Nine flavonoids isolated from the ethyl acetate extract of Pycnanthus angolensis were assayed for their potential apoptosis induction activities in human hepatoma HuH-7 cells. These flavonoids include eight isoflavones, namely irilone (1), tectorigenine (2), formononetin (3), genistein (4), 2'-hydroxybiochanin A (5), mixture of biochanin A (6) and prunetin (7), and 4',7-dihydroxy-2'-methoxyisoflavan (8), and th...