Compounds from the heartwood of Caesalpinia sappan and their anti-inflammatory activity.

Two new phenolics, (3S,4R)-3,7,2',3'-tetrahydroxy-3,4-dihydro-9H-indeno[6,5-c]chromene (caesalpiniaphenol E, 1), and (3R,4S)-3,7-dihydroxy-3-(3'-methoxy-4'-hydroxyphenyl)-4-methoxychroman (caesalpiniaphenol F, 2), together with eleven known compounds (3-13), were isolated from the heartwood of Caesalpinia sappan. Their chemical structures were established mainly by 1D and 2D NMR techniques and mass spectrometry. Their anti-inflammatory activity was evaluated against LPS-induced NO production in macrophage RAW264.7 cells. Among them, compounds 10 and 13 showed strong inhibitory activities toward the LPS-induced NO production in macrophage RAW264.7 cells, with IC(50) values of 12.5 and 8.1 μm, respectively. In addition, compounds 10 and 13 inhibited the inductions of iNOS mRNA in dose-dependent manners, indicating that these compounds attenuated the synthesis of these transcripts at the transcriptional level.