Two new guaiane sesquiterpenes from Datura metel L. with anti-inflammatory activity

Chemical investigation of an acidic methanol extract of the whole plants of Datura metel resulted in the isolation of two new guainane sesquiterpenes, 1 beta,5 alpha,7 beta-guaiane-4 beta,10 alpha,11-triol (1) and 1 beta,5 alpha,7 beta-11guaiene-2 alpha,3 beta,4 alpha,10 alpha,13-pentaol(2), along with eight known compounds: pterodontriol B (3), disciferitriol (4), scopolamine (5), kaempferol 3-O-beta-D-glucosyl(1 -> 2)-beta-D-galactoside 7-O-beta-Dglucoside (6), kaempferol 3-O-beta-glucopyranosyl(1 -> 2)-beta-glucopyranoside-7-O-alpha-rhamnopyranoside (7), pinoresinol 4 ''-O-beta-D-glucopyranoside (8), (7R,8S,7 ' S,8 ' R)-4,9,4 ',7 '-tetrahydroxy-3,3 '-dimethoxy7,9 '-epoxy-lignan-4-O-beta-D-glucopyranoside (9), and (7S,8R,7'S,8'S)-4,9,4 ',7 '-tetrahydroxy-3,3 '-dimethoxy-7,9 '-epoxylignan-4-O-beta-D-glucopyranoside (10). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. Compounds 2-4 and 6-10 were shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated BV cells. (C) 2017 Phytochemical Society of Europe. Published by Elsevier Ltd. All rights reserved.