Antibacterial constituents from Stemona sessilifolia.

Bioassay-guided fractionation led to the isolation of eight compounds from Stemona sessilifolia. Of the eight isolates, three new bibenzyls, stilbostemins M-O (1-3), and a new tocopherol, 6-methoxy-3,4-dehydro-delta-tocopherol (4) were revealed together with four known compounds 3,5-dihydroxy-2'-methoxy bibenzyl (5), 3,5-dihydroxy bibenzyl (6), beta-tocopherol (7), and gamma-tocopherol (8). Compounds 5, 6, and 8 exhibited strong antibacterial activities against Staphylococcus aureus and S. epidermidis.