Prostaglandin synthetase inhibition by alkaloids of Heimia salicifolia.

Two alkaloids from Heimia salicifolia, cryogenine and nesodine, were respectively 2.48 and 2.24 times as potent as aspirin as inhibitors of prostaglandin synthetase prepared from bovine seminal vesicles. Reference compounds, indomethacin and phenylbutazone, were respectively 2800 and 8.75 times as potent while a synthetic analogue of cryogenine, JB-1-0, was 0.656 times the potency of aspirin. This activity may help to explain the traditional medicine use of H. salicifolia in the Americas.