Lignans from Saururus chinensis with Inhibitory Effects on Nitric Oxide Production.

Three biogenetically related ent-sauchinone-type lignans (1-3), four 8-O-4'-type neolignans (4-7), a diaryldimethylbutane lignan (8), and a cyclic carbonate (9), along with 12 known compounds, have been isolated from a methanol extract of the aerial parts of Saururus chinensis. The structures of the new compounds (1-9) were determined by analysis of their 1D and 2D NMR spectra, HRESIMS, and ECD data. A putative biosynthetic pathway for the three ent-sauchinone-type lignans (1-3) was postulated. Compounds 1, 7, and 10 showed inhibitory effects on LPS-induced NO production in RAW 264.7 cells with IC50 values of 5.6, 8.6, and 9.2 μM, respectively.