Comparative Hypolipidaemic Effects of Allium cepa, Allium sativum and Zingiber officinale Aqueous Extracts on Alloxan-Induced Diabetic Rattus novergicus

This study compares the hypolipidaemic effects of the increasing dosages of A. cepa, A. sativum and Z. officinale aqueous extract on alloxan-diabetic Rattus novergicus for possible use in the management of hyperlipidaemia characteristic of diabetes mellitus. Diabetes mellitus was induced in 108 out of a total of 117 adult Rattus novergicus using 150mg/kg b wt of alloxan monohydrate. Increasing dosages (200, 250 and 300mg/kg bw ip) of A. cepa, A. sativum and Z. officinale aqueous extracts were given to the diabetic rats for six weeks while the control rats got either normal saline (1ml) or increasing dosage of glibenclamide ( 2.5, 3.8 and 5.0mg/kg b wt ip) during the same period. Total serum lipids and total serum cholesterol were assessed using routine methods. Increasing dosages of plants aqueous extracts produced a dose-dependent significant (P < 0.05) reductions in the total serum lipid and total serum cholesterol of diabetic rats. The most effective percentage reduction in total serum lipids and total serum cholesterol were observed at 300mg/kg bw ip and this was the same for the three extracts studied. A. cepa and A. sativum at 300mg/kg bw ip caused significant reductions in total serum lipids more effective than the diabetic control drug glibenclamide at 5.0 mg/kg bw ip. A. cepa at 300mg/kg bw ip was the most effective in reducing total serum lipids, reducing it by 44.4% (184.3 ± 8.4 to 129.7 ± 5.7). A. sativum at 300mg/kg bw ip was the most effective in reducing total serum cholesterol, 39.8%, that was from ( 128.7 ± 2.7 to 77.2 ± 4.9), A. cepa followed 27.2% (130.1 ± 3.7 to 94.7 ± 4.2) and Z. Officinale was next , 16.1% from (130.7 ± 4.4 to 109.7 ± 7.5). From our experimental findings, it can be concluded that the three plant extracts studied exhibited promising hypolipidaemic activity in alloxan-diabetic rats. The hypolipidaemic effect presents a protective mechanism against the development of atherosclerosis and hyperlipidaemia common in diabetes mellitus. Further studies on the extracts, their composition, mode of action and active ingredients are suggested. A research on the combined effects of the three plant extracts on hyperlipidaemia was recommended for future investigations. Keywords: Hypolipidaemic effects, Allium cepa, Allium sativum, Zingiber officinale Alloxan-Induced diabetic Rattus novergicus Bio-Research Vol. 6 (2) 2008: pp. 384-39