Antioxidant activity of methanolic extract of emblica fruit (Phyllanthus emblica L.) from six regions in China

The phenolic contents of methanolic extracts of emblica (Phyllanthus emblica L.) fruit from six regions in China were measured in this work. The antioxidant activities of these extracts were also evaluated. Total phenolic content was ranged from 81.5 to 120.9 mg gallic acid equivalents (GAE)/g and the flavonoid content was varied from 20.3 to 38.7 mg quecetin equivalents (QE)/g, while proanthocyanidin content was ranged from 3.7 to 18.7 mg catechin equivalents (CE)/g. Among all the methanolic extracts analyzed, the Huizhou sample exhibited a significantly higher phenolic content than other samples (P<0.05). The antioxidant activities were evaluated by in vitro experiments using scavenging assays of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, hydroxyl radicals, and superoxide anion radicals, chelating ability of ferrous ion, reducing power, and inhibition capability of Fe (II)-induced lipid peroxidation, respectively. The Huizhou sample was found to have the strongest antioxidant activities in scavenging DPPH radicals, superoxide anion radicals, and had the highest reducing power, while the Chuxiong sample showed the best performance in chelating iron and inhibiting lipid peroxidation. Furthermore, the Chuxiong sample exhibited a stronger inhibition activity of the hydroxyl radicals compared with other samples. The high correlation coefficient was existed between the phenolic content and superoxide anion radical scavenging activity, but no significant correlation was found between the former and hydroxyl radical scavenging activity. Methanolic extracts of emblica fruit from some selected regions exhibited stronger antioxidant activities compared to those of the commercial compounds (quercetin and BHA). It might be considered as a potential plant source of antioxidants.     

In vitro antioxidant activities of Stevia rebaudiana leaves and callus

Leaf extract of Stevia rebaudiana promotes effects on certain physiological systems such as the cardiovascular and renal and influences hypertension and hyperglycemia. Since these activities may be correlated with the presence of antioxidant compounds, leaf and callus extracts of Stevia rebaudiana were evaluated for their total phenols, flavonoids content and total antioxidant capacity. Total phenols and flavonoids were analyzed according to the Folin–Ciocalteu method and total antioxidant activity of water and methanolic extracts of stevia leaves and callus was assessed by ferric reducing/antioxidant power (FRAP) assay as well as 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The total phenolic compounds were found to be 25.18 mg/g for stevia leaves and 35.86 mg/g for callus on dry weight basis. The flavonoids content was found to be 21.73 and 31.99 mg/g in the leaf and callus, respectively. The total antioxidant activity was expressed as mg equivalent of gallic acid, ascorbic acid, BHA and trolox per gram on dry weight basis. Total antioxidant activity found was ranged from 9.66 to 38.24 mg and 11.03 to 36.40 mg equivalent to different standards in water and methanolic extract of stevia leaves, respectively. In case of stevia callus, it was found to be 9.44 to 37.36 mg for water extract and 10.14 to 34.37 mg equivalent to standards for methanolic extract. The concentrations required for 50% inhibition (IC₅₀) of DPPH radicals were 11.04, 41.04 and 57.14 μg/mL for gallic acid, trolox and butylated hydroxyanisole (BHA), respectively. The percent inhibition of DPPH radical of various extracts of stevia leaves and callus found were ranged from 33.17% to 56.82%. The highest percent of inhibition was observed in methanolic extract of callus.     

Radical scavenging,antioxidant and metal chelating activities of Annona cherimola Mill. (cherimoya) peel and pulp in relation to their total phenolic and total flavonoid contents

This study aimed to evaluate the total phenolic and flavonoid content, radical scavenging activity (by DPPH and ABTS tests) and antioxidant capacity (by β-carotene bleaching test) of Annona cherimola (cherimoya) fruits cultivated in Italy for human consumption. The metal chelating activity and ferric reducing power were also determined. A. cherimola peel and pulp were characterized by a total phenolic content of 14.6 and 12.6 mg chlorogenic acid equivalents/100 g fresh weight, respectively. A similar trend was observed with flavonoid content. Both extracts exhibited high antioxidant activity through different mechanisms of action. In particular, peel extract demonstrated the strongest free radical scavenging activity with an IC₅₀ value of 57.7 μg/mL. The same extract was more effective in preventing β-carotene oxidation (IC₅₀ value of 63.5 μg/mL after 60 min) and showed higher chelating ability (IC₅₀ value of 79.6 μg/mL) than pulp extract. This work demonstrated the high quality of cherimoya fruits cultivated in Italy, and recommends the peel of this fruit product that may be of interest from a functional point of view as a major source of natural antioxidants.     

Antioxidant properties of selected tropical wild edible mushrooms

Selected species of wild edible mushrooms were obtained from the interior areas of East Malaysia to determine the total phenolics and antioxidant properties, including free radical scavenging, reducing power and metal chelating activities. The in vitro antioxidant activities of petroleum ether (PE) and methanolic extracts of the edible wild mushrooms were comparable to the cultivated oyster mushroom. The radical scavenging activity was the highest in PE extract of Pleurotus porrigens (angel's wings) (85%), while methanolic extract of Hygrocybe conica (witch's hat mushroom) exhibited the highest (94%) chelating effect at 20 mg/ml. PE extracts were more effective than methanolic extract in scavenging ability on DPPH radicals, whereas methanolic extracts were more effective in reducing power and chelating ability on ferrous ions as evidenced by their lower EC₅₀ values. Principal component analysis (PCA) indicated phenolic group was the primary factor contributing to the metal chelating ability for PE extract although phenolic was better correlated with reducing power in methanolic extracts.     

Antioxidant activities and determination of phenolic compounds isolated from oriental plums (Soldam, Oishiwase and Formosa)

The purposes of this study were to determine phenolic compounds and to evaluate antioxidant activities of plums (Soldam, Oishiwase and Formosa). Soldam contains the highest amount of total phenolics among cultivars (Formosa: 4.0%, Oishiwase: 3.3%, Soldam: 6.4% for total phenolic) as well as the total flavonoids of which constituents were mainly myricetin and anthocyanidin. The antioxidant activities were measured by DPPH, ABTS radical scavenging, and SOD-like activities. The DPPH radical scavenging activity of Korean plum extracts (200 µg/mL) showed more than 43%, and the Soldam turned out to be the highest : ID₅₀ value: 160-177 µg/mL for Formosa and Oishiwase; 58-64 µg/mL for Soldam. The ABTS radical scavenging activity of Korean plum extracts (200 µg/mL) was found to be more than 50%. The SOD-like activity of Korean plum extracts (200 µg/mL) showed more than 70%. Among three kinds of cultivars, Soldam had the highest antioxidant activity. The nitrite scavenging activity of Soldam was 61.5%, which is the highest, compared with that of the other cultivars, about 50%. From these results, Korean plums turned out to be phytochemical rich fruit as well as to show high antioxidant activities.     

Radical scavenging-linked antioxidant activities of commonly used herbs and spices in Korea

Herbs and spices not only variety and racy flavour to Korean foods, they also are the richest source for antioxidant power. The present study evaluates the radical scavenging-linked antioxidant activities of hot water extracts from commonly used herbs and spices in Korea. 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical and superoxide anion scavenging activities of bay extract were 39.5% and 22.1%, respectively. The hydroxyl radical scavenging activity was in order of dill (50.0%) > bay (31.3%) > garlic (27.9%) > white pepper and black pepper (15.1–15.3%) > onion (10.1%) extracts. Bay extract had the highest total phenolic content (17.86 μg CE/g). High correlation coefficients were found between the total phenol content and DPPH radical scavenging activity (R = 0.9162). These results indicate that herbs and spices had high antioxidant activity that is partly due to the phenolic compounds and provide basic data for further development of processed food products.     

Fatty acid,tocopherol composition and the antioxidant activity of the lipid extract from the sorghum grains growing in Algeria

The aim of this study was to examine the fatty acid and tocopherol composition and the antioxidant activity of the lipids fractions of two varieties of sorghum grains grown in Algeria. The results revealed that the total oil contents in the sorghum ranged from 11 to 13%. Gas chromatography analysis of the oils revealed that the dominant fatty acids found are palmitic, oleic and linoleic. The oils contain a significant amount of unsaturated fatty acids (>84%). Oils were also high in tocopherol, with a wide variation (between 174.82 and 325.33 mg/kg) but with δ-tocopherol predominating in the two oils. The lipid extracts were subjected to screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl, phosphomolybdenum complex and FRAP assays. In the first case, IC₅₀ values of the extracts were 15.4 and 22.6 mg/mL in the red and in the white sorghum, respectively. In the phosphomolybdenum complex and the FRAP assays the antioxidant capacity of the extracts ranged, respectively, between 0.21–0.13 μmol/g vitamin E equivalents and 0.030–0.027 mmol/g vitamin C equivalents. In the three systems, the antioxidant capacities of vitamin E and ascorbic acid were also determined in parallel experiments.     

Determination of antioxidant activity and antioxidant compounds in wild edible mushrooms

The methanolic extracts of dried Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda, Russula delica, Boletus badius, and Verpa conica were analyzed for antioxidant activity in different systems including reducing power, free radical scavenging, superoxide anion radical scavenging, total antioxidant activity, and metal chelating activities. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), and α-tocopherol. The percentage inhibition methanolic extracts of dried Russula delica, Boletus badius, Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda and Verpa conica at 100 μg/mL concentrations on peroxidation in linoleic acid system were 99.7%, 99.2%, 98.8%, 98.4%, 98.3%, 97.9% and 97.7%, respectively, and greater than those 400 μg/mL of α-tocopherol, BHA and BHT (77%, 85%, and 97%). Among methanolic extracts from seven wild edible mushrooms, the reducing power of Russula delica and Verpa conica were excellent, and were 1.32 and 1.22 at 200 μg/mL, respectively. Methanolic extract from Verpa conica, Boletus badius and Russula delica proved to be better at scavenging O₂⁻ than other mushroom species. The scavenging effects of methanolic extracts from mushroom species and standards on the DPPH radical decreased in the order of BHA>α-tocopherol>Lepista nuda>Russula delica>Polyporus squamosus>Pleurotus ostreatus>Agaricus bisporus>Verpa conica>Boletus badius and were, at the concentration of 180 μg/mL, 97.4, 95.4, 91.3, 86.1, 82.8, 81.3, 77.5, 75.7 and 68.7, respectively. The metal scavenging effect of extract of the mushroom species and standards decreased in the order of Verpa conica>Lepista nuda>Russula delica>Boletus badius>Polyporus squamosus>BHT>Pleurotus ostreatus>Agaricus bisporus>BHA>α-tocopherol. On the other hand, total phenolic compounds, α-tocopherol, and β-carotene were determined in the methanolic extracts of dried Agaricus bisporus, Polyporus squamosus, Pleurotus ostreatus, Lepista nuda, Russula delica, Boletus badius, and Verpa conica.     

Antioxidant Activities and Total Phenolic Content of Aqueous Extract of Pleurotus ostreatus (Cultivated Oyster Mushroom)

Pleurotus ostreatus better known as oyster mushroom is widely cultivated and consumed as food in Malaysia. The present study aims to assess the antioxidative potential and total phenolic content of P. ostreatus aqueous extract. The antioxidant activities were evaluated against DPPH and ABTS radical-scavenging activity, ferric-reducing antioxidant power (FRAP) and β-carotene-linoleate bleaching assay, and the Folin-Ciocalteu method for total phenolic content (TPC). The DPPH and ABTS radical-scavenging activity was found to be 63.20% and 87.29% respectively; antioxidant activity using FRAP at 1.45 mM FE/100g and β-carotenelinoleate bleaching assay was 83.51%, while the TPC was found to be 798.55 mg GAE/100g. These antioxidant activities were compared to synthetic antioxidant, BHA and ascorbic acid. Ascorbic acid showed highest scavenging effects on DPPH and ABTS radical, followed by P. ostreatus and BHA (at maximum safety limit). The ferric reducing power of P. ostreatus was significantly higher than BHA and ascorbic acid. The antioxidant activity as assessed in β-carotene-linoleate bleaching assay was found to be higher in BHA compared to P. ostreatus. The aqueous extract of P. ostreatus was found to respond differently in antioxidant assays. The antioxidative activity of the aqueous extract of P. ostreatus correlated with its total phenolic content. Generally, the antioxidant activities of P. ostreatus' aqueous extract are comparable to that of BHA and ascorbic acid to a certain extent.     

Effects of soaking conditions on the antioxidant potentials of oolong tea

The antioxidant properties of water extracts of oolong tea (Commercial name: Fenghuangdancong) prepared using different soaking temperatures and times were investigated. The yield of powdered extract ranged from 6.7% at 80 °C for 3 min soaking to 22.7% at 100 °C for 10-min soaking. Oolong tea extracts reduced peroxidation of peanut oil and delayed the time of POV20 (peroxide value). Among these soaking treatments, soaking for 10 min in 100 °C water produced extracts with the greatest ability to inhibit the peroxidation of peanut oil. As well, the SC50 (scavenging-percentage) of the α, α-diphenyl-β-picrylhydrazyl radical (DPPH radical) was 0.119 mL of oolong tea extract using 3-min soaking at 100 °C, which is closed to the SC50 of 0.109 mL (2 mg/mL) for vitamin C. The DPPH radical scavenging activity of oolong tea extracts increased with increasing temperature of the soaking water indicating greater extraction of antioxidant compounds. In addition, inhibition of oxidation of peanut oil and DPPH radical scavenging activity by water extract of oolong tea was associated with polyphenol concentrations. Sensory assessment, found that the water extract of oolong tea using 3-min soaking at 95 °C had the strongest aroma and sweetness attributes.     

Antioxidant activity and phenolic content of fresh and dry nuts with or without the seed coat

Total antioxidant activities based on ABTS free radical scavenging activity and phenolic content of fresh or dry hazelnuts, walnuts and pistachios assayed with their seed coats changed between 3063 and 11,076 μmol trolox equivalents/100 g d.w. and 256 and 755 mg gallic acid equivalents/100 g d.w., respectively. The walnuts used in this study showed the highest antioxidant activity, followed by pistachios and hazelnuts. The removal of seed coat reduced the total antioxidant activity of hazelnuts, walnuts and pistachios almost 36, 90 and 55%, respectively. The total antioxidant activities of investigated fresh and dry nuts are not considerably different. However, phenolic content and antioxidant activity in hydrophilic and ethanolic fractions obtained by successive extraction of nuts showed some variation. The antioxidant activity in 1-serving portion of fresh or dry walnuts is equivalent to that in almost 2-serving portions of black tea, and 1.2–1.7-serving portions of green and Earl Grey tea. One-serving portions of dry hazelnuts and fresh or dry pistachios contained antioxidant activity equivalent to that in 0.7–1-serving portions of black tea. The antioxidant activity measurements correlated with phenolic content (r² = 0.70). This study showed the potential of using fresh or dry nuts to develop functional foods with high antioxidant activity.     

Isoeugenol-based novel potent antioxidants: synthesis and reactivity

We are attempting to develop the novel phenolic synthetic antioxidants aimed at retarding the effects of free radicals and oxidants. The phenolic compounds (7-12) were synthesized by Friedel-Crafts alkylation of isoeugenol (1) and phenol derivatives (2-6) and their structures were determined by spectroscopic methods. All the synthesized phenolic compounds (7-12) except 12 are new. Antioxidant and radical scavenging activities of synthesized compounds (7-12) were determined by using various in vitro assays such as 1,1-diphenyl-2-picrylhydrazyl free radicals (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radicals (ABTS(+)), and superoxide anion radicals (O(2)(-)) scavenging, ferric reducing antioxidant power (FRAP) and total antioxidant activity by ferric thiocyanate. The antioxidant activities of compounds were compared with standard antioxidants such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT) and trolox as positive controls. The results showed that the synthesized compounds, especially 10 and 11, had better properties than standard antioxidants (BHT, BHA and trolox).     

Carbohydrase inhibition and anti-cancerous and free radical scavenging properties along with DNA and protein protection ability of methanolic root extracts of Rumex crispus

The study elucidated carbohydrase inhibition, anti-cancerous, free radical scavenging properties and also investigated the DNA and protein protection abilities of methanolic root extract of Rumex crispus (RERC). For this purpose, pulverized roots of Rumex crispus was extracted in methanol (80% and absolute conc.) for 3 hrs for 60℃ and filtered and evaporated with vacuum rotary evaporator. RERC showed high phenolic content (211 µg/GAE equivalent) and strong 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging (IC₅₀ = 42.86 (absolute methanol) and 36.91 µg/mL (80% methanolic extract)) and reduced power ability. Furthermore, RERC exhibited significant protective ability in H₂O₂/Fe³⁺/ascorbic acid-induced protein or DNA damage and percentage inhibition of the HT-29 cell growth rate following 80% methanolic RERC exposure at 400 µg/mL was observed to be highest (10.2% ± 1.03). Moreover, methanolic RERC inhibited α-glucosidase and amylase effectively and significantly (P < 0.05). Conclusively, RERC could be considered as potent carbohydrase inhibitor, anti-cancerous and anti-oxidant.     

Phenolic and antioxidant composition of cider

Forty-four Asturian ciders were analysed for total phenolic content, phenolic profiles, and antioxidant capacity by the FRAP and the DPPH radical assays. The Folin index of ciders ranged between 446 and 1180 mg gallic acid/L. The phenolic profile of Asturian cider is mainly constituted by phenolic acids, flavan-3-ols, volatile phenols and dihydrochalcones. The methods to determine the antioxidant activity of ciders were optimised in terms of suitable reaction times, within-day and between-day repeatability. Thus, time courses of ciders in the DPPH and the FRAP assays were performed. Mean values for antioxidant activity of cider, expressed in ascorbic acid equivalents were 2.9 mM (as determined by the DPPH assay). When the FRAP assay was used, the antioxidant capacity of cider increased with the reaction time from 3.8 mM (4 min) to 5.4 mM (40 min). Multivariate approaches based on phenolic composition can be useful to predict the antioxidant capacity of cider. Folin index and flavanols and hydrocaffeic acid contents were the best predictors for antioxidant activity.     

Comparison of ABTS/DPPH assays to measure antioxidant capacity in popular antioxidant-rich US foods

To evaluate the comparability of the two most common radical scavenging assays using 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, the 50 most popular antioxidant-rich fruits, vegetables and beverages in the US diet were identified and analyzed for their antioxidant capacities, total phenolics and flavonoids content. Spearmans–Rho correlation coefficients were calculated in order to characterize the relationship between antioxidant capacities, total phenolics and flavonoids content. Antioxidant capacity showed a strong positive relationship comparing both assays (ρ = 0.949, p < 0.001). Antioxidant capacity detected by ABTS assay was stronger positively associated with the oxygen radical absorbance capacity (ORAC) from USDA database (for ABTS: ρ = 0.593, p < 0.001; for DPPH: ρ = 0.539, p < 0.001, respectively), phenolics (for ABTS: ρ = 0.946, p < 0.001; for DPPH: ρ = 0.897, p < 0.001, respectively) and flavonoids content (for ABTS: ρ = 0.718, p < 0.001; for DPPH: ρ = 0.708, p < 0.001, respectively). Antioxidant capacity detected by ABTS assay was significantly higher for fruits, vegetables and beverages compared to that by DPPH assay. The high-pigmented and hydrophilic antioxidants were better reflected by ABTS assay than DPPH assay. These data suggest that ABTS assay may be more useful than DPPH assay for detecting antioxidant capacity in a variety of foods.     

Total phenolics and antioxidant capacity of indigenous vegetables in the southeast United States: Alabama Collaboration for Cardiovascular Equality Project

Collard greens, mustard greens, kale, okra, green onion, butter beans, butter peas, purple hull peas, rutabagas, and eggplant are frequently consumed by African Americans in the southeast United States. Sweet potato greens and purslane are two novel vegetables in this region. The objective of this study was to analyze total phenolics and antioxidant capacity in these indigenous vegetables. The total phenolic content was analyzed using the Folin-Ciocalteu method and ranged from 7.4 to 53.5 mg gallic acid equivalents per gram of dried sample. The antioxidant capacity was analyzed using the radical DPPH(?) scavenging capacity assay and oxygen radical absorbance capacity assay (ORAC). At a concentration of 10.0 mg dried vegetable equivalent/ml, the extract of these vegetables was able to quench 13.2-88.5% DPPH(?) radical in 30 min. The ORAC value ranged from 2.5 to 100.7 μmoles of trolox equivalents per gram of dried sample. The antioxidant capacity of the vegetable samples was highly related to their total phenolic content. The results suggest that these indigenous vegetables consumed by African Americans in the southeastern United States are good sources of the phenolic compounds, which might provide anti-oxidative protection against free radicals in the human body. Consumption of these vegetables might reduce the risk of chronic diseases.     

Total phenolic compounds and antioxidant potential of Hedychium spicatum Buch. Ham. ex D. Don in west Himalaya,India

Total phenolic compounds and antioxidant potential of Hedychium spicatum were analyzed for 16 different natural populations located in Uttarakhand (west Himalaya) for promotion as health or medicinal food. Total phenolic compounds varied among populations from 4.70 mg gallic acid equivalent (GAE) to 2.84 mg GAE/g dry weight. Three in vitro antioxidant assays, i.e. azinobisethylbenzothiazoline-6-sulphonic acid radical scavenging (ABTS) assay, diphenyl-2-picrylhydrazyl (DPPH) assay and ferric reducing antioxidant power (FRAP) assay, showed significant (p < 0.05) differences across populations. ABTS assay showed highest values of antioxidant potential ranging from 2.581 mM ascorbic acid equivalent (AAE) per 100 g to 1.91 mM AAE per 100 g dry weight, followed by FRAP assay (1.921–0.6635 mM AAE per 100 g). Lowest values were observed for DPPH assay, which varied from 0.549 to 1.059 mM AAE per 100 g dry weight. All assays (ABTS, DPPH and FRAP) showed significant (p < 0.05) correlation with total phenolic compounds. Total phenolic compounds showed a significant relationship (p < 0.05) to altitude.     

Antioxidant activities of various extracts of lotus (Nelumbo nuficera Gaertn) rhizome

Lotus rhizome powder was extracted with solvents of different polarities. Antioxidant activities of the extracts were evaluated by a 2, 2'-diphenylpicrylhydrazyl (DPPH) assay and a beta-carotene bleaching assay, and compared with that of butylated hydroxyanisole (BHA) and ascorbic acid. Methanol showed the highest extract yield among all of solvents. Although acetone extract had the highest total phenolics content, methanol extract had the highest total phenolics recovery from lotus powder (20.1 mg catechin equivalents/100g lotus powder). Extract of either methanol or acetone demonstrated the highest DPPH scavenging activity at both 66.7 mg/L and 133.3 mg/L. All extracts exhibited higher antioxidant activity coefficient (AAC) than that of ascorbic acid, furthermore, dichloromethane and petroleum extracts had comparable AAC with BHA by the beta-carotene bleaching assay. The properties of the extracting solvents significantly affected the yield, total phenolics content and antioxidant activity of lotus rhizome extracts.     

Scavenging effects of methanolic extracts of broad beans on free-radical species

This report describes the antioxidant characteristics of methanolic extracts from broad beans (Vicia fava). The methanolic extracts of broad beans (MEBB) exhibited a marked scavenging effect on superoxide. MEBB also exerted scavenging activities on hydrogen peroxide and 1, 1-diphenyl-2-picrylhydrazyl radical. The radical scavenging activity of MEBB was highest when the scavenging effect of MEBB on Superoxide (IC₅₀ = 0.15 mg/ml) was examined. These results suggest that MEBB have effective activities both as a radical scavenger and as a hydrogen donor. The chelating activity of MEBB (0.70 mg/ml) on Fe²⁺ and Cu²⁺ was 31.2% and 28.5%, respectively. The antioxidant effect of MEBB on lipid peroxidation might be attributed to their properties of scavenging free-radical species and their chelating activity on metal ions. The antioxidant activity of MEBB against tert-butyl hydroperoxide (BHP)-induced oxidative stress in WI-38 cells was assessed. The activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (GSH-Px) were measured as indices of oxidative stress. WI-38 cells incubated with 0.1 mM BHP for 2 hr exhibited the increase of SOD, catalase and GSH-Px activities over the control. When the cells incubated in MEBB (45–450 μg/ml) for 18 hr were subjected to a BHP challenge test, SOD activity returned to its control value or lower at all levels tested. When catalase activity was determined, a similar trend occurred except in the cells incubated in 112.5 μ g/ml MEBB. These results imply that MEBB inhibit oxidative stress in WI-38 cells.     

Assessment of Antioxidant Potential,Total Phenolics and Flavonoids of Different Solvent Fractions of Monotheca Buxifolia Fruit

ObjectivesThis study was conducted to investigate the antioxidant potential of methanol extract and its derived fractions (hexane, ethyl acetate, butanol, and aqueous) of fruits of Monotheca buxifolia (Falc.) Dc., a locally used fruit in Pakistan.MethodsDried powder of the fruit of M. buxifolia was extracted with methanol and the resultant was fractionated with solvents having escalating polarity; n-hexane, chloroform, ethyl acetate, n-butanol and the residual soluble aqueous fraction. Total phenolic and total flavonoid contents were estimated for the methanol and various fractions. These fractions were also subjected to various in vitro assays to estimate the scavenging activity for 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), superoxide, hydroxyl, hydrogen peroxide and reductive ability for ferric ions and phosphomolybdate assay.ResultsThe n-butanol, aqueous and methanol fractions possessed high amount of phenolics and flavonoids compared with other fractions, and subsequently showed a pronounced scavenging activity on DPPH, ABTS, superoxide, hydroxyl and hydrogen peroxide radicals and had a potent reductive ability on ferric ion and phosphomolybdate assay. There was a found significant correlation between total phenolic and flavonoid contents and EC₅₀ of DPPH, superoxide, hydrogen peroxide radical and phosphomolybdate assays, whereas a nonsignificant correlation was found with the hydroxyl radical and ABTS radical assay.ConclusionM. buxifolia fruit can be used as natural antioxidant source to prevent damage associated with free radicals.