Abstract

Aqueous extract of Hibiscus sabdariffa L. is widely consumed in Nigeria as a local beverage used to quench thirst and also because of its antihypertensive action. The present study investigated the effect of consumption of aqueous extract of H. sabdariffa on thirst perception (TP) in mild to moderate hypertensive Nigerians. Fifty mild to moderate hypertensive patients attending medical out-patients clinic of Enugu State University Teaching Hospital were recruited for the study. They were randomly divided into two groups: A and B.  Those in group A were given equivalent dose of placebo while group B received 150 mg/kg of H. sabdariffa daily for 4 weeks. All the subjects were given weekly appointments and a week worth of infusion. Thirst perception, serum electrolytes and blood pressure (BP) were measured at baseline and weekly during treatment. TP reduced significantly (p<0.001) in H. sabdariffa group compared to placebo throughout the duration of the experiment. Serum Na⁺ reduced significantly (p<0.001) in H. sabdariffa compared to placebo group in weeks 3 and 4. Blood pressure (SBP, DBP and MAP) also reduced significantly (p<0.001) in weeks 3 and 4. Thus, consumption of H. sabdariffa reduced thirst perception in mild to moderate hypertensive Nigerians. This validates its traditional use to ‘quench thirst’ and complements its antihypertensive action. Reduction in serum Na⁺ may be the possible mechanism of action.

Key words: Hibiscus sabdariffa, thirst perception, essential hypertension, serum electrolytes.