Effect of berberine on arachidonic acid metabolism in rabbit platelets and endothelial cells.

The antiplatelet effect of berberine has been demonstrated in both laboratory research and clinical trials. In the present study, we show ex vivo that berberine significantly inhibited rabbit platelet aggregation induced by adenosine diphosphate, arachidonic acid, collagen or calcium ionophore A23187. The most potent inhibition was observed in collagen-induced platelet aggregation. Using radioimmunoassay, we show in vitro that berberine significantly inhibited synthesis of thromboxane A(2) in rabbit platelets induced by adenosine diphosphate, arachidonic acid or collagen in which collagen-induced thromboxane A(2) synthesis was also most potently inhibited. In our in vivo study using radioimmunoassay, the plasma prostacyclin level was reduced by 34.6% during a 30-min period after intravenous administration of 50 mg/kg of berberine. These results suggest that berberine might inhibit arachidonic acid metabolism in rabbit platelets and endothelial cells at two or more sites: cyclooxygenase in the arachidonic acid cascade and possibly the enzyme(s) for arachidonic acid liberation from membrane phospholipid(s).