Salprzesides A and B: two novel icetexane diterpenes with antiangiogenic activity from Salvia przewalskii Maxim

Two novel icetexane diterpenes were isolated from Salvia przewalskii Maxim., namely Salprzesides A (1) and B (2), together with two known abietane-type diterpenes respectively identified as sahandinone (3) and miltirone (4). The structures of isolated compounds were determined by UV, IR, HR-ESI-MS, 1D and 2D NMR analysis. The in vitro antiangiogenic activities of compounds 1-4 were studied against human umbilical vascular endothelial cells (HUVECs). The IC₅₀ values of compounds 1-4 ranged from 4.22 ± 1.07 to 39.31 ± 2.17 μM against HUVECs.