Bioactive components from the heartwood of Pterocarpus santalinus

One new phenanthrenedione, pterolinus K (1), and one new chalcone, pterolinus L (2) were isolated from the heartwood extract of Pterocarpus santalinus. The structures were elucidated by spectroscopic methods. Both 1 and 2 showed inhibitory effect on elastase release by human neutrophils in response to fMLP with an IC(50) value of 4.24 and 0.95 μM, and compound 1 also inhibited superoxide anion generation with IC(50) value of 0.99 μM. In addition, compound 1 showed selective cytotoxicity against HepG2 with IC(50) value of 10.86 μM, while compound 2 showed a moderate cytotoxicity against KB with IC(50) values of 17.18 μM.