ANTIOXIDANT ACTIVITY OF THE EXTRACTS FROM AMORPHA FRUTICOSA FRUITS

摘要

This study was carried out to elucidate the chemical structures of the constituents isolated from Amorpha fruticosa, as well as to evaluate their antioxidant activities. The air dried-powdered fruits of A. fruticosa were extracted with methanol (MeOH). The MeOH extracts were successively fractionated with n-hexane, dichloromethane (CH_2C1_2), and ethyl acetate (EtOAc). The soluble fractions in CH_2C1_2 and EtOAc were chromatographed with Sephadex LH-20 and silica gel column. The chemical structures of the constituents were analyzed by MS and NMR. We identified nine compounds; kaempferol-7-rhamnoside (1), methyl gallate (2), tephrosin (3), 2', 4', 5', 7-tetramethoxyisoflavone (4), fruticin (5), dalbinol 2'-[α-L-arabinopyranosyl (1→6)-β-D-glucopyranoside] (6), dalbinol-O-β-D-glucopyranoside (7), dalbinol (8), and gallic acid (9). Among the antioxidant activities of these compounds, the value of IC_(50) of methyl gallate (17.04 ppm) and gallic acid (20.09 ppm) were lower than those of positive controls, such as α-tocopherol (21.09 ppm) and butylated hydroxyl toluene (24.61 ppm) as well-known antioxidants.