Vinigrol, a novel antihypertensive and platelet aggregation inhibitory agent produced by a fungus, Virgaria nigra. II. Pharmacological characteristics.

Vinigrol, a novel diterpene produced by Virgaria nigra, was tested orally in conscious spontaneously hypertensive rats (SHR) to confirm its antihypertensive activity. Vinigrol (2 mg/kg, po) decreased the mean arterial blood pressure of SHR by approximately 15% for at least 6 hours. Vinigrol induced contraction of rat aortic smooth muscle preparation at 1.5 X 10(-7) M, the contraction was blocked by nilvadipine, a Ca2+ entry blocker, but was not inhibited by prazosin or yohimbine. Radio-receptor binding assay of alpha adrenoceptors of rat brain membrane revealed that vinigrol had no affinity for these receptors.