Three new anti-inflammatory stilbenoids and a diphenyl ether derivative from Cajanus cajan .

Three new stilbenoids, namely two rare plant-derived phenanthrenes denominated Cajananthrenes A and B ( 1 , 2 ) and one bibenzyl named Cajanbenzyl ( 3 ), together with a diphenyl ether derivative designated Cajanether ( 4 ), as well as five other known compounds ( 5 - 9 ) were isolated from the ethanolic extract of the leaves of Cajanus cajan . Their structures were determined through extensive spectroscopic analysis including UV, IR, NMR (1D and 2D) and HRESIMS as well. A plausible biogenesis pathway was proposed for the biosynthesis of compounds 1 - 3 . Compounds 1 and 2 displayed moderate anti-inflammatory activity as evident from the inhibitory effect on NO production in LPS-stimulated RAW 264.7 macrophages with IC 50 values of 73.6 and 44.6 μM respectively.