Influence of Haplophyllum tuberculatum on the Cardiovascular System

The aqueous extract of H. tuberculatum significantly decreased the contractility and the heart rate but did not affect the flow rate of isolated perfused rabbit heart. This effect was not blocked by atropine; however, the muscarinic antagonist blocked the fall in blood pressure seen when the extract was administered to anaesthetized cats. The extract also stimulated rabbit aortic strip, rat vas deferens, and rat anococcygeus muscles. These adrenergic effects were largely reduced by phentolamine. The extract may contain a mixture of pharmacologically active ingredients that necessiate its separation.