Antioxidative compounds from Quercus salicina Blume stem.

The chromatographic separation of MeOH extract from the Quercus salicina Blume Stem led to the isolation of five phenolic compounds. Using spectroscopic methods, the structures of these compounds were determined as D-threo-guaiacylglycerol 8-O-beta-D-(6'-O-galloyl)glucopyranoside (1), 9-methoxy-D-threo-guaiacylglycerol 8-O-beta-D-(6'-O-galloyl)glucopyranoside (2), 6''-O-galloyl salidroside (3), methyl gallate (4), quercetin (5). We measured radical scavenging activity with the DPPH method and the anti-lipid peroxidative efficacy on human LDL with TBARS assay, with the result that all these compounds exhibited the antioxidative activity.