Bioactive Secondary Metabolites from Vincetoxicum stocksii

The ethyl acetate soluble fraction of the methanolic extract of Vincetoxicum stocksii yielded four new compounds; vincetolate (1), vincetoside (2), vincetetrol (3) and vincetomine (4) along with seven know compounds; 1-(4-hydroxy-3-methoxyphenyl)-1,2,3,-propanetriol (5), feruloyl-6-O-beta-D-glucopyranoside (6), apocynin (7), 4-hydroxy-3,5-dimethoxybenzoic acid (8), 7-megastigmene-3,5,6,9-tetrol (9), qurcetin-3-O-beta-D-glucopyranoside (10) and 4'-methoxykaempferol-3-O-beta-D-glucopyranoside (11). The chemical structures of all the isolates were determined due to spectral analysis including sophisticated 1D- and 2D-NMR techniques and high resolution FABMS. Compounds 5-8 and 10 exhibited moderate to low antioxidant activity with IC50 values of 56.42 +/- 0.04-150 +/- 0.5 mu g/ml whereas, compounds 1, 5 and 8-11 showed significant antiurease activity with IC50 values in the range of 22.1 +/- 0.43-105.47 +/- 0.01 mu g/ml.