Dose-dependent inhibition of phosphoinositide metabolism in human platelets by aspirin in vitro and in vivo

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).

Prevention of recurrent myocardial infarction and sudden death with aspirin therapy

In October 1985, the Food and Drug Administration approved a new indication of aspirin for the secondary prevention of recurrent myocardial infarction (MI) and death in patients with MI or unstable angina. Clinical trials have demonstrated the efficacy of this drug, especially when treatment is begun soon after the initial event. The antiplatelet actions of aspirin seem to be the most plausible explanation for its efficacy in reducing mortality and the rate of reinfarction. A single daily 325-mg tablet is effective and produces side-effect incidences of only zero to two percent above those produced by placebo. This article assesses the current state of knowledge regarding the value of aspirin therapy in survivors of acute MI and the implications for clinical practice.