Phytochemical constituents from Elsholtzia ciliata (Thunb.) Hyl. and their nitric oxide production inhibitory activities

A new megastigmane glycoside, (3S,4R,7E)-megastigma-5,7-diene-9-one-3,4-diol 3-O-β-D-apiofuranosyl-(1→2)-β-D-glucopyranoside (1) and a new cyanogenic glycosyl derivative, (S)-2-(6'-O-R-rosmarinoyl-β-D-glucopyranosyloxy)-phenylacetonitrile (2) were isolated from the methanol extract of the Elsholtzia ciliata together with twelve known compounds, 1-O-β-D-glucopyranosyl-2-hydroxy-4-allylbenzene (3), citrusin C (4), 1,2-di-O-β-D-glucopyranosyl-4-allylbenzene (5), manglieside B (6), 4-allyl-2-hydroxyphenyl 1-O-β-D-apiofuranosyl-(1→6)-β-D-glucopyranoside (7), (-)-isolariciresinol 3α-β-D-glucopyranoside (8), 7R,8R-threo-4,7,9-trihydroxy-3,3'-dimethoxy-8-O-4'-neolignan-9'-O-β-D-glucopyranoside (9), 7R,8R-threo-4,7,9,9'-tetrahydroxy-3-methoxy-8-O-4'-neolignan-9'-O-β-D-glucopyranoside (10), cedrusin-4-O-β-D-glucopyranoside (11), icariside E3 (12), everlastoside L (13) and rosmarinic acid (14). Their chemical structures were elucidated on the basic of extensive 1D and 2D-NMR experiments, as well as their mass spectroscopic data. The absolute configurations of the compounds 1 and 2 were successfully indicated by both theoretical and calculated CD spectra. Compounds 3-7, 9 and 10 potential inhibited NO production in LPS-activated RAW264.7 cells with IC50 values of 6.71, 8.97, 12.38, 14.27, 16.13, 13.54, 16.27 µM, respectively, compared to that of the positive control of NG-monomethyl-L-arginine acetate (L-NMMA), IC50 = 32.51 µM.