New compounds from an extract of Vernonia colorata leaves with anti-inflammatory activity

Bioassay-directed fractionation of an anti-inflammatory CHCl3-MeOH (9:1) extract of leaves of Vernonia colorata, using a carrageenan-induced rat paw model, led to the isolation of six new compounds (16). These were assigned as two new androst-8-en glycosides, 3-O-{beta-D-galactopyranosyl-(1-2)-beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside}-5alpha,14alpha-androst-8-ene (1) and 3-O-[beta-D-glucopyranosyl-(1-->6)-beta-D-glucopyranoside]-5alpha,14alpha-androst-8-ene (2), two new stigmastane-type glycosides, 3beta,21,24-trihydroxy-21,23;22,28;26,28-triepoxy-5alpha-stigmasta-8(9),14(15)-dien-3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucopyranoside (3) and 3beta,21,24-trihydroxy-21,23;22,28;26,28-triepoxy-5alpha-stigmasta-8(9),14(15)-dien-3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-(6-acetyl)glucopyranoside (4), and two new stigmastane-type steroids, 3beta,25,29-trihydroxy-5alpha-stigmasta-8(9),14(15),24Z(28)-triene (5) and 3beta,23,25-trihydroxy-24,28-epoxy-5alpha-stigmasta-8(9),14(15)-diene (6). The structures of 1-6 were elucidated by spectral and chemical studies. Compounds 1-6 were tested for the anti-inflammatory activity, but all were inactive or weakly inactive as anti-inflammatory agents.