Triterpene glycosides from the flower petals of sunflower (Helianthus annuus) and their anti-inflammatory activity.

Two new oleanane-type triterpene glycosides, named helianthosides 4 (4) and 5 (5), along with four known triterpene glycosides, helianthosides 1 (1), 2 (2), 3 (3), and B (6), were isolated from an n-butanol-soluble fraction of a methanol extract of sunflower (Helianthus annuus) petals. The structures of the two new compounds were determined on the basis of spectroscopic and chemical methods. Upon evaluation of compounds 1-6 for inhibitory activity against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation (1.7 nmol/ear) in mice, all of the compounds tested exhibited marked anti-inflammatory activity, with ID50 values in the range 65-262 nmol per ear.