Changes In Serum Lipid Profiles And Heart Rate In Rats Treated With Aqueous Garlic Extract

摘要

The serum lipid profiles and heart rate in rats treated with aqueous garlic extract were estimated in 24 Wistar albino rats. The rats were divided into four groups of 6 rats each. Group A received water and standard feeds for 6 weeks. Group B was fed with hyperlipidaemic diets for 6 weeks, while groups C and D had the hyperlipidaemic diets for 3 weeks and in addition administered 100 and 200 mg/kg aqueous garlic extract for another 3 weeks respectively. The body weights of the animals were simultaneously estimated. The results showed that the rats in all the groups gained weight: 0.03% for group A (negative Control), 6.2% for group B (positive Control), and 1.9 and 2.1% for groups C and D respectively. At the 6th week, the serum levels of Tc, Tg and LDL-c decreased significantly (P<0.05). but the HDL-c value increased significantly (P<0.05) too. The atherogenic risk predictor ratios also increased. The changes in groups C and D followed a dose-related pattern. Garlic extracts are reported to inhibit 3-hydroxy-3-methoxy-butyryl-CoA reduetase. This could help to explain the decrease in serum lipid indices. The increase in aterogenic risk ratio confirms the beneficial use of the aqueous garlic extract in traditional medicine practice to manage hypertension and some cardiovascular related problems. The restoration of heart rate by the two doses of the extract tend to validate the hypolipidaemic and antiarrythmic potentials of the garlic extract. Introduction An elevated plasma level of cholesterol is linked to the development of atherosclerosis and Ischemic conditions. Many studies indicate that lowering serum cholesterol may prevent, control or even reverse atherosclerosis and coronary heart disease (Ononogbu and Emole,1999). In fact, it is almost accepted that atherosclerosis is a disorder of lipid transport and metabolism. Apart from the lipid from the diet source, the body in turn manufactures its own cholesterol. Inefficient clearance of excess cholesterol for reasons that are largely genetic (Kritchersky 1970) results in accumulation of cholesterol in the blood, and deposition lipid in the inner layer of arterial walls. Studies have however shown that increased high density lipoprotein cholesterol (HDL-c) appears to prevent the development of atherosclerosis while reduced level are associated with increased risk for coronary artery diseases (Mendez et al. 1975). Furthermore, high blood lipid levels, particularly total cholesterol (Tc) and low density lipoprotein cholesterol (LDL-c) are usually related to promoting atherosclerotic syndrome. Hence interventions that lower these lipids in the blood can prevent the progression of the disease processes. Epidemiological studies have shown that diet rich in fruits, spices and vegetables are associated with a low risk of cardiovascular disease. Heart rate which is a term used to describe the frequency of the cardiac cycle is also affected in the course of the disease. Some vegetables, including garlic are known to ameliorate the condition.Garlic acquired a reputation in the folklore of many culture over centuries as a formidable prophylactic and therapeutic medicinal agent. During the earliest Olympics in Greece, garlic was fed to the athletes for increasing stamina (Moyers, 1996; Lawson, 1998). The Indian ancient medical text (Charaka-Sambila) recommends garlic for the treatment of heart disease and arthritis. Garlic attracted the attention of modern medicine because of its widespread health use in different parts of the world. There is a common belief in folkloric medicine that it helps in maintaining good health, warding off illnesses and as a stimulant tonic.Recent animal and clinical studies showed that garlic extract: (i) reduce the risk factors for cardiovascular diseases and cancer, (ii) stimulate immune function (iii) enhance detoxification of xenobiotics (iv) confer hepatoprotection (v) exhibit antimicrobial effects and (vi) antioxidant properties (Banerjee and Maulik, 200