Trichocladabiflavone A, a chalcone-flavonone type biflavonoid from Selaginella trichoclada Alsto

A chalcone-flavonone type biflavonoid, trichocladabiflavone A (1), along with eight known biflavonoids (2–9) were isolated from the 70% EtOH extract of Selaginella trichoclada. Their structures were elucidated by extensive spectroscopic analyses. Compound 1 was the first chalcone-flavonone type biflavonoid reported in the genus Selaginella. Moreover, compound 1 exhibited moderate cytotoxicity against DU145, MCF-7 and PC3 human cancer cell lines.