Triterpenoids with antiplatelet aggregation activity from Ilex rotunda.

Phytochemical studies on the barks of Ilex rotunda Thunb. had resulted in the isolation of seven previously undescribed triterpenoids, rotundinosides E-K, along with sixteen known ones. The structures of previously undescribed compounds were elucidated on the basis of extensive spectroscopic analysis and the sugar moieties were further identified by HPLC and GC after acid hydrolysis. Among the isolates, rotundinoside F featured a rare triterpene-phenylpropanoid hybrid structure and rotundinoside H was an uncommon triterpene saponin with α-linked glucopyranosyl moiety at C-3. The antiplatelet aggregation of all compounds were evaluated against ADP induced rat platelet aggregation in vitro, and five compounds exhibited moderate inhibitory effects with IC values ranging from 22.4 to 32.8 μM.