Pterocarpus santalinus L. (Leguminosae) has been used for the treatment of inflammations, mental aberrations, ulcers, and diabetes. Previous reports showed that the main constituents are lignan, terpenoids, flavonoids and sterols. As part of our ongoing research for the discovery of plant-derived inhibitors of nitric oxide (NO) production, we found that the methanolic extract of the heartwood of P. santalinus inhibited the LPS-induced NO production in RAW 264.7 cells. In this study, the heartwood of P. santalinus were extracted with MeOH, and sequentially partitioned with n-hexane, CH2Cl2, EtOAc, and n-BuOH. Three lignans and a flavonoid were isolated from the methylene chloride fraction of the heartwood of P. santalinus. Their chemical structures were elucidated on the basis of spectroscopic data interpretation, especially 1D-NMR, ESI-MS. On the basis of their spectroscopic data, these compounds were identified as savinin (1) and calocedrin (2), hinokinin (3), and pinocembrin (4).[1],[2] All isolates were investigated for their inhibitory effects on the NO production in LPS-induced RAW 264.7 macrophage cells.
[1] Cho JY, Park J, Kim PS, Yoo ES, Baik KU, Park MH. Biol Pharm Bull. 2001; 24(2):167-71.
[2] Enders, D. & Milovanović, M. Zeitschrift für Naturforschung B 2014; 62(1):117-120.