Effect of aqueous extract of Hibiscus sabdariffa on some biochemical parameters in alloxan-induced diabetic rats.

This study investigated some biochemical effects associated with subchronic administration of the aqueous extract of Hibiscus sabdariffa to alloxan-induced diabetic rats. Twenty male albino Wistar rats were assigned to four groups of five rats per group. Diabetes was induced in rats in groups 1, 2 and 3 by a single intraperitoneal injection of alloxan monohydrate (150 mg/kg) while rats in group 4 served as positive control. Upon establishment of diabetes, rats in group 1 were treated with 30 mg/ml of H. sabdariffa extract ad libitum while those in group 3 were treated with glibenclamide (2 mg/kg), a known anti-diabetic drug. Rats in groups 2 and 4 were given clean water. All treatment lasted for 21 days. Blood glucose levels of the rats were assessed on days 0, 7, 14 and 21 while blood for clinical chemistry analyses (alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total cholesterol, triglycerides, high density lipoprotein) were collected on days 0 and 21. Low density lipoprotein (LDL) was calculated using Friedewald formula and very low density lipoprotein was gotten by dividing triglyceride by 5. In vitro antioxidant assay was carried out using ferric reducing antioxidant power model. Results showed that the blood glucose level of the extract-treated rats decreased significantly ( p < 0.05) from 296.00 ± 86.11 on day 0 to 30.87 ± 11.39 on day 21. This was comparable with reduction achieved by glibenclamide-treated group. The total cholesterol and LDL levels of the extract-treated rats were significantly ( p < 0.05) lower than that of the diabetic-untreated controls. There was no significant difference ( p > 0.05) in the mean activities of serum AST, ALT and ALP when compared across the groups. The results of in vitro antioxidant test revealed that the antioxidant activity of H. sabdariffa extract was concentration-dependent with the maximum antioxidant activity of 87 % at 400 mg/ml. The aqueous extract of H. sabdariffa exhibited hypoglycaemic, hypolipidaemic and antioxidant effects on alloxan-induced diabetic rats. [ABSTRACT FROM AUTHOR]