Antihypertensive effect of an aqueous extract of Zygophyllum coccineum L. in rats

The effects of an aqueous extract of Zygophyllum coccineum L. on rat blood pressure (BP) and on the mesenteric vascular bed were investigated. The ext ract dose-dependently reduced BP and heart rate in normotensive and spontan eously hypertensive rats (SHRs). It also reduced BP in pithed SHRs. In vitr o, the extract had no effect on basal perfusion pressure of the mesenteric vascular bed. When the perfusion pressure was raised with noradrenaline or potassium chloride, the extract produced a dose-dependent reduction in perf usion pressure. However, in preparations in which the perfusion pressure wa s raised with KCI, the depressor response to lower doses or the extract was abolished while higher doses produced responses that were reduced in magni tude when compared with similar responses in preparations in which the perf usion pressure was raised with noradrenaline. It was concluded that extract s of Z. coccineum possess significant antihypertensive activity that may in volve some membrane hyperpolarization. Copyright (C) 2001 John Wiley & Sons , Ltd.