Cytotoxic flavonoids and new chromenes from Ficus formosana f. formosana.

Two new chromenes, ficuformodiol A and ficuformodiol B, and nine known compounds including one chromene, spatheliachromen, six flavonoids, obovatin, carpachromene ( 5), apigenin ( 6), norartocarpetin ( 7), steppogenin, 6-prenylpinocembrin, one benzopyran, chromenylacrylic acid, and one isocoumarin, ( R)-(-)-mellein, were obtained from the cytotoxic chloroform-soluble fraction of the stems of Ficus formosana f. formosana (Moraceae). Their structures were determined by means of spectroscopic analyses. Compounds 5, 6 and 7 exhibited significant cytotoxicity against HepG2, PLC/PRF/5 and Raji cancer cell lines in vitro.