Cycloartane-type triterpenes from the leaves of Homonoia riparia with VEGF-induced angiogenesis inhibitory activity

Six new cycloartane-type triterpenes (1-6), 24-methylenecycloartane- 3β,6β,7β-triol (1), 24-methylenecycloartane-3β,6β, 7β,16β-tetraol (2), 24-methylenecycloartane-3β,6β,16β- triol (3), 24-methylenecycloartane-3β,7β,16β-triol 3-O-β-d-xylopyranoside (4), 24-methylenecycloartane-3β,6β, 16β-triol 3-O-β-d-xylopyranoside (5), and 24-methylenecycloartane- 3β,6β,7β-triol 3-O-β-d-xylopyranoside (6), were isolated from the leaves of Homonoia riparia, together with one known compound, 24-methylenecycloartane-3β,6β,7β,16β-tetraol 3-O-β-d-xylopyranoside (7). The structures of the new triterpenes were established by spectroscopic studies and from chemical evidence, and the inhibitory effects of compounds 1 and 3-7 on VEGF-induced vascular permeability were examined in vivo in rats using the Miles assay. In addition, the inhibitory effect of 7 on VEGF-induced tube formation by HUVECs in vitro was investigated.