Free Radical Scavenging Activity Assay Research Articles

Antioxidant activity and phytochemical screening of two Cucurbitaceae: Citrullus colocynthis fruits and Bryonia dioica roots

ObjectiveTo evaluate antioxidant activity and quantify total content of polyphenols and flavonoids in two Cucurbitaceae plant extracts, Citrullus colocynthis (C. colocynthis) fruits and Bryonia dioica (B. dioica) roots. MethodsQualitative and quantitative analysis of aqueous and butanolic extracts, prepared from C. colocynthis fruits and B. dioica roots was carried out using standard methods. Estimation of their antioxidant activity was determined by free radical scavenging activity assay using 2,2-diphenyl-l-picrylhydrazyl and ferric reducing antioxidant power assay. ResultsPreliminary phytochemical screening of the aqueous and organic extracts showed the presence of tannins, flavanoids, terpenoids, saponins and quinones. The content of phenolic compounds varies among the two species of cucurbits and even in the different extracts of the same species. The most important amount of total polyphenols and flavanoids expressed respectively as gallic acid and catechin equivalent per gram extract, was determined in butanolic extract of B. dioica roots (541.78 mg/g, 120.60 mg/g). The lowest values were noted in C. colocynthis fruit aqueous extract (219.58 mg/g, 46.13 mg/g). Butanolic extract of B. dioica roots exhibited an interesting free radical scavenging activity with IC50 = 2.25 µg/mL compared to IC50 = 1.5 µg/mL of ascorbic acid, followed by B. dioica roots aqueous extract (IC50 = 47.25 µg/mL), butanolic C. colocynthis fruit extract (IC50 = 61 µg/mL) and C. colocynthis fruit aqueous extract (IC50 = 241.25 µg/mL). A highest reducing power was observed in B. dioica roots butanolic extract compared to other extracts (C. colocynthis fruit aqueous and butanolic extracts and B. dioica roots aqueous extract). ConclusionsThe results indicate that the wealth of B. dioica roots extracts on polyphenols and flavonoids is more than C. colocynthis fruit extracts. These phytoconstituents ensure an interesting free radical scavenging activity and reducing power for the B. dioica roots extracts especially butanolic extract.

Chemical composition, antioxidant and antimicrobial activities of the essential oil and methanolic extract of Ferulago bernardii Tomk. & M. Pimen of Iran

The aim of the study was to investigate chemical composition, antioxidant, antibacterial and antifungal activities of the essential oil (EO), polar and nonpolar sub-fractions of methanolic extract of Ferulago bernardii. The chemical constituent of the EO was identified by means of GC–MS. The antimicrobial activities of the EO, polar and nonpolar extracts were evaluated by micro-dilution and agar disc diffusion assays. The antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) free radical scavenging activity assay. The main components of the EO were α-pinene (35.03%), z-β-ocimene (14.24%) and bornyl acetate (11.64%). Bacillus cereus and Salmonella typhimurium were the most susceptible and resistant to the antibacterial activity of the essential oil and extract, respectively. The free radical scavenging activities of all extracts and the essential oil were in the order: polar > non-polar > EO. Our findings indicate that F. bernardii essential oil and methanolic extract has a potential to be applied as antimicrobial and antioxidant agent.

Electron beam induced water-soluble silk fibroin nanoparticles as a natural antioxidant and reducing agent for a green synthesis of gold nanocolloid

The research proposes a novel water-soluble silk fibroin nanoparticles (WSSF-NPs) created by electron beam irradiation. In this report, we demonstrate the effects of electron beam irradiation doses ranging from 1 to 30 kGy on the molecular weight (MW), nanostructure formation, antioxidant activity and reducing power of the WSSF-NPs. Electron beam-induced degradation of SF causing MW reduction from 250 to 37 kDa. Chemical characteristic functions of SF still remained after exposing to electron beam. The WSSF-NPs with the MW of 37 kDa exhibited spherical morphology with a nanoscaled size of 40 nm. Antioxidant activities and reducing powers were investigated using 2,2-diphenyl-1-picrylhryl free radical (DPPH∙) scavenging activity and ferric reducing antioxidant power (FRAP) assays, respectively. The WSSF-NPs showed greater antioxidant activity and reducing power than non-irradiated SF. By increasing their antioxidant and reducing power efficiencies, WSSF-NPs potentially created gold nanocolloid. WSSF-NPs produced by electron beam irradiation would be a great merit for the uses as a natural antioxidant additive and a green reducing agent in biomedical, cosmetic and food applications.

Phytochemical, Free Radical Scavenging and Cytotoxic Assay of Cucumis Melo L. Extract and β-Carotene

Abstract—Deaths from cancer worldwide are estimated to continue rising. Free radicals are toxic to cellular components. It is known that they cause DNA damage, contribute to DNA instability and mutation, thus favor carcinogenesis. This research was conducted to determine the activity of Cucumis melo extract and β-carotene in antioxidative and cytotoxic potencies. The research was done by examining the 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity assay. The cytotoxic potency was determined by the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3- carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay on HeLa, HepG2 and NIH3T3 cell lines. β-carotene exhibited more active DPPH free radical scavenging activity compared with C. melo extract. C. melo extract showed more active anti-cancer both in HeLa (IC50: 23.649 μg/mL) and HepG2 (IC50: 110.403 μg/mL) cancer cells. C. melo extract (IC50: 16,670.404 μg/mL) and β-carotene (IC50: 50,645.994 μg/mL) had low cytotoxicity in NIH3T3 fibroblast. C. melo extract has lower antioxidant activity, but higher cytotoxic potency compared with β-carotene.

In vitro antioxidant activity studies of Artocarpus gomezianus

Extraction of fruits, aerial parts and roots from Artocarpus gomezianus were subjected for pharmacognostic analysis. Also these parts were subjected tohydro-alcohol (30:70) extraction by soxhlet extraction technique. The raw materials were dried and powdered and analyzed for various parameters. The moisture content was found to be in the range of 4.97 per cent to 11.09 per cent, extractive values - 14.92 per cent to 18.75 per cent, chloroform solubility 1.15 per cent to 6.99 per cent and water solubility ranged between 4.52 per cent to 5.77 per cent. Fluorescence analysis and ash values were also determined. Extraction yields with 30:70 solvents indicate the quantitative idea about some of the proximate components. The results are important in planning the extraction, phytochemical analysis and determination of their various beneficial biological activities. The study was undertaken to evaluate qualitatively for the contents of carbohydrates, glycosides, saponins, alkaloids, flavonoids, phenolics, tannins, Phytosterols, Triterpenoids, oils and fats present in the extracts from the Fruit, Aerial parts and Roots of Artocarpus gomezianus . The extracts when tested qualitatively for various phytochemicals, they found to contain carbohydrates, Glycosides, alkaloids, tannins, phytosterols and Triterpinoids. However, they do not contain saponins, oils and fats. Quantitative estimation of extracts for total phenols and total flavonoids reveals that most parts contain reasonably higher amounts. The results clearly demonstrate that the extracts can be considered for further studies which evaluate the biological activity such as antioxidant activities. Antioxidant assays such as Nitric oxide scavenging assay, Ferric ion reducing activity assay, ABTS free radical scavenging activity assay and total antioxidant assays were performed to ascertain the potency of the extracts. Fruit extract of Artocarpus gomezianus was found to have maximum ferric ion reducing property than other parts studied. Nitric oxide scavenging activity was found to be higher in fruit followed by aerial and root parts. ABTS radical scavenging activity of aerial part extract is found to be 5 mg/ml compared to the standard ascorbic acid with 4 mg/ml. The total antioxidant activity was found to be significantly high for the extract from fruit part than the extracts from aerial and root parts. It is clear from the studies that the extracts of aerial parts, fruits and roots possess potentially beneficial antioxidant activities. In view of their use in ancient medicine coupled with the recent understandings of these plant species, they may be considered for further exploration as they may yield very potent nutraceuticals.

Total anti-oxidant capacity, flavonoid, phenolic acid and polyphenol content in ten selected species of Zingiberaceae rhizomes.

Natural products such as herbs, fruits, spices, beverages, vegetables are becoming more popular among scientific community and consumers because of their potential to arrest the effect of free radicals in human system. This study determined the total antioxidant capacity of ten selected species of Zingiberaceae (Ginger) used as spices and for medicinal purposes in Southeast Asia. Methanol was used as the extraction solvent, 2,2 - diphenyl-1-picrylhydrazil (DPPH) for free radical scavenging activity and ferric reducing antioxidant power (FRAP) assays. Phenolic compounds were measured using Total flavonoid, Phenolic acid and Polyphenols content assay to evaluate the quality of the antioxidant capacity of the rhizomes and vitamin C as positive control. The results obtained revealed that Curcuma longa and Zingiber officinale had the highest free radical scavenging capacity of 270.07mg/TE/g DW and 266.95mg/TE/g DW and FRAP assay, Curcuma longa and Zingiber officinale also gave the highest ferric reducing power of 231.73mg/TE/g DW and 176.26mg/TE/g DW respectively. For Phenolic compounds, Curcuma longa and Curcuma xanthorrhiza gave the highest values of flavonoid (741.36mg/NGN/g DW and 220.53mg/NGN/g DW), phenolic acid (42.71mg/GAE/g DW and 22.03mg/GAE/g DW) and polyphenols (39.38mg/GAE/g DW and 38.01mg/GAE/g DW) respectively. Significant and positive linear correlations were found between Total antioxidant capacity and Phenolic compounds (R = 0.65 - 0.96). This study provides evidence that extracts of Zingiberaceae (Ginger) rhizomes are a potential source of natural antioxidants and could serve as basis for future drugs and food supplements.

The Effects of Solvents and Extraction Methods on the Antioxidant Activity of P. niruri

The effects of different types of solvents and extraction method were investigated to determine the presence of antioxidant contents and activity from the P. niruri plant. The aim of this study is to determine which extraction method will give higher natural antioxidant contents and antioxidant activity. The content of natural antioxidant and antioxidant activity were analysed by total phenolic content (TPC), total flavonoid content (TFC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity assay. The results showed that extracts from a supercritical fluid extraction (SFE) method without the addition of modifier showed the highest content of total phenolic (187.66 mg GAE/ g) and flavonoid (1100.93 mg QE/g) in P. niruri compared to the other methods of extraction with different type of solvents. The extract of P. niruri from different extraction methods showed antioxidant activity on DPPH radical scavenging assay. The soxhlet extraction method by methanol showed the lowest IC50 compared to the other methods of extraction. The results revealed that P. niruri extracts had different content of antioxidant and antioxidant activity. The solvent polarity and different methods of extraction play significant roles in determining the most suitable method for production of antioxidant contents and antioxidant activity from P. niruri extracts.

New chitin, chitosan, and O-carboxymethyl chitosan sources from resting eggs of Daphnia longispina (Crustacea); with physicochemical characterization, and antimicrobial and antioxidant activities

The paper describes the isolation and characterization of chitin and chitosan from Daphnia longispina resting eggs harvested from a reservoir. Resting eggs are fertilized eggs that are encased in chitinous shells called ‘ephippia’ and which ensure the survival of the Daphnia population in adverse conditions. The chitin-content of D. longispina resting eggs was found to be 23 ∼ 25% and the chitosan (having a 70 ∼ 75% deacetylation degree) yield of the chitin was 76 ∼ 77%. This high chitin-content indicates that D. longispina resting eggs can be exploited as a chitin source. The structure and thermal properties of chitin, extracted from D. longispina resting eggs, were characterized by employing Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. The crystallinity of the chitin was found to be very low (48%). Physicochemicallycharacterized chitosan and the produced O-carboxymethyl chitosan were tested for their antimicrobial and antioxidant activity. It has been observed that chitosan displays antimicrobial activity against all pathogenic bacteria, whereas O-carboxymethyl chitosan only exhibits inhibition activity against L. garvieae, L. Monocytogenes ATCC 7644, Y. enterocolitica NCTC 11175 and S. aureus ATCC 25923. In a free radical scavenging activity assay, the IC50 values of chitosan, O-carboxymethyl chitosan and butylated hydroxytoluene were found to be 23.01, 56.43 and 0.05, respectively. The ferric-reducing power of O-carboxymethyl chitosan (EC50 = 8.30) indicated higher activity than chitosan (EC50 = 10.12).

Total Antioxidant Capacity, Total Phenolic Compounds and the Effects of Solvent Concentration on Flavonoid Content in Curcuma longa and Curcuma xanthorhhiza Rhizomes

Natural products such as herbs, fruits, spices, beverages, vegetables are becoming more popular among scientific community and consumers because of their potential to arrest the effect of free radicals in human system. This study investigated the total antioxidant capacity of Curcuma longa and Curcuma xanthorrhiza use as spices and medicinal compound in Southeast Asia. Methanol was used as the extraction solvent, 2,2 – diphenyl -1- picrylhydrazil (DPPH) for free radical scavenging activity and ferric reducing antioxidant power (FRAP) assays. Phenolic acid and polyphenol content were both measured. Different concentrations of methanol were used for the extraction to determine flavonoid content and ascorbic acid was used as the control. The results revealed that C. longa had a higher values in all the assays including DPPH (270.1 mg TE/g dw), FRAP (231.7 mg TE/g dw), phenolic acid (42.7 mg GA/g dw) and polyphenols (39.4 mg GA/g dw). The 90% methanol extract showed the highest flavonoid content in both species of Zingiberaceae. This study provides evidence that the yield of extracts of C. longa and C. Xanthorrhiza obtained are directly proportional to solvent concentration and could be a source of natural antioxidant.

Antibacterial and Antioxidant Activities of Various Medicinal Plants Used in Oriental Medicine

The antibacterial activities of the ethanol extracts of 35 medicinal plants were screened against Escherichia coli, Bacillus cereus, and Staphylococcus aureus by following standard antimicrobial susceptibility testing procedures. The ethanol extracts of Coptis chinensis and Glycyrrhiza uralensis showed antibacterial activity against all three test bacterial species. The screened extracts were also tested for their antioxidant activities using the DPPH free radical scavenging activity assay, and for their cytotoxic and antioxidant activity in vitro using an assessment of cell viability on mouse embryonic fibroblast cells. The ethanol extracts of both C. chinensis and G. uralensis showed good radical scavenging antioxidant properties and attenuated the rate of cell death caused by oxidative damage. Our results showed that C. chinensis and G. uralensis are promising sources of natural products with good antibacterial and antioxidant activities.

Antioxidant Activity and Total Phenolic Content of Oils Extracted from Pinus pinaster Sawdust Waste. Screening of Different Innovative Isolation Techniques

Essential oils from Pinus pinaster sawdust waste was extracted using different technologies including conventional hyrodistillation method (HD) and some intensified technologies namely turbo-hydrodistillation (THD), ultrasound assisted extraction HD (UAE-HD) and two microwave techniques; microwave hydrodiffusion and gravity (MHG) and solvent-free microwave extraction (SFME). The essential oils were qualified and quantified using chromatography coupled to mass spectrometry analysis. The analysis of the oil has resulted in the identification of 45 components; α-terpineol and β-caryophyllene were the main components. The antioxidant activity was assessed by diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP) assays. The highest radical-scavenging activity was obtained for the two microwave techniques with IC50 value about 15 μg/ml, followed by the other techniques for which IC50 ranged between 59.8 and 123 μg/ml. For FRAP assay, the same classification was obtained with the highest values of 0.598 and 0.591 μg/ml for respectively microwave extractions (MHG and SFME) and 0.307, 0.322 and 0.401 μg/ml respectively for HD, THD and UAE-HD. DPPH and FRAP assays were found to be highly correlated. The total phenolic compounds (TPC) were more present in microwave extracts (78.5 and 74.6 GAE/g extract) respectively for MHG and SFME) compared to other technique for which the values ranger between 54.1 and 56.6 GAE/g extract. TPC were correlated with DPPH and FRAP (R2 > 0.95; p < 0.01) indicating that the total phenols are highly contributes to the antioxydant activity.

Protective effect of Clerodendrum colebrookianum Walp., on acute and chronic inflammation in rats

Aim:To evaluate antioxidant, anti-inflammatory potential of the aqueous extracts and its aqueous, n-butanol, ethyl-acetate, and chloroform fractions of Clerodendrum colebrookianum Walp. leaves.Materials and Methods:In this present study, all the test samples were evaluated on in-vivo inflammatory model such as carrageenan and histamine-induced acute-inflammation and cotton pellet induced granuloma formation in albino male rats. Test samples were also employed in in-vitro assays like DPPH* free radical scavenging activity and COX inhibition assay.Results:The test samples at the dose of 200mg/kg/p.o. were found to cause significant inhibition of carrageenan and histamine-induced inflammation and cotton pallet-induced granuloma formation on acute and chronic inflammation in rats. The test samples, except n-butanol fraction, exhibited inhibitory effect for both COX-1 and COX-2, in in-vitro assay but their percentage of inhibition values differs from each other. The test samples (aqueous extracts, aqueous, n-butanol, ethyl-acetate, and chloroform fractions) at 100 μg concentration exhibits 54.37%, 33.88%, 62.85%, 56.28%, and 57.48% DPPH* radical-scavenging effect respectively in in-vitro antioxidant study.Conclusion:These observations established the anti-inflammatory effect of C. colebrookianum leaves in acute and chronic stages of inflammation by free radical scavenging and inhibition of COX-1 and COX-2.

Nitrogen-Containing Apigenin Analogs: Preparation and Biological Activity

A series of nitrogen-containing apigenin analogs 4a–j was synthesized via Mannich reactions to develop anticancer, antibacterial, and antioxidant agents from plant-derived flavonoids. The chemical structures of these compounds were confirmed using 1H-NMR, 13C-NMR, and ESI-MS. The in vitro biological activities of the analogs were evaluated via assays of their antiproliferative, antibacterial, and antioxidant activities. The prepared apigenin analogs exhibited different antiproliferative activities against four human cancer cell lines, namely human cervical (HeLa), human hepatocellular liver (HepG2), human lung (A549), and human breast (MCF-7) cancer cells. Compound 4i showed the most favorable in vitro antiproliferative activity with IC50 values of 40, 40, 223, and 166 μg/mL against HeLa, HepG2, A549, and MCF-7, respectively. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity assay also showed that 4i had the most potent antioxidant activity, with the smallest IC50 value (334.8 μg/mL). The antibacterial activities of the analogs were determined using a two-fold serial dilution technique against four pathogenic bacteria, namely Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Pseudomonas aeruginosa. All the prepared apigenin analogs exhibited more potent activities than the parent apigenin. Compounds 4h and 4j, in particular, exhibited the best inhibitory activities against the Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis with MIC values of 3.91 and 1.95 μg/mL, respectively.

Total antioxidant, polyphenol, phenolic acid, and flavonoid content in Ficus deltoidea varieties

This research aimed to study the antioxidant activities in hot and cold aqueous extracts extracted from fresh leaf of Ficus deltoidea using 2,2-diphenyl-1-picrylhydrazil (DPPH) free radical scavenging activity and ferric reducing antioxidant power (FRAP) assays. Phenolic compounds were measured using total polyphenol, phenolic acid, and flavonoid content. Different extraction conditions significantly affected the total antioxidant activities, polyphenol, phenolic acid, and flavonoid content of the extracts. The decreasing order of antioxidant activities using DPPH method in hot aqueous extracts were as follows: var.kunstleri > var. trengganuensis > var. angustifolia, while cold aqueous extracts: var.kunstleri > var. angustifolia > var. trengganuensis. The total antioxidant content using FRAP method showed the highest activity in hot aqueous extracts of F2 with 2.13 mg Trolox equivalent per gram fresh weight (TE/g FW). Hot aqueous extract for F2 and F11 contained the highest total polyphenol content with 0.88 mg gallic acid equivalent (GAE)/g FW, while the lowest in cold aqueous of M6 contained total polyphenol content with 0.47 mg GAE/g FW. Total phenolic acid ranged from 0.54 to 2.19 mg GAE/g FW in hot aqueous extracts, while 0.59 to 1.96 mg GAE/g FW for cold aqueous extract. Total flavonoid content ranged from 0.17 to 0.66 and 0.18 to 0.51 mg catechin equivalents (CE)/g FW in hot and cold aqueous extracts, respectively. All of the antioxidant compounds correlated positively with total polyphenol, phenolic acid, and flavonoid. Key words: Ficus deltoidea, antioxidant, polyphenol, phenolic acid, flavonoid.

Antimicrobial and Antioxidant Activities of Extracts and Lichen Acids Obtained from SomeUmbilicariaSpecies from Central Anatolia, Turkey

In this study, the methanolic extracts and lichens acids obtained from six Umbilicaria species were tested for their antimicrobial activity (against three Gram-positive bacteria, five Gram-negative bacteria and two yeasts species) and their antioxidant activity. Total phenolic content in the extracts was determined by the Folin–Ciocalteu assay. It ranged from 0.91 to 48.25 mg gallic acid/g. The antioxidant ability was measured using a free radical-scavenging activity assay using 2,2-diphenyl-1-picrylhydrazyl (DPPH). The methanolic extracts showed moderate DPPH radical-scavenging activity. Among the lichen acids, umbilicaric acid showed the highest antioxidant activity with 68.14% inhibition. Antimicrobial activity was determined by the agar diffusion method. Extracts were found to possess antimicrobial activity against some of the bacteria and yeasts tested. Gyrophoric acid was effective against six out of eight bacteria tested, but no activity was observed against the yeasts. Practical Applications This article evaluates antimicrobial, antioxidant activities and their active compounds have been shown in some Umbilicaria lichens species. This is the first study reporting in vitro biological activities of U. aprina var. halei, U. cylindrica, U. decussata, U. leiocarpa, U. nylanderiana, U. virginis, gyrophoric acid, leconaric acid and umbilicaric acid isolated from them. Results of this study will contribute significantly to efforts to used antimicrobial and antioxidant agents in the country and elsewhere in Turkey.

Comparative effects of gamma and electron beam irradiation on the antioxidant potential of Portuguese chestnuts (Castanea sativa Mill.)

Chestnuts (Castanea sativa Mill.) are widely consumed all over the world, and have been recently studied for their antioxidant potential. The present study reports the effect of e-beam and gamma radiation (doses of 0, 0.5, 1 and 3kGy) on the antioxidant potential of Portuguese chestnuts. Irradiation might be an alternative preservation method, since Methyl Bromide, a widely used fumigant, was banished by the European Union in 2010 due to its toxicity. The antioxidant activity was evaluated through 2,2-diphenyl-1-pycrylhydrazyl (DPPH) free radical scavenging activity assay, reducing power by the Ferricyanide/Prussian blue assay, and lipid peroxidation inhibition by β-carotene/linoleate and thiobarbituric acid reactive substances (TBARS) assays. The analysis of total phenolics and flavonoids was performed by spectrophotometric assays. Irradiated samples preserved total phenolics content (but not flavonoids) and revealed higher antioxidant activity (lower EC50 values) than the control samples. The most indicated doses to maintain antioxidants content, and to increase antioxidant activity were 1 and 3kGy for electron beam and gamma radiation, respectively.

Evaluation of nutritional composition and antioxidant activity of Borage (Echium amoenum) and Valerian (Valerian officinalis).

The nutritional composition and antioxidant activity (in aqueose and solvent extracts) of two medicinal plants of Iranian origin Borage (Echium amoenum) and Valerian (Valerian officinalis) used as tea were determined. Samples were analyzed for antioxidant components viz. polyphenols, vitamin C, β carotene, flavonoids, anthocyanins and tannins. Antioxidant assays such as free radical scavenging activity, reducing power and total antioxidant activity were carried out for ethanol, methanol, acetone, 80% methanol and 80% ethanolic extracts. In borage highest and least activity was observed in water and acetone extract respectively in all assays. In Valerian, 80% methanolic extract showed highest activity in reducing power and free radical scavenging activity assay. Total polyphenols in borage and valerian were 1,220 and 500mg in ethanolic extracts and 25 and 130mg in acetonic extracts respectively. Total carotenoids and vitamin C contents were 31.6 and 133.69mg and 51.2 and 44.87mg for borage and valerian respectively. Highest amount of tannins were extracted in 80% methanolic extract. It can be concluded that borage and valerian exhibited antioxidant activity in all extracts. The antioxidant activity could be attributed to their polyphenol and tannin and flavonoids contents. In all assays borage showed higher activity than valerian.

EVALUATION OF ANTIOXIDANT ACTIVITY OF FLAVONOID AND PHENOLIC CONTENTS OF LUFFA ECHINATA ROXB. FRUITS AND NYCTANTHUS ARBOR-TRISTIS LEAVES

Objective : To obtain a systematic record of the relative antioxidant activity of flavonoid and phenolic contents of Luffa echinata Roxb fruit and Nyctanthus arbor-tristis leaves extracts. Methods : Phenolic and flavonoid content were determined by using gallic acid and quercetin as standard, antioxidant properties were evaluated by the methods, namely the Trolox equivalent antioxidant capacity assay (TEAC), Oxygen radical absorbance capacity (ORAC) Assay and DPPH free radical scavenging activity assay. Results : Total phenolic content were found 76.34±0.44 and 45.53±0.65 mg/g, while flavonoid contents were found 65.98±0.83 and 34.92±0.76 mg/g in Luffa echinata Roxb and Nyctanthus arbor-tristis respectively. In the Trolox equivalent antioxidant capacity assay, TEAC value were found 0.34 mmole/g and 0.28 mmole/g, while in Oxygen radical absorbance capacity assay, ORAC value was found 253.7m moles TE # / g and 221.6 m moles TE # / g, where as DPPH free radical scavenging activity assay showed IC 50 value 188±0.87 and 176±0.68 for Luffa echinata Roxb and Nyctanthus arbor-tristis extracts . Conclusion : The present studies suggest that both the plants have moderate to potent antioxidant activity.

Screening of Endophytic Fungi Having Ability for Antioxidative and α-Glucosidase Inhibitor Activities Isolated from Taxus sumatrana

Endophytic microbes are considered as an important source of natural products. They show antibiotic, anticancer, antioxidative and antidiabetic activities. Therefore, there are many reports on the isolation and bioactivity screening of endophytic fungi from various plants including Taxus species. Taxus sumatrana (Miq.) de Laub is found in Indonesia. The objective of this study is to conduct an in vitro screening of 14 endophytic fungi isolated from Taxus sumatrana having antioxidative and alpha-glucosidase inhibitor activities. Each endophytic fungus was cultured for 7 days and the fungal mycelium and medium were extracted with methanol and ethyl acetate, respectively, to produce each extract. The antioxidative activity of each extract was tested by DPPH free radical scavenging activity and beta-carotene bleaching assays, whereas antidiabetic activity was tested based on alpha-glucosidase inhibitor activity. The screening results showed that fungal mycelia of TSC 13 had the best alpha-glucosidase inhibitor activity and TSC 24 had the best antioxidative activity. Isolation of bioactive compounds from TSC 13 and TSC 24 is being conducted. This is the first report that endophytic fungi isolated from T. sumatrana exhibited anti alpha-glucosidase inhibitory and anti oxidative activities.

Polyphenol Content and Antioxidant Properties of Colored Soybean Seeds from Central Europe

The antioxidant activity and contents of various polyphenol classes in the seeds of seven soybean varieties of different seed color and one yellow seed cultivar, representing a reference genotype, were evaluated. Total polyphenols and tannins were determined after extraction of plant material with 70% aqueous acetone, and total flavonoids were extracted with methanol and acetic acid, whereas anthocyanins were extracted with 20% aqueous ethanol. In addition, isoflavone content and composition were determined using high-performance liquid chromatography analysis. Antioxidant activity of seed extracts was evaluated by the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity assay. A positive linear correlation between antioxidant activity and contents of total polyphenols and anthocyanins was established. The highest antioxidant activity was observed in the extracts of black and brown varieties, which also showed high levels of all polyphenol classes examined. Yellow seed had the highest total isoflavone content (3.62 mg/g of dry material). The highest concentration of total daidzein was determined in black seeds (>2.0 mg/g of dry material), and the highest total glycitein and genistein contents occurred in the yellow cultivar (0.53 and 1.49 mg/g of dry material, respectively). According to our results, varieties of black and brown seeds could be of special interest not only for their large content of total polyphenols, ranging from 4.94 to 6.22 mg of gallic acid equivalents/g of dry material, but also for their high content of natural antioxidants such as anthocyanins.