Vasodilator effect of olive leaf.

We studied the importance of the smooth vascular muscle endothelium in the vasodilator action of the decoction of olive (Olea europaea) leaf. The decoction caused relaxation of isolated rat aorta preparations both in the presence (IC50 1.12 +/- 0.33 mg/ml) and in the absence (IC50 1.67 +/- 0.16 mg/ml) of endothelium. The results indicate that the relaxant activity of the lyophilized decoction is independent of the integrity of the vascular endothelium. We also showed that oleuropeoside is a component responsible for vasodilator activity but, from the results, it seems likely that at least one other principle is to be found in the olive leaf which is either a vasodilator itself or else potentiates the relaxant effect of oleuropeoside.