Smooth muscle relaxant action of benzyl benzoates and salicylic acid derivatives from Brickellia veronicaefolia on isolated guinea-pig ileum.

A dichloromethane-MeOH extract prepared from the aerial parts of Brickellia veronicaefolia inhibited the spontaneous contractions (IC50 = 39.22 microg/mL) of the guinea-pig ileum. Bioassay-guided fractionation of the extract led to the isolation of three new benzoic acid derivatives, 1,2-bis-O-(2-methoxybenzoyl)-beta-d-glucopyranoside (1), 3-(beta-glucopyranosyloxy)benzyl 2,6-dimethoxybenzoate (2) and 3-hydroxybenzyl 2,6-dimethoxybenzoate (3), together with the known compounds taraxasteryl acetate (4), 4-allyl-2-methyloxyphenyl-beta-glucopyranoside (5), 2-hydroxy-6-methoxybenzoic acid (6), 2-methoxybenzoic acid (7), chamazulene (8), 2-methoxybenzyl 2-hydroxybenzoate (9), benzyl 2,6-dimethoxybenzoate (10), 3-methoxybenzyl 2-hydroxy-6-methoxybenzoate (11), benzyl 2-hydroxy-6-methoxybenzoate (12), benzyl 2,3,6-trimethoxybenzoate (13), benzyl 2-hydroxy-3,6-dimethoxybenzoate (14) and 3-methoxybenzyl 2,6-dimethoxybenzoate (15). The isolates were characterized by spectral means. Compounds 2 - 6, 8 - 11, 14 and 15 induced a concentration-dependent inhibition of the spontaneous contractions of the guinea-pig ileum with IC50 values ranging from 1.49 to 4.96 microM. Their activity was comparable to that of papaverine (IC50 = 4.23 microM).