Bioactive phenols from the leaves of Baccaurea ramiflora.

Two new phenols, 6'- O-vanilloylisotachioside ( 1) and 6'- O-vanilloyltachioside ( 2), together with nine known compounds, were isolated from the leaves of Baccaurea ramiflora (Euphorbiaceae). The structures of the new compounds were elucidated mainly by analysis of physical and spectroscopic data. Compounds 1 - 10 were tested for antioxidant activities by using MTT and DPPH assays. Seven compounds, 1, 2, and 4 - 8, revealed potent antioxidant activities against H (2)O (2)-induced impairment in PC12 cells, and exhibited significant DPPH radical-scavenging activities with IC (50) values of 86.9, 142.9, 15.2, 37.6, 35.9, 30.2, and 79.8 microM, respectively.