Tectona grandis Linn. (Verbenaceae) leaf ethanol extract in renal artery occluded hypertensive rats

Hypertension is one of the principal health problems and leading cause of cardio-vascular deaths in various communities worldwide. An elevated arterial pressure is an important public health issue. Although it is common, asymptomatic and readily detectable, but it can often lead to lethal complications, if left untreated. Many new drugs have been introduced which may demonstrate better efficacy but posses side effects. Recently attention has been focused towards herbal preparations which are traditionally used as potential therapeutic agents in the prevention and management of cardiovascular diseases.

Ethanol extract of Tectona grandis Linn. leaf (Family: Verbenaceae) was evaluated for its antihypertensive activity in renal artery occluded hypertensive rats. Wistar rats (160–250g) were pretreated with ethanol extract of T. grandis for 6 weeks. Hypertension was induced in animals by clamping the renal artery with renal bulldog clamp for 4h. Ischemia of the kidneys caused elevation of blood pressure by activation of the renin-angiotensin system. Elevated blood pressure of the animals was significantly (p<0.05) decreased by the ethanol extract of T. grandis at the dose levels of 20, 40 and 80mg/kg, i.v. Captopril, angiotensin converting enzyme inhibitor (ACE-I) at the dose of 1mg/kg, i.v. showed significantly (p<0.05) reduction in the elevated blood pressure. The antihypertensive activity of ethanol extract of T. grandis may be due to the action on rennin-angiotensin system. This result would tend to justify the traditional use of the herb for the management hypertension.

Keywords: Tectona grandis, antihypertensive activity, rennin-angiotensin system