The antioxidant activities of 22 Indonesian medicinal plants (JAMU) were measured by the #alpha#,#alpha#-Diphenyl-#beta#-dipicryl hydrazyl (DPPH) method. Eleven of them exhibited higher DPPH radical scavenging activities than those of BHT at the comparable concentrations. Among them, the methanol extract of Cuscuta chinensis was fractionated with several solvents and the ethyl acetate fraction, having strong antioxidant activity, was further purified by silica gel column chromatography. The isolated active compound weas identified as methyl gallate with H-NMR, ~13C-NMR, IR, EI-Mass. The DPPH radical scavenging activity of methyl gallate was about seven times as high as that of BHT and its inhibitory effect on microsomal lipid peroxidation was also examined by the thiobarbituric acid (TBA) method. Methyl gallate exhibited strong inhibitory activity (about 99) against free radical-mediated lipid peroxidation, which was stronger than those of BHT and BHA.
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