Evaluation of Diuretic and Antihypertensive Activity of Leaf Extracts of <em>Thymus Schimperi</em> in Rats

Abstract

The present study was performed to evaluate diuretic activity of aqueous and essential oil extract and antihypertensive activity of the aqueous extract of <em>Thymus Schimperi</em> leaves against salt-sucrose induced hypertension in rats. Aqueous extract of <em>T. Schimperi</em> leaves at the doses of 250, 500, 750 and 1000 mg/kg and the essential oil at 1.0 and 1.5 mL/kg were administered orally with normal saline to male wistar rats (n = 6). Normal saline and hydrochlorothiazide were used as negative and positive control, respectively. Urine volume and its electrolyte contents (Na⁺, K⁺ and Cl-) were measured to study diuretic activity of <em>T. Schimperi</em> leaves. On the other hand, for antihypertensive study, rats were randomly divided into control and treatment groups (n = 6). Treatment groups were given daily aqueous extracts (250 and 500 mg/kg) orally with 2% NaCl and 10% sucrose solution. Whereas, positive, negative and normal control received captopril (20 mg/kg/day with 2% NaCl and 10% sucrose solution), only 2% NaCl and 10% sucrose solution <em>ad libitum</em> and water <em>ad libitum</em> for 6 weeks, respectively. The blood pressure was measured every week using tail cuff blood pressure analyzer and after 6 weeks the blood was sampled to evaluate effect on serum lipid profile (TC, TG and BG) and liver function indicator enzymes (ALT & ALP) using clinical chemistry analyzer. The oral administration of aqueous extract of <em>T. Schimperi</em> leaves (500 mg/Kg/day) for six weeks produced significant (p<0.05) prevention in systolic blood pressure increment. The oral administration of aqueous extract of <em>T. Schimperi</em> (250, 500, 750 and 1000 mg/kg) showed positive diuretic activity at 5 h. The aqueous extract of <em>T. Schimperi</em> (750 and 10000 mg/kg, orally) significantly increased Na⁺, K⁺ and Cl- excretion in 5 h and additionally essential oil of <em>T. Schimperi</em> (1 and1.5 mL/kg) showed significant kaliuretic effect. The results of the present study revealed the antihypertensive and diuretic activity of aqueous extract of <em>T. Schimperi</em> leaves. These effects might be attributed to the presence of the potassium or phenolic components of the thymus leaves.