Abstract

Background: Hibiscus sabdariffa L. (Hs; Malvaceae) is commonly known as roselle or red sorrel in English or karkadè in Arabic. It is a tropical plant native to India and Malaysia. Roselle extracts have been widely reported to have beneficial health effects. The aim of this study was to determine the effective dose of Hs aqueous extract, which is a possible reducing agent in diet-induced obese rats, and monitoring any toxicological effect. Methods: Male Sprague Dawley rats (n= 24) aged 6-7 weeks and weighing 210 ± 3.5 g (mean ± S.E.M) were used. The rats were fed a high fat diet (HFD) for 8 consecutive weeks to induce obesity. The animals were then randomly assigned to one of five groups based on the concentration of Hs aqueous extract. The normal group (NG) received a normal diet (commercial chow) throughout the study. The obese group (ObG) included obese rats administered with tap water ad libitum. Groups 1 (150 mg/kg), 2 (200 mg/kg), 3 (250 mg/kg), and 4 (300 mg/kg) were obese rats continuously fed with HFD in combination with the Hs extract for 10 weeks. The effect of Hs on some haematological and blood biochemical parameters were also evaluated. Results: Hs aqueous extract is a rich source of anthocyanins. The main compounds detected are delphinidin-3-O-sambubioside and delphinidin-3-O-sambubioside. The extract also possesses high antioxidant properties which may be caused by these anthocyanins. The anti-obesity effect of Hs aqueous extract was demonstrated by the significant reduction in the weight gain and abdominal weight (p < 0.05) between treated and non-treated groups, which was dose-dependent. Overall, our study demonstrated that oral administration of Hs at doses of 150, 200, 250, and 300 mg/kg for ten weeks did not cause any toxicity effect within the obese rats. Conclusions: The results of the study implied Hs aqueous extract at 300 mg/kg is the dose which can the most weight reduction effect with no severe haematological and biochemical changes in all experimental animals.

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