EFFECT OF PYGEUM-AFRICANUM EXTRACT ON A23187-STIMULATED PRODUCTION OFLIPOXYGENASE METABOLITES FROM HUMAN POLYMORPHONUCLEAR CELLS

Pygeum africanum extract has been used for more than 20 years in Franc e in patients suffering from benign prostatic hypertrophy (BPH). The e xtract displays anti-inflammatory activity and inhibits bladder hyperr eactivity during the above conditions. However, the mechanism of actio n of P. africanum extract has never been clearly resolved. It has been recently demonstrated that infiltration by inflammatory cells may be involved in the development of BPH. Certain of these cell types, such as macrophages, are known to produce chemotactic mediators including l eukotrienes, and thus may contribute to the development of the disease . In order to investigate the potential effect of P. africanum extract on arachidonate metabolism, we examined its effect in vitro on leukot riene (LT) synthesis in human polymorphonuclear cells stimulated with the calcium ionophore A23187. Two formulations of the extract were tes ted, one dissolved in DMSO and one aqueous solution obtained after alk alinization (0.1 N; NaOH/acidification (0.1 N; HCl). Neither formulati on had any effect on cell viability which was above 95% in both cases. P. africanum extract dissolved in DMSO significantly inhibited the pr oduction of 5-lipoxygenase metabolites (5-HETE, 20-COOH LTB4, LTB4 and 20-OH LTB(4)) at concentrations as low as 3 mu g/ml (p < 0.01), while the same extract dissolved in NaOH/HCl only exhibited an inhibitory e ffect at 10 mu g/ml (p < 0.01). This difference apparently reflects th e greater solubility of the active components in the extract in DMSO. The ability of P. africanum to antagonize 5-lipoxygenase metabolite pr oduction may contribute, at least in part, to its therapeutic activity in inflammatory component of BPH.