Investigation of Antioxidant Activity of Flacourtia Indica Stem Bark

Abstract

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Antioxidants are essential compounds to maintain proper health conditions in human body by diminishing the oxidative stress. Synthetic antioxidants are found to be unsafe for human health. Hence, there is a growing interest on searching for natural resources with potent antioxidant activity. The antioxidant activity o f the fractions o f total ethanol extract o f F. indica bark was determined by in vitro antioxidant assays. Previous studies have evaluated the antioxidant activity o f methanolic and aqueous extracts o f F. indica leaves. This study was aimed on investigating the antioxidant activity o f petroleum ether, ethyl acetate, ethanol and total ethanol extract o f F. indica bark using different antioxidant assays and fractionation o f total ethanol extract. Total ethanolic extract of F. indica bark was obtained by extraction o f the air-dried, powdered stem bark with ethanol using cold extraction technique. Ethanol extract was purified further by fraction using Dry Column Flash Chromatography (DCFC). The final 10 fractions were subjected to invitro 2, 2-diphenyl-2-picrylhydrazyl (DPPH) assay to determine the percent radical scavenging activity. The total ethanol crude extract exhibited a good percent radical scavenging activity o f 93.4%. Among fractions, F6 and F10 showed the highest scavenging effect o f 93.4% and 92.5% respectively. The fractions F9, F4 and F8 showed moderate free radical scavenging activity having 85.3%, 65.8%, and 64.9% respectively. FI and F2 fractions demonstrated the lowest scavenging effect o f 6.4% and 5.5%. Sequential petroleum ether, sequential ethyl acetate, sequential ethanol and total ethanol extracts showed 7.8%, 37%, 62% and 93% percent radical scavenging activity, respectively. Ferric Reducing Antioxidant Power (FRAP) values o f sequential ethyl acetate, sequential ethanol and total ethanol extracts were 354.51±3.69, 393.31±6.07 and 463.10±2.3 mg TE/g extract respectively. Oxygen Radical Absorbance Capacity (ORAC) values o f sequential ethyl acetate, sequential ethanol and total ethanol extracts were 625.27 ±0.1, 652 ± 0.12, 515 ± 0.12 mg TE/g extract, respectively. Present investigation suggests that total ethanol extract fractions and sequential extracts except sequential petroleum ether extract exhibited high antioxidant activity. Furthermore, polar fractions and extracts showed more potency towards antioxidant activity than non-polar fractions and extracts. F. indica stem bark may be used as a potential source o f antioxidant ingredient in nutraceutical products.