Ninety patients (aged 30-80 years; mean, 53 years) with untreated mild-to-moderate hypertension were randomly assigned to receive 500 ml of Hibiscus sabdariffa tea once a day before breakfast or 25 mg of captopril twice a day for 4 weeks. Hibiscus tea was prepared by adding 10 g of dry calyx from H. sabdariffa to 500 ml of boiling water and letting stand for 10 minutes. Seventy patients completed the trial. In the hibiscus group, the mean systolic blood pressure (BP) decreased from 139.1 to 123.7 mm Hg (p < 0.03) and the mean diastolic BP decreased from 90.8 to 79.5 mm Hg (p < 0.06). The mean reductions in systolic and diastolic BP in the captopril group were slightly, but not significantly, greater than the reductions in the hibiscus group. A reduction in diastolic BP of at least 10 mm Hg was seen in 79% of patients receiving hibiscus and 84% of patients receiving captopril (p > 0.25). Hibiscus had a natriuretic effect: mean 24-hour urinary sodium excretion increased from 106 mEq to 125 mEq (p < 0.001). Both treatments were well tolerated.
Comment: These results suggest that Hibiscus sabdariffa tea is as effective, or nearly as effective, as captopril in the treatment of mild-to-moderate hypertension. Other natural treatments for hypertension that have been shown to be effective include magnesium, calcium, hawthorn, essential fatty acids, and coenzyme Q10. Despite this seemingly large arsenal of natural antihypertensives, non-pharmacological treatment of hypertension often produces disappointing results. While Rauwolfia serpentina (the natural source of reserpine) is a fairly strong antihypertensive agent, it has the potential to cause depression. According to the German Commission E Monographs, Hibiscus sabdariffa is considered nontoxic; its use should therefore be considered for hypertensive patients.
Herrera-Arellano A, et al. Effectiveness and tolerability of a standardized extract from Hibiscus sabdariffa in patients with mild to moderate hypertension: a controlled and randomized clinical trial. Phytomedicine 2004;11:375-382.
