Synthesis of Hydroxystilbene Derivatives and their Antioxidant Activity by DPPH Method

Five hydroxystilbene derivatives were synthesized and their structures were determined using high-resolution mass spectrometry, ^1H NMB, and IR. In this study, the antioxidant activities of eight hydroxystilbenes （five synthesized hydroxystilbene derivatives and three other compounds） were evaluated with the free radiced scavenging model 1,1-diphenyl-2-picrylhydraxyl. It was observed that there exists a very significant linear rehtionship between the reciprocal of the EC50 value of each of the compounds and the maximum wavelength of the ultraviolet absorption peaks, It is believed that this result will be helpful for the further synthesis of such antioxidants.

Chemical Composition, Phenolics, Anthocyanins Concentration and Antioxidant Activity of Ten Wild Edible Plants

Plants were collected and prepared for chemical analysis, total phenolics, anthocyanins concentrations, and free radical scavenging activity. Results showed that, protein concentration of Malva parviflora (22.9%) was the highest among the plants. Ruta chalepensis had high levels of fat and carbohydrates (4.2% and 51.7%, respectively), but had the lowest level of ash (8.7%). Mineral concentrations varied and found to have appreciable amounts of Ca, Na, K, Cu, Fe, Mg, Mn, Zn and P. Total phenolic ranged from 163.1 (Tetragonolobus palaestinus) to 1328.8 mg GAE/100g (Ruta chalepensis). Anthocyanins ranged between 18.1 (Gundelia tournefortii) and 100.1 mg/100g (Rumex acetosella). These plants differed in free radical scavenging activity. It was concluded that these plants could be considered as natural sources for antioxidants and valuable natural resources as a new addition to the diet of inhabitants.

Effect of Plant Ash on Nutrient Quality and Antioxidant Activity of African Yam Bean Seed Porridge in Relation to Cooking Time

The present study aimed to investigate the nutrient quality, antioxidant activity and sensory acceptability of hard-to-cook African yam bean (AYB) seeds cooked for 5 h (control) and for 2 h with plant ash. The plant ash were unripe plantain peel ash (UPA), corn cob ash (CCA) and UPA and CCA mixture. Standard methods of Association of Official Analytical Chemists (AOAC) were used for the proximate and mineral analysis, DPPH, ABTS and FRAP assays were used to investigate the antioxidant activity. A completely randomized design with one way analysis of variance (ANOVA) was used for data analysis. The results showed that cooking of AYB seeds for 2 h with 8 g/100mL plant ash solution improved the nutrient contents, antioxidant activity and sensory scores of the porridge. Higher values of proteins, ash and energy were obtained in 8 g/100mL UPA/CCA and in 8 g/100mL CCA additives. However, moisture, fat and fibre contents were not affected by plant ash additives and were higher in 5 h cooked porridge. Cooking with 8 g/100mL plant ash solution for 2 h significantly increased mineral elements in the porridge. Phenolic compounds (total polyphenols and flavonoids), and antioxidant activity (DPPH, ABTS and FRAP) showed higher values with plant ash additives. This study reveals that addition of plant ash did not only reduce the cooking time of AYB seed by 60%, but also improved the nutrient quality, antioxidant activity and sensory acceptability.

Antioxidant Activity and Phytochemical Screening in Acacia rigidula Benth. Leaves

This study aimed to compare the total phenolic content (TPC) and antioxidant activities of A. rigidula extracts. It also aimed to identify phenolic acids present in the extracts. The 2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and ferric thiocyanate lipid peroxidation antioxidant assays were performed. High performance liquid chromatography was used to identify phenolic acids. There was no solvent effect on TPC nor on scavenging activities, and inhibition of lipid peroxidation (p > 0.05) among solvent extracts. On the other hand, 1:1:3 water: acetone: methanol extract (10.22 mg GAE/g sample) had significantly higher reducing potential than 50% ethanol extract (EE) (9.259 mg GAE/g sample) (p < 0.05);but EE was not significantly different from 80% methanol extract (9.781 mg GAE/g sample) (p > 0.05). Phenolic fraction designated as fraction 4 had the highest antioxidant activity (p < 0.05) with 69.49% ABTS scavenging activity and FRAP reducing potential, 22.26 mg of GAE/g sample. DPPH scavenging activities of fractions 4 (55.59%) and 5 (55.64%) were significantly higher than the other fractions (p A. rigidula extracts contain gallic, caffeic, vanillic, p-coumaric, salicylic acids and vanillin.

A pilot study of antioxidant potential of endophytic fungi from some Sudanese medicinal plants

Objective: To evaluate the total phenolic content and total antioxidant capacity of ethyl acetate extracts of 21 endophytic fungi isolated from five Sudanese medicinal plants: Calotropis procera, Catharanthus roseus, Euphorbia prostrate, Vernonia amygdalina and Trigonella foenumgraecum. Methods: Crude extracts of endophytic fungi and their host plants were tested by classical Folin-Ciocalteu colorimetric method to determine the total phenolic content, also total antioxidant capacity was estimated using 1,1-diphenyl-2-picrylhydrazyl free radical scavenging in vitro method. Results: Among the endophytes, endophytic fungus Aspergillus sp. from Trigonella foenum-graecum seeds demonstrated the highest both total phenolic content in term of gallic acid equivalent(GAE) [(89.9±7.1 mg GAE/g)] and antioxidant activity for 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay [IC50:(18.0±0.1 μg/m L)]. A high positive linear correlation(R2=0.999 1) was found between total antioxidant capacity and total phenolic content of endophytic fungi isolated from Vernonia amygdalina. Conclusions: The present study revealed that some endophytic fungi from the five Sudanese medicinal plants could be a potential source of novel natural antioxidant compounds.

Antioxidant activity of polyaniline nanofibers

Well-confined uniform polyaniline （PANI） nanofibers were synthesized by using photo-assisted chemical oxidative polymer- ization of aniline in the presence of different dopant acids, and the radical scavenging ability of the produced PANI nanofibers was determined by the DPPH assay. It was found that the antioxidant activity of PANI nanofibers was higher than conventional PANI, and increased with decreasing of averaged diameter of the nanofibers. The enhanced antioxidant activity was concerned with increased surface area of PANI nanofibers.

Antioxidant Activity of Different Solvent Extracts of Blumea Megacephala in Vitro

[Objectives] The aim was to study the antioxidant activity of different solvent extracts of Blumea Megacephala in vitro. [Methods] The removal rates of DPPH free radicals and ABTS free radicals and the reduction capacity of Fe^(3+) by ethanol extract( EE),acetone extract( AE) and ethyl acetate extract( EAE) of Blumea Megacephala were detected. [Results]The three extracts of Blumea Megacephala had certain antioxidant activity,of which the antioxidant activity of ethyl acetate extract was the strongest and has great potential for development.[Conclusions]The study can provide scientific reference for the deep research on the antioxidant activity of Blumea Megacephala.

Antioxidant Activity of Hydro-Acetonic, Hydro-Methanolic and Aqueous Leaf and Bark Extracts of <i>Sclerocaria birrea</i>(A. Rich.) Hochst

Bioactive compounds in plants are associated with the reduction of chronic diseases. The free radical scavenging activity of different extracts of a medicinal plant, Sclerocarya birrea, has been investigated using the DPPH test, ABTS test and FRAP. Three extracts were prepared from the leaves and bark: hydro-methanolic, hydro-acetonic and aqueous. Phytochemical screening was carried out the standard methods followed by the determination of the polyphenol by Folin-Ciocalteu method. The analysis of variance (ANOVA) with the STATISTICA 7.1 and statistical significance was set at p < 0.05. Evolution of percent inhibition (PI) as well as the IC50 of the extracts was obtained using the Origin Pro 8.5 software and Microsoft Excel. The results show that the bark extracts are about twice as rich in polyphenols as the leaves. With DPPH at 1.25 mg/mL, the bark has a PI of 91.04% ± 0.001% while leaves, reach 99.80% ± 0.021%. As for the ABTS test, the bark extract reached its maximum activity at 1.25 mg/mL with a PI of 99.80% ± 0.003% while leaves extract greater value of PI is 99.75 ± 0.003 at 2.5 mg/mL. With FRAP test at 1.25 mg/mL, the bark has a PI of 79.29% ± 0.005% while leaves, reach 80.33% ± 0.001%. The IC50 of the bark and leaf extracts on the smallest DPPH are 0.156 ± 0.001 mg/mL in hydro-methanol, 0.301 ± 0.00 mg/mL in hydro-acetone and 0.407 ± 0.00 mg/mL in aqueous extract. With ABTS test, the best IC50 are obtained with hydro-acetone extracts with value of 0.247 ± 0.001 mg/mL for bark and 0.248 ± 0.0005 mg/mL for leaves while in hydro-methanolic and aqueous extracts the best IC50 are respectively 0.255 ± 0.00 mg/mL and 0.463 ± 0.00 mg/mL. Using ascorbic acid as our standard, the PI was 94.86% ± 0.008% with an IC50 of 0.213 ± 0.00 mg/mL. According to these results, the reducing power of the bark is slightly higher than that of the leaves. We can say that the bark has better activity than the leaves and the alcoholic extracts have given better results than the aqueous extract.

In Vitro Antioxidant and Cytotoxic Activities of 18 Plants from the Erkowit Region,Eastern Sudan

We investigated the antioxidant potential and cytotoxicity towards human CCRF-CEM leukemia cells of 57 extracts obtained from 18 plants collected in the Erkowit region,eastern Sudan.The antioxidant activity was determined by measuring the radical scavenging effects against 2,2-diphenyl-1-picrylhydrazyl(DPPH)and N,N-dimethyl-p-phenylendi-amine(DMPD),metal-chelation capacity,ferric-reducing(FRAP)and phosphomolibdenum-reducing antioxidant power(PRAP)methods using ELISA microtiter assays.Total phenol and flavonoid amounts of the extracts were determined spectrophotometrically.Cytotoxicity towards CCRF-CEM cells was evaluated by the resazurin reduction assay.Geranium favosum followed by Kalanchoe glaucescens,Malva parviflora,Aizoon canariense,and Coleus barbatus,respectively,possessed the highest antioxidant activity among the studied plants.Chrozophora oblongifolia and K.glaucescens exerted considerable cytotoxicity against CCRF-CEM leukemia cells.These plants may serve as source for the further development of natural antioxidant and antitumor agents.

Antimicrobial and antioxidant properties of medicinal plants used by the Bentian tribe from Indonesia

Some selected medicinal plants used by Bentian tribe from Indonesia were evaluated for potential antimicrobial and antioxidant properties.The leaves stem bark and root of the plants were extracted with n-hexane,ethyl acetate and ethanol to give respective extracts.Antimicrobial activity against Propionibacterium acnes and Candida albicans was determined by an agar well diffusion method.Antioxidant activity was assayed by the DPPH radical scavenging activity mechanism.The results showed that n-hexane,ethyl acetate and ethanol extracts of Cananga odorata,ethanolic extract of Chromolaena odorata,and ethanolic extracts of Hyptis capitata and Ampelocissus cinnamomeae displayed good activity against P.acnes at 25–400μg/well of the extracts tested.The n-hexane and ethanol extracts of Chromolaena odorata and H.capitata,and the n-hexane,ethyl acetate and ethanol extracts of Cananga odorata displayed more activity against C.albicans than others at 25–400μg/well of the extracts tested.The most antioxidant activities against DPPH were displayed by the ethanol extracts of Ficus variegata stem bark,Leucosyke quadrinerva root and Clausena excavata leaves exhibiting 91%,91%and 86%inhibition,respectively.The present results showed potential of some medicinal plants used by Bentian tribe from Indonesia as natural anti-microbial and anti-oxidant and potentially anti-inflammatory agents.

Antioxidant Activity of the Natural Flavonoid 7-Hydroxy-5,6,4’-trimethoxyflavone Isolated from the Leaves of Lippia rugosa A. Chev

Phytochemical studies and antioxidant activities were carried out on n-hexane, ethyl acetate, ethanol and methanol extracts of the leaves of Lippia rugosa A. Chev (Verbenaceae), a medicinal plant used traditionally in the Cameroonian savannah’s region to protect foodstuffs and to cure degenerative diseases. Results indicated that theses extracts contain terpenoids, phenolic and flavonoid compounds. Except the n-hexane extract, all of the obtained extracts exhibit antioxidant activities with the ethanol extract being the most effective with an inhibition percentage of 85.668% ± 1.233% and an inhibition concentration (IC50) of 58 μg/ml (R2 = 0.987, P < 0.01) at a concentration of 100 mg/ml. Chromatographic separation on silica gel of the ethanol extract led to the isolation of a pure organic compound which was characterized as 7-hydroxy-5,6,4'-trimethox- yflavone by extensive 1D and 2D NMR spectroscopy, a flavonoid exhibiting antioxidative activity with an inhibitory percentage of 25.506% ± 0.205% and inhibition concentration (IC50) of 221 μg/ml (R2 = 0.966, P < 0.01). This is the first time that 7-hydroxy-5,6,4'-trimethoxyflavone is being isolated from L. rugosa and its antioxidant activity evaluated.

HPLC-DPPH法评价雪松松针抗氧化活性成分

目的评价雪松松针抗氧化活性成分。方法以维生素C(VC)和没食子酸为阳性对照,采用高效液相色谱(HPLC)法测定1,1-二苯基-2-苦肼基(DPPH)溶液加入雪松松针抗氧化活性成分后DPPH峰面积的衰减情况,并通过计算DPPH自由基的清除率和半数抑制浓度(IC_(50)),来评价雪松松针3种有效部位及8个单体成分的抗氧化活性。采用Agilent Eclipse Plus-C_(18)(250 mm×4.6 mm,5μm)为色谱柱,乙腈-水(62∶38,V/V)为流动相;检测波长为517 nm;流速为1.0 mL/min;柱温为25℃;进样量为20μL。结果雪松松针各有效部位清除DPPH自由基活性的能力大小依次为总黄酮>总多酚>总木脂素,IC_(50)分别为76.10、100.50、115.40μg/mL。与阳性对照比较,除山柰酚-3-O-β-D-葡萄糖苷外,7个单体化合物清除DPPH自由基活性的能力大小依次为二氢杨梅素>金丝桃苷>原儿茶酸>没食子酸>阿魏酸>杨梅素>山柰酚-3-O-(6″-O-E-阿魏酰基)-β-D-吡喃葡萄糖苷>VC>异鼠李素,IC50分别为16.50、19.40、23.73、27.24、32.10、32.20、47.60、93.20、297.20μg/mL。结论建立了HPLC-DPPH法用于评价雪松松针抗氧化活性;雪松松针具有较强的抗氧化活性,其中有效部位总黄酮、总多酚及单体成分二氢杨梅素、金丝桃苷等是具有开发前景的纯天然抗氧化剂。

Assessment of Nutrient Composition and Antioxidant Activity of Some Popular Underutilized Edible Crops of Nagaland, India

In Nagaland ~70% of population lives in rural areas and depends on forest products for livelihood. Being part of the biodiversity hotspot, state is rich in biodiversity. The present study was an attempt made to understand the nutritional properties of 22 popular underutilized edible plants (UEP) Kohima, Phek, Tuensang districts. Results revealed moisture content of 22 studied plants ranged between 4.8 to 88.15 g/100g, while protein content varied between 0.00269 - 0.773 g/100g with highest in Terminalia chebula (0.773 g/100g) fruit while lowest protein content was in Setaria italica (0.00269 g/100g). Total carbohydrate content was between 0.198 - 5.212 g/100g with highest in Setaria italica (5.212 g/100g) and lowest in Juglans regia (0.198 g/100g). Of the 22 samples, maximum antioxidant activity was in Terminalia chebula fruits (37.49 μg/ml) followed by Clerodendrum glandulosum (65.29 μg/ml) leaves, Phyllanthus emblica (79.08 μg/ml) fruits against Trolox (96.89 μg/ml). Highest total phenol content (TPC) was recorded in Terminalia chebula (53.11 mg GAE/g) and Rhus chinensis (43.99 mg GAE/g) while in other 20 crops the values varied from 0.09 - 8.44 mg GAE/g. Total flavonoid content (TFC) varied between 0.004 - 43.67 mg QE/g with clerodendrum glandulosum (43.67 mg QE/g) and Terminalia chebula (27.78 mg QE/g) were found to be highest among the 22 plant samples. Findings suggest that these underutilized edible plants should be popularized as they can contribute to nutritional support to different region of the state for health improvement and cultivated them commercially to help and develop various value added local product to improve the livelihood status of the rural population and also add to the economy of the state and region.

Comparison of Total Phenolic Content and Total Antioxidant Activity in Local Red Wines Determined by Spectrophotometric Methods

In this study, the antioxidant activity of local red wines was determined by four different analytical methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS?+) radical cation decolourisation, ferric reducing/antioxidants power (FRAP) and cupric ion reducing capacity in the presence of neocuproine (CUPRAC) for the evaluation of reducing power (PR). They were correlated with the total phenolic content (TPC) determined with the Folin-Ciocalteu’s reagent using gallic acid as a standard. The total polyphenol concentration was found to vary from 2599.90 to 4846.57 mg/L gallic acid equivalents (GAE). The total antioxidant activity determined by DPPH, ABTS, FRAP and CUPRAC methods was found to vary from 7.49 - 15.93 mmol/L, 12.02 - 24.73 mmol/L, 12.65 - 27.68 mmol/L and 13.19 - 31.07 mmol/L, respectively. The total phenolic contents of red wine samples exhibited a good correlation (p < 0.01) with antioxidant properties.

Antioxidant Activity of Pigment Extracted from Green-Wheat-Bran

The anthocyanin pigment extracted from green-wheat-bran was studied to identify its antioxidant activity.The antioxidant activities of the pigment were evaluated by anti-lipid peroxidation,total antioxidant activity （TAA）,superoxide anion radical scavenging activity （SARSA）,active oxygen scavenging activity （AOSA）,and DPPH （1,1-diphenyl-2 picrylhydrazyl free radical） radical scavenging activity.The results showed that the pigment had higher antioxidant activity and TAA,SARSA,AOSA and DPPH.scavenging activities at a certain concentration than Vc （antiscorbutic vitamin,vitamin C）,and the capacity increased with the increase of pigment concentration.Its TAA was 51.06 U mL-1,1.73 times of Vc,and SARSA 18 025.21 U mL-1,2.26% higher than Vc,and AOSA 3 776.31 U mL-1,1.24 times of Vc.As to the DPPH.scavenging activity of the pigment,there was a trend that higher concentration performed higher activity significantly improved with the company of Vc.The pigment showed significant antioxidant activities evaluated by different assays.Results will provide a better understanding on antioxidant activity of green wheat and allow the screening or breeding of green wheat varieties with higher antioxidant activity for food processing.

Antioxidant activity and free radical scavenging activities of Streptomyces sp.strain MJM 10778

Objective:To investigate the antioxidant activity of soil-borne aetinobacteria.Methods:The total phenolic contents,the level of antioxidant potential by DPPH radical scavenging activity,MO scavenging activity,and ABTS radical scavenging activity in ethyl acelale extract were determined.Results:The 16 S rDNA sequencing analysis revealed that Streptomyces sp.strain MJM 10778.which was isolated from Hambak Mountain.Korea,has 99.9% similarity to Streptomyces misionensis(S.misionenis) NBRC 13063.The physiological and the morphological test revealed that the strain MJM 10778 has different characteristics from the strain NBRC.13063.The entire antioxidant assay with the ethyl acelale extract displayed good radical scavenging activity.The IC_(50) values of the strain MJM 10778 extract on DPPH,.NO.and ABTS radicals were identified to he 92.8 μg/mL,0.02 μg/ml,and 134.9 μg/mL,respectively.The ethyl acetate extract of the strain MJM 10778 showed an 81.500% of cell viability at 100 μg/mL in Raw264.7cell viability assay.Conclusions:The results obtained suggesl that the ethyl acetate extract of Streptomyces sp.strain MJM 10778 could be considered as a potential source of drug for the diseases that is caused by free radicals with its anti-oxidant activities and low cytotoxicity.

Antioxidant Activity Determination of Citronellal and Crude Extracts of <i>Cymbopogon citratus</i>by 3 Different Methods

Cymbopogon citratus, better known as lemongrass, is a plant commonly used for culinary purposes. It is known to contain the compound citronellal, which is responsible for the lemon-scent of many of the plants of the genus Cymbopogon. A chloroform extract of Cymbopogon citratus was screened to determine its free radical scavenging activities. Three different methods were used to test the antioxidant activity of the extract, including FRAP assay (Ferric reducing antioxidant potential), DPPH radical scavenging assay (1,1-diphenyl-2-picryl hydrazyl radical reducing power methods), and β-carotene bleaching assay. Cymbopogon citratus showed low radical scavenging activities compared to ascorbic acid, gallic acid and quercetin. The results obtained suggest that Cymbopogon citratus is best appreciated for its refreshing aroma and delicate taste, but has little to offer as a source of antioxidants.

Phytochemical composition and in vitro antioxidant activity of aqueous extract of Aerva lanata(L.) Juss.ex Schult.Stem(Amaranthaceae)

Objective:To analyze the phytochemical composition and in vitro antioxidant properties of aqueous extract of Aerva Lanata（A.lanata） stem.Methods:During the preliminary phytochemical analysis,the aqueous extract of A.Ianata was screened for the presence of carbohydrates,proteins,phenolic compounds,oil and fats,saponins,flavonoids,alkaloids. tannins and phytosterols.Antioxidant activity of the extract was determined by 2.2-dipbenyl- 1-picrylhydrazyl radical scavenging activity,metal chelating activity,reducing power activity and DNA damage inhibition activity.Analysis of phenolic compounds was performed by FolinCiocaiteau reagent method and gradient high performance liquid chromatography technique. Results:Preliminary phytochemical analysis exhibited the presence of phenolic compounds, saponins.flavonoids.tannins and phytosterols as major phytochemical groups.The extract exhibited high 2.2—diphenyl-1-picrylhydrazyl radical scavenging activity(IC50= 110.74μg/ mL).metal chelating activity(IC50= 758.17μg/mL).reducing power activity and DIA damage inhibition efficiency.The extract was reported to possess a high amount of total phenolic content and some of them were identified as gallic acid（3,4,3-OH）,apigenin-7—O-glucoside tapigetrin), quercetin-3—O-rutinoside（rutin） and myricetin（3,5,7,3,4,5-OH）by high performance liquid chromatography analysis.The extract was found non toxic towards human erythrocytes in the hemolytic assay(IC50= 24.89 mg/mL).Conclusions:These results conclud that A.lanata stem possesses high antioxidant activity and can he used for the development of natural and sale antioxidant compounds.

Endophytic actinobacteria of medicinal plant Aloe vera: Isolation, antimicrobial, antioxidant, cytotoxicity assays and taxonomic study

Objective: To explore the new sources of novel bioactive compounds having pharmaceutical and agricultural interest and to search the endophytic actinobacteria from medicinal plants. Methods: NAF-1 an endophyte actinobacteria was isolated from leaves of medicinal plant Aloe vera collected in Marrakesh, Morocco using Bennett agar as selective medium. NAF-1 was tested for its antimicrobial activity against five pathogenic bacteria such as Staphylococcus aureus PIC 53156, Micrococcus luteus ATCC381, Bacillus subtilis ATCC 14579, Pseudomonas aeruginosa DSM 50090 and Escherichia coli ATCC 8739 and four human clinic fungi belonging to the Candida, Aspergillus and Microsporum genera. Several antioxidant activities were studied such as DPPH free radical scavenging, β-carotene and linoleic acid and reducing power assays. The total of phenol and flavonoid was also calculated. Using Artemia salina shrimp assay, the cytotoxicity of NAF-1 crude extract was determined. Results: The results revealed that the actinobacteria showed a high activity(≥20 mm) against only Gram positive bacteria but it had a moderate activity(between 13 and 15 mm) against Human clinic fungi. The isolate also exhibited a LD50 of 14.20 μg/mL in the cytotoxicity assay. The result showed that the crude extract presented an interesting free radical-scavenging activity with IC50 value of(5.58 ± 0.26) μg/mL and a high value of phenolic and flavonoid compounds with(15.41 ± 0.18) μg GAE/mg extract and(11.41± 0.06) μg QE/mg extract respectively. Moreover, the taxonomic position of our endophyte actinobacteria using the morphological and physiological criteria and using 16 S r RNA gene sequence(polyphasic approach) showed that the NAF-1 isolate was similar to Streptomyces hydrogenans which was never described as an endophyte actinobacteria. Conclusions: This isolated strain appears promising resources of bioactive agents and can be exploited to produce therapeutic agents active against pathogenic disease.

Evaluation of antioxidant activities of some Nigerian medicinal plants

Objective:The methanol extracts of the leaves of Kolancheo(K.) pinnata,Aspilia(A.) africana,Mucuna (M.) pruriens,Emilia(E.) coccinea,Triumfetta(T.) rhomboidea,Laportea(L.) ovalifolis,Celosia(C.) trigynea,Cucurbita(C.)moschata and Asystesia(A.)gangestica were evaluated for antioxidant activities,the reducing potentials of these plants were also determined and phytochemical screening of some of these plants were carried out.Methods:The antioxidant activities of these plants were evaluated by the use of 2,2-diphenyl -1 -picrylhydrazyl(DPPH) free radical assay and spectrophotomer.The reducing potentials of these plants were determined using Ferric chloride,Potassium Ferricyanide and Trichloroacetic acid proceedures. The phytochemical screenings of the medicinal plants were equally done using standard procedures.Results: The percentage of antioxidant activities values for the plants were:(31.00±1.80)%,(58.40±1.26) %,(59.10±1.60)%,(60.00±1.05)%,(60.80±1.28)%,(62.40±1.26)%,(64.80±2. 10)%,(75.70±2.60)%and(82.70±2.80)%for A.gangestica,C.moschata,C.trigynea,L. ovalifolia,E.coccinea,M.pruriens,A.africana,K.pinnata and T.rhomboidea.respectively.These values were dose-dependent and statistically significant at P < 0.05(ANOVA).The results showed that T.rhomboidea had the highest antioxidant activity value(82.70±2.80%) while A.gangestica had the least value (31.00±1.80%).The percentage of antioxidant activities of these plants were comparable to the standard used,Tocopherol which was found to be(97.20±1.06)%.The reducing potentials of the plants were found to be positively correlated to the antioxidant activities of the plants.Phytochemical screenings revealed the presence of alkaloids,flavonoids,terpenoids,saponins and tannins in the medicinal plants.Conclusion:The findings from this study have revealed the potentials of these plants as antioxidants.This could be exploited in drug development in search of powerful antioxidants which are urgently needed to challenge free radicals in biological systems.It will consequently help to prevent the body from free radicals originated ailments.However, further study needs to be done to isolate and characterize the active principles in these plants.