Isoprenylated xanthones and flavonoids from Cudrania tricuspidata.

Further phytochemical investigation on the roots of Cudrania tricuspidata afforded a new isoprenylated xanthone, cudratricusxanthone I (1), two new isoprenylated flavanones, cudraflavanones C and D (2 and 3, resp.), and seven known compounds, 1,7-dihydroxy-3,6-dimethoxyxanthone (4), macluraxanthone C (5), cudraxanthones E, K, and L (6, 7, and 8, resp.), cudraflavanone A (9), and cudraflavone C (10). Their structures were identified by spectroscopic methods. Cudratricusxanthone H (12), macluraxanthone B (13), two xanthones previously isolated from this plant, and 5, showed significant inhibitory effects on four kinds of human digestive apparatus tumor cell lines (HCT-116, SMMC-7721, SGC-7901, and BGC-823) with IC50 values of 2.70-12.66 microM.