AGONIST-DEPENDENT DIFFERENTIAL-EFFECTS OF BERBERINE IN HUMAN PLATELET-AGGREGATION

This study was conducted to investigate the antiplatelet effects of be rberine, an alkaloid found in Berberis aristata and some other plants. Platelet rich plasma, prepared from blood of normal human volunteers, was treated with varying concentrations of berberine, and the platele t aggregation in response to various agonists was measured by a Lumi-a ggregometer. The results show that berberine selectively inhibited pla telet aggregation induced by collagen (638 nM) in a dose-dependent man ner (1-100 mu M). In contrast, low doses of berberine (up to 30 mu M) potentiated the ADP (4 mu M)-induced aggregation. The aggregation indu ced by other platelet agonists, AA (1.7 mM), adrenaline (20 mu M), cal cium ionophore, A23187 (1 mu M) and PAF (800 nM) was not affected by b erberine at a dose range of 1-100 mu M. These results are indicative t hat berberine selectively inhibits collagen-induced platelet aggregati on. Since berberine was unable to inhibit the aggregation mediated by activation of thromboxane Az, increase in calcium influx, or stimulati on of G-protein linked pathways, it is likely that berberine selective ly inhibits platelet aggregation by interfering with the collagen-medi ated adhesion process. (C) 1998 John Wiley & Sons, Ltd.