| Abstract: | Reevesia formosana Sprague (Sterculiaceae) is an endemic deciduous tree that grows in southern Taiwan. There are about 25 species of Reevesia worldwide, with two species in Central America, 14 in mainland China, and one in Taiwan. The remainders are found mostly in Southeast Asia. Over 1,300 species of Formosan plants have been screened for cytotoxicity against MCF-7, NCI-H460, and HepG2 cancer cell lines in vitro, and R. formosana was found to be one of the most bioactive species. The methanolic extract of the fruits of this species showed cytotoxicity and partitioned into ethyl acetate-soluble and water-soluble layers, and both of the two layers showed potent cytotoxicity. Bioassay-guided fractionation of the active ethyl acetate-soluble layer of the fruits of this plant led to the isolation of one new cardenolide, reevesioside J (1), and one new sesquiterpenoid, reevesiterpenol D (2), together with 23 known compounds (3-25) including seven lignans, five cardenolides, four steroids, three benzenoids, two sesquiterpenoids, and two triterpenoids. The structures of these compounds were elucidated by the spectroscopic analysis. Among the isolates, cardenolides: reevesioside A (3), reevesioside B (4), reevesioside F (5), and epi-reevesioside F (6) displayed especially potent cytotoxicity against the MCF-7 and NCI-H460 cancer cell lines, already reported in previous study. |
