Tyrosinase inhibitory and anti-tumor promoting activities of 14 compounds isolated from safflower and cotton oil cakes were evaluated together with the two genins of glycosides, trachorogenin (8a) and quercetin (12a). Catechin (11) and quercetin (12a) showed moderate tyrosinase inhibitory activity.N-(p-Coumaroyl)serotonin (1) and its 5-O-glucoside (3) exhibited weak anti-tyrosinase activity, but potent inhibitory activity on melanine production in the assay. Serotonin derivatives (1-4). 2-hydroxyarctiin (8), matairesinol glycoside (9) and sesquiterpene glucosides (13, 14) exhibited potent inhibitory activity on phorbol-12-myristate-13-acetate induced Epstein-Barr virus early antigen activation, which is the short termin vitroassay for anti-tumor-promoting activity.