Sample records for pyrocatechol
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Monitoring of pyrocatechol indoor air pollution
NASA Astrophysics Data System (ADS)
Eškinja, I.; Grabarić, Z.; Grabarić, B. S.
Spectrophotometric and electrochemical methods for monitoring of pyrocatechol (PC) indoor air pollution have been investigated. Spectrophotometric determination was performed using Fe(III) and iodine methods. The adherence to Beer's law was found in the concentration range between 0 and 12 μg ml - for iodine method at pH = 5.7 measuring absorbance at 725 nm, and in the range 0-30 μg ml - for Fe(III) method at pH = 9.5 measuring absorbance at 510 nm. The former method showed greater sensitivity than the latter one. Differential pulse voltammetry (DPV) and chronoamperometric (CA) detection in flow injection analysis (FIA) using carbon paste electrode in phosphate buffer solution of pH = 6.5 was also used for pyrocatechol determination. The electrochemical methods allowed pyrocatechol quantitation in submicromolar concentration level with an overall reproducibility of ± 1%. The efficiency of pyrocatechol sampling collection was investigated at two temperatures (27 and 40°C) in water, 0.1 M NaOH and 0.1 M HCl solutions. Solution of 0.1 M HCl gave the best collection efficiency (95.5-98.5%). A chamber testing simulating the indoor pollution has been performed. In order to check the reliability of the proposed methods for monitoring of the indoor pyrocatechol pollution, the air in working premises with pyrocatechol released from meteorological charts during mapping and paper drying was analyzed using proposed methods. The concentration of pyrocatechol in the air during mapping was found to be 1.8 mg m -3 which is below the hygienic standard of permissible exposure of 20 mg m -3 (≈ 5 ppm). The release of pyrocatechol from the paper impregnated with pyrocatechol standing at room temperature during one year was also measured. The proposed methods can be used for indoor pyrocatechol pollution monitoring in working premises of photographic, rubber, oil and dye industries, fur and furniture dyeing and cosmetic or pharmaceutical premises where pyrocatechol and related compounds are in use.
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[Isolation and purification of Mn-peroxidase from Azospirillum brasilense Sp245].
Kupriashina, M A; Selivanov, N Iu; Nikitina, V E
2012-01-01
Homogenous Mn-peroxidase of a 26-fold purity grade was isolated from a culture of Azospirillum brasilense Sp245 cultivated on a medium containing 0.1 mM pyrocatechol. The molecular weight of the enzyme is 43 kD as revealed by electrophoresis in SDS-PAAG. It was shown that the use of pyrocatechol and 2,2'-azino-bis(3-ethylbenzotiazoline-6-sulfonate) at concentrations of 0.1 and I mM as inductors increased the Mn-peroxidase activity by a factor of 3.
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Su, Jing; Sun, Yuan-Qiang; Huo, Fang-Jun; Yang, Yu-Tao; Yin, Cai-Xia
2010-11-01
A novel strategy for the determination of oxalate anions was successfully established using a copper ion and pyrocatechol violet (PV) ensemble. The sensor ensemble can discriminate oxalate over other common anions including F(-), Cl(-), I(-), Br(-), HPO(4)(2-), PO(4)(3-), AcO(-), CO(3)(2-), SO(4)(2-), ClO(4)(-), P(2)O(7)(4-), S(2-) (deposited by Ag(+)), CN(-) (shielded by Fe(3+)) and can detect oxalate at low microgram levels in quasi-physiological aqueous solutions. The detection of the oxalate anion gives rise to a rapid observable visual color change from blue to yellow.
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Shivakiran, M S; Venkataramana, M; Lakshmana Rao, P V
2016-01-01
Dipicolinic acid (DPA) is an important chemical marker for the detection of bacterial spores. In this study, complexes of lanthanide series elements such as erbium, europium, neodymium, and terbium were prepared with pyrocatechol violet and effectively immobilized the pyrocatechol violet (PV)-metal complex on a filter paper using polyvinyl alcohol. These filter paper strips were employed for the onsite detection of bacterial spores. The test filter papers were evaluated quantitatively with different concentrations of DPA and spores of various bacteria. Among the four lanthanide ions, erbium displayed better sensitivity than the other ions. The limit of detection of this test for DPA was 60 μM and 5 × 10(6) spores. The effect of other non-spore-forming bacteria and interfering chemicals on the test strips was also evaluated. The non-spore-forming bacteria did not have considerable effect on the test strip whereas chemicals such as EDTA had significant effects on the test results. The present test is rapid and robust, capable of providing timely results for better judgement to save resources on unnecessary decontamination procedures during false alarms.
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Lebedev, A V; Ivanova, M V; Timoshin, A A; Ruuge, E K
2008-01-01
Ca2+-induced increase in the rate of pyrocatechol and dopamine oxidation by dioxygen and Ca2+-dependent acid-base properties of the catechols were studied by potentiometric titration, UV/Vis-spectrophotometry, EPR-spectroscopy, and by measurement of oxygen consumption. The effect of Ca2+ on the chain reactions of oxidation can be explained by additional deprotonation (decrease in pKai) of the catechols that accelerates one electron transport to dioxygen and formation of calcium semiquinonate, undergoing further oxidation. The described Ca2+-dependent redox-conversion of ortho-phenols proposes that an additional function of calcium in the cell can be its involvement in free radical oxidoreductive reactions at pH > pKai.
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Zhu, Jun; Wu, Xiao-Yan; Shan, Dan; Yuan, Pei-Xin; Zhang, Xue-Ji
2014-12-01
In this work, the electrodeposition of pyrocatechol violet (PCV) was initially investigated by the electrochemical surface plasmon resonance (ESPR) technique. Subsequently, PCV was used as redox-mediator and was electrodeposited on the surface of pencil graphite electrode (PGE) modified with single-wall carbon nanotubes (SWCNTs). Owing to the remarkable synergistic effect of SWCNTs and PCV, PGE/SWCNTs/PCV exhibited excellent electrocatalytic activity towards dihydronicotinamide adenine dinucleotide (NADH) oxidation at low potential (0.2V vs. SCE) with fast amperometric response (<10s), broad linear range (1.3-280 μM), good sensitivity (146.2 μA mM(-1)cm(-2)) and low detection limit (1.3 μM) at signal-to-noise ratio of 3. Thus, this PGE/SWCNTs/PCV could be further used to fabricate a sensitive and economic ethanol biosensor using alcohol dehydrogenase (ADH) via a glutaraldehyde/BSA cross-linking procedure. Copyright © 2014 Elsevier B.V. All rights reserved.
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Amin, A S
2001-03-01
A fairly sensitive, simple and rapid spectrophotometric method for the determination of some beta-lactam antibiotics, namely ampicillin (Amp), amoxycillin (Amox), 6-aminopenicillanic acid (6APA), cloxacillin (Clox), dicloxacillin (Diclox) and flucloxacillin sodium (Fluclox) in bulk samples and in pharmaceutical dosage forms is described. The proposed method involves the use of pyrocatechol violet as a chromogenic reagent. These drugs produce a reddish brown coloured ion pair with absorption maximum at 604, 641, 645, 604, 649 and 641 nm for Amp, Amox, 6APA, Clox, Diclox and Flucolx, respectively. The colours produced obey Beer's law and are suitable for the quantitative determination of the named compounds. The optimization of different experimental conditions is described. The molar ratio of the ion pairs was established and a proposal for the reaction pathway is given. The procedure described was applied successfully to determine the examined drugs in dosage forms and the results obtained were comparable to those obtained with the official methods.
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2013-01-01
Background For clinicians, it is important to rely on accurate laboratory results for patient care and optimal use of health care resources. We sought to explore our observations that urine protein:creatinine ratios (PrCr) ≥30 mg/mmol are seen not infrequently associated with normal pregnancy outcome. Methods Urine samples were collected prospectively from 160 pregnant women attending high-risk maternity clinics at a tertiary care facility. Urinary protein was measured using a pyrocatechol violet assay and urinary creatinine by an enzymatic method on Vitros analysers. Maternal/perinatal outcomes were abstracted from hospital records. Results 91/233 (39.1%) samples had a PrCr ≥30 mg/mmol, especially when urinary creatinine concentration was <3 mM (94.1%) vs. ≥3 mM (16.4%) (p < 0.001). When using the last sample before delivery, 47/160 (29.4%) had a PrCr ≥30 mg/mmol in diluted urine vs. only 17/160 (15.4%) in more concentrated urine (p < 0.001); PrCr positive results were also more frequent among the 32 (20.0%) women with known normal pregnancy outcome (90.9% vs. 0) (p < 0.001). Using the same analyser, 0.12 g/L urinary protein was ‘detected’ in deionised water. Re-analysis of data from two cohorts revealed substantially less inflation of PrCr in dilute urine using a pyrogallol red assay. Conclusions Random urinary PrCr was overestimated in dilute urine when tested using a common pyrocatechol violet dye-based method. This effect was reduced in cohorts when pyrogallol red assays were used. False positive results can impact on diagnosis and patient care. This highlights the need for both clinical and laboratory quality improvement projects and standardization of laboratory protein measurement. PMID:23865673
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NASA Astrophysics Data System (ADS)
Gao, Zhiyong; Liu, Xiao; Chang, Jiuli; Wu, Dapeng; Xu, Fang; Zhang, Lingcui; Du, Weimin; Jiang, Kai
2017-01-01
Graphene incorporated, N doped activated carbons (GNACs) are synthesized by alkali activation of graphene-polypyrrole composite (G-PPy) at different temperatures for application as electrode materials of supercapacitors. Under optimal activation temperature of 700 °C, the resultant samples, labeled as GNAC700, owns hierarchically porous texture with high specific surface area and efficient ions diffusion channels, N, O functionalized surface with apparent pseudocapacitance contribution and high wettability, thus can deliver a moderate capacitance, a high rate capability and a good cycleability when used as supercapacitor electrode. Additionally, the GNAC700 electrode demonstrates high catalytic activity for the redox reaction of pyrocatechol/o-quinone pair in H2SO4 electrolyte, thus enables a high pseudocapacitance from electrolyte. Under optimal pyrocatechol concentration in H2SO4 electrolyte, the electrode capacitance of GNAC700 increases by over 4 folds to 512 F g-1 at 1 A g-1, an excellent cycleability is also achieved simultaneously. Pyridinic- N is deemed to be responsible for the high catalytic activity. This work provides a promising strategy to ameliorate the capacitive performances of supercapacitors via the synergistic interaction between redox-active electrolyte and catalytic electrodes.
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Zheng, Ren-Chao; Tang, Xiao-Ling; Suo, Hui; Feng, Li-Lin; Liu, Xiao; Yang, Jian; Zheng, Yu-Guo
2018-05-01
Tyrosine phenol-lyase (TPL) catalyzes the reversible cleavage of l-tyrosine to phenol, pyruvate and ammonia. When pyrocatechol is substituted for phenol, l-dihydroxyphenylalanine (l-DOPA) is produced. The TPL-catalyzed route was regarded as the most economic process for l-DOPA production. In this study, a novel TPL from Fusobacterium nucleatum (Fn-TPL) was successfully overexpressed in Escherichia coli and screened for l-DOPA synthesis with a specific activity of 2.69Umg -1 . Fn-TPL was found to be a tetramer, and the optimal temperature and pH for α, β-elimination of l-tyrosine was 60°C and pH 8.5, respectively. The enzyme showed broad substrate specificity toward natural and synthetic l-amino acids. Kinetic analysis suggested that the k cat /K m value for l-tyrosine decomposition was much higher than that for l-DOPA decomposition, while Fn-TPL exhibited similar catalytic efficiency for synthesis of l-tyrosine and l-DOPA. With whole cells of recombinant E. coli as biocatalyst, l-DOPA yield reached 110gL -1 with a pyrocatechol conversion of 95%, which was comparable to the reported highest level. The results demonstrated the great potential of Fn-TPL for industrial production of l-DOPA. Copyright © 2017 Elsevier Inc. All rights reserved.
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1996-06-01
switches 5-43 Figure 5-27. Mechanical interference between ’Pull Spring’ devices 5-45 Figure 5-28. Array of LIGA mechanical relay switches 5-49...like coating DM Direct metal interconnect technique DMD ™ Digital Micromirror Device EDP Ethylene, diamine, pyrocatechol and water; silicon anisotropic...mechanical systems MOSIS MOS Implementation Service PGA Pin grid array, an electronic die package PZT Lead-zirconate-titanate LIGA Lithographie
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Radioprotective property of the ethanolic extract of Piper betel Leaf.
Bhattacharya, Sayanti; Subramanian, Mahesh; Roychowdhury, Susri; Bauri, Ajay K; Kamat, Jaya P; Chattopadhyay, Subrata; Bandyopadhyay, Sandip Kumar
2005-06-01
The radioprotective activity of Piper betel ethanolic extract (PE) has been studied using rat liver mitochondria and pBR 322 plasmid DNA as two model in vitro systems. The extract effectively prevented gamma-ray induced lipid peroxidation as assessed by measuring thiobarbituric acid reactive substrates, lipid hydroperoxide and conjugated diene. Likewise, it prevented radiation-induced DNA strand breaks in a concentration dependent manner. The radioprotective activity of PE could be attributed to its hydroxyl and superoxide radicals scavenging property along with its lymphoproliferative activity. The radical scavenging capacity of PE was primarily due to its constituent phenolics, which were isolated and identified as chevibetol and allyl pyrocatechol.
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Method for increasing subterranean formation permeability
DOE Office of Scientific and Technical Information (OSTI.GOV)
Harvey, R.R.
1966-09-06
In a waterflooding operation the water premeability of the reservoir rock may be improved be adding certain chemical compounds to the waterflood. These compounds are selected from a group consisting of quebracho, pyrocatechole and hydroquinone. The amounts of chemicals used are in the ranges of 0.01 to 10 wt % based on floodwater. In one aspect of the method, the reservoir rock is rendered perferentially oil-wet by injecting quebracho tannin with the floodwater in an amount ranging from 0.5 to 5.0 wt % based on floodwater. In this case the floodwater should have a pH range of 7 to 14.more » (6 claims)« less
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Thermometric titration studies of mixed ligand complexes of thorium.
Kugler, G C; Carey, G H
1970-10-01
Mixed-ligand chelates consisting of two different multidentate ligands linked to a central thorium(IV) ion have been prepared in aqueous solution and their heats of formation studied thermo metrically. Pyrocatechol, tiron, chromotropic acid, potassium hydrogen phthalate, 8-hydroxyquinoline-S-sulphonic acid, iminodiacetic acid, 5-sulphosalicylic acid and salicylic acid were used as the secondary ligands, while ethylenediaminetetra-acetate and 1, 2-diaminocyclohexane-N,N,N',N'-tetra-acetate were used as primary ligands. DeltaH values for the overall reactions are given, and where possible, the DeltaH and DeltaS values for the specific secondary ligand addition were calculated. The overall stability of the mixed-ligand chelates and the enhanced stability of EDTA mixed chelates relative to the analogous DCTA chelates were found to be due to entropy rather than enthalpy effects.
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DOE Office of Scientific and Technical Information (OSTI.GOV)
Evreinova, T.N.; Kuzin, A.M.; Kryukova, L.M.
1976-01-01
The purpose of the study was to determine the possibility of stabilization of protein-carbohydrate and protein-nucleic acid systems by products of the abiogenic oxidation of pyrocatechol, pyrogallol, and o-dianisidine using the energy of gamma radiation. The protein-nucleic acid system was produced by mixing the following reagents: histone, DNA, acetate buffer, and a solution of oxidized compounds. The protein-carbohydrate system was produced by mixing the following reagents: histone, gum arabic, acetate buffer, and a solution of oxidized compounds. Results indicated that the stabilization of coacervate systems occurs when stabilizing low-molecular-weight compounds of the type of quinones and the imino form ofmore » o-dianisidine are included in them. These compounds may be formed under the action of physical factors without the participation of enzymes. (HLW)« less
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Micromachined mold-type double-gated metal field emitters
NASA Astrophysics Data System (ADS)
Lee, Yongjae; Kang, Seokho; Chun, Kukjin
1997-12-01
Electron field emitters with double gates were fabricated using micromachining technology and the effect of the electric potential of the focusing gate (or second gate) was experimentally evaluated. The molybdenum field emission tip was made by filling a cusplike mold formed when a conformal film was deposited on the hole-trench that had been patterned on stacked metals and dielectric layers. The hole-trench was patterned by electron beam lithography and reactive ion etching. Each field emitter has a 0960-1317/7/4/009/img1 diameter extraction gate (or first gate) and a 0960-1317/7/4/009/img2 diameter focusing gate (or second gate). To make a path for the emitted electrons, silicon bulk was etched anisotropically in KOH and EDP (ethylene-diamine pyrocatechol) solution successively. The I - V characteristics and anode current change due to the focusing gate potential were measured.
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[On the enzymatics of the microbial breakdown of pyrazone (author's transl)].
Sauber, K; Blobel, F; Haug, S; Eberspächer, J
1976-07-01
From samples of earth taken in different parts of the world bacteria were isolated which grow on pyrazone as the only source of carbon. When these bacteria are grown in a pyrazone mineral salt medium, four compounds are excreted into the medium. The structures of these compounds furnish information on the catabolic route of pyrazone. Since the suggested scheme of breakdown was incomplete, enzymatic tests were carried out to clarify the matter. It was possible to carry out the first steps of breakdown also in the cell-free extract of the pyrazone-degrading bacteria. For the second step of pyrazone breakdown, 2 different enzymes of the same catalytic activity were identified. For the oxidative cleavage of the pyrocatechole derivative 2 different enzymes were found: an ortho- and a meta-clearing enzyme. The 2-hydroxy muconic acid decarboxylase was identified as a further enzyme. The importance of this enzyme is discussed in connection with the further breakdown.
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Hernandez, Silvia R; Kergaravat, Silvina V; Pividori, Maria Isabel
2013-03-15
An approach based on the electrochemical detection of the horseradish peroxidase enzymatic reaction by means of square wave voltammetry was developed for the determination of phenolic compounds in environmental samples. First, a systematic optimization procedure of three factors involved in the enzymatic reaction was carried out using response surface methodology through a central composite design. Second, the enzymatic electrochemical detection coupled with a multivariate calibration method based in the partial least-squares technique was optimized for the determination of a mixture of five phenolic compounds, i.e. phenol, p-aminophenol, p-chlorophenol, hydroquinone and pyrocatechol. The calibration and validation sets were built and assessed. In the calibration model, the LODs for phenolic compounds oscillated from 0.6 to 1.4 × 10(-6) mol L(-1). Recoveries for prediction samples were higher than 85%. These compounds were analyzed simultaneously in spiked samples and in water samples collected close to tanneries and landfills. Published by Elsevier B.V.
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Shekari, Nafiseh; Vosough, Maryam; Tabar Heidar, Kourosh
2018-05-01
In the current study, gas chromatography-mass spectrometry (GC-MS) fingerprinting of herbal slimming pills assisted by chemometric methods has been presented. Deconvolution of two-way chromatographic signals of nine herbal slimming pills into pure chromatographic and spectral patterns was performed. The peak clusters were resolved using multivariate curve resolution-alternating least squares (MCR-ALS) by employing appropriate constraints. It was revealed that more useful chemical information about the composition of the slimming pills can be obtained by employing sophisticated GC-MS method coupled with proper chemometric tools yielding the extended number of identified constituents. The thorough fingerprinting of the complex mixtures proved the presence of some toxic or carcinogen components, such as toluene, furfural, furfuryl alcohol, styrene, itaconic anhydride, citraconic anhydride, trimethyl phosphate, phenol, pyrocatechol, p-propenylanisole and pyrogallol. In addition, some samples were shown to be adulterated with undeclared ingredients, including stimulants, anorexiant and laxatives such as phenolphthalein, amfepramone, caffeine and sibutramine. Copyright © 2018 Elsevier B.V. All rights reserved.
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Immunomodulatory Activity of Oenothein B Isolated from Epilobium angustifolium1
Schepetkin, Igor A.; Kirpotina, Liliya N.; Jakiw, Larissa; Khlebnikov, Andrei I.; Blaskovich, Christie L.; Jutila, Mark A.; Quinn, Mark T.
2009-01-01
Epilobium angustifolium has been traditionally used to treat of a number of diseases; however, not much is known regarding its effect on innate immune cells. Here, we report that extracts of E. angustifolium activated functional responses in neutrophils and monocyte/macrophages. Activity-guided fractionation, followed by mass spectroscopy and NMR analysis, resulted in the identification of oenothein B as the primary component responsible for phagocyte activation. Oenothein B, a dimeric hydrolysable tannin, dose-dependently induced a number of phagocyte functions in vitro, including intracellular Ca2+ flux, production of reactive oxygen species (ROS), chemotaxis, nuclear factor (NF)-κB activation, and proinflammatory cytokine production. Furthermore, oenothein B was active in vivo, inducing keratinocyte chemoattractant (KC) production and neutrophil recruitment to the peritoneum after intraperitoneal administration. Biological activity required the full oenothein B structure, as substructures of oenothein B (pyrocatechol, gallic acid, pyrogallol, 3,4-dihydroxybenzoic acid) were all inactive. The ability of oenothein B to modulate phagocyte functions in vitro and in vivo suggests that this compound is responsible for at least part of the therapeutic properties of E. angustifolium extracts. PMID:19846877
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Jeong, Jae-Yong; Lee, Uen-Do; Chang, Won-Seok; Jeong, Soo-Hwa
2016-11-01
In this study, palm residues were pyrolyzed in a bench-scale (3kg/h) fast pyrolysis plant equipped with a fluidized bed reactor and bio-oil separation system for the production of bio-oil rich in acetic acid and phenol. Pyrolysis experiments were performed to investigate the effects of reaction temperature and the types and amounts of activated carbon on the bio-oil composition. The maximum bio-oil yield obtained was approximately 47wt% at a reaction temperature of 515°C. The main compounds produced from the bio-oils were acetic acid, hydroxyacetone, phenol, and phenolic compounds such as cresol, xylenol, and pyrocatechol. When coal-derived activated carbon was applied, the acetic acid and phenol yields in the bio-oils reached 21 and 19wt%, respectively. Finally, bio-oils rich in acetic acid and phenol could be produced separately by using an in situ bio-oil separation system and activated carbon as an additive. Copyright © 2016 Elsevier Ltd. All rights reserved.
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Comparison of twin-cell centrifugal partition chromatographic columns with different cell volume.
Goll, Johannes; Audo, Gregoire; Minceva, Mirjana
2015-08-07
Two twin-cell centrifugal partition chromatographic columns (SCPC 250 and SCPE-250-BIO, Armen Instrument, France) with the same column volume but different cell size and number were compared in terms of stationary phase retention and column efficiency. The columns were tested with two types of solvent systems: a commonly used organic solvent based biphasic system from the ARIZONA solvent system family and a polymer/salt based aqueous two phase system (ATPS). The efficiency of the columns was evaluated by pulse injection experiments of two benzenediols (pyrocatechol and hydroquinone) in the case of the ARIZONA system and a protein mixture (myoglobin and lysozyme) in the case of the ATPS. As result of high stationary phase retention, the column with the lower number of larger twin-cells (SCPE-250-BIO) is suitable for protein separations using ATPS. On the other hand, due to higher column efficiency, the column with the greater number of smaller cells (SCPC 250) is superior for batch elution separations performed with standard liquid-liquid chromatography organic solvent based biphasic systems. Copyright © 2015 Elsevier B.V. All rights reserved.
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Role of degradation products of chlorogenic acid in the antioxidant activity of roasted coffee.
Kamiyama, Masumi; Moon, Joon-Kwan; Jang, Hae Won; Shibamoto, Takayuki
2015-02-25
Antioxidant activities of brewed coffees prepared from six commercial brands ranged from 63.13 ± 1.01 to 96.80 ± 1.68% at the highest levels tested. Generally, the degree of antioxidant activity of the brewed coffee was inversely proportional to the total chlorogenic acid concentration. A sample obtained from the major chlorogenic acid, 5-caffeoylquinic acid (5-CQA), heated at 250 °C exhibited potent antioxidant activity (79.12 ± 2.49%) at the level of 10 μg/mL, whereas unheated 5-CQA showed only moderate antioxidant activity (44.41 ± 0.27%) at the level of 100 μg/mL. Heat produced relatively high levels of pyrocatechol (2,809.3 μg/g) and 2-methoxy-4-vinylphenol (46.4 μg/g) from 5-CQA, and their antioxidant activity levels were 76.57 ± 3.00 and 98.63 ± 0.01%, respectively. The results of the present study suggest that roasting degrades chlorogenic acids to form potent antioxidants and thus plays an important role in the preparation of high-antioxidant low-acid coffee.
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Arroyo, Fátima; Font, Oriol; Fernández-Pereira, Constantino; Querol, Xavier; Juan, Roberto; Ruiz, Carmen; Coca, Pilar
2009-08-15
In this study the purity of the germanium end-products obtained by two different precipitation methods carried out on germanium-bearing solutions was evaluated as a last step of a hydrometallurgy process for the recovery of this valuable element from the Puertollano Integrated Gasification Combined Cycle (IGCC) fly ash. Since H(2)S is produced as a by-product in the gas cleaning system of the Puertollano IGCC plant, precipitation of germanium as GeS(2) was tested by sulfiding the Ge-bearing solutions. The technological and hazardous issues that surround H(2)S handling conducted to investigate a novel precipitation procedure: precipitation as an organic complex by adding 1,2-dihydroxy benzene pyrocatechol (CAT) and cetyltrimethylammonium bromide (CTAB) to the Ge-bearing solutions. Relatively high purity Ge end-products (90 and 93% hexagonal-GeO(2) purity, respectively) were obtained by precipitating Ge from enriched solutions, as GeS(2) sulfiding the solutions with H(2)S, or as organic complex with CAT/CTAB mixtures and subsequent roasting of the precipitates. Both methods showed high efficiency (>99%) to precipitate selectively Ge using a single precipitation stage from germanium-bearing solutions.
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Kumar, Vinay; Maitra, S S
2016-12-01
Bacteria of the genus Methylobacillus are methanotrophs, a metabolic feature that is widespread in the phylum Proteobacteria. The study demonstrates the isolation and characterization of a newly isolated Methylobacillus sp. V29b. which grows on methanol, protocatechuate, monobutyl phthalate, dibutyl phthalate, diethyl phthalate, benzyl butyl phthalate, dioctyl phthalate and diisodecyl phthalate. Methylobacillus sp. V29b was characterized with scanning electron microscopy, transmission electron microscopy, Gram staining, antibiotics sensitivity tests and biochemical characterization. It degrades 70 % of the initial DBP in minimal salt medium and 65 % of the initial DBP in samples contaminated with DBP. DBP biodegradation kinetics was explained by the Monod growth inhibition model. Values for maximum specific growth rate (µ max ) and half-velocity constant (K s ) are 0.07 h -1 and 998.2 mg/l, respectively. Stoichiometry for DBP degradation was calculated for Methylobacillus sp. V29b. Four metabolic intermediates, dibutyl phthalate (DBP), monobutyl phthalate, phthalic acid and pyrocatechol, were identified. Based on the metabolic intermediates identified, a chemical pathway for DBP degradation was proposed. Six genes for phthalic acid degradation were identified from the genome of Methylobacillus sp. V29b.
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Tuzen, Mustafa; Uluozlu, Ozgur Dogan; Mendil, Durali; Soylak, Mustafa; Machado, Luana O R; Dos Santos, Walter N L; Ferreira, Sergio L C
2018-04-15
This paper proposes a simple, rapid and green ultrasound assisted and ionic liquid dispersive microextraction procedure using pyrocatechol violet (PV) as complexing reagent and 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide [C 6 MIM][Tf 2 N] as ionic liquid for the detection of tin employing electrothermal atomic absorption spectrometry (ETAAS). The optimization step was performed using a two-level full factorial design involving the following factors: pH of the working media, amount reagents, ionic liquid volume and extraction time and the chemometric response was tin recovery. The procedure allowed the determination of tin with limits of detection and quantification of 3.4 and 11.3 ng L -1 , respectively. The relative standard deviation was 4.5% for a tin solution of 0.50 µg L -1 . The validation method was confirmed by analysis of rice flour certified reference material. The method was applied for the quantification of tin in several food samples. The concentration range found varied from 0.10 to 1.50 µg g -1 . Copyright © 2017 Elsevier Ltd. All rights reserved.
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Pereira, Catarina Guerreiro; Barreira, Luísa; da Rosa Neng, Nuno; Nogueira, José Manuel Florêncio; Marques, Cátia; Santos, Tamára F; Varela, João; Custódio, Luísa
2017-09-01
Aromatic halophyte plants are an outstanding source of bioactive compounds and natural products with potential use in the food industry. This work reports the in vitro antioxidant activity, toxicity, polyphenolic profile and mineral contents of infusions and decoctions from stems, leaves and flowers of Crithmum maritimum L., an aromatic and edible maritime halophyte (sea fennel). Aspalathus linearis (Burm.f.) Dahlg. (rooibos) herbal tea was used as a reference. Sea fennel's tisanes, particularly from leaves, were rich in phenolic compounds and five of them (p-hydroxybenzoic and ferulic acids, epicatechin, pyrocatechol and 4-hydroxybenzaldehyde) were here described in C. maritimum for the first time. Chlorogenic acid was the dominant phenolic determined. Na was the most abundant mineral in all tisanes followed by Ca and Mg in leaves' tisanes and K in flowers. Sea fennel's samples had a similar antioxidant activity than those from A. linearis, and had no significant toxicity towards four different mammalian cell lines. Altogether, our results suggest that sea fennel can be a source of products and/or molecules for the food industry with antioxidant properties and minerals in the form, for example, of innovative health-promoting herbal beverages. Copyright © 2017 Elsevier Ltd. All rights reserved.
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Yurlova, N.A.; de Hoog, G.S.; Fedorova, L.G.
2008-01-01
Dothideaceous black yeast-like fungi (BYF) are known to synthesise DHN-melanin that is inhibited by the systemic fungicide tricyclazole. The final step of the DHN melanin pathway is the conjoining of 1,8-DHN molecules to form the melanin polymer. There are several candidate enzymes for this step, including phenoloxidases such as tyrosinase and laccases, peroxidases, and perhaps also catalases. We analysed the type polyphenoloxidases that are involved in biosynthesis of BYF melanins. For that purpose we used substrates of o-diphenoloxidases (EC 1.10.3.1.): 4-hydroxyphenyl-pyruvic acid, L-β-phenyllactic acid, tyrosine, pyrocatechol, 3,4-dihydroxyphenylalanine and homogentisic acid, as well as substrates of p-diphenoloxidases (EC 1.10.3.2.): syringaldazine, resorcinol, p-phenylenediamine, phloroglucinol, guaiacol and pyrogallic acid. Fourteen strains of black yeasts originating from different natural biotopes were investigated. The tested strains could be divided into four groups based on their ability to produce dark pigments when cultivated on aromatic substrates of o- and on p-diphenoloxidases. It was established that syringaldazine, pyrogallic acid and 4-hydrophenyl-pyruvic acid, β-phenyllactic acid optimally promote melanin biosynthesis. Average intensity of pigmentation of all strains studied was minimal when guaiacol was used as a substrate. The present investigation indicates that the melanisation process may involve more enzymes and more substrates than those commonly recognised. Black yeasts are likely to contain a multipotent polyphenoloxidase. PMID:19287525
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Kergaravat, Silvina V; Pividori, Maria Isabel; Hernandez, Silvia R
2012-01-15
The electrochemical detection for horseradish peroxidase-cosubstrate-H(2)O(2) systems was optimized. o-Phenilendiamine, phenol, hydroquinone, pyrocatechol, p-chlorophenol, p-aminophenol and 3,3'-5,5'-tetramethylbenzidine were evaluated as cosubstrates of horseradish peroxidase (HRP) enzyme. Therefore, the reaction time, the addition sequence of the substrates, the cosubstrate:H(2)O(2) ratio and the electrochemical techniques were elected by one-factor optimization assays while the buffer pH, the enzymatic activity and cosubstrate and H(2)O(2) concentrations for each system were selected simultaneously by response surface methodology. Then, the calibration curves for seven horseradish peroxidase-cosubstrate-H(2)O(2) systems were built and the analytic parameters were analyzed. o-Phenilendiamine was selected as the best cosubstrate for the HRP enzyme. For this system the reaction time of 60s, the phosphate buffer pH 6.0, and the concentrations of 2.5×10(-4)molL(-1) o-phenilendiamine and of 1.25×10(-4)molL(-1) H(2)O(2) were chosen as the optimal conditions. In these conditions, the calibration curve of horseradish peroxidase by square wave voltammetry showed a linearity range from 9.5×10(-11) to 1.9×10(-8)molL(-1) and the limit of detection of 3.8×10(-11)molL(-1) with RSD% of 0.03% (n=3). Copyright © 2011 Elsevier B.V. All rights reserved.
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Mushrooms as possible antioxidant and antimicrobial agents.
Kosanić, Marijana; Ranković, Branislav; Dašić, Marko
2012-01-01
The aim of the study is to examine in-vitro antioxidant and antimicrobial activity of the acetonic and methanolic extracts of the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini. Antioxidant activity was evaluated by using free radical scavenging activity and reducing power. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. As a result of the study acetonic extracts from Boletus edulis was more powerful antioxidant activity with IC50 value of 4.72 μg/mL which was similar or greater than the standard antioxidants, ascorbic acid (IC50 = 4.22 μg/mL), BHA (IC50 = 6.42 μg/mL) and α-tocopherol (IC50 = 62.43 μg/mL). Moreover, the tested extracts had effective reducing power. A significant relationship between total phenolic and flavonoid contents and their antioxidative activities was significantly observed. The antimicrobial activity of each extract was estimated by determination of the minimum inhibitory concentration by using microdilution plate method against five species of bacteria and five species of fungi. Generally, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi were 1.25 - 10 mg/ mL. The present study shows that tested mushroom species demonstrated a strong antioxidant and antimicrobial activity. It suggests that mushroom may be used as good sources of natural antioxidants and for pharmaceutical purposes in treating of various deseases.
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Biodegradation of naphthalene and phenanthren by Bacillus subtilis 3KP
NASA Astrophysics Data System (ADS)
Ni'matuzahroh, Trikurniadewi, N.; Pramadita, A. R. A.; Pratiwi, I. A.; Salamun, Fatimah, Sumarsih, Sri
2017-06-01
The purposes of this research were to know growth response, degradation ability, and uptake mechanism of naphthalene and phenanthrene by Bacillus subtilis 3KP. Bacillus subtilis 3KP was grown on Mineral Synthetic (MS) medium with addition of 1% yeast extract and naphthalene and phenanthrene respectively 200 ppm in different cultures. Bacillus subtilis 3KP growth response was monitored by Total Plate Count (TPC) method, the degradation ability was monitored by UV-Vis spectrophotometer, and the uptake mechanism of hydrocarbon was monitored by emulsification activity, decrease of surface tension, and activity of Bacterial Adherence to Hydrocarbon (BATH). Bacillus subtilis 3KP was able to grow and show biphasic growth pattern on both of substrates. Naphthalene and phenanthrene were used as a carbon source for Bacillus subtilis 3KP growth that indicated by the reduction of substrate concomitant with the growth. At room temperature conditions (± 30°C) and 90 rpm of agitation for 7 days, Bacillus subtilis 3KP could degrade naphthalene in the amount of 70.5% and phenanthrene in the amount of 24.8%. Based on the analysis of UV-Vis spectrophotometer, three metabolites, 1-hydroxy-2-naphthoic acid, salicylic acid, and pyrocatechol were found in both cultures. The metabolite identification became basis of propose degradation pathway of naphthalene and phenanthrene by Bacillus subtilis 3KP. The results of hydrocarbon uptake mechanism test show that Bacillus subtilis 3KP used all of the mechanism to degrade naphthalene and phenanthrene.
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Kosanić, Marijana; Ranković, Branislav; Rančić, Aleksandar; Stanojković, Tatjana
2016-07-01
This study is designed for the determination of metal concentrations, antioxidant, antimicrobial, and anticancer potential of two edible mushrooms Lactarius deliciosus and Macrolepiota procera. Concentrations of nine metals are determined and all metals are present in the allowable concentrations in the tested mushrooms except Cd in M. procera. Antioxidant activity was evaluated by free radical scavenging and reducing power. M. procera extract had more potent free radical scavenging activity (IC 50 =311.40 μg/mL) than L. deliciosus extract. Moreover, the tested extracts had effective reducing power. The total content of phenol in the extracts was examined using Folin-Ciocalteu reagent and obtained values expressed as pyrocatechol equivalents. Further, the antimicrobial potential was determined with a microdilution method on 15 microorganisms. Among the tested species, extract of L. deliciosus showed a better antimicrobial activity with minimum inhibitory concentration values ranging from 2.5 mg/mL to 20 mg/mL. Finally, the cytotoxic activity was tested using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method on human epithelial carcinoma HeLa cells, human lung carcinoma A549 cells, and human colon carcinoma LS174 cells. Extract of both mushrooms expressed similar cytotoxic activity with IC 50 values ranging from 19.01 μg/mL to 80.27 μg/mL. Copyright © 2016. Published by Elsevier B.V.
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Svane, Simon; Kjeldsen, Frank; McKee, Vickie; McKenzie, Christine J
2015-07-14
The three dimetallic compounds [Ga2(bpbp)(OH)2(H2O)2](ClO4)3, [In2(bpbp)(CH3CO2)2](ClO4)3 and [Zn2(bpbp)(HCO2)2](ClO4) (bpbp(-) = 2,6-bis((N,N'-bis(2-picolyl)amino)methyl)-4-tertbutylphenolate) were evaluated as stable solid state precursors for reactive solution state receptors to use for the recognition of the biologically important anion pyrophosphate in water at neutral pH. Indicator displacement assays using in situ generated complex-pyrocatechol violet adducts, {M2(bpbp)(HxPV)}(n+) M = Ga(3+), In(3+), Zn(2+), were tested for selectivity in their reactions with a series of common anions: pyrophosphate, phosphate, ATP, arsenate, nitrate, perchlorate, chloride, sulfate, formate, carbonate and acetate. The receptor employing Ga(3+) showed a slow but visually detectable response (blue to yellow) in the presence of one equivalent of pyrophosphate but no response to any other anion, even when they were present in much higher concentrations. The systems based on In(3+) or Zn(2+) show less selectivity in accord with visibly discernible responses to several of the anions. These results demonstrate a facile method for increasing anion selectivity without modification of an organic dinucleating ligand scaffold. The comfortable supramolecular recognition of pyrophosphate by the dimetallic complexes is demonstrated by the single crystal X-ray structure of [Ga2(bpbp)(HP2O7)](ClO4)2 in which the pyrophosphate is coordinated to the two gallium ions via four of its oxygen atoms.
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Mushrooms as Possible Antioxidant and Antimicrobial Agents
Kosanić, Marijana; Ranković, Branislav; Dašić, Marko
2012-01-01
The aim of the study is to examine in-vitro antioxidant and antimicrobial activity of the acetonic and methanolic extracts of the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini. Antioxidant activity was evaluated by using free radical scavenging activity and reducing power. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. As a result of the study acetonic extracts from Boletus edulis was more powerful antioxidant activity with IC50 value of 4.72 μg/mL which was similar or greater than the standard antioxidants, ascorbic acid (IC50 = 4.22 μg/mL), BHA (IC50 = 6.42 μg/mL) and α-tocopherol (IC50 = 62.43 μg/mL). Moreover, the tested extracts had effective reducing power. A significant relationship between total phenolic and flavonoid contents and their antioxidative activities was significantly observed. The antimicrobial activity of each extract was estimated by determination of the minimum inhibitory concentration by using microdilution plate method against five species of bacteria and five species of fungi. Generally, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi were 1.25 - 10 mg/ mL. The present study shows that tested mushroom species demonstrated a strong antioxidant and antimicrobial activity. It suggests that mushroom may be used as good sources of natural antioxidants and for pharmaceutical purposes in treating of various deseases. PMID:24250542
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Kageyama, C; Kato, K; Iyozumi, H; Inagaki, H; Yamaguchi, A; Furuse, K; Baba, K
2006-01-01
Biophotons are ultraweak light emissions from biochemical reactions in a living body. They increase in suspension-cultured rice (Oryza sativa L.) cells when elicited by N-acetylchitooligosaccharide. Biochemical analyses were undertaken to investigate the relationship between disease response and biophotons in order to clarify the emission mechanism of biophotons caused by this elicitor. Photon emissions induced by N-acetylchitohexaose were suppressed when cells were pretreated with the reactive oxygen species (ROS)-generating inhibitors: pyrocatechol-3,5-disulfonic acid disodium salt (Tiron); diphenylene iodonium (DPI); and salicylhydroxamic acid (SHAM). Conversely, exogenously applied ROS (superoxide and hydrogen peroxide) were able to induce photon emissions. The effects of protein phosphorylation (K-252a) and the Ca(2+) signaling inhibitors, ethylene glycol-bis(beta-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA) and LaCl(3), caused photon emissions to decrease. It is clear that photon emissions from rice cells elicited by N-acetylchitohexaose are closely associated with the ROS-generating system, and are regulated by Ca(2+) signaling and protein phosphorylation. Exogenously applied phosphatidic acid (PA), the second messenger in the signal transduction of disease response, raised photon emissions in rice cells. Comparisons of photon emissions from PA and N-acetylchitohexaose regarding time courses, spectral compositions, and the inhibition ratios of several inhibitors, as well as a loss- and gain-of-function assay using the protein synthesis inhibitor cycloheximide (CHX) and PA, showed the possibility that photon emissions from rice cells elicited by N-acetylchitooligosaccharide were generated through PA, an intermediate of phospholipid signaling.
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The antitumor effect of bromophenol derivatives in vitro and Leathesia nana extract in vivo
NASA Astrophysics Data System (ADS)
Shi, Dayong; Li, Jing; Guo, Shuju; Su, Hua; Fan, Xiao
2009-05-01
To investigate the antitumor effect of bromophenol derivatives in vitro and Leathesia nana extract in vivo, six bromophenol derivatives 6-(2,3-dibromo-4,5-dihydroxybenzyl)-2,3-dibromo-4,5-dihydroxy benzyl methyl ether (1), (+)-3-(2,3-dibromo-4,5-dihydroxyphenyl)-4-bromo-5,6-dihydroxy-1,3-dihydroisobenzofuran (2), 3-bromo-4-(2,3-dibromo-4,5-dihydroxybenzyl)-5-methoxymethyl-pyrocatechol (3), 2,2',3,3'-tetrabromo-4,4',5,5'-tetrahydroxy-diphenylmethane (4), bis(2,3-dibromo-4,5-dihydroxybenzyl) ether (5), 2,2',3-tribromo-3',4,4',5-tetrahydroxy-6'-ethyloxymethyldiphenylmethane (6) were isolated from brown alga Leathesia nana, and their cytotoxicity were tested by MTT assays in human cancer cell lines A549, BGC-823, MCF-7, B16-BL6, HT-1080, A2780, Bel7402 and HCT-8. Their inhibitory activity against protein tyrosine kinase (PTK) with over-expression of c-kit was analyzed also by ELISA. The antitumor activity of ethanolic extraction of Leathesia nana (EELN) was evaluated on S180-bearing mice. All compounds showed very potent cytotoxicity against all of the eight cancer cell lines with IC50 below 10 μg/mL. In PTK inhibition study, all bromophenol derivatives showed moderate inhibitory activity and compounds 2, 5 and 6 showed significant bioactivity with the inhibition ratio of 77.5%, 80.1% and 71.4%, respectively. Pharmacological studies reveal that EELN could inhibit the growth of Sarcoma 180 tumor and increase the indices of thymus and spleen to improve the immune system remarkably in vivo. Results indicated that the bromophenol derivatives and EELN can be used as potent antitumor agents for PTK over-expression of c-kit and considered in a new therapeutic strategy for treatment of cancer.
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In vitro antioxidant activity of pet ether extract of black pepper
Singh, Ramnik; Singh, Narinder; Saini, B.S.; Rao, Harwinder Singh
2008-01-01
Objective: To investigate the in vitro antioxidant activity of different fractions (R1, R2 and R3) obtained from pet ether extract of black pepper fruits (Piper nigrum Linn.) Materials and Methods: The fractions R1, R2 and R3 were eluted from pet ether and ethyl acetate in the ratio of 6:4, 5:5 and 4:6, respectively. 1,1-Diphenyl-2-picryl-hydrazyl (DPPH) radical, superoxide anion radical, nitric oxide radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the extract. Results: The free radical scavenging activity of the different fractions of pet ether extract of P. nigrum (PEPN) increased in a concentration dependent manner. The R3 and R2 fraction of PEPN in 500 µg/ml inhibited the peroxidation of a linoleic acid emulsion by 60.48±3.33% and 58.89±2.51%, respectively. In DPPH free radical scavenging assay, the activity of R3 and R2 were found to be almost similar. The R3 (100µg/ml) fraction of PEPN inhibited 55.68±4.48% nitric oxide radicals generated from sodium nitroprusside, whereas curcumin in the same concentration inhibited 84.27±4.12%. Moreover, PEPN scavenged the superoxide radical generated by the Xanthine/Xanthine oxidase system. The fraction R2 and R3 in the doses of 1000µg/ml inhibited 61.04±5.11% and 63.56±4.17%, respectively. The hydroxyl radical was generated by Fenton's reaction. The amounts of total phenolic compounds were determined and 56.98 µg pyrocatechol phenol equivalents were detected in one mg of R3. Conclusions: P. nigrum could be considered as a potential source of natural antioxidant. PMID:20040947
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Xu, Hui; Guo, Meng-Yuan; Gao, Yan-Hua; Bai, Xiao-Hui; Zhou, Xuan-Wei
2017-02-23
Manganese peroxidase (MnP) of white rot basidiomycetes, an extracellular heme enzyme, is part of a peroxidase superfamily that is capable of degrading the different phenolic compounds. Ganoderma, a white rot basidiomycete widely distributed worldwide, could secrete lignin-modifying enzymes (LME), including laccase (Lac), lignin peroxidases (LiP) and MnP. After the selection of a G. lucidum strain from five Ganoderma strains, the 1092 bp full-length cDNA of the MnP gene, designated as G. lucidum MnP (GluMnP1), was cloned from the selected strain. We subsequently constructed an eukaryotic expression vector, pAO815:: GlMnP, and transferred it into Pichia pastoris SMD116. Recombinant GluMnP1 (rGluMnP1) was with a yield of 126 mg/L and a molecular weight of approximately 37.72 kDa and a specific enzyme activity of 524.61 U/L. The rGluMnP1 could be capable of the decolorization of four types of dyes and the degradation of phenol. Phenol and its principal degradation products including hydroquinone, pyrocatechol, resorcinol, benzoquinone, were detected successfully in the experiments. The rGluMnP1 could be effectively expressed in Pichia pastoris and with a higher oxidation activity. We infer that, in the initial stages of the reaction, the catechol-mediated cycle should be the principal route of enzymatic degradation of phenol and its oxidation products. This study highlights the potential industrial applications associated with the production of MnP by genetic engineering methods, and the application of industrial wastewater treatment.
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NASA Astrophysics Data System (ADS)
Nirmala, G.; Rahiman, A. Kalilur; Sreedaran, S.; Jegadeesh, R.; Raaman, N.; Narayanan, V.
2010-09-01
A series of N-benzoylated cyclam ligands incorporating three different benzoyl groups 1,4,8,11-tetra-(benzoyl)-1,4,8,11-tetraazacyclotetradecane (L 1), 1,4,8,11-tetra-(2-nitrobenzoyl)-1,4,8,11-tetraazacyclotetradecane (L 2) and 1,4,8,11-tetra-(4-nitrobenzoyl)-1,4,8,11-tetraazacyclotetradecane (L 3) and their nickel(II) and copper(II) complexes are described. Crystal structure of L 1 is also reported. The ligands and complexes were characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectral studies. N-benzoylation causes red shift in the λmax values of the complexes. The cyclic voltammogram of the complexes of ligand L 1 show one-electron, quasi-reversible reduction wave in the region -1.00 to -1.04 V, whereas that of L 2 and L 3 show two quasi-reversible reduction peaks. Nickel complexes show one-electron quasi-reversible oxidation wave at a positive potential in the range +1.05 to +1.15 V. The ESR spectra of the mononuclear copper(II) complexes show four lines, characteristic of square-planar geometry with nuclear hyperfine spin 3/2. All copper(II) complexes show a normal room temperature magnetic moment values μeff 1.70-1.73 BM which is close to the spin-only value of 1.73 BM. Kinetic studies on the oxidation of pyrocatechol to o-quinone using the copper(II) complexes as catalysts and hydrolysis of 4-nitrophenylphosphate using the copper(II) and nickel(II) complexes as catalysts were carried out. All the ligands and their complexes were also screened for antimicrobial activity against Gram-positive, Gram-negative bacteria and human pathogenic fungi.
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Biological activities and chemical composition of lichens from Serbia
Kosanic, Marijana; Rankovic, Branislav; Stanojkovic, Tatjana; Vasiljevic, Perica; Manojlovic, Nedeljko
2014-01-01
The aim of this study is to investigate chemical composition of acetone extracts of the lichens Parmelia arseneana and Acarospora fuscata and in vitro antioxidant, antimicrobial, and anticancer activities of these extracts and gyrophoric acid isolated from A. fuscata. The HPLC-UV method was used for the identification of secondary metabolites. Stictic acid, norstictic acid, gyrophoric acid, usnic acid, atranorin and chloroatranorin were identified in the A. fuscata. In P. arseneana, we detected stictic acid, norstictic acid, usnic acid and atranorin, while gyrophoric acid was not identified. Antioxidant activity was evaluated by measuring the scavenging capacity of tested samples on DPPH and superoxide anion radicals, reducing the power of samples and determination of total phenolic compounds in extracts. As a result of the study, gyrophoric acid was found to have the largest DPPH radical scavenging activity with an IC50 value of 105.75 µg/ml. Moreover, the tested samples had an effective superoxide anion radical scavenging and reducing power. The total content of phenol in extracts was determined as pyrocatechol equivalent. The antimicrobial activity was estimated by determination of the minimal inhibitory concentration by the broth microdilution method. The most active was also gyrophoric acid, with minimum inhibitory concentration values ranging from 0.019 to 1.25 mg/ml. Anticancer activity was tested against LS174 (human colon carcinoma cell line), A549 (human lung carcinoma cell line), Fem-x (malignant melanoma cell line), and a chronic myelogeneous leukaemia K562 cell line using the MTT method. Extract of P. arseneana expressed the strongest anticancer activity against all cell lines with IC50 values ranging from 11.61 to 47.06 µg/ml. PMID:26417336
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Chemsa, Ahmed Elkhalifa; Zellagui, Amar; Öztürk, Mehmet; Erol, Ebru; Ceylan, Ozgür; Duru, Mehmet Emin; Lahouel, Mesbah
2018-06-01
Anthemis species are traditionally used to treat infectious and inflammatory processes, among others clinical disturbances. In the current study, the chemical composition, the total phenolic and flavonoid contents, the antioxidant, anticholinesterase, antimicrobial, and antibiofilm activities of Anthemis stiparum subsp. sabulicola aerial parts methanolic extract (As-ME) and essential oil (As-EO) were investigated. The chemical composition of As-EO was established by GC-MS and GC-FID. Total phenolic and flavonoid contents of As-ME were spectrophotometrically determined. Diphenyl-1-picrylhydrazyl (DPPH ● ) radical scavenging, cupric reducing antioxidant capacity (CUPRAC) and β-carotene bleaching assays were applied to evaluate the antioxidant potential. The anticholinesterase activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were carried out spectrophotometrically. The antimicrobial activity was assessed by Minimal Inhibitory Concentration (MIC) using broth microdilution method against 7 ATCC ® bacterial and one ATCC ® yeast reference strains. The antibiofilm effect was determined quantifying the percentage of adhesion inhibition. GC-MS and GC-FID identified 72 compounds (99.02%), being As-EO predominantly constituted by germacrene D (11.13%), t-cadinol (11.01%), camphor (6.73%), spathulenol (6.50%) and isoamyl salicylate (6.45%). The total phenolic and flavonoid contents of As-ME were 13.6 ± 0.03 and 5.9 ± 0.04 pyrocatechol equivalents and quercetin equivalents, respectively. In β-carotene-linoleic acid assay, As-ME showed the best lipid peroxidation inhibition activity with an IC 50 = 9.96 μg/mL followed by As-EO with an IC 50 = 619.98 μg/mL. In contrast, in DPPH assay, As-ME and As-EO showed moderate to low activity with an IC 50 = 92.69 μg/mL for As-ME and 917.69 μg/mL for As-EO. While in CUPRAC assay, As-EO and As-ME indicated a less to moderate reducing activity. As-ME inhibited AChE (IC 50 = 490.46 μg/mL) and BChE (IC 50 = 142.07 μg/mL), while As-EO was inactive against AChE and revealed a discreet inhibitory action against BChE (IC 50 = 212.14 μg/mL). As-ME displayed better antimicrobial activity than As-EO, being active against Staphylococcus aureus (ATCC ® 25923) and Bacillus subtilis (ATCC ® 6633), with MIC of 1.56 mg/mL. An expressive fungal adhesion inhibition (80.02%) on Candida albicans (ATCC ® 10239) was detected with As-ME at 6.25 mg/mL. These results showed that A. stiparum subsp. sabulicola is a natural source of active compounds with antibiotic and antibiofilm effects against S. aureus and B. subtilis, and C. albicans, respectively, and also presents antioxidant and anticholinesterase properties. Copyright © 2018 Elsevier Ltd. All rights reserved.
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Li, Liya; Seeram, Navindra P
2011-07-27
Maple syrup is made by boiling the sap collected from certain maple ( Acer ) species. During this process, phytochemicals naturally present in tree sap are concentrated in maple syrup. Twenty-three phytochemicals from a butanol extract of Canadian maple syrup (MS-BuOH) had previously been reported; this paper reports the isolation and identification of 30 additional compounds (1-30) from its ethyl acetate extract (MS-EtOAc) not previously reported from MS-BuOH. Of these, 4 compounds are new (1-3, 18) and 20 compounds (4-7, 10-12, 14-17, 19, 20, 22-24, 26, and 28-30) are being reported from maple syrup for the first time. The new compounds include 3 lignans and 1 phenylpropanoid: 5-(3″,4″-dimethoxyphenyl)-3-hydroxy-3-(4'-hydroxy-3'-methoxybenzyl)-4-(hydroxymethyl)dihydrofuran-2-one (1), (erythro,erythro)-1-[4-[2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3,5-dimethoxyphenyl]-1,2,3-propanetriol (2), (erythro,threo)-1-[4-[2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3,5-dimethoxyphenyl]-1,2,3-propanetriol (3), and 2,3-dihydroxy-1-(3,4- dihydroxyphenyl)-1-propanone (18), respectively. In addition, 25 other phenolic compounds were isolated including (threo,erythro)-1-[4-[(2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3-methoxyphenyl]-1,2,3-propanetriol (4), (threo,threo)-1-[4-[(2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3-methoxyphenyl]-1,2,3-propanetriol (5), threo-guaiacylglycerol-β-O-4'-dihydroconiferyl alcohol (6), erythro-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2,6-dimethoxyphenoxy]-1,3-propanediol (7), 2-[4-[2,3-dihydro-3-(hydroxymethyl)-5-(3-hydroxypropyl)-7-methoxy-2-benzofuranyl]-2,6-dimethoxyphenoxy]-1-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol (8), acernikol (9), leptolepisol D (10), buddlenol E (11), (1S,2R)-2-[2,6-dimethoxy-4-[(1S,3aR,4S,6aR)-tetrahydro-4-(4-hydroxy-3,5-dimethoxyphenyl)-1H,3H-furo[3,4-c]furan-1-yl]phenoxy]-1-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol (12), syringaresinol (13), isolariciresinol (14), icariside E4 (15), sakuraresinol (16), 1,2-diguaiacyl-1,3-propanediol (17), 2,3-dihydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (19), 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)propan-1-one (20), dihydroconiferyl alcohol (21), 4-acetylcatechol (22), 3',4',5'-trihydroxyacetophenone (23), 3,4-dihydroxy-2-methylbenzaldehyde (24), protocatechuic acid (25), 4-(dimethoxymethyl)pyrocatechol (26), tyrosol (27), isofraxidin (28), and 4-hydroxycatechol (29). One sesquiterpene, phaseic acid (30), which is a known metabolite of the phytohormone abscisic acid, was also isolated from MS-EtOAc. The antioxidant activities of MS-EtOAc (IC(50) = 75.5 μg/mL) and the pure isolates (IC(50) ca. 68-3000 μM) were comparable to that of vitamin C (IC(50) = 40 μM) and the synthetic commercial antioxidant butylated hydroxytoluene (IC(50) = 3000 μM), in the diphenylpicrylhydrazyl radical scavenging assay. The current study advances scientific knowledge of maple syrup constituents and suggests that these diverse phytochemicals may impart potential health benefits to this natural sweetener.
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LI, LIYA; SEERAM, NAVINDRA P.
2011-01-01
Maple syrup is made by boiling the sap collected from certain maple (Acer) species. During this process, phytochemicals naturally present in tree sap are concentrated in maple syrup. We previously reported 23 phytochemicals from a butanol extract of Canadian maple syrup (MS-BuOH). Here we report the isolation and identification of 30 additional compounds (1–30) from its ethyl acetate extract (MS-EtOAc) not previously reported from MS-BuOH. Of these, 4 compounds are new (1–3, 18) and 20 compounds (4–7, 10–12, 14–17, 19–20, 22–24, 26, 28–30) are being reported from maple syrup for the first time. The new compounds include 3 lignans and 1 phenylpropanoid: 5-(3″,4″-dimethoxyphenyl)-3-hydroxy-3-(4′-hydroxy-3′-methoxybenzyl)-4-hydroxymethyl-dihydrofuran-2-one (1), (erythro, erythro)-1-[4-[2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3,5-dimethoxyphenyl]-1,2,3-propanetriol (2), (erythro, threo)-1-[4-[2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3,5-dimethoxyphenyl]-1,2,3-propanetriol (3) and 2,3-dihydroxy-1-(3,4-dihydroxyphenyl)-1-propanone (18), respectively. In addition, 25 other phenolic compounds were isolated including (threo, erythro)-1-[4-[(2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3-methoxyphenyl]-1,2,3-propanetriol (4), (threo, threo)-1-[4-[(2-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-1-(hydroxymethyl)ethoxy]-3-methoxyphenyl]-1,2,3-propanetriol (5), threo-guaiacylglycerol-β-O-4′-dihydroconiferyl alcohol (6), erythro-1-(4-hydroxy-3-methoxyphenyl)-2-[4-(3-hydroxypropyl)-2,6-dimethoxyphenoxy]-1,3-propanediol (7), 2-[4-[2,3-dihydro-3-(hydroxymethyl)-5-(3-hydroxypropyl)-7-methoxy-2-benzofuranyl]-2,6-dimethoxyphenoxy]-1-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol (8), acernikol (9), leptolepisol D (10), buddlenol E (11), (1S,2R)-2-[2,6-dimethoxy-4-[(1S,3aR,4S,6aR)-tetrahydro-4-(4-hydroxy-3,5-dimethoxyphenyl)-1H,3H-furo[3,4-c]furan-1-yl]phenoxy]-1-(4-hydroxy-3-methoxyphenyl)-1,3-propanediol (12), syringaresinol (13), isolariciresinol (14), icariside E4 (15), sakuraresinol (16), 1,2-diguaiacyl-1,3-propanediol (17), 2,3-dihydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)-1-propanone (19), 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)propan-1-one (20), dihydroconiferyl alcohol (21), 4-acetylcatechol (22), 3′,4′,5′-trihydroxyacetophenone (23), 3,4-dihydroxy-2-methylbenzaldehyde (24), protocatechuic acid (25), 4-(dimethoxymethyl)-pyrocatechol (26), tyrosol (27), isofraxidin (28) and 4-hydroxycatechol (29). One sesquiterpene, phaseic acid (30), which is a known metabolite of the phytohormone, abscisic acid, was also isolated from MS-EtOAc. The antioxidant activities of MS-EtOAc (IC50 = 75.5 μg/mL), and the pure isolates (IC50 ca. 68–3000 μM) were comparable to vitamin C (IC50 = 40 μM) and the synthetic commercial antioxidant, butylated hydroxytoluene (IC50 = 3000 μM), in the diphenylpicrylhydrazyl radical scavenging assay. The current study advances scientific knowledge of maple syrup constituents and suggest that these diverse phytochemicals may impart potential health benefits to this natural sweetener. PMID:21675726