Abstract:
Hibiscus sabdariffa Linn, is commonly called in Thai as “ Krachiap-daeng ”. H. sabdariffa has been reported to have a broad range of therapeutic effects. This study examined subacute effects of H. sabdariffa aqueous extract on the activities of cytochrome P450 (CYP), involving in drug metabolism and carcinogenic/mutagenic bioactivation, such as CYP 1 Al, 1A2, 2B1/2, 2E1 and 3A in rats. In addition, effects of this extract on clinical blood chemistry and hematology were also determined. Thirty male Wistar rats were randomly divided into 3 groups, each group comprised 10 rats. Rats in the first group were given distilled water 1 ml/kg/day orally for 30 days, serving as a control group. The other two groups of rats were given H. sabdariffa aqueous extract orally at dosages of 250 and 1,000 mg/kg/day for 30 days. At the end of the treatment, rats were anesthesized. Blood samples were collected by heart puncture and serum was prepared for measuring hematology and clinical blood chemistry. Microsomes were prepared from livers and being used for determining of total CYP contents as well as the activities of CYP 1A1, 1A2, 2B1/2, 2E1 and 3A. The results showed that H. sabdariffa aqueous extract at both doses did not affect hepatic total CYP contents and the activities of CYP 1 Al, 1A2, 2B1/2, 2E1 and 3A. Both dosage regimens of H. sabdariffa did not cause any significant changes of these following clinical blood chemistry and hematology in rats: ALT, AST, ALP, total bilirubin, direct bilirubin, total protein, albumin, globulin, BUN, SCr, total cholesterol, TG, LDL-C, HDL-C, glucose, uric acid, calcium, sodium, potassium, chloride, hemoglobin, hematocrit, RBC count, RBC indices (mean corpuscular volume, MCV; mean corpuscular hemoglobin, MCH; mean corpuscular hemoglobin concentration, MCHC), RBC morphology, platelet count, white blood cell (WBC) count and % differential WBCs. These results suggested that H. sabdariffa aqueous extract at both doses used in this study did not modulate the activities of most phase I hepatic CYPs involving in drug metabolism and carcinogenic/mutagenic bioactivation. In addition, this extract did not exhibit harmful effects on several important organs/systems such as liver, kidney, blood system, electrolytes as well as lipid and carbohydrate metabolism.
