Prostaglandin synthetase inhibitors in feverfew

The IC50 values for the in-vitro inhibition of the prostaglandin synthetase (bovine seminal vesicle mitochondrial fraction) mediated PGE2 production from arachidonic acid by parthenolide, michefuscalide and chrysanthenyl acetate were 11.0 +/- 0.44, 12.1 +/- 0.51 and 14.2 +/- 0.58 microM (mean +/- 95% confidence limits), respectively.