Pharmacological activity of feverfew (Tanacetum parthenium (L) Schultz-Bip): Assessment by inhibition of human polymorphonuclear leukocyte chemiluminescence in-vitro

The bioactivity of feverfew (Tanacetum parthenium) leaf extracts has been analysed, by use of a human polymorphonuclear leukocyte (PMNL) bioassay, to assess the relative contributions of solvent extraction and parthenolide content to the biological potency of the extract. Extracts prepared in acetone-ethanol (system 1) contained significantly more parthenolide (mean+/-s.d. 1.3+/-0.2% dry leaf weight) than extracts in chloroform-PBS (phosphate-buffered saline; system 2; 0.1+/-0.04% dry leaf weight) or PBS alone (system 3; 0.5+/-0.1% dry leaf weight). Extract bioactivity, measured as inhibition of phorbol 12-myristate 13-acetate-induced, 5-amino-2,3-dihydro-1,4-phthalazinedione (luminol)-enhanced PMNL chemiluminescence, followed a similar trend. Extracts inhibited phorbol 12-myristate 13-acetate-induced oxidative burst by amounts which, if solely attributable to parthenolide, indicated parthenolide concentrations for the respective solvent systems of 2.2+/-0.6%, 0.2+/-0.1% and 0.9+/-0.1% dry leaf weight. The mean ratio of parthenolide concentration to the parthenolide equivalent/PMNL-bioactivity value, for acetone-ethanol and PBS extracts were both 1:1.7. Parthenolide, although a key determinant of biological activity for T. parthenium leaf extracts based on the PMNL-bioassay, seems not to be the sole pharmacologically-active constituent. The identical and elevated bioactivity-parthenolide ratios for both organic and aqueous-phase leaf extracts suggest that a proportion of the other bioactive compounds have solubilities similar to that of parthenolide.