Cytotoxic flavonoids with isoprenoid groups from Morus mongolica

A new pyranoflavanone, sanggenol L (1), a Diels-Alder type adduct regarded as a cycloaddition product of a dehydrogeranylflavanone and a prenylchalcon e, sanggenol M (2), along with four new 8-arylbenzofurans with isoprenoid u nits, mulberrofurans W-Z (3-6), were isolated together with 10 known flavon oids from Chinese Morus mongolica. The structures of these novel compounds were elucidated by spectroscopic methods. All flavanones investigated here showed higher cytotoxicity against human oral tumor cell lines (HSC-2 and H SG) than against normal human gingival fibroblasts (HGF). Among them, the c ytotoxicity of compound 2 and the Diels-Alder type flavanone sanggenon C (7 ) isolated from Morus cathayana were the most potent. On the other hand, se ven 2-arylbenzofurans exhibited lower cytotoxicity and tumor specificity as compared with flavanones.