Isolation and Characterization of Compounds from the Leaves of Pterocarpus indicus Willd and Their Antioxidant Activity

Abstract

The flavone glycoside was isolated from ethyl acetate fraction of ethanol extract of leaves Pterocarpus indicus Willd. The isolation was conducted by gravitation column chromatography and eluted successively with hexane, ethyl acetate and methanol by gradient, and purified by sephadex-LH20. The structure was elucidated base on spectroscopy data of NMR (1D and 2D), UV, LC-MS and FT-IR. Antioxidant was evaluated using 2,2-diphenyl-1-picrylhidrazyl (DPPH) radical scavenging. The isolation and identification led a stigmasterol as Compound 1 and a new flavonol-glycoside [(2R)-7-hydroxy-3-(3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yloxy)-2-(3,4,5-trihydroxy phe nyl)chroman-4-one] or ptevon-3-D- glycoside as Compound 2. Antioxidant activity of Compound 2 showed IC₅₀ for 18.53 μmol and blank of quercetin was 7.94 μmol and Vitamin C was 40.25 μmol. These compounds and antioxidant activities are the first time reported from this plant.