[Triterpenes constituents from male flowers of Eucommia ulmoides].

Nine triterpenes compounds were isolated from the male flowers of Eucommia ulmoides by recrystallization and chromatographic techniques over silica gel, Sephadex LH-20, and RP-18 gel. Their chemical structures were identified on the basis of spectral analysis and as 3-oxo-12-en-ursane-28-O-α-L-arabinofuranosyl (1 --> 6) -β-D-glucopyranoside (1), 2α, 3β-dihydroxyurs-12-en-28-oic acid(28 --> 1) -β-D-glucopyranosyl ester (2), ursolic acid (3), α-amyrin (4), uvaol (5), ursolic acid acetate (6), 3-O-acetate oleanoic acid (7), betulinic acid (8), and betulinol (9). Compound 1 was a new compound, and compounds 2, 4-7 were isolated from the Eucommiu genus for the first time. Cytotoxic activity was tested for all the compounds against K562 and HepG2 cells. The results showed that only compound 3, exhibited cytotoxic activity.