The effect of furanoheliangolides from Tithonia diversifolia on superoxide anion generation in human neutrophils

Four known lactones were isolated from Tithonia diversifolia: furanoheliangolides 1,3-dihydroxy-3,10-epoxy-8-(-2-methylpropanoyloxy)-germacra-11(13)-ene-6,12-olide (1), 1,3-dihydroxy-3,10-epoxy-8-(2-methylpropanoyloxy)-germacra-4,11(13)-diene-6,12-olide (2), 1,3-dimethoxy-3,10-epoxy-8-(2-methylpropanoyloxy)-germacra-4,11(13)-diene-6,12-olide (3) and, observed in natural source for the first time, furanoheliangolide 1-hydroxy-3-methoxy-3,10-epoxy-8-(2-methylpropanoyloxy)-germacra-4,11(13)-diene-6,12-olide (4). The activity of sesquiterpene lactones on superoxide anion (O2°−) generation from PMA-activated neutrophils was evaluated. Compound 1 did not show a full dose dependent behavior. The IC100 was 8 ± 1, 12 ± 1, and 17 ± 3 μM for 2 to 4, respectively.