Bioassay guided isolation and identification of the antioxidant constituent from Holostemma Ada-kodien shcult

Abstract

Holostemma ada-kodien shcult (Syn: Holostemma annulare) is a traditionally used in Indian herbal medicine. The objective of this study is to investigate the antioxidant activity of a bioassay-guided fractionation and its active components/compounds. Compounds were isolated by high performance thin layer chromatography (HPTLC) and preparative high performance liquid chromatography (pre-HPLC) and their structures were established by mass spectrometry (MS), Nuclear magnetic resonance (NMR) and fourier transform infrared spectroscopy (FT-IR) spectroscopic analyses. The antioxidant activity of ethyl acetate extract of Holostemma ada-kodien shcult and its fractions (CE, CF, EAF, MF and AF) were investigated using free radical scavenging activity, superoxide radical-scavenging assay, hydroxyl radical scavenging assay and assay of FeCl₃ power. The results revealed that the antioxidant activity of different fractionations such as CE and EAF showed prominent activity when compared with butylated hydroxyltoluene (BHT) in a dose-dependent manner. Two compounds were isolated from Fraction –D among them quercetin and acacetin were reported for the first time in H. ada-kodien. Quercetin showed a more prominent antioxidant activity potential at concentrations (10, 20, 30, 40 and 50μg/mL) when compared with the other compounds. In conclusion the ethyl acetate fraction proved to have significant therapeutic potential for antioxidant effect.