Phenolic constituents from Elsholtzia ciliata (Thunb.) Hyland and their NO production inhibition activity

Abstract

Elsholtzia ciliata (Thunb.) Hyl. (Elsholtzia cristata (Willd.), Lamiaceae is a medicinal and spice plant widely used in Vietnam. Phytochemical study on this plant led to the isolation of eleven phenolic glycosides compounds, kaempferol- 3-β-D-(6-O-trans-p-coumaroyl) glucopyranoside (tiliroside, 1), rosmarinic acid methyl ester (2), 3-0-β-D- glucopyranosyl-1-(3',5'-dimethoxy-4-hydroxyphenyl-1-propanone) (3), β-hydroxypropiovanillone 3-0-β-D- glucopyranoside (4), 4-(3',4'-dihydroxyphenyl)-butan-2-one 3'-O-β-D-glucopyranoside (5), 4-(3'-glucopyranosyloxy- hydroxyphenyl)-(E)-3-buten-2-one (6), syringin (7), icariside F2 (8), methyl salicylate a-L-arabinopyranosyl-(16)-β D-glucopyranoside (9), methyl 2-0-β-D-glucopyranosyl benzoate (10), and 1-0-caffeoylglycerol (11). Their chemical structures were evidenced by ESIMS, CD, and NMR spectra in comparison with those in the literature. All the isolated compounds were evaluated their NO production inhibition activity on LPS-activated RAW264.7 cells. Compounds 2, 9, and 10 inhibited NO production with IC₅₀ values of 19.23±1.30, 16.51±1.56, and 13.73±0.95 µM, respectively, compared to that of the positive control of NG-monomethyl-L-arginine acetate (L-NMMA) with an IC₅₀ value of 32.51±3.70 μΜ. Whereas, the other compounds showed no activity with the IC₅₀ values over 100 µM.