Hibiscus sabdariffa ethanolic extract protects against dyslipidemia and oxidative stress induced by chronic cholesterol administration in rabbits.

Excessive intake of cholesterol (CHOL) and induction of free radical production play a critical role in the pathophysiology of several human diseases. Dietary therapy with plant products rich in flavonoids has been shown to provide benefits without the adverse effects of agents used in clinical practice. Hibiscus sabdariffa (HS) has been used for various purposes due to myriads of flavonoids present in it. In this study, the chemopreventive property of HS ethanolic extract (HSE) was investigated in dyslipidemia and oxidant stress associated with prolonged CHOL administration in rabbits. Twenty-five (25) adult male rabbits weighing between 1.5 and 1.7 kg were used and randomly divided into five groups of five rabbits per group. The CHOL-fed rabbits received 1 g/kg/day of CHOL suspended in 1 ml of corn oil for 8 weeks. Group 1 received 1 ml of corn oil and served as control. Group 2 was fed with CHOL only while groups 3, 4 and 5 received daily doses ofcholestyramine (questran, 260 mg/kg), HSE 200 mg/kg and HSE 300 mg/kg respectively along with CHOL. Animals were sacrificed by cervical dislocation 24-hours after last dose. Enzymic and non-enzymic markers of oxidative stress and lipid profile were analysed in serum, liver, kidney and heart of rabbits. HSE significantly attenuated the alteration in lipid levels and antioxidant status induced by high CHOL intake in rabbits in this study. Both serum and tissue levels of low density lipoprotein-CHOL, triglycerides, phospholipids, and total CHOL decreased with increase in high density lipoprotein-CHOL except in the heart, following treatment with HSE in CHOL-fed rabbits when compared with the untreated group (p<0.05). Similarly, HSE prevented CHOL-induced depletion of enzymic (superoxide dismutase, catalase) and non-enzymic (reduced glutathione, vitamin C) antioxidants with the attendant increases in lipid peroxidation and xanthine oxidase activity in these animals. The effectiveness of HSE in this condition was comparable with that of cholestyramine but with greater in potency. Data from this study demonstrate the hypolipidaemic and antioxidant activities of HSE and suggest its therapeutic potential in disorders of lipid metabolism and cardiovascular events associated with hypercholesterolemia.