Azino-bis(3-ethylbenzothiazoline)-6-sulfonate Research Articles

Caffeoyl Phenylethanoid Glycosides from Unripe Fruits of Forsythia Suspensa

Chemical investigations of the 70% alcohol extract of F. suspensa have afforded a new caffeoyl phenylethanoid glycoside, lianqiaoxinoside C (1), together with the known calceolarioside C (2). A practical 1H NMR spectrum rule was firstly summarized for assisting determination of lianqiaoxinoside C, whose structure was unambiguously determined as 3,4-dihydroxy-β-phenethyl-O-β-xylopyranosyl-(1→6)-3-O-caffeoyl-β- glucopyranoside on the basis of 1H NMR spectrum and HR-ESI-MS. The 1H NMR rule summarized here may be very helpful for assisting analysis and identification of the analogous caffeoyl phenylethanoid glycosides in the genus Forsythia. Calceolarioside C was also first reported from the genus Forsythia and showed obvious antioxidant activities in vitro by the 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS) radical-scavenging assay.

Study on the antioxidant cosmetic preparation from Spirulinaplatensis and gold nanoparticles

Oxidation can generate free radicals which damage important molecules including lipids, proteins, and nucleic acid, and causes premature aging. The oxidation of skin cells manifests as wrinkles, freckles and many other serious symptoms. To develop natural products with high antioxidant ability for skin care, we developed mixtures of Spirulina platensis biomass, gold nanoparticles (AuNP: 10 nm) and vitamin C at different ratios. The antioxidant activity of the mixtures was measured by ABTS (2,2′-azino-bis (3- ethylbenzothiazoline-6-sulfonic acid) diammonium salt) assay. The mixture of S. platensis (1000 ppm), AuNP (10 ppm), and vitamin C (10 ppm) showed excellent antioxidant activity with 95 % efficiency after 30 minutes and 100 % efficiency after 120 minutes under the reaction conditions. The combination of the mixture and the polyvinylpyrrolidone (PVP) binder was sterilized by gamma Co-60 radiation. The sterilization dose of 16 kGy was selected due to theabsence of aerobic microorganisms in the antioxidant cosmetic preparation. Thus, the cosmetic preparation in paste form containing three main components of S. platensis, gold nanoparticles, and vitamin C combinated with PVP binder has a potential applications in the field of cosmetics, especially for facial skin rejuvenation.

Phenolic Composition from Different Loquat (Eriobotrya japonica Lindl.) Cultivars Grown in China and Their Antioxidant Properties

China is one of the most important centers of diversity for Eriobotrya japonica Lindl. in the world. In this study, seven loquat cultivars grown in China were evaluated for their phenolic compounds and antioxidant activity. Eleven phenolic compounds, i.e., 3-p-coumaroylquinincacid (3-p-CoQA), 5-caffeoylquinic acid (5-CQA), 4-caffeoylquinic acid (4-CQA), 3-caffeoylquinic acid (3-CQA), 5-feruloylquinic acid (5-FQA), quercetin-3-O-galactoside (Q-3-Gal), quercetin-3-O-glucoside (Q-3-Glu), quercetin-3-O-rhamnoside (Q-3-Rha), kaempferol-3-O-galactoside (K-3-Gal), kaempferol-3-O-rhamnoside (K-3-Rha), and kaempferol-3-O-glucoside (K-3-Glu) were identified and quantified in the peel and pulp of the cultivars tested. 3-CQA and 5-CQA were the predominant components in both fruit parts. 2,2-Diphenyl-1-picrylhydrazyl radicals (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate (ABTS), and ferric reducing antioxidant power (FRAP) assays were used for the antioxidant evaluation. Results showed that peel extracts had higher antioxidant activities than their pulp counterparts in all the cultivars tested, which was correlated with their higher total phenolic contents. The antioxidant potency composite (APC) index showed obvious variations ranging from 64.15 to 100 in the peel and from 59.49 to 97.95 in the pulp of different cultivars, where “Dahongpao” (DHP) and “Luoyangqing” (LYQ) had the highest APC index in the peel and pulp, respectively. Overall, loquat cultivars rich in hydroxycinnamic acids (HCAs) such as 3-p-CoQA, 5-CQA, 4-CQA, 3-CQA and 5-FQA showed relatively higher antioxidant activities, and may be excellent sources of phytochemicals and natural antioxidants.

황금찰수수 도정부산물의 항산화 및 항염증 활성

유색 수수인 황금찰수수를 도정할 때 grain과 함께 발생하는 도정부산물인 hull과 bran의 4가지 용매 추출물의 총 폴리페놀 함량, 항산화 활성, 천연색소 함량과 RAW 264.7 세포주를 이용하여 항염증 활성을 검정하였으며 결과를 요약하면 아래와 같다. 1. 도정부산물인 hull의 100% 메탄올과 70% 에탄올 추출물에서 총 폴리페놀 함량이 <TEX>$29.4{\pm}0.4$</TEX>와 <TEX>$29.7{\pm}0.2mg\;GAE/100g$</TEX>으로 가장 많았고, ABTS 라디컬 소거능(<TEX>$IC_{50}$</TEX>)이 <TEX>$6.8{\pm}0.4$</TEX>, <TEX>$6.3{\pm}0.1{\mu}g/mL$</TEX>로 가장 높은 항산화 활성을 나타내었다. 2. 총 천연색소 함량에서도 수수 hull의 0.5% 염산 함유 100% 메탄올 추출물에서 <TEX>$322.6{\pm}14.5mg/100g$</TEX>으로 가장 많은 색소 함량을 나타내었고 hull, bran, grain 모두의 경우에서 0.5% 염산을 함유한 100% 메탄올을 용매로 추출한 경우에서 가장 많아 수수를 이용하여 천연색소를 추출할 경우 수수 부산물인 hull을 산을 함유한 메탄올로 추출하였을 때 가장 많은 색소 추출물을 얻을 수 있었다. 3. 수수 도정부산물과 grain 추출물을 LPS로 NO 생성을 유도한 RAW 264.7 세포에 처리하였을 때, 세포 독성이 없는 100 ug/mL 농도 이하에서의 NO 생성 억제량은 hull, bran, grain 추출물의 순으로 나타났고 hull 추출물의 경우에 농도에 따라 가장 큰 NO 생성 억제를 보였으며 천연색소 화합물 중에서는 apigeninidin의 NO 생성 억제 활성을 확인하였다. 4. 위 결과를 종합해 볼 때, 수수 도정부산물 중 hull은 grain에 비해 총 폴리페놀 화합물과 천연색소 함량이 높고 항산화 활성과 RAW 264.7 대식세포에서의 NO 생성량 억제 활성이 우수하여 앞으로 수수 부산물이 항산화 및 항염증 소재로 가능성이 있음을 확인하였다. Sorghum has been consumed as one of the important staple food in the semiarid tropics of Africa and Asia. Sorghum is rich in starch, protein, essential vitamins and minerals and grows relatively well in dry climate regions when it compared with other staple food crops. Sorghum has taken an increased interest due to several studies that report about the beneficial effects of sorghum on human health. In the present study, we investigated the antioxidative and activity of extract of milling by-products (hull and bran) of Korean sorghum cultivar, 'Hwanggeaumchal' as well as its grain. Hull extract showed the highest total polyphenol contents (<TEX>$29.7{\pm}0.2mg\;GAE/100g$</TEX>) and major four pigments content (<TEX>$322.6{\pm}14.5mg/100g$</TEX>). From results of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate (ABTS) radical scavenging activity, hull extract (<TEX>$IC_{50}$</TEX>, <TEX>$6.3{\pm}0.1{\mu}g/mL$</TEX>) was also showed the strongest antioxidative effects. Bran and grain showed similar polyphenol, pigments contents and antioxidative effects. We determined cell viability by MTT assay and evaluated the anti-inflammatory activity by measuring nitric oxide (NO) of hull, bran and grain methanol extract (0.5% HCl v/v) on RAW 264.7 cells. Hull extract treatment was significantly decreased NO production with dose-dependant manner. Apigeninidin as one of the major pigment of hull was showed inhibitory activity against NO production without cytotoxicitiy. Therefore, sorghum milling by-products can be used as a good source of antioxidative and anti-inflammatory agents.

Improved production of poly-γ-glutamic acid by Bacillus subtilis D7 isolated from Doenjang, a Korean traditional fermented food, and its antioxidant activity.

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 ± 0.64g/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.

Antioxidant activity and polyphenol content of methanol extracts from Arisarum vulgare

Arisarum vulgare is generally known as a toxic plant but it has some medicinal uses. The plant collected from National Park of El-Kala (north-east of Algeria), is phytochemically screened [1], and the total phenolic [2] and flavonoids [3] compounds were measured for its methanolic extract. In addition, the antioxidant capacity of the methanolic extract of this plant is evaluated by ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic)) and DPPH (2,2-diphenyl-1-picrylhydrazyl) tests expressed by vitamin C Equivalent Antioxidant Capacity (VCEAC) [4]. The VCEAC values are 0.3472 g and 0.2768 g of VCEAC/100 g of dry weight; as determined by ABTS and DPPH tests respectively. The total phenolic and total flavonoids contents are, respectively: 2.138 g of gallic acid equivalent/100 g of dry weight, and 7.126 g of quercetin equivalents/100 g of dry weight. A direct correlation between phenolic compounds and antioxidant activity was observed (R2= 0.95). According to the results, it is observed that the Arisarum vulgare possess a considerable antioxidant and antiradical capacity, therefore the antioxidant properties might increase the therapeutic value of this medicinal plant. Key words:Arisarum vulgare, antioxidant, polyphenols, flavonoids, ABTS, DPPH.

Screening for polyphenols, antioxidant and antimicrobial activitiesof extracts from eleven Helianthemum taxa (Cistaceae) used in folk medicine in south-eastern Spain

Ethnopharmacological relevanceThe Helianthemum genus contains approximately one hundred taxa. Some of them are important medicinal plants used in several countries for many different purposes. However, studies addressing the phytochemistry of many of these species or their biological activities are currently nonexistent. Aim of the studyTo perform a comparative analysis of the qualitative composition of secondary metabolites and biological activities of the leaves of the most commonly distributed and used Spanish Helianthemum taxa in order to find a relationship between chemotype, biological activity and uses. Materials and methodswater and 80% methanolic extracts derived from 11 different Helianthemum taxa were analyzed for their phytochemical composition using standard methods. Furthermore, HPLC analysis was performed for the estimation of gallic acid, ellagic acid, tannins and flavonols as marker compounds. The antioxidant activity was measured by employing the scavenging activity on DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonate) radicals. The 80% methanolic extracts were evaluated for antibacterial (Gram-positive Staphylococcus aureus, Enterococcus faecalis and Listeria monocytogenes and Gram-negative Escherichia coli and Salmonella enterica) activity using the micro dilution technique. ResultsThe total polyphenolic content and antioxidant capabilities differed significantly among the Helianthemum leaf extracts. A strong correlation between total phenolic content, antioxidant properties and antimicrobial activity was found. The polyphenolic profile was specific for each taxon. Whereas Helianthemum alypoides, Helianthemum cinereum subsp. rotundifolium, Helianthemum hirtum, Helianthemum asperum, and Helianthemum marifolium subsp. marifolium were characterized by the presence of gallic acid, egallic derivatives and ellagitannins; the polyphenolic profile of Helianthemum apenninum subsp. cavanillesianum, Helianthemum syriacum and Helianthemum polygonoides was mostly based on flavonoids. Helianthemum cinereum, Helianthemum alypoides and Helianthemum marifolium consistently presented the strongest radical scavenging activity (in water extracts EC50 ranges from 29.88 to 38.1 against DPPH and from 8.11 to 20.8 against ABTS, and in 80% MeOH extracts from 25.3 to 31.8 against DPPH and from 6.15 to 8.6 against ABTS), total phenol content (>117mg GAE/l) and antimicrobial activities. ConclusionThe Helianthemum taxa used in folk medicine did not cluster in a unique section, being equally distributed in two out of the four sections analysed. There was not a clear relationship between the chemotype, based on the polyphenolic composition of the taxa, and their taxonomical classification. However, the composition of the methanolic and water extracts from the leaves of plants belonging to the Helianthemum genus was strongly related to their medicinal uses.

Comparison of antioxidant capacity and phenolic composition of peel and flesh of some apple varieties

Apples contain a large concentration of phenolic compounds, dependent on factors such as cultivar, harvest, storage conditions, and processing. This study aims to identify the essential phenolic compounds present in various apple varieties, to measure their total antioxidant capacity (TAC) with the CUPRAC (cupric ion reducing antioxidant capacity) and ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate)) methods, and to correlate their TAC values with HPLC findings. The order of TAC (mmol Trolox g(-1) fresh weight) of apple peels determined with the CUPRAC method was: Granny Smith > Amasya > Sky Spur > Ervin Spur > King Luscious ≥ Arap Kizi ≥ Lutz Golden. The theoretically calculated TAC values of HPLC-quantified compounds, with the aid of the combined HPLC-CUPRAC method, accounted for 18.4-33.5% of the experimentally observed CUPRAC capacity of peel extracts and 19.5-56.3% of flesh extracts, depending on apple variety. In synthetic samples of apple antioxidants, the CUPRAC-TAC values of constituents, identified and analyzed by HPLC, proved to be additive, enabling measurement of the cooperative action of antioxidants using the proposed methodology. Apple peel showed higher contents of phenolics and therefore higher TAC than apple flesh, confirming the health benefit of the consumption of apples together with peel.

Enzyme inhibitory and antioxidant activities of traditional medicinal plants: Potential application in the management of hyperglycemia

BackgroundTraditional Indian and Australian medicinal plant extracts were investigated to determine their therapeutic potential to inhibit key enzymes in carbohydrate metabolism, which has relevance to the management of hyperglycemia and type 2 diabetes. The antioxidant activities were also assessed.MethodsThe evaluation of enzyme inhibitory activity of seven Australian aboriginal medicinal plants and five Indian Ayurvedic plants was carried out against α-amylase and α-glucosidase. Antioxidant activity was determined by measuring (i) the scavenging effect of plant extracts against 2, 2-diphenyl-1-picryl hydrazyl (DPPH) and 2, 2′-azinobis-3-ethylbenzothiazoline-6-sulfonate (ABTS) and (ii) ferric reducing power. Total phenolic and total flavonoid contents were also determined.ResultsOf the twelve plant extracts evaluated, the highest inhibitory activity against both α-amylase and α-glucosidase enzymes was exerted by Santalum spicatum and Pterocarpus marsupium with IC50 values of 5.43 μg/ml and 0.9 μg/ml, respectively, and 5.16 μg/ml and 1.06 μg/ml, respectively. However, the extracts of Acacia ligulata (IC50 = 1.01 μg/ml), Beyeria leshnaultii (0.39 μg/ml), Mucuna pruriens (0.8 μg/ml) and Boerhaavia diffusa (1.72 μg/ml) exhibited considerable activity against α-glucosidase enzyme only. The free radical scavenging activity was found to be prominent in extracts of Acacia kempeana, Acacia ligulata followed by Euphorbia drummondii against both DPPH and ABTS. The reducing power was more pronounced in Euphorbia drummondii and Pterocarpus marsupium extracts. The phenolic and flavonoid contents ranged from 0.42 to 30.27 μg/mg equivalent of gallic acid and 0.51 to 32.94 μg/mg equivalent of quercetin, respectively, in all plant extracts. Pearson’s correlation coefficient between total flavonoids and total phenolics was 0.796.ConclusionThe results obtained in this study showed that most of the plant extracts have good potential for the management of hyperglycemia, diabetes and the related condition of oxidative stress.

Preliminary screening of some fractions of Loxostylis alata (Anacardiaceae) for antimicrobial and antioxidant activities

An acetone extract of Loxostylis alata was separated into six fractions based on polarity by a solventsolvent fractionation procedure and the different fractions were screened for antimicrobial and antioxidant activities. The number of antimicrobial compounds in the carbon tetrachloride (CCl 4 ), chloroform (CC), aqueous methanol (AM) and butanol (BT) fractions were determined by bioautography. Each fraction was loaded onto thin layer chromatography (TLC) plates and eluted using two different mobile solvent systems, namely chloroform/ethyl acetate/formic acid (5:4:1): (CEF) and ethyl acetate/methanol/water (40:5.4:5) (EMW). Relative front (R f ) values of active compounds against bacteria ranged from 0.4 - 0.9 in CEF and EMW solvent system. Similarly, the Rf values of compounds active against fungi were in the range of 0.7 - 0.9. Hexane, carbon tetrachloride, chloroform, aqueous methanol and butanol fractions showed areas of inhibition against bacterial organisms, while only hexane and carbon tetrachloride fractions depicted areas of fungal growth inhibition on their chromatograms. The CCl 4 extract was active against six out of the nine microbial strains used and was particularly active against Staphylococcus aureus, Enterococcus faecalis, Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans and Microsporum canis with minimum inhibitory concentration (MIC) of 0.04, 0.04, 0.1, 0.1, 0.06 and 0.03 mg/ml, respectively. M. canis was the most sensitive organism with the lowest average MIC of 0.16 mg/ml. Qualitative antioxidation using diphenylpicryl- hydrazyl (DPPH) and qualitative assay using both 2,2'-azinobis-3-ethylbenzothiazoline-6- sulfonate (ABTS) and DPPH radicals revealed the presence of three antioxidant compounds in the AM and BT fractions, while the water fraction had only one antioxidant compound. However, the concentration of the antioxidant compounds was more in the AM and BT fractions as revealed by their pronounced colour intensity on the TLC plates. The water fraction had more free radical scavenging effect against DPPH with EC 50 value of 0.62 ± 0.03 μg/ml. The lower the EC 50 value of an extract, the more effective its antioxidant activity. In a similar manner, TEAC value of water fraction was 2.97, which further indicates superior free radical scavenging effect of the fraction against ABTS radical. The greatest reduction of reactive oxygen species (ROS) production induced by diclofenac was also achieved by the water fraction which on overall shows that the water fraction contains more antioxidants. The presence of antimicrobial and antioxidant activities in the fractions of L. alata suggests that this plant may be a source of pharmacologically active substances with beneficial actions towards disease control and treatment in animals and humans. Key words : Medicinal plant, antibacterial, antifungal, serial microdilution, minimum inhibitory concentration, antioxidants.

Modified Carbon Nanoball on Electrode Surface Using Plasma in Enzyme-Based Biofuel Cells

Biofuel cells performed similarly to those conventional fuel cells are regarded as one of potential substitute for fossil fuel. Developments of biofuel cells demonstrate the advantages on reduction of greenhouse gas emissions as well as increasing energy security. Enzyme-based biofuel cells is one kind of the biofuel cells, enzyme-based biofuel cells convert chemical energy into electrical energy via specific enzymes as biocatalysts. Glucose oxidase and laccase were immobilized onto carbon paper as bioanode and biocathode, respectively in enzyme-based biofuel cells system. Mediator and enzyme were mixed in phosphate buffer (pH 7) and citrate buffer (pH 5) solutions, respectively. A Nafion membrane117 was inserted to separate the two half cells. The power density with respect to different operating voltages was obtained with a glucose concentration of 10mM. Potassium hexacyanoferrate III and ABTS (2, 2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) as mediators were added to the bioanode and biocathode cell, respectively. Carbon nanoballs were coated on the carbon paper and enormous enhancement of power density was achieved.The power-voltage with the CNB surface modifying by using plasma was with oxygen bubbling in cathode directly in the cell achieved up to 0.114V. The power density was 65.5μW/cm2. The assembled enzyme-based biofuel cells were studied under nitrogen at 37°C in bioanode.

Expression, characterization and 2,4,6-trichlorophenol degradation of laccase from Monilinia fructigena

A novel laccase gene from Monilinia fructigena was synthesized chemically according to the yeast bias codon and integrated into the genome of Pichia pastoris GS115 by electroporation. The expressed enzyme was recovered from the culture supernatant and purified. The result of enzyme activity assay and SDS-PAGE demonstrated that the recombinant laccase was induced and extracellularly expressed in P. pastoris. Main biochemical properties of this laccase, such as thermodependence and thermostability, optimal pH and pH stability, and the effect of metal ions and inhibitors, were characterized. With 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate (ABTS) as the substrate, MfLcc had its optimal pH at 3.5 and optimal temperature at 45°C. The Km values of the ABTS, guaiacol were 0.012 and 0.016Mm, respectively, and the corresponding V (max) values are 243.9 and 10.55Ummin(-1)mg(-1), respectively. The recombinant laccase degraded 80% 2,4,6-trichlorophenol after 8h under the optimal conditions. The recombinant strain and its laccase can be considered as candidate for treating waste water polluted with trichlorophenols.

Suppression of the loss of an electroactive dopant from polypyrrole by using a non-aqueous electrolyte of dopant-phobicity

Loss of electroactive dopants from conducting polymers (CPs) was investigated by electrochemical quartz crystal microgravimetry (EQCM). pPy[ABTS], polypyrrole doped with ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonate), was used as a model system. Two different kinds of electrolytes were used for studying the loss of dopants under electrochemical stimuli: one is a solvent to dissolve the dopant (dopant-philic) while the dopant is insoluble in the other (dopant-phobic). Degradation of polypyrrole backbone as well as loss of the dopant from pPy[ABTS] was observed in the dopant-philic electrolyte. Severe chemical overoxidation of polypyrrole by the most oxidized state of ABTS {(ABTS 2+) 2−} was emphasized as a factor responsible for de-doping in addition to potential-driven overoxidation or ion exchange. In the dopant-phobic electrolyte, however, the chemical degradation of the polymer film was suppressed.

Chemical Composition and, Cellular Evaluation of the Antioxidant Activity of Desmodium adscendens Leaves.

Desmodium adscendens plant is widely used as juice or tea in various parts of the world against a wide range of diseases. This study determines the quality and the quantity of polyphenols, flavonoids, anthocyanins, and tannins in D. adscendens leaves by UV-spectrophotometry and RP-HPLC methods. In addition, the antioxidant capacity of these phenolic compounds is evaluated by ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic)), DPPH (2,2-diphenyl-1 picrylhydrazyl), and Cellular tests. D. adscendens leaves are mainly composite of flavonoid compounds with 12.8 mg of catechin equivalent (CE)/g dw. The amounts of total polyphenol compounds are 11.1 mg of gallic acid equivalent (GAE)/g dw. The quantity of total anthocyanin and total tannin compounds is not considerable 0.0182 mg CgE/g dw and 0.39 mg CE/g dw, respectively. A direct correlation between phenolic compounds and antioxidant activity is observed (R 2 = 0.96). The RP-HPLC analyses reveal that the main phenolic compound identified in the methanol-water extract is quercetrin dihydrat (2.11 mg/mL). According to the results, it is observed that D. adscendens leaves possess a considerable scavenging antioxidant and antiradical capacity, therefore these antioxidant properties might increase the therapeutic value of this medicinal plant.

Antioxidant characteristics of Dichrostachys glomerata spice extractsCaracterísticas antioxidantes de los extractos de la especia Dichrostachys glomerata

The antioxidant activity of aqueous extract, ethanol extract, and hydroethanolic pod extract of a Cameroonian spice Dichrostachys glomerata (D. glomerata) was investigated. When compared with the two other extracts, the aqueous extract exhibited the lowest phenolic content, AEABTS (Antiradical Efficiency) and AEDPPH values whereas the ethanol extract had the highest phenolic content, AEABTS and AEDPPH values. The DPPH (α, α-diphenyl-β-picrylhydrazyl) radical and ABTS (2, 2′ -azinobis (3-ethylbenzothiazoline-6-sulfonic acid) cation radical scavenging activities were proven and correlated with the reductive potential and phenolic content of the extracts with r 2 greater than 0.9. All extracts had effective, superoxide anion radical, hydroxyl radical and nitric oxide scavenging activity, at all tested concentrations in a concentration-dependent manner. Each extract showed a concentration-dependent effect on chelating activity and α-linoleic acid oxidation inhibition activity. When compared with the controls, each extract significantly decreased malondialdehyde and lipid hydroperoxides formation in low-density lipoprotein (LDL). The hydroethanolic extract exhibited the highest inhibition of LDL oxidation. These results suggest that pods from D. glomerata can be good source of natural antioxidants.

Characterization of immobilized laccase from γ-proteobacterium JB: Approach towards the development of biosensor for the detection of phenolic compounds

The two factors important when optimization of enzyme immobilization for the fabrication of biosensor are: activity and stability. The present study investigates the 2 factors when laccase was immobilized on various supports by different methods. Immobilization of partially purified laccase showed that enzyme expressed 100% activity when immobilized on the nitrocellulose membrane. pH and temperature optimum of immobilized laccase was 6.5 and 55°C respectively, when syringaldazine was used as a substrate. Immobilized laccase on nitrocellulose membrane was 100% stable at 4°C -30°C for three months. At 60°C enzyme showed 50% stability after 30 min. Immobilized laccase showed best response with syringaldazine which gave reaction even at 1 to 5μM concentration. Immobilized laccase gave response to catechol, catechin and L-methyl DOPA in the range of 40 to 90, 40 to 60, 30 to 70 µM respectively. ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonate)) also showed response to the laccase from 0.1 to 0.2 mM.

Involvement of independent mechanism upon poly(ADP‐ribose) polymerase (PARP) activation in methylmercury cytotoxicity in rat cerebellar granule cell culture

Poly(ADP-ribose) polymerase (PARP) activation plays a role in repairing injured DNA, while its overactivation is involved in various diseases, including neuronal degradation. In the present study, we investigated the use of a PARP inhibitor, 3,4-dihydro-5-[4-(1-piperidinyl)butoxy]-1(2H)-isoquinolinone (DPQ), whether methylmercury-induced cell death in the primary culture of cerebellar granule cells involved PARP activation. DPQ decreased the methylmercury-induced cell death in a dose-dependent manner. Unexpectedly, this protective effect was DPQ specific; none of the other PARP inhibitors--1,5-dihydroxyisoquinoline, 3-aminobenzamide, or PJ34--affected neuronal cell death. Methylmercury-induced cell death involves the decrease of glutathione (GSH) and production of reactive oxygen species. Therefore, to understand the mechanism by which DPQ inhibits cytotoxicity, we first studied the effect of DPQ on buthionine sulfoximine- or diethyl maleate-induced death of primary cultured cells and human neuroblastoma IMR-32 cells, both of which are mediated by GSH depletion. DPQ inhibited the cell death of both cultured cells, but it did not restore the decrease of cellular GSH by buthionine sulfoximine to the control level. Second, we evaluated the antioxidant activity of PARP inhibitors by methods with ABTS (2-2'-azinobis(3-ethylbenzothiazoline 6-sulfonate) or DPPH (1,1-diphenyl-2-picrylhydrazyl) used as a radical because antioxidants also efficiently suppress methylmercury-induced cell death. The antioxidant activity of DPQ was the lowest among the tested PARP inhibitors. Taken together, our results indicate that DPQ effectively protects cells against methylmercury- and GSH depletion-induced death. Furthermore, they suggest that DPQ exerts its protective effect through a mechanism other than PARP inhibition and direct antioxidation, and that PARP activation is not involved in methylmercury-induced neuronal cell death.

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

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

Free radical scavenging and radioprotective activity of dehydrozingerone against whole body gamma irradiation in Swiss albino mice

Dehydrozingerone (DZ) was explored for in vitro– in vivo antioxidant potential and in vivo radioprotective activity against whole body gamma irradiation in Swiss albino mice. DZ scavenged the ABTS (2, 2′-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) and DPPH (1, 1-dipehnyl-2-picrylhydrazyl) free radicals at room temp. DZ reduced Fe (III) to Fe (II) at pH 7.4 and scavenged the NADH/phenazine methosulfate generated superoxide radical in cell free system. DZ also scavenged the nitric oxide radical generated by sodium nitroprusside. To evaluate the radioprotective activity, mice were exposed to whole body gamma irradiation 30 min after the drug treatment at a dose rate of 1.66 Gy/min. Pretreatment with DZ 75, 100 and 125 mg/kg, i.p. reduced the radiation induced mortality and increased the mean survival times (MSTs). An i.p. dose of DZ 100 mg/kg was found the most effective dose in preventing radiation sickness and increasing the MST. Pretreatment DZ100 mg/kg maintained the spleen index (spleen weight/body weight × 100) and stimulates the endogenous spleen colony forming units (CFU). Pretreatment with DZ100 mg/kg maintained the villus height close to normal, prevents mucosal erosion and basement membrane damage in irradiated mice jejunum. However, no significant reductions in dead, inflammatory and mitotic cells were observed in DZ pretreated mice, but there was an increased in crypt cells proliferation and regeneration. Pretreatment with DZ100 mg/kg significantly elevated the endogenous antioxidant enzymes (GSH, GST and SOD) in mice at 2, 4 and 8 h post sham irradiation. Radiation induced fall in endogenous antioxidant enzymes was significantly prevented by DZ pretreatment. Pretreatment with DZ 75 and 100 mg/kg reduced the radiation induced micronucleated polychromatic erythrocytes (MPCE) and normochromatic erythrocytes (MNCE) in mice bone marrow. DZ also maintained the polychromatic erythrocytes (PCE) and normochromatic erythrocytes (NCE) ratio ( P/ N ratio) in irradiated mice. Dose modifying factor (DMF) was calculated by using the graded radiation dose (8.0, 9.0, 9.5 and 10 Gy). DZ 100 mg/kg elevated radiation LD 50 from 9.1 to 10.0 Gy, indicating the DMF of 1.09.

Catalytic activity of oxidases hosted in lipidic cubic phases on electrodes

The monoolein-based liquid crystalline cubic phase was used as the matrix to incorporate redox enzymes — glucose (GOx), pyranose (PyOx) oxidases and laccase. Thin layer of the cubic phase embedding GOx or PyOx activated glucose oxidation in the presence and absence of appropriate mediators. The electrodes exhibited unchanged voltammetric response to glucose for not less than six days. The potentials and ratio of catalytic to diffusion currents could be modified by choosing appropriate electroactive probes as mediators. Ferrocenecarboxylic acid and Ru(NH 3) 6 2+ provided contact between the electrode and the enzyme. The sensitivity to glucose for glucose oxidase was 0.4 ± 0.05, 11 ± 3.1 μA/cm 2/mM without mediator and with ferrocenecarboxylic acid respectively and 0.9 ± 0.06, 31 ± 5.6 μA/cm 2/mM for pyranose oxidase without and with mediator. The system based on glucose oxidase and Ru(NH 3) 6 2+ as mediator was found useful due to the most negative potential of the process. The catalyses of oxygen reduction by two laccases: Cerrena unicolor and Trametes hirsuta embedded in the cubic phase together with 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonate (ABTS) as the mediator were found efficient and the reduction potential was positive enough to be considered in the application of lyotropic liquid crystals as a material for biofuel cells.