Pilot study of the effect of raubasine on platelet biological activity.

A pilot study was carried out to determine the action of raubasine (ajmalicine) an alkaloid derived from Rauwolfia serpentina, on platelet biological function in 14 patients selected because they were at risk due to complications of atherosclerosis. The determinations of platelet aggregation were done ex vivo and the following substances were used as inducing agents: adenosine diphosphate (2.5 and 5.0 X 10(-6) mol/l), collagen (0.05 mg/ml), and epinephrine (adrenaline) (1.68 X 10(-4) mol/l). 12 out of the 14 patients treated showed a reduction in platelet aggregation in at least 2 of the 3 test curves. This reduction was statistically significant for collagen (p less than 0.02) and epinephrine (p less than 0.01). A statistically significant (p less than 0.05) prolongation of the latency period of aggregation produced by collagen was found in 12 out of 14 patients and a prolongation of recalcification time produced by the reduction in platelet factor 3 was found in 9 out of 14 patients. In addition to the fact that the effect of a reduction in platelet aggregation was more evident in the second wave, these results suggest that raubasine has an inhibitory action on the release reaction of the platelets. The results obtained merit further study to confirm this property of the drug.