IN VITRO EVALUATION OF ANTIOXIDANT ACTIVITY OF SKIMMIA ANQUETILIA LEAVES EXTRACTS

Abstract

The purpose of the present study is to evaluate in vitro antioxidant and free radical scavenging potential of different organic and aqueous fractions of Skimmia anquetilia Tayl. Initially the phytochemical constituents of the plant were extracted in methanol and then methanolic extract was dissolved in dist. water and fractionated with n-hexane, dichloromethane, ethyl acetate and n-butanol respectively. Eight methods were used for the determination of antioxidant potential of the fractions such as "2,2'-azinobis(3-ethylbenzothiazoline-6-sulpohonic acid) (ABTS) radical cation scavenging", the "ferric reducing antioxidant power (FRAP)", "2,2´-diphenyl-1-picrylhydrazil (DPPH) radical scavenging", "total phenolic contents (TPC)", "total flavonoid contents (TFC)", "total antioxidant activity by phosphomolybedenum method", "superoxide anion radical scavenging activity" and "metal chelating activity". The results showed that in ABTS assay the trolox equivalent antioxidant capacity (TEAC) values for different fractions ranged from 8.87-0.95 µg/ml. EtOAc fraction showed highest activity as compared to other fractions, having EC50 value 2.87 µg/ml. It also exhibited highest FRAP value (146.28 mM/mL FeSO4 equivalents) as well as highest total phenolic contents (3.04 mg/ml GAE) and highest DPPH radical scavenging activity. The remaining aqueous fraction exhibited highest superoxide anion radical scavenging activity (99.5 %). Dichloromethane fraction showed highest total antioxidant activity i.e. 0.55 ± 0.25. Crude methanolic extract exhibited highest total flavonoid contents (1698 mg/g quercetin equivalents) as well as highest metal chelating activity 73.5 %. The amass results of different assays showed that S. anquetilia is affluent source of antioxidants.