Hinokiflavone (1) was isolated as the cytotoxic principle from the drupes of Rhus succedanea L. A comparison of the cytotoxicity of 1 and other related biflavonoids, including amentoflavone (2), robustaflavone (3), agathisflavone (4), rhusflavone (5), rhusflavanone (6) and its hexaacetate (7),
Eleven biflavonoids, including amentoflavone (1), agathisflavone (2), robustaflavone (3), hinokiflavone (4), volkensiflavone (5), morelloflavone (7), rhusflavanone (9), succedaneaflavanone (10), GB-1a (11), GB-1a 7"-O-beta-glucoside (13), and GB-2a (14) isolated from Rhus succedanea and Garcinia