic and aqueous extract of both aerial part and root was almost similar in superoxide radical scavenging activity. Reducing power was determined on the basis of Fe³⁺-Fe⁺ transformation in the presence of extract. Total phenolic and flavonoid contents were also measured by spectroscopic method. Results showed that the ethanolic fraction of aerial part is most active towards antioxidant potential and this activity is related to its polyphenolic content and reducing potential. Thus, P. fraternus extract can be used as potent natural antioxidant.

Evaluation of exposures of hospital employees to anesthetic gases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lambeth, J.D.

1988-01-01

Hospital employees who work in hospital operating and recovery rooms are often exposed to a number of anesthetic gases. There is evidence to support the belief that such exposures have led to higher rates of miscarriages and spontaneous abortions of pregnancies among women directly exposed to these gases than among women not exposed. Most of the studies assessing exposure levels were conducted prior to the widespread use of scavenging systems. Air sampling was conducted in hospital operatories and recovery rooms of three large hospitals to assess the current exposure levels in these areas and determine the effectiveness of these systemsmore » in reducing exposures to fluoride-containing anesthetic gases. It was determined that recovery-room personnel are exposed to levels of anesthesia gases that often approach and exceed the recommended Threshold Limit Value-Time Weighted Average (TLV-TWA) of 2.0 ppm. Recovery-room personnel do not have the protection from exposure provided by scavenging systems in operating rooms. Operating-room personnel were exposed to anesthesia gas levels above the TLV-TWA only when patients were masked, or connected and disconnected from the scavenging systems. Recovery-room personnel also need to be protected from exposure to anesthesia gases by a scavenging system.« less

Effect of air-entry angle on performance of a 2-stroke-cycle compression-ignition engine

NASA Technical Reports Server (NTRS)

Earle, Sherod L; Dutee, Francis J

1937-01-01

An investigation was made to determine the effect of variations in the horizontal and vertical air-entry angles on the performance characteristics of a single-cylinder 2-stroke-cycle compression-ignition test engine. Performance data were obtained over a wide range of engine speed, scavenging pressure, fuel quantity, and injection advance angle with the optimum guide vanes. Friction and blower-power curves are included for calculating the indicated and net performances. The optimum horizontal air-entry angle was found to be 60 degrees from the radial and the optimum vertical angle to be zero, under which conditions a maximum power output of 77 gross brake horsepower for a specific fuel consumption of 0.52 pound per brake horsepower-hour was obtained at 1,800 r.p.m. and 16-1/2 inches of Hg scavenging pressure. The corresponding specific output was 0.65 gross brake horsepower per cubic inch of piston displacement. Tests revealed that the optimum scavenging pressure increased linearly with engine speed. The brake mean effective pressure increased uniformly with air quantity per cycle for any given vane angle and was independent of engine speed and scavenging pressure.

The main constituents of Tulipa systola Stapf. roots and flowers; their antioxidant activities.

PubMed

Ibrahim, Mohammed Farhad; Hussain, Faiq Hama Saeed; Zanoni, Giuseppe; Vidari, Giovanni

2017-09-01

People living on the mountains of the Kurdistan Region, Iraq make a large use of herbs in the local traditional medicine. Among them, Tulipa systola, which grows under and between rocks, is very popular as an anti-inflammatory remedy and pain-relief. The phytochemical study of an ethanolic extract obtained from flowers and roots of Tulip (T systola Stapf.) afforded three compounds, identified as (+)-1-O-E-feruloyl-3-O-E-p-coumaroylglycerol (1), (+)-6-tuliposide A (2), and (-)-kaempferol-3-O-rutinoside (3). The significant radical scavenging and antioxidant activity of the isolated compounds were evaluated on three tests, by determining the DPPH free radical scavenging activity, the total antioxidant activity and the hydrogen peroxide scavenging activity. Tuliposide A shows potent allergenic activity.

Free radical scavenging activities of yellow gentian (Gentiana lutea L.) measured by electron spin resonance.

PubMed

Kusar, A; Zupancic, A; Sentjurc, M; Baricevic, D

2006-10-01

Yellow gentian (Gentiana lutea L.) is a herbal species with a long-term use in traditional medicine due to its digestive and stomachic properties. This paper presents an investigation of the free radical scavenging activity of methanolic extracts of yellow gentian leaves and roots in two different systems using electron spin resonance (ESR) spectrometry. Assays were based on the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) and the superoxide radicals (O2*-) generated by the xanthine/xanthine oxidase (X/XO) system. The results of gentian methanolic extracts were compared with the antioxidant capacity of synthetic antioxidant butylated hydroxyanisole (BHA). This study proves that yellow gentian leaves and roots exhibit considerable antioxidant properties, expressed either by their capability to scavenge DPPH or superoxide radicals.

Ginkgo biloba leaf extract action in scavenging free radicals and reducing mutagenicity and toxicity of cigarette smoke in vivo.

PubMed

Wang, Chang G; Dai, Ya; Li, Dong L; Ma, Kuo Y

2010-01-01

In this study, ginkgo biloba leaf extract (GBE) was added to sample cigarettes, including in the filter (0.8 mg/cigarette) and/or the cut filler (0.8 mg/cigarette). The effects of GBE in scavenging free radicals and reducing mutagenicity and toxicity of cigarette smoke in vivo were investigated. Smoke analysis results indicated that GBE eliminated up to 30% of free radicals. Biological experiments, conducted for both GBE cigarettes and control samples, included the Ames test, acute toxicity, neutral red cytotoxicity assay and chronic toxicity. Results showed that the mutagenicity and toxicity of the GBE cigarettes were lower than for the control cigarettes. A possible mechanism of GBE in scavenging free radicals is discussed in this article.

The experimental scavenging capacity and the degradation potential of the mixture of carotenoid and vitamin E, vitamin C

NASA Astrophysics Data System (ADS)

Tuyet, Nguyen Thi Ngoc; Khoa, Tran Anh; Quan, Vu Thi Hong; Chinh, Vuong Ngoc; Phung, Le Thi Kim

2017-09-01

The antioxidant capacity of Gac oil can be enhanced by the presence of these other active antioxidants such as vitamin E, vitamin C. Since many of these natural antioxidants are consumed together in foods, the potential for scavenging capacity is high in the human diet. The aim of this study was to determine what concentrations and combinations of antioxidants among Gac oil, vitamin E, vitamin C are capable of producing high scavenging capacity. The fact has resulted in detailed studies of antioxidation capacity of carotenoid of and vitamin. In addition, the antioxidant capacity and degradation potential of the combined mixture of carotenoid and vitamin E, vitamin C were discussed in view of their antioxidant properties as beneficial species in preventing various diseases.

Antioxidant potential and radical-scavenging effects of flavonoids from the leaves of Psidium cattleianum grown in French Polynesia.

PubMed

Ho, R; Violette, A; Cressend, D; Raharivelomanana, P; Carrupt, P A; Hostettmann, K

2012-01-01

Psidium cattleianum J. Sabine (Myrtaceae) is a traditional medicinal plant in French Polynesia. The leaves and roots possess many medicinal properties. These effects may be correlated with the presence of antioxidant compounds. Seven flavonoids along with a benzoic acid were isolated from the leaves of P. cattleianum. The compounds indicated strong antioxidant and radical-scavenging activities in ALP, DPPH(·), ABTS(·-) and ORAC assays. This study demonstrates that the leaves of P. cattleianum possess main compounds with interesting antioxidant and radical-scavenging activities, as clarified by four biological assays. Our findings may justify the use of these leaves in the traditional medicine of French Polynesia. Among the total eight known compounds, reynoutrin and luteolin were isolated for the first time from the genus Psidium.

Direct degradation of dyes by piezoelectric fibers through scavenging low frequency vibration

NASA Astrophysics Data System (ADS)

Zhu, Ruijian; Xu, Yunhua; Bai, Qing; Wang, Zengmei; Guo, Xinli; Kimura, Hideo

2018-06-01

A newly discovered nanometer material-mediated piezoelectrochemical (PZEC) for the direct conversion of mechanical energy to chemical energy has attracted increasing attention, for its great potential to be a green dye water decomposition technique. However, it is far from being a cost-effective and practical technique because only ultrasonic can be scavenged to decomposed organic pollutant in previous studies. Here, we prepared 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT-BCT) piezoelectric fibers for the degradation of dye solution via slow stirring and studied the degradation mechanism. It provides a practical, green and low-cost method for decomposing organic dye by scavenging waste mechanical energy from the surrounding environment.

Antioxidative effects of a processed grain food.

PubMed

Minamiyama, Y; Yoshikawa, T; Tanigawa, T; Takahashi, S; Naito, Y; Ichikawa, H; Kondo, M

1994-10-01

Antioxidant biofactor: AOB is a unique processed grain food. It is a yellow-green powder. It contains the following extracts: germ extracts, soybean, rice bran, tear grass, sesame, wheat, citron, green tea, green leaf extract, and malted rice. These materials were slowly roasted under a powdered oure at less than 60 degrees C and fermented with Aspergillus oryzae over 3 days to transform each ingredient into low molecular weight substances. These conditions were different by each material, environmental humidity and temperature. It probably contains a variety of substances having antioxidant activity including flavonoids, alpha-tocopherol, vitamin C, and tannins. We investigated its antioxidative properties using electron spin resonance (ESR) and autoxidation of rat brain homogenates. The superoxide, hydroxyl radical, and the stable free radical, diphenyl-p-picrylhydrazyl (DPPH) radical scavenging activity of AOB was investigated using ESR spectrometry. In an in vitro study, a suspension of AOB was added directly to a superoxide generating system (hypoxanthine-xanthine oxidase; HX/XO) and investigated using 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) as a spin trapping agent. At final concentrations of 0.01, 0.05, and 0.1 mg/ml, AOB dose-dependent scavenging activity was observed as 0.103, 0.619, and 1.369 U/ml, respectively. A concentration of 1.0 mg/ml completely scavenged DMPO-OOH signals; 1.0 mg/ml of AOB inhibited the DMPO-OH signal generated by Fenton's reaction, but its inhibitory effect was not competitive, and was inhibition of the Fenton's reaction. 1.0, 3.0, and 5.0 mg/ml of AOB were significantly inhibited the DPPH radical. In an in vivo study, rats were fed AOB orally at doses of 1 or 5 g/day for 24 h or for 3 days and the superoxide scavenging activity was measured in plasma. With the administration of 1 g/day for 3 days, the superoxide scavenging activity was about 1.8 times that of the control group fed a basal diet; 1.5 times the control with 5 g/day for 1 day, and 2.6 times the control with 5 g/day for 3 days, all of which represented significant increases in superoxide scavenging activity. AOB strongly inhibited the autoxidation of rat brain homogenates in vitro in a dose-dependent manner. However, each ingredient before roast and fermentation little inhibited lipid peroxidation. Roasting and fermentation with A. oryzae way be important to transform each ingredient into low molecular weight substances. Therefore, it was suggested that AOB possesses strong antioxidant and free radical scavenging activities.

Effect of matrix components on UV/H2O2 and UV/S2O8(2-) advanced oxidation processes for trace organic degradation in reverse osmosis brines from municipal wastewater reuse facilities.

PubMed

Yang, Yi; Pignatello, Joseph J; Ma, Jun; Mitch, William A

2016-02-01

When reverse osmosis brines from potable wastewater reuse plants are discharged to poorly-flushed estuaries, the concentrated organic contaminants are a concern for receiving water ecosystems. UV/hydrogen peroxide (UV/H2O2) and UV/persulfate (UV/S2O8(2-)) advanced oxidation processes (AOPs) may reduce contaminant burdens prior to discharge, but the effects of the high levels of halide, carbonate and effluent organic matter (EfOM) normally present in these brines are unclear. On the one hand, these substances may reduce process efficiency by scavenging reactive oxygen species (ROS), hydroxyl (OH) and sulfate (SO4(-) radicals. On the other, the daughter radicals generated by halide and carbonate scavenging may themselves degrade organics, offsetting the effect of ROS scavenging. UV/H2O2 and UV/S2O8(2-) AOPs were compared for degradation of five pharmaceuticals spiked into brines obtained from two reuse facilities and the RO influent from one of them. For UV/H2O2, EfOM scavenged ∼75% of the OH, reducing the degradation efficiency of the target contaminants to a similar extent; halide and carbonate scavenging and the reactivities of associated daughter radicals were less important. For UV/S2O8(2-), anions (mostly Cl(-)) scavenged ∼93% of the SO4(-). Because daughter radicals of Cl(-) contributed to contaminant degradation, the reduction in contaminant degradation efficiency was only ∼75-80%, with the reduction driven by daughter radical scavenging by EfOM. Conversion of SO4(-) to more selective halogen and carbonate radicals resulted in a wider range of degradation efficiencies among the contaminants. For both AOPs, 250 mJ/cm(2) average fluence achieved significant removal of four pharmaceuticals, with significantly better performance by UV/S2O8(2-) treatment for some constituents. Accounting for the lower brine flowrates, the energy output to achieve this fluence in brines is comparable to that often applied to RO permeates. However, much higher fluence was required for the least reactive pharmaceutical. Comparing AOP application to the RO influent or brine, equal or greater removal was achieved for brine treatment for comparable energy input. AOP treatment of brines could be applied to reduce, but not eliminate, contaminant burdens prior to discharge. Copyright © 2015 Elsevier Ltd. All rights reserved.

Isolation of 8-hydroxyglycitein and 6-hydroxydaidzein from soybean miso.

PubMed

Hirota, Akira; Inaba, Miyuki; Chen, Yu-Chi; Abe, Naoki; Taki, Shoji; Yano, Masamichi; Kawaii, Satoru

2004-06-01

We isolated from soybean miso 8-hydroxyglycitein and 6-hydroxydaidzein as DPPH-radical scavengers, and elucidated their chemical structures by mass spectrometric, and (1)H- and (13)C-NMR spectrosopic analyses. These compounds showed DPPH-radical scavenging activity as high as that of alpha-tocopherol, 8-hydroxygenistein and 8-hydroxydaidzein. This is the first report of the isolation of 8-hydroxyglycitein from a natural source.

Acclimation to Chronic O3 in Field-grown Soybean is Characterized by Increased Levels of TCA Cycle Transcripts and ROS Scavenging Compounds in Addition to Decreased Photosynthetic Capacity

USDA-ARS?s Scientific Manuscript database

Tropospheric ozone (O3) is a pollutant that is generated by volatile organic compounds, nitrogen oxides and sunlight. When plants take in O3 through stomata, harmful reactive oxygen species (ROS) are produced that induce the production of ROS scavenging antioxidants. Climate change predictions indic...

Natural Attenuation of the Lead Scavengers 1,2-Dibromoethane (EDB) and 1.2-Dichloroethane (1,2-DCA) at Motor Fuel Release Sites and Implications for Risk Management

EPA Science Inventory

The lead scavengers 1,2-dibromoethane (EDB) and 1,2-dichloroethane (1,2-DCA) were included along with lead in conventional leaded gasoline used for automobiles in the US prior to 1988. Old spills of leaded gasoline from underground storage tank systems (USTs) at gasoline service...

Hydroxyl radical-scavenging property of secoisolariciresinol diglucoside (SDG) isolated from flax-seed.

PubMed

Prasad, K

1997-03-01

Recently there has been a moderate resurgence in the use of flax-seed in a variety of ways including bread. The scientific basis of its use is very limited. There is some claim for beneficial effects in cancer and lupus nephritis. These claims could be due to its ability to scavenge oxygen radicals. However, its antioxidant activity is not known. Recently a method has been developed to isolate secoisolariciresinol diglucoside (SDG) from defatted flax-seed in large quantity (patent pending). We investigated the ability of SDG to scavenge .OH using high pressure liquid chromatography (HPLC) method. .OH was generated by photolysis of H2O2 (1.25-10.0 mumoles/ml) with ultraviolet light and was trapped with salicylic acid which is hydroxylated to produce .OH-adduct products 2,3-dihydroxybenzoic acid (DHBA) and 2,5-DHBA. H2O2 produced a concentration-dependent .OH as estimated by 2,3-DHBA and 2,5-DHBA. A standard curve was constructed for known concentrations of 2,3-DHBA and 2,5-DHBA against corresponding area under the peaks which then was used for measurement of 2,3-DHBA and 2,5-DHBA generated by UV irradiation of H2O2 in the presence of salicylic acid. SDG in the concentration range of 25, 50, 100, 250, 500, 750, 1000 and 2000 micrograms/ml (36.4, 72.8, 145.6, 364.0, 728.0, 1092.0, 1456.0 and 2912.0 microM respectively) produced a concentration-dependent decrease in the formation of 2,3-DHBA and 2,5-DHBA, the inhibition being 4 and 4.65% respectively with 25 micrograms/ml (36.4 microM) and 82 and 74% respectively with 2000 micrograms/ml (2912.0 microM). The decrease in .OH-adduct products was due to scavenging of .OH and not by scavenging of formed 2,3-DHBA and 2,5-DHBA. SDG prevented the lipid peroxidation of liver homogenate in a concentration-dependent manner in the concentration range from 319.3-2554.4 microM. These results suggest that SDG scavenges .OH and therefore has an antioxidant activity.

Manganoporphyrin-Polyphenol Multilayer Capsules as Radical and Reactive Oxygen Species (ROS) Scavengers

DOE PAGES

Alford, Aaron; Kozlovskaya, Veronika; Xue, Bing; ...

2017-12-18

Local modulation of oxidative stress is crucial for a variety of biochemical events including cellular differentiation, apoptosis, and defense against pathogens. Currently employed natural and synthetic antioxidants exhibit a lack of biocompatibility, bioavailability, and chemical stability, resulting in limited capability to scavenge reactive oxygen species (ROS). To mediate these drawbacks, we have developed a synergistic manganoporphyrin-polyphenol polymeric nanothin coating and hollow microcapsules with efficient antioxidant activity and controllable ROS modulation. These materials are produced by multilayer assembly of a natural polyphenolic antioxidant, tannic acid (TA), with a synthesized copolymer of polyvinylpyrrolidone containing a manganoporphyrin modality (MnP-PVPON) which mimics the enzymaticmore » antioxidant superoxide dismutase. The redox activity of the copolymer is demonstrated to dramatically increase the antioxidant response of MnP-PVPON/TA capsules versus unmodified PVPON/TA capsules through reduction of a radical cationic dye and to significantly suppress the proliferation of superoxide via cytochrome C competition. Inclusion of MnP-PVPON as an outer layer enhances radical-scavenging activity as compared to localization of the layer in the middle or inner part of the capsule shell. In addition, we demonstrate that TA is crucial for the synergistic radical-scavenging activity of the MnP-PVPON/TA system which exhibits a combined superoxide dismutase-like ability and catalase-like activity in response to the free radical superoxide challenge. The MnP-PVPON/TA capsules exhibit a negligible, 8% loss of shell thickness upon free radical treatment, while PVPON/TA capsules lose 39% of their shell thickness due to the noncatalytic free-radical-scavenging of TA, as demonstrated by small angle neutron scattering (SANS). Finally, we have found the manganoporphyrin-polyphenol capsules to be nontoxic to splenocytes from NOD mice after 48 h incubation. In conclusion, our study illustrates the strong potential of combining catalytic activity of manganoporphyrins with natural polyphenolic antioxidants to design efficient free-radical-scavenging materials that may eventually be used in antioxidant therapies and as free radical dissipating protective carriers of biomolecules for biomedical or industrial applications.« less

Extraction, Structural Characterization, and Potential Antioxidant Activity of the Polysaccharides from Four Seaweeds

PubMed Central

He, Jinzhe; Xu, Yaoyang; Chen, Hongbo; Sun, Peilong

2016-01-01

Four seaweed polysaccharides were extracted from Sarcodia ceylonensis, Ulva lactuca L., Gracilaria lemaneiformis, and Durvillaea antarctica, respectively, by microwave-assisted extraction. The effect of three significant variables (extraction time, extraction temperature, and the ratio of water to raw material) on the process for extracting polysaccharides was investigated, along with the optimization of the extraction using the response surface method (RSM) with a Box–Behnken design. The polysaccharide structure, monosaccharide composition, degree of sulfation, and molecular weight (MW) distribution were analyzed by infrared (IR) spectrometry, gas chromatography (GC), and high-performance gel permeation chromatography (HPGPC). IR spectrometry showed that Sarcodia ceylonensis polysaccharide (SCP), Ulva lactuca L. polysaccharide (ULLP), and Durvillaea antarctica polysaccharide (DAP) were all sulfated polysaccharides and, except Gracilaria lemaneiformis polysaccharide (GLP), all belong to β-pyranosidic polysaccharides. The average molecular weight (MW) of SCP, ULLP, GLP, and DAP was 466, 404, 591, and 482 kDa, respectively. The quantitative and comparative results with external standards indicated that the main monosaccharide in SCP and ULLP was mannose; and GLP and DAP were mainly composed of galactose and glucose, respectively. Then the in vitro antioxidant activity of all of the polysaccharides was evaluated using different assays—2,2–azino –bis (3-ethylbenzthiazoline-6- sulfonate) (ABTS), hydroxyl radical, nitrite scavenging capacity, and reducing power—and the relationship between their antioxidant activity and chemical characteristics were also examined. ULLP presented the highest ABTS radical scavenging activity; ULLP, SCP and DAP also showed a strong effect on the ABTS radical scavenging activity. SCP and ULLP exhibited excellent hydroxyl radical scavenging activities, about 83.33% ± 2.31% and 80.07% ± 2.17%, respectively, at 4 mg/mL. The reducing power of DAP was relatively more pronounced than that of the three other polysaccharides. However, the nitrite scavenging activities of the four seaweed polysaccharides were weaker than other antioxidant activity (ABTS), hydroxyl radical scavenging capacity, and reducing power. In addition, GLP exhibited lower activities than the other three samples in all of the tests for the antioxidant activity. PMID:27916796

Extraction, Structural Characterization, and Potential Antioxidant Activity of the Polysaccharides from Four Seaweeds.

PubMed

He, Jinzhe; Xu, Yaoyang; Chen, Hongbo; Sun, Peilong

2016-11-28

Four seaweed polysaccharides were extracted from Sarcodia ceylonensis , Ulva lactuca L., Gracilaria lemaneiformis , and Durvillaea antarctica , respectively, by microwave-assisted extraction. The effect of three significant variables (extraction time, extraction temperature, and the ratio of water to raw material) on the process for extracting polysaccharides was investigated, along with the optimization of the extraction using the response surface method (RSM) with a Box-Behnken design. The polysaccharide structure, monosaccharide composition, degree of sulfation, and molecular weight ( M W ) distribution were analyzed by infrared (IR) spectrometry, gas chromatography (GC), and high-performance gel permeation chromatography (HPGPC). IR spectrometry showed that Sarcodia ceylonensis polysaccharide (SCP), Ulva lactuca L. polysaccharide (ULLP), and Durvillaea antarctica polysaccharide (DAP) were all sulfated polysaccharides and, except Gracilaria lemaneiformis polysaccharide (GLP), all belong to β-pyranosidic polysaccharides. The average molecular weight ( M W ) of SCP, ULLP, GLP, and DAP was 466, 404, 591, and 482 kDa, respectively. The quantitative and comparative results with external standards indicated that the main monosaccharide in SCP and ULLP was mannose; and GLP and DAP were mainly composed of galactose and glucose, respectively. Then the in vitro antioxidant activity of all of the polysaccharides was evaluated using different assays-2,2-azino -bis (3-ethylbenzthiazoline-6- sulfonate) (ABTS), hydroxyl radical, nitrite scavenging capacity, and reducing power-and the relationship between their antioxidant activity and chemical characteristics were also examined. ULLP presented the highest ABTS radical scavenging activity; ULLP, SCP and DAP also showed a strong effect on the ABTS radical scavenging activity. SCP and ULLP exhibited excellent hydroxyl radical scavenging activities, about 83.33% ± 2.31% and 80.07% ± 2.17%, respectively, at 4 mg/mL. The reducing power of DAP was relatively more pronounced than that of the three other polysaccharides. However, the nitrite scavenging activities of the four seaweed polysaccharides were weaker than other antioxidant activity (ABTS), hydroxyl radical scavenging capacity, and reducing power. In addition, GLP exhibited lower activities than the other three samples in all of the tests for the antioxidant activity.

Manganoporphyrin-Polyphenol Multilayer Capsules as Radical and Reactive Oxygen Species (ROS) Scavengers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alford, Aaron; Kozlovskaya, Veronika; Xue, Bing

Local modulation of oxidative stress is crucial for a variety of biochemical events including cellular differentiation, apoptosis, and defense against pathogens. Currently employed natural and synthetic antioxidants exhibit a lack of biocompatibility, bioavailability, and chemical stability, resulting in limited capability to scavenge reactive oxygen species (ROS). To mediate these drawbacks, we have developed a synergistic manganoporphyrin-polyphenol polymeric nanothin coating and hollow microcapsules with efficient antioxidant activity and controllable ROS modulation. These materials are produced by multilayer assembly of a natural polyphenolic antioxidant, tannic acid (TA), with a synthesized copolymer of polyvinylpyrrolidone containing a manganoporphyrin modality (MnP-PVPON) which mimics the enzymaticmore » antioxidant superoxide dismutase. The redox activity of the copolymer is demonstrated to dramatically increase the antioxidant response of MnP-PVPON/TA capsules versus unmodified PVPON/TA capsules through reduction of a radical cationic dye and to significantly suppress the proliferation of superoxide via cytochrome C competition. Inclusion of MnP-PVPON as an outer layer enhances radical-scavenging activity as compared to localization of the layer in the middle or inner part of the capsule shell. In addition, we demonstrate that TA is crucial for the synergistic radical-scavenging activity of the MnP-PVPON/TA system which exhibits a combined superoxide dismutase-like ability and catalase-like activity in response to the free radical superoxide challenge. The MnP-PVPON/TA capsules exhibit a negligible, 8% loss of shell thickness upon free radical treatment, while PVPON/TA capsules lose 39% of their shell thickness due to the noncatalytic free-radical-scavenging of TA, as demonstrated by small angle neutron scattering (SANS). Finally, we have found the manganoporphyrin-polyphenol capsules to be nontoxic to splenocytes from NOD mice after 48 h incubation. In conclusion, our study illustrates the strong potential of combining catalytic activity of manganoporphyrins with natural polyphenolic antioxidants to design efficient free-radical-scavenging materials that may eventually be used in antioxidant therapies and as free radical dissipating protective carriers of biomolecules for biomedical or industrial applications.« less

Population Pharmacokinetics of Metronidazole Evaluated Using Scavenged Samples from Preterm Infants

PubMed Central

Ouellet, Daniele; Smith, P. Brian; James, Laura P.; Ross, Ashley; Sullivan, Janice E.; Walsh, Michele C.; Zadell, Arlene; Newman, Nancy; White, Nicole R.; Kashuba, Angela D. M.; Benjamin, Daniel K.

2012-01-01

Pharmacokinetic (PK) studies in preterm infants are rarely conducted due to the research challenges posed by this population. To overcome these challenges, minimal-risk methods such as scavenged sampling can be used to evaluate the PK of commonly used drugs in this population. We evaluated the population PK of metronidazole using targeted sparse sampling and scavenged samples from infants that were ≤32 weeks of gestational age at birth and <120 postnatal days. A 5-center study was performed. A population PK model using nonlinear mixed-effect modeling (NONMEM) was developed. Covariate effects were evaluated based on estimated precision and clinical significance. Using the individual Bayesian PK estimates from the final population PK model and the dosing regimen used for each subject, the proportion of subjects achieving the therapeutic target of trough concentrations >8 mg/liter was calculated. Monte Carlo simulations were performed to evaluate the adequacy of different dosing recommendations per gestational age group. Thirty-two preterm infants were enrolled: the median (range) gestational age at birth was 27 (22 to 32) weeks, postnatal age was 41 (0 to 97) days, postmenstrual age (PMA) was 32 (24 to 43) weeks, and weight was 1,495 (678 to 3,850) g. The final PK data set contained 116 samples; 104/116 (90%) were scavenged from discarded clinical specimens. Metronidazole population PK was best described by a 1-compartment model. The population mean clearance (CL; liter/h) was determined as 0.0397 × (weight/1.5) × (PMA/32)2.49 using a volume of distribution (V) (liter) of 1.07 × (weight/1.5). The relative standard errors around parameter estimates ranged between 11% and 30%. On average, metronidazole concentrations in scavenged samples were 30% lower than those measured in scheduled blood draws. The majority of infants (>70%) met predefined pharmacodynamic efficacy targets. A new, simplified, postmenstrual-age-based dosing regimen is recommended for this population. Minimal-risk methods such as scavenged PK sampling provided meaningful information related to development of metronidazole PK models and dosing recommendations. PMID:22252819

In vitro evaluation of the antioxidant potential, phenolic and flavonoid contents of the stem bark ethanol extract of Anogeissus leiocarpus.

PubMed

Olugbami, J O; Gbadegesin, M A; Odunola, O A

2014-09-01

Plant-derived antioxidants with free radical scavenging activities can be relevant as chemopreventive agents against the numerous diseases associated with free radicals and reactive oxygen species. Some phytoconstituents possess antioxidant activities in biological systems. On this basis, we evaluated the antioxidant potential, and determined the total phenolic and flavonoid contents of the e thanol e xtract of the s tem bark of A nogeissus l eiocarpus [ EESAL ]. Antioxidant assays carried out include: 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, phosphomolybdate, β-carotene bleaching, ferric reducing, and hydroxyl radical scavenging activities. Results of DPPH assay showed no significant difference ( p < 0.001) between EESAL and butylated hydroxyanisole [BHA], while EESAL exhibited a significantly ( p < 0.001) higher activity than BHT [butylated hydroxytoluene]. Phosphomolybdate method recorded a total antioxidant capacity of 190.00 ± 70.53 µg butylated hydroxytoluene equivalents [BHTE]/mg dry extract, while β-carotene bleaching assay gave percent antioxidant activities of both EESAL and BHT as 81.46±1.62 and 80.90±1.39 respectively. Ferric reducing abilities of both EESAL and ascorbic acid increased in a concentration-dependent manner with EESAL displaying a significantly ( p < 0.001) higher reductive activity than vitamin C. EESAL displayed a significantly higher hydroxyl radical scavenging activity as compared with BHT at the lowest concentration with no significant difference at the highest concentration. Total phenolic and flavonoid contents of EESAL were obtained as 608.10 ± 2.12 µg GAE/mg and 78.96 ± 3.37 µg QE/mg respectively. Taken together, the free radical scavenging and antioxidant activity of EESAL is likely due to its high phenolic content with complementary effects of the flavonoid components.

Acute Pre-/Post-Treatment with 8th Day SOD-Like Supreme (a Free Radical Scavenging Health Product) Protects against Oxidant-Induced Injury in Cultured Cardiomyocytes and Hepatocytes In Vitro as Well as in Mouse Myocardium and Liver In Vivo.

PubMed

Leong, Pou Kuan; Chen, Jihang; Chan, Wing Man; Leung, Hoi Yan; Chan, Lincoln; Ko, Kam Ming

2017-04-10

8th Day superoxide dismutase (SOD)-Like Supreme (SOD-Like Supreme, a free radical scavenging health product) is an antioxidant-enriched fermentation preparation with free radical scavenging properties. In the present study, the cellular/tissue protective actions of SOD-Like Supreme against menadione toxicity in cultured H9c2 cardiomyocytes and in AML12 hepatocytes as well as oxidant-induced injury in the mouse myocardium and liver were investigated. SOD-Like Supreme was found to possess potent free radical scavenging activity in vitro as assessed by an oxygen radical absorbance capacity assay. Incubation with SOD-Like Supreme (0.5-3% (v/v)) was shown to protect against menadione-induced toxicity in H9c2 and AML12 cells, as evidenced by increases in cell viability. The ability of SOD-Like Supreme to protect against menadione cytotoxicity was associated with an elevation in the cellular reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio in menadione-challenged cells. Consistent with the cell-based studies, pre-/post-treatment with SOD-Like Supreme (0.69 and 2.06 mL/kg, three intermittent doses per day for two consecutive days) was found to protect against isoproterenol-induced myocardial injury and carbon tetrachloride hepatotoxicity in mice. The cardio/hepatoprotection afforded by SOD-Like Supreme was also paralleled by increases in myocardial/hepatic mitochondrial GSH/GSSG ratios in the SOD-Like Supreme-treated/oxidant-challenged mice. In conclusion, incubation/treatment with SOD-Like Supreme was found to protect against oxidant-induced injury in vitro and in vivo, presumably by virtue of its free radical scavenging activity.

Inhibition of Procarcinogen Activating Enzyme CYP1A2 Activity and Free Radical Formation by Caffeic Acid and its Amide Analogues.

PubMed

Narongchai, Paitoon; Niwatananun, Kanokporn; Narongchai, Siripun; Kusirisin, Winthana; Jaikang, Churdsak

2016-01-01

Caffeic acid (CAF) and its amide analogues, ethyl 1-(3',4'-dihydroxyphenyl) propen amide (EDPA), phenethyl 1-(3',4'-dihydroxyphenyl) propen amide (PEDPA), phenmethyl 1- (3',4'-dihydroxyphenyl) propen amide (PMDPA) and octyl 1-(3',4'-dihydroxyphenyl) propen amide (ODPA) were investigated for the inhibition of procarcinogen activating enzyme. CYP1A2 and scavenging activity on formation of nitric oxide, superoxide anion, DPPH radical and hydroxyl radical. It was found that they inhibited CYP1A2 enzyme by uncompetitive inhibition. Apparent Ki values of CAF, EDPA, PEDPA, PMDPA and ODPA were 0.59, 0.39, 0.45, 0.75 and 0.80 µM, respectively suggesting potent inhibitors of CYP1A2. Moreover, they potentially scavenged nitric oxide radical with IC 50 values of 0.12, 0.22, 0.28, 0.22 and 0.51 mM, respectively. The IC50 values of superoxide anion scavenging were 0.20, 0.22, 0.44, 2.18 and 2.50 mM, respectively. 1, 1- diphenyl-2- picrylhydrazyl (DPPH) radical-scavenging ability, shown as IC50 values, were 0.41, 0.29, 0.30, 0.89 and 0.84 mM, respectively. Moreover, the hydroxyl radical scavenging in vitro model was shown as IC50 values of 23.22, 21.06, 17.10, 17.21 and 15.81 µM, respectively. From our results, caffeic acid and its amide analogues are in vitro inhibitors of human CYP1A2 catalytic activity and free radical formation. They may be useful to be developed as potential chemopreventive agents that block CYP1A2-mediated chemical carcinogenesis.

Gray Wolves as Climate Change Buffers in Yellowstone

PubMed Central

Getz, Wayne M

2005-01-01

Understanding the mechanisms by which climate and predation patterns by top predators co-vary to affect community structure accrues added importance as humans exert growing influence over both climate and regional predator assemblages. In Yellowstone National Park, winter conditions and reintroduced gray wolves (Canis lupus) together determine the availability of winter carrion on which numerous scavenger species depend for survival and reproduction. As climate changes in Yellowstone, therefore, scavenger species may experience a dramatic reshuffling of food resources. As such, we analyzed 55 y of weather data from Yellowstone in order to determine trends in winter conditions. We found that winters are getting shorter, as measured by the number of days with snow on the ground, due to decreased snowfall and increased number of days with temperatures above freezing. To investigate synergistic effects of human and climatic alterations of species interactions, we used an empirically derived model to show that in the absence of wolves, early snow thaw leads to a substantial reduction in late-winter carrion, causing potential food bottlenecks for scavengers. In addition, by narrowing the window of time over which carrion is available and thereby creating a resource pulse, climate change likely favors scavengers that can quickly track food sources over great distances. Wolves, however, largely mitigate late-winter reduction in carrion due to earlier snow thaws. By buffering the effects of climate change on carrion availability, wolves allow scavengers to adapt to a changing environment over a longer time scale more commensurate with natural processes. This study illustrates the importance of restoring and maintaining intact food chains in the face of large-scale environmental perturbations such as climate change. PMID:15757363

Gray wolves as climate change buffers in Yellowstone.

PubMed

Wilmers, Christopher C; Getz, Wayne M

2005-04-01

Understanding the mechanisms by which climate and predation patterns by top predators co-vary to affect community structure accrues added importance as humans exert growing influence over both climate and regional predator assemblages. In Yellowstone National Park, winter conditions and reintroduced gray wolves (Canis lupus) together determine the availability of winter carrion on which numerous scavenger species depend for survival and reproduction. As climate changes in Yellowstone, therefore, scavenger species may experience a dramatic reshuffling of food resources. As such, we analyzed 55 y of weather data from Yellowstone in order to determine trends in winter conditions. We found that winters are getting shorter, as measured by the number of days with snow on the ground, due to decreased snowfall and increased number of days with temperatures above freezing. To investigate synergistic effects of human and climatic alterations of species interactions, we used an empirically derived model to show that in the absence of wolves, early snow thaw leads to a substantial reduction in late-winter carrion, causing potential food bottlenecks for scavengers. In addition, by narrowing the window of time over which carrion is available and thereby creating a resource pulse, climate change likely favors scavengers that can quickly track food sources over great distances. Wolves, however, largely mitigate late-winter reduction in carrion due to earlier snow thaws. By buffering the effects of climate change on carrion availability, wolves allow scavengers to adapt to a changing environment over a longer time scale more commensurate with natural processes. This study illustrates the importance of restoring and maintaining intact food chains in the face of large-scale environmental perturbations such as climate change.

Invasive carnivores alter ecological function and enhance complementarity in scavenger assemblages on ocean beaches.

PubMed

Brown, Marion B; Schlacher, Thomas A; Schoeman, David S; Weston, Michael A; Huijbers, Chantal M; Olds, Andrew D; Connolly, Rod M

2015-10-01

Species composition is expected to alter ecological function in assemblages if species traits differ strongly. Such effects are often large and persistent for nonnative carnivores invading islands. Alternatively, high similarity in traits within assemblages creates a degree of functional redundancy in ecosystems. Here we tested whether species turnover results in functional ecological equivalence or complementarity, and whether invasive carnivores on islands significantly alter such ecological function. The model system consisted of vertebrate scavengers (dominated by raptors) foraging on animal carcasses on ocean beaches on two Australian islands, one with and one without invasive red foxes (Vulpes vulpes). Partitioning of scavenging events among species, carcass removal rates, and detection speeds were quantified using camera traps baited with fish carcasses at the dune-beach interface. Complete segregation of temporal foraging niches between mammals (nocturnal) and birds (diurnal) reflects complementarity in carrion utilization. Conversely, functional redundancy exists within the bird guild where several species of raptors dominate carrion removal in a broadly similar way. As predicted, effects of red foxes were large. They substantially changed the nature and rate of the scavenging process in the system: (1) foxes consumed over half (55%) of all carrion available at night, compared with negligible mammalian foraging at night on the fox-free island, and (2) significant shifts in the composition of the scavenger assemblages consuming beach-cast carrion are the consequence of fox invasion at one island. Arguably, in the absence of other mammalian apex predators, the addition of red foxes creates a new dimension of functional complementarity in beach food webs. However, this functional complementarity added by foxes is neither benign nor neutral, as marine carrion subsidies to coastal red fox populations are likely to facilitate their persistence as exotic carnivores.

Monocyte-macrophage membrane possesses free radicals scavenging activity: stimulation by polyphenols or by paraoxonase 1 (PON1).

PubMed

Rosenblat, M; Elias, A; Volkova, N; Aviram, M

2013-04-01

In the current study, we analysed free radicals scavenging activity of monocytes-macrophages in the absence or presence of antioxidants such as polyphenols or paraoxonase 1 (PON1). THP-1 human monocytic cell line, murine J774A.1 macrophages, as well as human primary monocytes have the capability to scavenge free radicals, as measured by the 1-diphenyl-2-picryl-hydrazyl (DPPH) assay. This effect (which could be attributed to the cell's membrane) was cell number and incubation time dependent. Upon incubation of J774A.1 macrophages with acetylated LDL (Ac-LDL), with VLDL, or with the radical generator, AAPH, the cells' lipid peroxides content, and paraoxonase 2 (PON2) activity were significantly increased. While non-treated cells decreased DPPH absorbance by 65%, the Ac-LDL-, VLDL- or AAPH-treated cells, decreased it by only 33%, 30%, or 45%, respectively. We next analysed the effect of J774A.1 macrophage enrichment with antioxidants, such as polyphenols or PON1 on the cells' free radicals scavenging activity. Non-treated cells decreased DPPH absorbance by 50%, whereas vitamin E-, punicalagin- or PJ-treated cells significantly further decreased it, by 75%. Similarly, in PON1-treated cells DPPH absorbance was further decreased by 63%, in association with 23% increment in PON1 catalytic activity. In cells under oxidative stress [treated with AAPH-, or with oxidized LDL], PON1 activity was decreased by 31% or 40%, as compared to the activity observed in PON1 incubated with non-treated cells. We conclude that monocytes-macrophages possess free radicals scavenging activity, which is decreased under atherogenic conditions, and increased upon cell enrichment with potent antioxidants such as nutritional polyphenols, or PON1.

Improved production of poly-γ-glutamic acid by Bacillus subtilis D7 isolated from Doenjang, a Korean traditional fermented food, and its antioxidant activity.

PubMed

Lee, Na-Ri; Lee, Sang-Mee; Cho, Kwang-Sik; Jeong, Seong-Yun; Hwang, Dae-Youn; Kim, Dong-Seob; Hong, Chang-Oh; Son, Hong-Joo

2014-06-01

The objectives of this study was to improve poly-γ-glutamic acid (γ-PGA) production by Bacillus subtilis D7 isolated from a Korean traditional fermented food and to assess its antioxidant activity for applications in the cosmetics and pharmaceutical industries. Strain D7 produced γ-PGA in the absence of L-glutamic acid, indicating L-glutamic acid-independent production. However, the addition of L-glutamic acid increased γ-PGA production. Several tricarboxylic acid cycle intermediates and amino acids could serve as the metabolic precursors for γ-PGA production, and the addition of pyruvic acid and D-glutamic acid to culture medium improved the yield of γ-PGA markedly. The maximum yield of γ-PGA obtained was 24.93 ± 0.64 g/l in improved medium, which was about 5.4-fold higher than the yield obtained in basal medium. γ-PGA was found to have 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (46.8 ± 1.5 %), hydroxyl radical scavenging activity (52.0 ± 1.8 %), 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS) radical scavenging activity (42.1 ± 1.8 %), nitric oxide scavenging activity (35.1 ± 1.3 %), reducing power (0.304 ± 0.008), and metal chelating activity (91.3 ± 3.5 %). These results indicate that γ-PGA has a potential use in the food, cosmetics, and biomedical industries for the development of novel products with radical scavenging activity. As far as we are aware, this is the first report to describe the antioxidant activityof γ-PGA produced by bacteria.

In-vitro free radical scavenging activity of biosynthesized gold and silver nanoparticles using Prunus armeniaca (apricot) fruit extract

NASA Astrophysics Data System (ADS)

Dauthal, Preeti; Mukhopadhyay, Mausumi

2013-01-01

In-vitro free radical scavenging activity of biosynthesized gold (Au-NPs) and silver (Ag-NPs) nanoparticles was investigated in the present study. Natural precursor Prunus armeniaca (apricot) fruit extract was used as a reducing agent for the nanoparticle synthesis. The 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 assay. The synthesized nanoparticles were characterized by UV-Visible spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive spectroscopy, and fourier transform infrared spectroscopy (FTIR). Appearance of optical absorption peak at 537 nm (2.20 keV) and 435 nm (3 keV) within 0.08 and 0.5 h of reaction time was confirmed the presence of metallic Au and Ag nanoclusters, respectively. Nearly spherical nanoparticles with majority of particle below 20 nm (TEM) for both Au-NPs and Ag-NPs were synthesized. XRD pattern confirmed the existence of pure nanocrystalline Au-NPs while few additional peaks in the vicinity of fcc silver-speculated crystallization of metalloproteins of fruit extract on the surface of the Ag-NPs and vice versa. FTIR spectra was supported the role of amino acids of protein/enzymes of fruit extract for synthesis and stabilization of nanoparticles. Dose-dependent scavenging activity was observed for Au-NPs and Ag-NPs in both DPPH and ABTS in-vitro assay. 50 % scavenging activity for DPPH were 11.27 and 16.18 mg and for ABTS 3.40 and 7.12 mg with Au-NPs and Ag-NPs, respectively.

CCN activity of secondary aerosols from terpene ozonolysis under atmospheric relevant conditions

NASA Astrophysics Data System (ADS)

Yuan, Cheng; Ma, Yan; Diao, Yiwei; Yao, Lei; Zhou, Yaoyao; Wang, Xing; Zheng, Jun

2017-04-01

Gas-phase ozonolysis of terpenes is an important source of atmospheric secondary organic aerosol. The contribution of terpene-derived aerosols to the atmospheric cloud condensation nucleus (CCN) burden under atmospheric conditions, however, remains highly uncertain. The results obtained in previous studies under simple laboratory conditions may not be applicable to atmospheric relevant conditions. Here we present that CCN activities of aerosols from terpene ozonolysis can be significantly affected by atmospheric relevant species that can act as stabilized Criegee intermediate (SCI) or OH scavengers. Ozonolysis reactions of α-pinene, limonene, α-cedrene, and α-humulene were conducted in a 4.5 m3 collapsible fluoropolymer chamber at near-atmospheric concentrations in the presence of different OH scavengers (cyclohexane, 2-butanol, or CO) and SCI scavengers (CH3COOH, H2O, or SO2). The number size distribution and CCN activity of aerosol particles formed during ozonolysis were simultaneously determined. Additionally, particulate products were chemically analyzed by using a Filter Inlet for Gases and AEROsols High-Resolution Time-of-Flight Chemical-Ionization Mass Spectrometer. Results showed that aerosol CCN activity following monoterpene ozonolysis was more sensitive to the choice of OH scavengers, while that from sesquiterpene ozonolysis was significantly affected by SCI scavengers. Combined with chemical analysis results, it was concluded that the unimolecular decomposition of CIs giving hygroscopic organic products can be largely suppressed by bimolecular reactions during sesquiterpene ozonolysis but was not significantly impacted in monoterpene ozonolysis. Our study underscores the key role of CIs in the CCN activity of terpene ozonolysis-derived aerosols. The effects of atmospheric relevant species (e.g., SO2, H2O, and CO) need to be considered when assessing the contribution of biogenic terpenes to the atmospheric CCN burden under ambient conditions.

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

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

PubMed

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.

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.

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

Scavenging and fractionation of particle-reactive radioisotopes 7Be, 210Pb and 210Po in the atmosphere

NASA Astrophysics Data System (ADS)

Chen, Jinfang; Luo, Shangde; Huang, Yipu

2016-09-01

The scavenging and fractionation of 7Be, 210Pb, and 210Po in the atmosphere are investigated by measuring their activities in rainwater collected from 68 rain events during March 2004 to April 2006 at a coastal station of Xiamen, southeastern China. In addition to documenting the large temporal variations in activities, fluxes, and isotope ratios of 7Be, 210Pb and 210Po in rainwater and the role of rainfall intensity in radionuclide scavenging, our results show that an enhanced deposition of 7Be and 210Pb occurs in the spring than in other seasons and is attributed to the "funnel effect" due to the increased atmospheric vertical convective mixing in the spring. This latter hypothesis is further supported by the observed seasonal and inter-annual variations in 7Be/210Pb and 210Po/210Pb ratios showing that the weakening of vertical convective mixing or stratosphere-troposphere exchange (STE) at the study site is linked with the enhancement of summer monsoons. It appears that the rainfall intensity, in connection with the vertical (e.g., STE) and horizontal (summer monsoons) air transport, exerts an important control on the activities, fluxes, and isotope ratios of 7Be, 210Pb, and 210Po in the atmosphere. Application of the observational data to a theoretical model shows that there are significant fractionations among 7Be, 210Pb, and 210Po in the atmosphere, with the scavenging rate constant or reciprocal of the residence time of radionuclide in the atmosphere being 210Pb > 7Be > 210Po. A revised Poet et al. (1972)'s method is proposed for quantitative constraint on the scavenging behavior of radionuclide, aerosols, and aerosol-associated trace pollutants in the atmosphere.

HBOC Vasoactivity: Interplay Between Nitric Oxide Scavenging and Capacity to Generate Bioactive Nitric Oxide Species

PubMed Central

Friedman, Joel M.

2013-01-01

Abstract Significance: Despite many advances in blood substitute research, the development of materials that are effective in maintaining blood volume and oxygen delivery remains a priority for emergency care and trauma. Clinical trials on hemoglobin (Hb)-based oxygen carriers (HBOCs) have not provided information on the mechanism of toxicity, although all commercial formulations have safety concerns. Specifically, it is important to reconcile the different hypotheses of Hb toxicity, such as nitric oxide (NO) depletion and oxidative reactions, to provide a coherent molecular basis for designing a safe HBOC. Recent Advances: HBOCs with different sizes often exhibit differences in the degree of HBOC-induced vasoactivity. This has been attributed to differences in the degree of NO scavenging and in the extent of Hb extravasation. Additionally, it is appears that Hb can undergo reactions that compensate for NO scavenging by generating bioactive forms of NO. Critical Issues: Engineering modifications to enhance bioactive NO production can result in diminished oxygen delivery by virtue of increased oxygen affinity. This strategy can prevent the HBOC from fulfilling the intended goal on preserving oxygenation; however, the NO production effects will increase perfusion and oxygen transport. Future Directions: Hb modifications influence NO scavenging and the capacity of certain HBOCs to compensate for NO scavenging through nitrite-mediated reactions that generate bioactive NO. Based on the current understanding of these NO-related factors, possible synthetic strategies are presented that address how HBOC formulations can be prepared that: (i) effectively deliver oxygen, (ii) maintain tissue perfusion, and (iii) limit/reverse underlying inflammation within the vasculature. Antioxid. Redox Signal. 18, 2284–2297. PMID:23249305

Direct antioxidant properties of methotrexate: Inhibition of malondialdehyde-acetaldehyde-protein adduct formation and superoxide scavenging.

PubMed

Zimmerman, Matthew C; Clemens, Dahn L; Duryee, Michael J; Sarmiento, Cleofes; Chiou, Andrew; Hunter, Carlos D; Tian, Jun; Klassen, Lynell W; O'Dell, James R; Thiele, Geoffrey M; Mikuls, Ted R; Anderson, Daniel R

2017-10-01

Methotrexate (MTX) is an immunosuppressant commonly used for the treatment of autoimmune diseases. Recent observations have shown that patients treated with MTX also exhibit a reduced risk for the development of cardiovascular disease (CVD). Although MTX reduces systemic inflammation and tissue damage, the mechanisms by which MTX exerts these beneficial effects are not entirely known. We have previously demonstrated that protein adducts formed by the interaction of malondialdehyde (MDA) and acetaldehyde (AA), known as MAA-protein adducts, are present in diseased tissues of individuals with rheumatoid arthritis (RA) or CVD. In previously reported studies, MAA-adducts were shown to be highly immunogenic, supporting the concept that MAA-adducts not only serve as markers of oxidative stress but may have a direct role in the pathogenesis of inflammatory diseases. Because MAA-adducts are commonly detected in diseased tissues and are proposed to mitigate disease progression in both RA and CVD, we tested the hypothesis that MTX inhibits the generation of MAA-protein adducts by scavenging reactive oxygen species. Using a cell free system, we found that MTX reduces MAA-adduct formation by approximately 6-fold, and scavenges free radicals produced during MAA-adduct formation. Further investigation revealed that MTX directly scavenges superoxide, but not hydrogen peroxide. Additionally, using the Nrf2/ARE luciferase reporter cell line, which responds to intracellular redox changes, we observed that MTX inhibits the activation of Nrf2 in cells treated with MDA and AA. These studies define previously unrecognized mechanisms by which MTX can reduce inflammation and subsequent tissue damage, namely, scavenging free radicals, reducing oxidative stress, and inhibiting MAA-adduct formation. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Long-term baited lander experiments at a cold-water coral community on Galway Mound (Belgica Mound Province, NE Atlantic)

NASA Astrophysics Data System (ADS)

Lavaleye, Marc; Duineveld, Gerard; Bergman, Magda; van den Beld, Inge

2017-11-01

A long-term lander employing a baited camera system was developed to study temporal variation in the presence of scavenging fish and invertebrates at a cold-water coral community on Galway Mound (Belgica Mound Province, NE Atlantic). The camera system was tested during two successful long-term deployments for periods of 6 and 12 months respectively. The baited system, consisting of two separate video cameras with infrared lights and a bait dispenser with 24 bait positions, recorded more than 15,500 clips of 17 s, regularly spread over both periods. New bait, consisting of sardines in oil, was offered at regular time intervals, and attracted scavengers over the whole period of deployment, and especially the crab Chaceon affinis did still eat from it till the end of the deployments. However, the attractiveness for some scavengers, i.e. amphipods, diminished quite quickly. In addition to invertebrate scavengers, namely C. affinis, two other crab species, amphipods, a shrimp and a starfish, also 7 species of fish were recorded near the bait, of which Lepidion eques was by far the most common. Though there was no concrete evidence for seasonal patterns, the observations showed substantial temporal variation in the abundance of several species, especially the crabs C. affinis and Bathynectes maravigna and the fish Phycis blennoides. It is concluded that long-term deployments of such a baited camera system can produce novel data. For instance such a system could be employed for monitoring impacts of disturbances on the deep-sea floor (e.g. mining), as we infer that mobile scavengers will be among the first organisms to show a visible reaction to any chemically and physically (noise, vibrations) alteration of the environment similar to a mine canary.

Studies on free radical scavenging, cancer cell antiproliferation, and calf thymus DNA interaction of Schiff bases.

PubMed

da Silva, Cleiton M; Silva, Marina M; Reis, Fabiano S; Ruiz, Ana Lúcia T G; de Carvalho, João E; Santos, Josué C C; Figueiredo, Isis M; Alves, Rosemeire B; Modolo, Luzia V; de Fátima, Ângelo

2017-07-01

Thirty-nine Schiff bases were synthesized by performing microwave-assisted condensation of the corresponding aldehydes and aromatic amines. Their reactive nitrogen species (RNS) scavenging activity and inhibitory effects against cancer cell growth were then subsequently investigated. Additionally, the interaction between the calf thymus DNA (ctDNA) and selected Schiff bases was evaluated using fluorescence spectroscopy, and their binding parameters were determined. The yields of the various compounds ranged from moderate to excellent (43-99%) after only a 2-min reaction. The hydroxylated Schiff bases 2, 8, 15, 16, 18, 20, 29, 32, 34, and 37 were found to be potent scavengers of 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals with half-maximal scavenging concentration (SC 50 ) values lower than that of the positive control, resveratrol. The presence of hydroxyl substituents on the aromatic rings also proved essential to the cytotoxicity of the compounds. The binding constants (K b ) obtained using fluorescence spectroscopy ranged from 0.37 to 3.07×10 5 Lmol -1 , and were strongly influenced by the structure and hydroxylation degree. Schiff bases 3 and 8 showed promising cytotoxic activity, with half-maximal growth inhibitory (GI 50 ) values in the same order of magnitude as those exhibited by the reference drug, doxorubicin against various cell lines. Interestingly, these compounds also showed the highest K b , suggesting that the cytotoxic activity could be related to their interaction with the DNA of the tumor cells. The results of this study highlighted some Schiff bases as potential lead compounds for the design of new free radical scavengers and anticancer agents. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of free radical scavenging and antityrosinase activities of standardized longan fruit extract.

PubMed

Rangkadilok, Nuchanart; Sitthimonchai, Somkid; Worasuttayangkurn, Luksamee; Mahidol, Chulabhorn; Ruchirawat, Mathuros; Satayavivad, Jutamaad

2007-02-01

The protective effects of fruits and vegetables against chronic diseases have been attributed to the antioxidant properties of some secondary metabolites present in these foods. Plant polyphenols have been reported to exhibit bioactive properties, and in particular antioxidant activities. Longan seeds are found to contain high levels of some beneficial polyphenolic compounds such as corilagin, gallic acid and ellagic acid. The present study examined the free radical scavenging activity of longan seed extract by using three different assay methods. Longan extracts contained corilagin ranging from zero to 50.64 mg/g DW, gallic acid from 9.18 to 23.04 mg/g DW, and ellagic acid from 8.13 to 12.65 mg/g DW depending on the cultivars. Dried longan seed extracts of cultivar Edor contained high levels of gallic acid and ellagic acid and also exhibited the highest radical scavenging activities when comparing fresh seed and dried pulp extracts. For scavenging activity of DPPH and superoxide radicals, longan seed extract was found to be as effective as Japanese green tea extract while dried longan pulp and mulberry green tea extracts showed the least scavenging activities. In the ORAC assay, both fresh and dried longan seed also had higher activity than dried pulp and whole fruit. However, the results demonstrate that three polyphenolics may not be the major contributors of the high antioxidant activity of longan water extracts but this high activity may be due to other phenolic/flavonoid glycosides and ellagitannins present in longan fruit. In addition, longan seed also showed tyrosinase inhibitory activity with IC(50) values of 2.9-3.2 mg/ml. Therefore, the preliminary observations suggest that longan seed extract could be another potential source of potent natural dietary antioxidants and also in an application as a new natural skin-whitening agent.

Phytochemical composition and in vitro pharmacological activity of two rose hip (Rosa canina L.) preparations.

PubMed

Wenzig, E M; Widowitz, U; Kunert, O; Chrubasik, S; Bucar, F; Knauder, E; Bauer, R

2008-10-01

The aim of the present study was to compare powdered rose hip with and without fruits (Rosae pseudofructus cum/sine fructibus, Rosa canina L., Rosaceae) with regard to their phytochemical profile and their in vitro anti-inflammatory and radical-scavenging properties. The two powders were subsequently extracted with solvents of increasing polarity and tested for inhibition of cyclooxygenase (COX-1, COX-2) and of 5-LOX-mediated leukotriene B(4) (LTB(4)) formation as well as for DPPH-radical-scavenging capacity. While the water and methanol extracts were inactive in the COX-1, COX-2 and LTB(4) inhibition assays, the n-hexane and the dichloromethane extracts inhibited all three enzymes. In the active extracts, the triterpenoic acids ursolic acid, oleanolic acid and betulinic acid were identified, although only in minute amounts. Furthermore, oleic, linoleic and alpha-linolenic acid were identified apart from several saturated fatty acids. Even though unsaturated fatty acids are known to be good inhibitors of COX-1, COX-2 and LT formation, no clear correlation between their concentration in the extracts and their activity was found. We suggest that other, yet unidentified, lipophilic constituents might play a more important role for the observed in vitro inhibitory activity on arachidonic acid metabolism. Some of the extracts also showed considerable DPPH radical scavenging activity, the methanolic extracts being most potent. The radical scavenging activity of the extracts correlated very well with their total phenolic content, while ascorbic acid contributes only little to the radical-scavenging activity due to its low concentration present in the extracts. In summary, extracts derived from powdered rose hip without fruits were more effective in all assays carried out compared with extracts derived from powdered rose hip with fruits.

Ab initio study of the operating mechanisms of tris(trimethylsilyl) phosphite as a multifunctional additive for Li-ion batteries

NASA Astrophysics Data System (ADS)

Kim, Dong Young; Park, Hosang; Choi, Woon Ih; Roy, Basab; Seo, Jinah; Park, Insun; Kim, Jin Hae; Park, Jong Hwan; Kang, Yoon-Sok; Koh, Meiten

2017-07-01

Tris(trimethylsilyl) phosphite (P(OSi(CH3)3)3) is a multifunctional electrolyte additive for scavenging HF and forming a cathode electrolyte interphase (CEI). Systematic analysis of the HF reaction pathways and redox potentials of P(OSi(CH3)3)3, OP(OSi(CH3)3)3, P(OSiF3)3, and OP(OSiF3)3, and their reaction products, using ab initio calculations allowed us to elucidate the operating mechanism of P(OSi(CH3)3)3 and verify the rules that determine its HF reaction pathways and electrochemical stability. While Osbnd Si cleavage is the predominant HF scavenging pathway for P(OSi(CH3)3)3, Osbnd P cleavage is stabilized by replacing CH3 with an electron-withdrawing group. Thus, P(OSiF3)3 scavenges HF mainly through Osbnd P cleavage to produce PF3, which has high oxidation stability. However, the Osbnd Si cleavage pathway produces P(OSi(CH3)3)2OH, P(OSi(CH3)3) (OH)2, and P(OH)3 sequentially, along with Si(CH3)3F. These PO3 systems, which are oxidized earlier than carbonate solutions and form tightly bonded units following oxidation, act as seed units for compact CEI growth. Moreover, the HF scavenging ability of PO3 systems is maintained during oxidation until all Osbnd Si bonds are broken. As a strategy for developing additives with enhanced functionality, modifying P(OSi(CH3)3)3 by replacing CH3 with an electron-donating group to exclusively utilize the Osbnd Si cleavage pathway for HF scavenging is recommended.

Free radical-scavenging activities of Crataegus monogyna extracts.

PubMed

Bernatoniene, Jurga; Masteikova, Rūta; Majiene, Daiva; Savickas, Arūnas; Kevelaitis, Egidijus; Bernatoniene, Rūta; Dvorácková, Katerina; Civinskiene, Genuvaite; Lekas, Raimundas; Vitkevicius, Konradas; Peciūra, Rimantas

2008-01-01

The aim of this study was to investigate antiradical activity of aqueous and ethanolic hawthorn fruit extracts, their flavonoids, and flavonoid combinations. Total amount of phenolic compounds and the constituents of flavonoids were determined using a high-performance liquid chromatography. The antioxidant activity of Crataegus monogyna extracts and flavonoids (chlorogenic acid, hyperoside, rutin, quercetin, vitexin-2O-rhamnoside, epicatechin, catechin, and procyanidin B(2)) quantitatively was determined using the method of spectrophotometry (diphenyl-1-picrylhydrazyl (DPPH.) radical scavenging assay and 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid)(ABTS.+) radical cation decolorization assay). The level of tyrosine nitration inhibition was determined using a high-performance liquid chromatography. Ethanolic hawthorn fruit extract contained 182+/-4 mg/100 mL phenolic compounds, i.e. threefold more, as compared to aqueous extract. The antioxidant activity according to DPPH. reduction in the ethanolic extracts was higher 2.3 times (P<0.05). The ABTS.+ technique showed that the effect of ethanolic extracts was by 2.5 times stronger than that of aqueous extracts. Tyrosine nitration inhibition test showed that the effect of ethanolic extracts was by 1.4 times stronger than that of aqueous extracts. The investigation of the antiradical activity of the active constituents in aqueous and ethanolic extracts revealed that epicatechin and catechin contribute to radical-scavenging properties more than other components. Procyanidin B(2) only insignificantly influenced the antiradical activity of the extracts. Both aqueous and ethanolic hawthorn extracts had antiradical activity, but ethanolic extract had stronger free radical-scavenging properties, compared to the aqueous extract. The antioxidant activity of the studied preparations was mostly conditioned by epicatechin and catechin. The individual constituents of both extracts had weaker free radical-scavenging properties than the combination of these substances did.

Production of the α and β Subunits of Spirulina Allophycocyanin and C-Phycocyanin in Escherichia coli : A Comparative Study of Their Antioxidant Activities.

PubMed

Cherdkiatikul, Thiti; Suwanwong, Yaneenart

2014-07-01

Allophycocyanin and c-phycocyanin have been reported to be potent antioxidants. In this work, the genes encoding the apo-proteins of allophycocyanin α (ApcA), allophycocyanin β (ApcB), c-phycocyanin α (CpcA), and c-phycocyanin β (CpcB) from Spirulina platensis were cloned, and the recombinant proteins were produced in Escherichia coli to study their antioxidant effects. All four recombinant phycocyanins could be produced in the soluble form and purified to more than 97% purity. The results of radical scavenging assays showed that the Trolox equivalent values for peroxyl radical scavenging by the ApcA, ApcB, CpcA, and CpcB proteins were 1.81 ± 0.2 µM, 1.98 ± 0.22 µM, 0.95 ± 0.15 µM, and 1.49 ± 0.15 µM, respectively. The IC50 values for hydroxyl radical scavenging of ApcA, ApcB, CpcA, CpcB, and Trolox were 269 ± 9 µg/mL, 190 ± 5 µg/mL, 129 ± 8 µg/mL, 108 ± 4 µg/mL, and 195 ± 12 µg/mL, respectively. These results indicated that allophycocyanin exhibited higher activity than c-phycocyanin in scavenging peroxyl radicals, whereas c-phycocyanin exhibited higher activity than allophycocyanin in scavenging hydroxyl radicals. All of the apo-phycocyanin subunits possessed strong antioxidant activities and can be further developed and applied to the food and drug industries. However, the selection of the most useful antioxidant should depend on the type of targeted free radical to obtain the highest efficiency. © 2014 Society for Laboratory Automation and Screening.

Effect of heat shock preconditioning on ROS scavenging activity in rat skeletal muscle after downhill running.

PubMed

Shima, Yosuke; Kitaoka, Katsuhiko; Yoshiki, Yumiko; Maruhashi, Yoshinobu; Tsuyama, Takeshi; Tomita, Katsuro

2008-10-01

The mechanisms of the protective effect conferred by heat shock preconditioning (HS) are currently unknown. The purpose of this study was to determine the effect of HS on muscle injury after downhill running and to address the mechanism of the effect. Female Wistar rats were assigned to three groups: HS, downhill running (E), and downhill running after heat shock preconditioning (HS + E). The HS and HS + E rats were placed in a heat chamber for 60 min (ambient temperature 42 +/- 1.0 degrees C) 48 h before downhill running. Reactive oxygen species (ROS) scavenging activity was determined by electron spin resonance (ESR), and heat shock protein 72 (HSP72) mRNA expression was measured in rat quadriceps femoris. Leukocyte infiltration and degenerated muscle fibers were determined histopathologically. ROS scavenging activity significantly increased at 3 days after HS (151 +/- 18%) and HSP72 mRNA expression increased immediately after HS (1750 +/- 1914%). No decrease in ROS scavenging activity was observed in the HS + E rats at 2 days after exercise compared with the E rats (102 +/- 9% vs. 79 +/- 5%). Degenerated muscle fibers in HS + E rats were significantly less than in E rats at 2, 3, and 7 days after exercise (0.8 +/- 1.0 vs. 2.8 +/- 1.6, 0.8 +/- 1.0 vs. 1.8 +/- 1.6, 0 vs. 0.3 +/- 0.6, respectively). These data demonstrated that HS can reduce muscle injury after downhill running, and this effect may be mediated by increased ROS scavenging activity. Furthermore, HS may protect the antioxidant defense system in skeletal muscle by enhancing the adaptive HSP72 mRNA response.

Surveillance of avian influenza virus type A in semi-scavenging ducks in Bangladesh

PubMed Central

2013-01-01

Background Ducks are the natural reservoir of influenza A virus and the central host for highly pathogenic avian influenza (H5N1), while domestic ducks rearing in semi-scavenging system could serve as re-assortment vessels for re-emerging new subtypes of influenza viruses between birds to human. Avian influenza virus (AIV) surveillance in Bangladesh has been passive, relying on poultry farmers to report suspected outbreaks of highly pathogenic H5N1 influenza. Here, the results of an active surveillance effort focusing on the semi-scavenging ducks are presented. Result A total of 2100 cloacal swabs and 2100 sera were collected from semi-scavenging ducks from three wintering-sites of Bangladesh during three successive winter seasons, December through February in the years between 2009 and 2012. Virus isolation and identification were carried out from the cloacal swabs by virus propagation in embryonated hen eggs followed by amplification of viral RNA using Avian influenza virus (AIV) specific RT-PCR. The overall prevalence of avian influenza type A was 22.05% for swab samples and 39.76% ducks were sero-positive for avian influenza type A antibody. Extremely low sero-prevalence (0.09%) of AIV H5N1 was detected. Conclusions Based on our surveillance results, we conclude that semi-scavenging ducks in Bangladesh might play important role in transmitting Avian Influenza virus (AIV) type A. However, the current risk of infection for humans from domestic ducks in Bangladesh is negligible. We believe that this relatively large dataset over three winters in Bangladesh might create a strong foundation for future studies of AIV prevalence, evolution, and ecology in wintering sites around the globe. PMID:24099526

Scavenger removal: Bird and bat carcass persistence in a tropical wind farm

NASA Astrophysics Data System (ADS)

Villegas-Patraca, Rafael; Macías-Sánchez, Samuel; MacGregor-Fors, Ian; Muñoz-Robles, Carlos

2012-08-01

Energy produced by wind farms has diverse positive environmental effects, but can also be related to negative impacts, including wildlife mortality through collisions with wind turbines. Bird and bat mortality caused by collisions with wind turbines can be estimated indirectly by counting carcasses within wind farms. However, carcass removal by scavengers often biases such measurements. In this study, we identified the main scavengers removing bird and bat carcasses in a tropical wind farm. A known fate analysis was done to assess the effect of carcass type (i.e., small bird, large bird, bat), vegetation type (i.e., secondary vegetation, croplands) and season (dry and rainy seasons of 2009) on carcass persistence rates. We identified three main scavenger groups, with mammals being the most abundant group. Our results show high rates of carcass removal relative to previous studies, especially for bats; there were fewer remaining carcasses after 20 days in our tropical site than in non-tropical environments reported elsewhere. We found a higher carcass persistence rate during the rainy season than in the dry season, possibly due to a greater abundance of food resources for scavenger organisms in the rainy season. Although we found some evidence for higher persistence rates for large bird carcasses than for small bird and bat carcasses during the rainy season, overall carcass type was not a strong predictor of persistence rates. Similarly, we did not find a strong effect of vegetation type on carcass persistence rates. Results suggest that in order to estimate accurate bird and bat mortality in tropical wind farm areas, seasonality should be incorporated to correction factors of carcass removal rates.

Antioxidant and Antilipid Peroxidation Potential of Supercritical Fluid Extract and Ethanol Extract of Leaves of Vitex Negundo Linn.

PubMed Central

Nagarsekar, K. S.; Nagarsenker, M. S.; Kulkarni, S. R.

2011-01-01

Supercritical fluid extract and ethanol extract of Vitex negundo Linn. were subjected to the chromatographic evaluation for identification of their constituents. Free radical scavenging activity of both extracts was studied by subjecting them to DPPH assay. IC50 values of ethanol and supercritical fluid extract of Vitex negundo indicate that ethanol extract has stronger reducing potential and ability to scavenge free radicals as compared to the supercritical fluid extract. The in vivo effect of extracts on lipid peroxidation was studied using ethanol induced oxidative stress model in rat. Ingestion of extracts for 14 days exhibited significant reduction in plasma MDA level of stressed animals. Ethanol extract exhibited higher in vivo antilipid peroxidation potential as compared to supercritical fluid extract which correlated well with radical scavenging potential of extract. PMID:22707827

High-performance liquid chromatography coupled with post-column dual-bioactivity assay for simultaneous screening of xanthine oxidase inhibitors and free radical scavengers from complex mixture.

PubMed

Li, D Q; Zhao, J; Li, S P

2014-06-06

Xanthine oxidase (XO) can catalyze hypoxanthine and xanthine to generate uric acid and reactive oxygen species (ROS), including superoxide anion radical (O₂(•-)) and hydrogen peroxide. XO inhibitors and free radical scavengers are beneficial to the treatment of gout and many related diseases. In the present study, an on-line high-performance liquid chromatography (HPLC) coupled with post-column dual-bioactivity assay was established and successfully applied to simultaneously screening of XO inhibitors and free radical scavengers from a complex mixture, Oroxylum indicum extract. The integrated system of HPLC separation, bioactivity screening and mass spectrometry identification was proved to be simple and effective for rapid and sensitive screening of individual bioactive compounds in complex mixtures. Copyright © 2014 Elsevier B.V. All rights reserved.

Bioefficacy of Graviola leaf extracts in scavenging free radicals and upregulating antioxidant genes.

PubMed

Son, Yu-Ra; Choi, Eun-Hye; Kim, Goon-Tae; Park, Tae-Sik; Shim, Soon-Mi

2016-02-01

The aims of this study were to determine bioactive components of Graviola leaf extracts and to examine the radical scavenging capacity, gene expression and transcription factors of antioxidant enzymes. Rutin, kaempferol-rutinoside, and vitamin U were identified from the steaming and 50% EtOH extracts of Graviola leaves. Graviola leaf extracts effectively scavenged peroxy and nitrogen radicals. 50% EtOH of Graviola leaves provided a 1-2.9 times higher trolox equivalent than the steaming extract. It also had a higher VCEAC. Graviola leaf extracts reduced the generation of reactive oxygen species (ROS) induced by H2O2 in a dose-dependent manner. The 50% EtOH extract of Graviola leaves upregulated SOD1 and Nrf2, but catalase and HMOX1 were not altered by the 50% EtOH extract of Graviola leaves.

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.

Edible solid lipid nanoparticles (SLN) as carrier system for antioxidants of different lipophilicity

PubMed Central

Oehlke, Kathleen; Behsnilian, Diana; Mayer-Miebach, Esther; Weidler, Peter G.; Greiner, Ralf

2017-01-01

Ferulic acid (FA) and tocopherol (Toc) loaded solid lipid nanoparticles (SLN) were prepared by a hot homogenisation method. The particle size distribution, zeta potential and melting behaviour of the SLN as well as the stability, encapsulation efficiency and radical scavenging activity of FA and Toc in the SLN were analysed. The different formulations containing up to 2.8 mg g−1 of FA or Toc were stable during at least 15 weeks of storage at room temperature. Despite partial degradation and / or release of FA and Toc during storage, significant radical scavenging activity was maintained. DSC measurements and radical scavenging tests after different time periods revealed that the re-structuring of the lipid matrix was connected to the enhanced antioxidant activity of Toc but did not affect the activity of FA. PMID:28192494

Antioxidant Potential of White Oyster Culinary-Medicinal Mushroom, Pleurotus florida (Higher Basidiomycetes).

PubMed

Ganeshpurkar, Aditya; Pardhi, Priya; Bhadoriya, Santosh Singh; Jain, Nikhil; Rai, Gopal; Jain, Alok Pal

2015-01-01

The present work was focused to evaluate in vitro antioxidant of Pleurotus florida. The hydroethanolic extract was prepared by macerating basidiocarp with water:ethanol (1:1). The antioxidant potential was evaluated by 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical scavenging activity, reducing power, chelating effects on ferrous ions, total antioxidant capacity, and lipid peroxidation inhibitory activity. Further total flavonoid and phenolic content was also estimated. The comparison between different antioxidant assays was done by correlation coefficient. The results from the antioxidant assays showed that hydroethanolic extract (HEE) might act as radical scavenger to a certain extent. The distinct scavenging activities of HEE can be due to the diverse phytochemical constituents. Being a rich source of antioxidants, P. florida can be used as an accessible source of natural antioxidants with consequential health benefits.

Increasing the Air Charge and Scavenging the Clearance Volume of a Compression-Ignition Engine

NASA Technical Reports Server (NTRS)

Spanogle, J A; Hicks, C W; Foster, H H

1934-01-01

The object of the investigation presented in this report was to determine the effects of increasing the air charge and scavenging the clearance volume of a 4-stroke-cycle compression-ignition engine having a vertical-disk form combustion chamber. Boosting the inlet-air pressure with normal valve timing increased the indicated engine power in proportion to the additional air inducted and resulted in smoother engine operation with less combustion shock. Scavenging the clearance volume by using a valve overlap of 145 degrees and an inlet-air boost pressure of approximately 2 1/2 inches of mercury produced a net increase in performance for clear exhaust operation of 33 percent over that obtained with normal valve timing and the same boost pressure. The improved combustion characteristics result in lower specific fuel consumption, and a clearer exhaust.

Hybrid isotope separation scheme

DOEpatents

Maya, Jakob

1991-01-01

A method of yielding selectively a desired enrichment in a specific isotope including the steps of inputting into a spinning chamber a gas from which a scavenger, radiating the gas with a wave length or frequency characteristic of the absorption of a particular isotope of the atomic or molecular gas, thereby inducing a photochemical reaction between the scavenger, and collecting the specific isotope-containing chemical by using a recombination surface or by a scooping apparatus.

Overexpression of CaAPX Induces Orchestrated Reactive Oxygen Scavenging and Enhances Cold and Heat Tolerances in Tobacco

PubMed Central

Wang, Jiangying; Wu, Bin; Fan, Zhengqi; Li, Xinlei; Ni, Sui

2017-01-01

Ascorbate peroxidase (APX) acts indispensably in synthesizing L-ascorbate (AsA) which is pivotal to plant stress tolerance by detoxifying reactive oxygen species (ROS). Enhanced activity of APX has been shown to be a key step for genetic engineering of improving plant tolerance. However it needs a deeper understanding on the maintenance of cellular ROS homeostasis in response to stress. In this study, we identified and characterized an APX (CaAPX) gene from Camellia azalea. Quantitative real-time PCR (qRT-PCR) analysis showed that CaAPX was expressed in all tissues and peaked in immature green fruits; the expression levels were significantly upregulated upon cold and hot stresses. Transgenic plants displayed marked enhancements of tolerance under both cold and heat treatments, and plant growth was correlated with CaAPX expression levels. Furthermore, we monitored the activities of several ROS-scavenging enzymes including Cu/Zn-SOD, CAT, DHAR, and MDHAR, and we showed that stress tolerance was synchronized with elevated activities of ROS-scavenging. Moreover, gene expression analysis of ROS-scavenging enzymes revealed a role of CaAPX to orchestrate ROS signaling in response to temperature stresses. Overall, this study presents a comprehensive characterization of cellular response related to CaAPX expression and provides insights to breed crops with high temperature tolerances. PMID:28386551

Advanced lipid peroxidation end products in oxidative damage to proteins. Potential role in diseases and therapeutic prospects for the inhibitors.

PubMed

Negre-Salvayre, A; Coatrieux, C; Ingueneau, C; Salvayre, R

2008-01-01

Reactive carbonyl compounds (RCCs) formed during lipid peroxidation and sugar glycoxidation, namely Advanced lipid peroxidation end products (ALEs) and Advanced Glycation end products (AGEs), accumulate with ageing and oxidative stress-related diseases, such as atherosclerosis, diabetes or neurodegenerative diseases. RCCs induce the 'carbonyl stress' characterized by the formation of adducts and cross-links on proteins, which progressively leads to impaired protein function and damages in all tissues, and pathological consequences including cell dysfunction, inflammatory response and apoptosis. The prevention of carbonyl stress involves the use of free radical scavengers and antioxidants that prevent the generation of lipid peroxidation products, but are inefficient on pre-formed RCCs. Conversely, carbonyl scavengers prevent carbonyl stress by inhibiting the formation of protein cross-links. While a large variety of AGE inhibitors has been developed, only few carbonyl scavengers have been tested on ALE-mediated effects. This review summarizes the signalling properties of ALEs and ALE-precursors, their role in the pathogenesis of oxidative stress-associated diseases, and the different agents efficient in neutralizing ALEs effects in vitro and in vivo. The generation of drugs sharing both antioxidant and carbonyl scavenger properties represents a new therapeutic challenge in the treatment of carbonyl stress-associated diseases.

Antioxidant capacity and radical scavenging effect of polyphenol rich Mallotus philippenensis fruit extract on human erythrocytes: an in vitro study.

PubMed

Gangwar, Mayank; Gautam, Manish Kumar; Sharma, Amit Kumar; Tripathi, Yamini B; Goel, R K; Nath, Gopal

2014-01-01

Mallotus philippinensis is an important source of molecules with strong antioxidant activity widely used medicinal plant. Previous studies have highlighted their anticestodal, antibacterial, wound healing activities, and so forth. So, present investigation was designed to evaluate the total antioxidant activity and radical scavenging effect of 50% ethanol fruit glandular hair extract (MPE) and its role on Human Erythrocytes. MPE was tested for phytochemical test followed by its HPLC analysis. Standard antioxidant assays like DPPH, ABTS, hydroxyl, superoxide radical, nitric oxide, and lipid peroxidation assay were determined along with total phenolic and flavonoids content. Results showed that MPE contains the presence of various phytochemicals, with high total phenolic and flavonoid content. HPLC analysis showed the presence of rottlerin, a polyphenolic compound in a very rich quantity. MPE exhibits significant strong scavenging activity on DPPH and ABTS assay. Reducing power showed dose dependent increase in concentration absorption compared to standard, Quercetin. Superoxide, hydroxyl radical, lipid peroxidation, nitric oxide assay showed a comparable scavenging activity compared to its standard. Our finding further provides evidence that Mallotus fruit extract is a potential natural source of antioxidants which have a protective role on human Erythrocytes exhibiting minimum hemolytic activity and this justified its uses in folklore medicines.

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. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

Fermentation of Smilax china root by Aspergillus usami and Saccharomyces cerevisiae promoted concentration of resveratrol and oxyresveratrol and the free-radical scavenging activity.

PubMed

Yoon, So-Ra; Yang, Seung-Hwan; Suh, Joo-Won; Shim, Soon-Mi

2014-07-01

Smilax china root, which is rich in resveratrol and oxyresveratrol, has been used as emergency foods as well as folk medicine. This study investigated changes in concentration of bioactive components and the free-radical scavenging capacity of Smilax china root during fermentation by Aspergillus usami and Saccharomyces cerevisiae. Resveratrol, oxyresveratrol and piceid were quantified as major constituents in Smilax china root by using UPLC-ESI-MS. The concentration of oxyresveratrol and resveratrol remarkably increased through fermentation and the transformation of piceid to resveratrol. Its concentration in 4% Smilax china root was 1.16-2.95 times higher than that of a 2% preparation throughout fermentation. The vitamin C equivalent antioxidant capacity of 2% Smilax china root was 1.51-1.91 times higher than that of 4% Smilax china root during fermentation. Meanwhile, ABTS free-radical scavenging capacity was enhanced up to 95.07 and 99.35% for 2% and 4% Smilax china root, respectively. Results from our study propose that bioactive components in Smilax China root were highly extracted by fermentation followed by saccharification and ethanol production, resulting in enhanced free-radical scavenging capacity. © 2013 Society of Chemical Industry. © 2013 Society of Chemical Industry.

Antioxidant Potential of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Higher Basidiomycetes) Cultivated on Artocarpus heterophyllus Sawdust Substrate in India.

PubMed

Rani, P; Lal, Merlin Rajesh; Maheshwari, Uma; Krishnan, Sreeram

2015-01-01

The artificial cultivation of Ganoderma lucidum (MTCC1039) using Artocarpus heterophyllus as sawdust substrate was optimized and free radical scavenging activities of the generated fruiting bodies were investigated. The choice of A. heterophyllus as substrate was due to its easy availability in South India. Sawdust supplemented with dextrose medium yielded better spawn hyphae and early fruiting body initiation (15 days). The biological yield obtained was 42.06 ± 2.14 g/packet and the biological efficiency was 8.41 ± 0.48%. Both aqueous and methanolic extracts of fruiting body were analyzed for radical scavenging activity. Methanolic extract showed maximum scavenging activity for 1,1-diphenyl-2-picrylhydrazyl (IC50 = 290 μg/ml) and 2,2'-azino-bis(3-ethylbenzothiazoline- 6-sulphonic acid (IC50 = 580 μg/ml), whereas aqueous extract had better scavenging for ferric reducing antioxidant power (IC50 = 5 μg/ml). Total phenolic content and total antioxidant capacity were significantly higher in methanolic extract (p < 0.01). A positive correlation existed between the phenolic content and antioxidant activity. Our results indicated that fruiting bodies of G. lucidum cultivated in sawdust medium possess antioxidant property, which can be exploited for therapeutic application.

HPLC PROFILING OF PHENOLIC ACIDS AND FLAVONOIDS AND EVALUATION OF ANTI-LIPOXYGENASE AND ANTIOXIDANT ACTIVITIES OF AQUATIC VEGETABLE LIMNOCHARIS FLAVA.

PubMed

Ooh, Keng-fei; Ong, Hean-Chooi; Wong, Fai-Chu; Chai, Tsun-Thai

2015-01-01

Limnocharis flava is an edible wetland plant, whose phenolic acid and flavonoid compositions as well as bioactivities were underexplored. This study analyzed the profiles of selected hydroxybenzoic acids, hydroxycinnamic acids and flavonoids in the aqueous extracts of L. flava leaf, rhizome and root by high performance liquid chromatography (HPLC). Anti-lipoxygenase and antioxidant (iron chelating, 2,2-diphenyl-l-picrylhydrazyl (DPPH) radical scavenging, and nitric oxide (NO) scavenging) activities of the extracts were also evaluated. Leaf extract had the highest phenolic contents, being most abundant in p-hydroxybenzoic acid (3861.2 nmol/g dry matter), ferulic acid (648.8 nmol/g dry matter), and rutin (4110.7 nmol/g dry matter). Leaf extract exhibited the strongest anti-lipoxygenase (EC50 6.47 mg/mL), iron chelating (EC50 6.65 mg/mL), DPPH scavenging (EC50 15.82 mg/mL) and NO scavenging (EC50 3.80 mg/mL) activities. Leaf extract also had the highest ferric reducing ability. This is the most extensive HPLC profiling of phenolic acids and flavonoids in L.flava to date. In conclusion, L. flava leaf is a source of health-promoting phenolics, anti-lipoxygenase agents and antioxidants.

[Resistance of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ to reactive oxygen species].

PubMed

Zhang, Shuwen; Lv, Jiaping; Menghe, Bilige; Zhang, Heping; Zhang, Liyu; Song, Jinhui; Wang, Zhifei

2009-02-01

We evaluated antioxidative effect of two antioxidative strains, isolated from the traditional fermented dairy products. Both intact cells and cell-free extract of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ were used to study the inhibited effect of linoleic acid peroxidation, the ability of scavenging 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, superoxide anion radical,the ability of tolerancing hydrogen peroxide and the chelating capacity of ferrous ion and reducting activity. Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ demonstrated highest inhibition on linoleic acid peroxidation by 62.95% and 66.16%, respectively. The cell-free extract showed excellent scavenging superoxide anion and hydroxyl radicals activity. However, the intact cells of Lactobacillus delbrueckii subsp. bulgaricus LJJ scavenging superoxide and hydroxyl radicals capacity were not detected. The intact cells of Lactobacillus casei subsp. casei SY13 and Lactobacillus delbrueckii subsp. bulgaricus LJJ on 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability and chelating ferrous ion capacity were superior to cell-free extract. The highest reduced activety was equivalent to 305 micromol/L and 294 micromol/L L-cysteine. Two latobacilli strains had good antioxidant capacity. As potential probiotics, it can be used in future.

Enhanced photo-degradation of paracetamol on n-platinum-loaded TiO2: The effect of ultrasound and OH/hole scavengers.

PubMed

Ziylan-Yavaş, Asu; Ince, Nilsun H

2016-11-01

Elimination/mineralization of paracetamol (PCT) was investigated by catalytic oxidation under ultrasound, UV and both. The catalyst was synthesized by immobilization of nPt on TiO2 to benefit from the ability of Pt to facilitate charge transfer processes and to separate e(-)/h(+) pairs. It was found that increasing the Pt-loading enhanced the rate of sonochemical reactions, but retarded that of photolytic reactions, due to reduced UV absorption on the surface. Simultaneous application of sonolysis and photolysis was synergistic due to disaggregation of the particles and homogenization of the active species over the catalyst surface. The decay of PCT was highly dependent on the availability of OH, as the reactions were nearly terminated in the presence of a strong OH scavenger-2-propanol. However, a remarkable rate enhancement was observed in the presence of a suitable dose of I(-), which scavenges both OH and hvb(+). The result was explained by the production of excess radicals upon sonolysis of iodide solutions, and the reactivity of PCT with them. Finally, carbon mineralization was significantly hindered in the presence of both scavengers due to increased competition for OH and inefficient formation of hydroquinone arising from reduced availability of hvb(+). Copyright © 2016 Elsevier Ltd. All rights reserved.

Electrochemically Reduced Water Protects Neural Cells from Oxidative Damage

PubMed Central

Hamasaki, Takeki; Kinjo, Tomoya; Nakamichi, Noboru; Teruya, Kiichiro; Kabayama, Shigeru

2014-01-01

Aging-related neurodegenerative disorders are closely associated with mitochondrial dysfunction and oxidative stresses and their incidence tends to increase with aging. Brain is the most vulnerable to reactive species generated by a higher rate of oxygen consumption and glucose utilization compared to other organs. Electrochemically reduced water (ERW) was demonstrated to scavenge reactive oxygen species (ROS) in several cell types. In the present study, the protective effect of ERW against hydrogen peroxide (H2O2) and nitric oxide (NO) was investigated in several rodent neuronal cell lines and primary cells. ERW was found to significantly suppress H2O2 (50–200 μM) induced PC12 and SFME cell deaths. ERW scavenged intracellular ROS and exhibited a protective effect against neuronal network damage caused by 200 μM H2O2 in N1E-115 cells. ERW significantly suppressed NO-induced cytotoxicity in PC12 cells despite the fact that it did not have the ability to scavenge intracellular NO. ERW significantly suppressed both glutamate induced Ca2+ influx and the resulting cytotoxicity in primary cells. These results collectively demonstrated for the first time that ERW protects several types of neuronal cells by scavenging ROS because of the presence of hydrogen and platinum nanoparticles dissolved in ERW. PMID:25383141

Influence of conventional and ultrasonic-assisted extraction on phenolic contents, betacyanin contents, and antioxidant capacity of red dragon fruit (Hylocereus polyrhizus).

PubMed

Ramli, Nurul Shazini; Ismail, Patimah; Rahmat, Asmah

2014-01-01

The aim of this study was to examine the effects of extraction methods on antioxidant capacities of red dragon fruit peel and flesh. Antioxidant capacities were measured using ethylenebenzothiozoline-6-sulfonic acid (ABTS) radical cation assay and ferric reducing antioxidant power assay (FRAP). Total phenolic content (TPC) was determined using Folin-Ciocalteu reagent while quantitative determination of total flavonoid content (TFC) was conducted using aluminium trichloride colorimetric method. Betacyanin content (BC) was measured by spectrophotometer. Red dragon fruit was extracted using conventional (CV) and ultrasonic-assisted extraction (UE) technique to determine the most efficient way of extracting its antioxidant components. Results indicated that UE increased TFC, reduced the extraction yield, BC, and TPC, but exhibited the strongest scavenging activity for the peel of red dragon fruit. In contrast, UE reduced BC, TFC, and scavenging activity but increased the yield for the flesh. Nonetheless, UE slightly increases TPC in flesh. Scavenging activity and reducing power were highly correlated with phenolic and flavonoid compounds. Conversely, the scavenging activity and reducing power were weakly correlated with betacyanin content. This work gives scientific evidences for the consideration of the type of extraction techniques for the peel and flesh of red dragon fruit in applied research and food industry.

A novel multi-hyphenated analytical method to simultaneously determine xanthine oxidase inhibitors and superoxide anion scavengers in natural products.

PubMed

Qi, Jin; Sun, Li-Qiong; Qian, Steven Y; Yu, Bo-Yang

2017-09-01

Natural products, such as rosmarinic acid and apigenin, can act as xanthine oxidase inhibitors (XOIs) as well as superoxide anion scavengers, and have potential for treatment of diseases associated with high uric acid levels and oxidative stress. However, efficient simultaneous screening of these two bioactivities in natural products has been challenging. We have developed a novel method by assembling a multi-hyphenated high performance liquid chromatography (HPLC) system that combines a photo-diode array, chemiluminescence detector and a HPLC system with a variable wavelength detector, to simultaneously detect components that act as both XOIs and superoxide anion scavengers in natural products. Superoxide anion scavenging activity in the analyte was measured by on-line chemiluminescence chromatography based on pyrogallol-luminol oxidation, while xanthine oxidase inhibitory activity was determined by semi-on-line HPLC analysis. After optimizing multiple elements, including chromatographic conditions (e.g., organic solvent concentration and mobile phase pH), concentrations of xanthine/xanthine oxidase and reaction temperature, our validated analytical method was capable of mixed sample analysis. The final results from our method are presented in an easily understood visual format including comprehensive bioactivity data of natural products. Copyright © 2017. Published by Elsevier B.V.

Antioxidant potential of n-butanol fraction from extract of Jasminum mesnyi Hance leaves.

PubMed

Borar, Sakshi; Punia, Priyanka; Kalia, A N

2011-01-01

Methanolic extract of Jasminum mesnyi Hance leaves having antidiabetic activity was subjected to fractionation to obtain antioxidant and antihyperglycemic rich fraction. Different concentrations of ethyl acetate and n-butanol fractions were subjected to antioxidant assay by DPPH method, nitric oxide scavenging activity and reducing power assay. The fractions showed dose dependent free radical scavenging property in all the models. IC50 values for ethyl acetate and n-butanol fractions were 153.45 +/- 6.65 and 6.22 +/- 0.25 microg/ml, respectively, as compared to L-ascorbic acid and rutin (as standards; IC50 values 6.54 +/- 0.24 and 5.43 +/- 0.21 microg/ml, respectively) in DPPH model. In nitric oxide scavenging activity, IC50 values were 141.54 +/- 9.95 microg/ml, 35.12 +/- 1.58 microg/ml, 21.06 +/- 0.95 microg/ml and 29.93 +/- 0.32 microg/ml for ethyl acetate, n-butanol fractions, L-ascorbic acid and rutin, respectively. n-Butanol fraction showed a good reducing potential and better free radical scavenging activity as compared to ethyl acetate fraction. Potent antioxidant n-butanol fraction showed better oral glucose tolerance test (antihyperglycemic) at par with metformin (standard drug), n-Butanol fraction contained secoiridoid glycosides which might be responsible for both antioxidant and antihyperglycemic activity.

Separation of nanoparticles: Filtration and scavenging from waste incineration plants.

PubMed

Förster, Henning; Thajudeen, Thaseem; Funk, Christine; Peukert, Wolfgang

2016-06-01

Increased amounts of nanoparticles are applied in products of everyday life and despite material recycling efforts, at the end of their life cycle they are fed into waste incineration plants. This raises the question on the fate of nanoparticles during incineration. In terms of environmental impact the key question is how well airborne nanoparticles are removed by separation processes on their way to the bag house filters and by the existing filtration process based on pulse-jet cleanable fibrous filter media. Therefore, we investigate the scavenging and the filtration of metal nanoparticles under typical conditions in waste incineration plants. The scavenging process is investigated by a population balance model while the nanoparticle filtration experiments are realized in a filter test rig. The results show that depending on the particle sizes, in some cases nearly 80% of the nanoparticles are scavenged by fly ash particles before they reach the bag house filter. For the filtration step dust cakes with a pressure drop of 500Pa or higher are found to be very effective in preventing nanoparticles from penetrating through the filter. Thus, regeneration of the filter must be undertaken with care in order to guarantee highly efficient collection of particles even in the lower nanometre size regime. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Antioxidant Capacity and Radical Scavenging Effect of Polyphenol Rich Mallotus philippenensis Fruit Extract on Human Erythrocytes: An In Vitro Study

PubMed Central

Gautam, Manish Kumar; Sharma, Amit Kumar; Tripathi, Yamini B.; Goel, R. K.; Nath, Gopal

2014-01-01

Mallotus philippinensis is an important source of molecules with strong antioxidant activity widely used medicinal plant. Previous studies have highlighted their anticestodal, antibacterial, wound healing activities, and so forth. So, present investigation was designed to evaluate the total antioxidant activity and radical scavenging effect of 50% ethanol fruit glandular hair extract (MPE) and its role on Human Erythrocytes. MPE was tested for phytochemical test followed by its HPLC analysis. Standard antioxidant assays like DPPH, ABTS, hydroxyl, superoxide radical, nitric oxide, and lipid peroxidation assay were determined along with total phenolic and flavonoids content. Results showed that MPE contains the presence of various phytochemicals, with high total phenolic and flavonoid content. HPLC analysis showed the presence of rottlerin, a polyphenolic compound in a very rich quantity. MPE exhibits significant strong scavenging activity on DPPH and ABTS assay. Reducing power showed dose dependent increase in concentration absorption compared to standard, Quercetin. Superoxide, hydroxyl radical, lipid peroxidation, nitric oxide assay showed a comparable scavenging activity compared to its standard. Our finding further provides evidence that Mallotus fruit extract is a potential natural source of antioxidants which have a protective role on human Erythrocytes exhibiting minimum hemolytic activity and this justified its uses in folklore medicines. PMID:25525615

Control of scavenger receptor-mediated endocytosis by novel ligands of different length.

PubMed

Guaderrama-Díaz, Margarita; Solís, Carlos F; Velasco-Loyden, Gabriela; Laclette, Juan P; Mas-Oliva, Jaime

2005-03-01

The scavenger receptor recognized as a multiligand family of receptors falls in the group that is internalised through endocytosis. In this report we used several recombinant fragments of the tapeworm protein paramyosin, known to form filamentous dimers that bind collagenous structures as ligands of different length for the class A type I scavenger receptor (SR-AI). While native CHO cells are unresponsive to any of the recombinant fragments, it is shown that CHO cells transfected with this receptor efficiently internalise recombinant fragments that correspond to two thirds of the full-length paramyosin. In contrast, recombinant products corresponding to one-third of the full-length paramyiosin are not internalised. It is also shown that important molecules in the organization of the coated pit, are enriched when the two-thirds long paramyosin fragments were bound and internalised through the SR-AI. Moreover, internalisation of these fragments trigger a classical apoptotic pathway shown by the presence of TUNEL positive cells and the appearance of apoptotic bodies. We report paramyosin as a new ligand for the scavenger receptor and provide evidence supporting the notion that these receptors upon the formation of arrays with length-specific molecules, not only trigger endocytosis but also seem to regulate the synthesis of molecules involved in the organization of coated pits.

Ecological Potential for Rabies Virus Transmission via Scavenging of Dead Bats by Mesocarnivores.

PubMed

Theimer, Tad C; Dyer, Annie C; Keeley, Brian W; Gilbert, Amy T; Bergman, David L

2017-04-01

Multiple species of bats are reservoirs of rabies virus in the Americas and are occasionally the source of spillover infections into mesocarnivore species. Although rabies transmission generally is assumed to occur via bite, laboratory studies have demonstrated the potential for rabies transmission via ingestion of rabid animals. We investigated the ecological potential for this mode of transmission by assessing mesocarnivore scavenging behavior of dead bats in suburban habitats of Flagstaff, Arizona, US. In autumn 2013, summer 2014, and autumn 2015, we placed 104 rabies-negative bat carcasses either near buildings, in wildland areas, or in residential yards and then monitored them with trail cameras for 5 d. Overall, 52 (50%) bat carcasses were scavenged, with 39 (75%) of those scavenged by striped skunks ( Mephitis mephitis ). Within our study area, striped skunks had a higher ecological potential to contract rabies via ingestion of bat carcasses compared to other mesocarnivore species, due both to a greater number of encounters and a higher probability of ingestion per encounter (91%), and they were significantly more likely to approach bat carcasses in yards than in wildland areas. Raccoons ( Procyon lotor ) and gray foxes ( Urocyon cinereoargenteus ) had fewer encounters (nine and 13, respectively) and lower probability of ingesting bats (33% and 8%, respectively).

Particle scavenging in a cylindrical ultrasonic standing wave field using levitated drops

NASA Astrophysics Data System (ADS)

Merrell, Tyler; Saylor, J. R.

2015-11-01

A cylindrical ultrasonic standing wave field was generated in a tube containing a flow of particles and fog. Both the particles and fog drops were concentrated in the nodes of the standing wave field where they combined and then grew large enough to fall out of the system. In this way particles were scavenged from the system, cleaning the air. While this approach has been attempted using a standing wave field established between disc-shaped transducers, a cylindrical resonator has not been used for this purpose heretofore. The resonator was constructed by bolting three Langevin transducers to an aluminum tube. The benefit of the cylindrical geometry is that the acoustic energy is focused. Furthermore, the residence time of the particle in the field can be increased by increasing the length of the resonator. An additional benefit of this approach is that tubes located downstream of the resonator were acoustically excited, acting as passive resonators that enhanced the scavenging process. The performance of this system on scavenging particles is presented as a function of particle diameter and volumetric flow rate. It is noted that, when operated without particles, the setup can be used to remove drops and shows promise for liquid aerosol retention from systems where these losses can be financially disadvantageous and/or hazardous.

Overexpression of CaAPX Induces Orchestrated Reactive Oxygen Scavenging and Enhances Cold and Heat Tolerances in Tobacco.

PubMed

Wang, Jiangying; Wu, Bin; Yin, Hengfu; Fan, Zhengqi; Li, Xinlei; Ni, Sui; He, Libo; Li, Jiyuan

2017-01-01

Ascorbate peroxidase (APX) acts indispensably in synthesizing L-ascorbate (AsA) which is pivotal to plant stress tolerance by detoxifying reactive oxygen species (ROS). Enhanced activity of APX has been shown to be a key step for genetic engineering of improving plant tolerance. However it needs a deeper understanding on the maintenance of cellular ROS homeostasis in response to stress. In this study, we identified and characterized an APX ( CaAPX ) gene from Camellia azalea . Quantitative real-time PCR (qRT-PCR) analysis showed that CaAPX was expressed in all tissues and peaked in immature green fruits; the expression levels were significantly upregulated upon cold and hot stresses. Transgenic plants displayed marked enhancements of tolerance under both cold and heat treatments, and plant growth was correlated with CaAPX expression levels. Furthermore, we monitored the activities of several ROS-scavenging enzymes including Cu/Zn-SOD , CAT , DHAR , and MDHAR , and we showed that stress tolerance was synchronized with elevated activities of ROS-scavenging. Moreover, gene expression analysis of ROS-scavenging enzymes revealed a role of CaAPX to orchestrate ROS signaling in response to temperature stresses. Overall, this study presents a comprehensive characterization of cellular response related to CaAPX expression and provides insights to breed crops with high temperature tolerances.

Influence of Conventional and Ultrasonic-Assisted Extraction on Phenolic Contents, Betacyanin Contents, and Antioxidant Capacity of Red Dragon Fruit (Hylocereus polyrhizus)

PubMed Central

Ramli, Nurul Shazini; Ismail, Patimah; Rahmat, Asmah

2014-01-01

The aim of this study was to examine the effects of extraction methods on antioxidant capacities of red dragon fruit peel and flesh. Antioxidant capacities were measured using ethylenebenzothiozoline-6-sulfonic acid (ABTS) radical cation assay and ferric reducing antioxidant power assay (FRAP). Total phenolic content (TPC) was determined using Folin-Ciocalteu reagent while quantitative determination of total flavonoid content (TFC) was conducted using aluminium trichloride colorimetric method. Betacyanin content (BC) was measured by spectrophotometer. Red dragon fruit was extracted using conventional (CV) and ultrasonic-assisted extraction (UE) technique to determine the most efficient way of extracting its antioxidant components. Results indicated that UE increased TFC, reduced the extraction yield, BC, and TPC, but exhibited the strongest scavenging activity for the peel of red dragon fruit. In contrast, UE reduced BC, TFC, and scavenging activity but increased the yield for the flesh. Nonetheless, UE slightly increases TPC in flesh. Scavenging activity and reducing power were highly correlated with phenolic and flavonoid compounds. Conversely, the scavenging activity and reducing power were weakly correlated with betacyanin content. This work gives scientific evidences for the consideration of the type of extraction techniques for the peel and flesh of red dragon fruit in applied research and food industry. PMID:25379555

The melanin synthesis inhibition and radical scavenging activities of compounds isolated from the aerial part of Lespedeza cyrtobotrya.

PubMed

Lee, Mi Yeon; Kim, Jin Hee; Choi, Jung Nam; Kim, Jiyoung; Hwang, Geum Sook; Lee, Choonghwan

2010-06-01

The EtOAc fraction of Lespedeza cyrtobotrya showed mushroom tyrosinase inhibitory and radical scavenging activity. Four active compounds were isolated based on LH-20 chromatography and HPLC, and the structures were elucidated on the basis of their LC-MS and NMR spectral data, as 2-(2,4-Dihydroxyphenyl)-6-hydroxybenzofuran (1), eriodictyol-7-O-glucopyranoside (2), haginin A (3), and dalbergioidin (4), respectively. 2-(2,4-Dihydroxyphenyl)-6-hydroxybenzofuran (1) showed mushroom tyrosinase inhibitory activity with an IC50 value of 5.2 micronM and acted as a competitive inhibitor. Furthermore, 37.3 micronM of compound 1 reduced 50 % of the melanin content on a human melanoma (MNT-1) cells. The radical scavenging activity of 2-(2,4-dihydroxyphenyl)-6-hydroxybenzofuran (1), eriodictyol-7-O-glucopyranoside (2), haginin A (3), and dalbergioidin (4) was shown with IC50 values of 11.0, 24.5, 9.0 and 36.5 micronM in an ABTS system and with IC50 values of 42.7, 36.0, 37.7 and 61.7 micronM in a DPPH system, respectively. The mushroom tyrosinase inhibitory activity of EtOAc fraction of Lespedeza cyrtobotrya was contributed by compound 1, 3 and 4, and radical scavenging activity of it was contributed by compound 1-4.

Antioxidant and Protective Effect of Ethyl Acetate Extract of Podophyllum Hexandrum Rhizome on Carbon Tetrachloride Induced Rat Liver Injury

PubMed Central

Ganie, Showkat Ahmad; Haq, Ehtishamul; Masood, Akbar; Hamid, Abid; Zargar, Mohmmad Afzal

2011-01-01

The antioxidant and hepatoprotective activities of ethyl acetate extract was carefully investigated by the methods of DPPH radical scavenging activity, Hydroxyl radical scavenging activity, Superoxide radical scavenging activity, Hydrogen peroxide radical scavenging activity and its Reducing power ability. All these in vitro antioxidant activities were concentration dependent which were compared with standard antioxidants such as BHT, α-tocopherol. The hepatoprotective potential of Podophyllum hexandrum extract was also evaluated in male Wistar rats against carbon tetrachloride (CCl4)-induced liver damage. Pre-treated rats were given ethyl acetate extract at 20, 30 and 50 mg/kg dose prior to CCl4 administration (1 ml/kg, 1:1 in olive oil). Rats pre-treated with Podophyllum hexandrum extract remarkably prevented the elevation of serum AST, ALT, LDH and liver lipid peroxides in CCl4-treated rats. Hepatic glutathione levels were significantly increased by the treatment with the extract in all the experimental groups. The extract at the tested doses also restored the levels of liver homogenate enzymes (glutathione peroxidase, glutathione reductase, superoxide dismutase and glutathione-S- transferase) significantly. This study suggests that ethyl acetate extract of P. hexandrum has a liver protective effect against CCl4-induced hepatotoxicity and possess in vitro antioxidant activities. PMID:21394192

Environmentally compatible solid rocket propellants

NASA Technical Reports Server (NTRS)

Jacox, James L.; Bradford, Daniel J.

1995-01-01

Hercules' clean propellant development research is exploring three major types of clean propellant: (1) chloride-free formulations (no chlorine containing ingredients), being developed on the Clean Propellant Development and Demonstration (CPDD) contract sponsored by Phillips Laboratory, Edwards Air Force Base, CA; (2) low HCl scavenged formulations (HCl-scavenger added to propellant oxidized with ammonium perchlorate (AP)); and (3) low HCl formulations oxidized with a combination of AN and AP (with or without an HCl scavenger) to provide a significant reduction (relative to current solid rocket boosters) in exhaust HCl. These propellants provide performance approaching that of current systems, with less than 2 percent HCl in the exhaust, a significant reduction (greater than or equal to 70 percent) in exhaust HCl levels. Excellent processing, safety, and mechanical properties were achieved using only readily available, low cost ingredients. Two formulations, a sodium nitrate (NaNO3) scavenged HTPB and a chloride-free hydroxy terminated polyether (HTPE) propellant, were characterized for ballistic, mechanical, and rheological properties. In addition, the hazards properties were demonstrated to provide two families of class 1.3, 'zero-card' propellants. Further characterization is planned which includes demonstration of ballistic tailorability in subscale (one to 70 pound) motors over the range of burn rates required for retrofit into current Hercules space booster designs (Titan 4 SRMU and Delta 2 GEM).

Characteristic Vertical Profiles of Cloud Water Composition in Marine Stratocumulus Clouds and Relationships With Precipitation

NASA Astrophysics Data System (ADS)

MacDonald, Alexander B.; Dadashazar, Hossein; Chuang, Patrick Y.; Crosbie, Ewan; Wang, Hailong; Wang, Zhen; Jonsson, Haflidi H.; Flagan, Richard C.; Seinfeld, John H.; Sorooshian, Armin

2018-04-01

This study uses airborne cloud water composition measurements to characterize the vertical structure of air-equivalent mass concentrations of water-soluble species in marine stratocumulus clouds off the California coast. A total of 385 cloud water samples were collected in the months of July and August between 2011 and 2016 and analyzed for water-soluble ionic and elemental composition. Three characteristic profiles emerge: (i) a reduction of concentration with in-cloud altitude for particulate species directly emitted from sources below cloud without in-cloud sources (e.g., Cl- and Na+), (ii) an increase of concentration with in-cloud altitude (e.g., NO2- and formate), and (iii) species exhibiting a peak in concentration in the middle of cloud (e.g., non-sea-salt SO42-, NO3-, and organic acids). Vertical profiles of rainout parameters such as loss frequency, lifetime, and change in concentration with respect to time show that the scavenging efficiency throughout the cloud depth depends strongly on the thickness of the cloud. Thin clouds exhibit a greater scavenging loss frequency at cloud top, while thick clouds have a greater scavenging loss frequency at cloud base. The implications of these results for treatment of wet scavenging in models are discussed.

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.