Blood lipids and lipid metabolism in the liver of streptozotocin-induced diabetes rats fed organic extracts of yam (d.cayenensis, cv. round leaf yellow yam) and dasheen (c. esculenta)

ABSTRACT

Yams and dasheen are widely produced in the caribbean where they grow readily. They are important sources of carbohydrates and vitamins. They were basically traditional foods of the people of Africa and the Caribbean until the introduction of `western diets'. It has been insinuated that this shift has led to the increase in cardiovascular diseases and diabetes. This study aims at examining the effects of organic extracts of yams and dasheen on diabetic rats in the light of the fact that they have been shown to contain linamarin in low quantities. Linamarin, a cyanoglucoside, is suspected to be involved in the aggravation of diabetes mellitus. A study was conducted on the lipid metabolism of the streptozotocin-induced diabetic rats fed supplements of organic extracts of yam and dasheen for four weeks. The levels of blood glucose and lipids were determined. Lipid metabolism and transaminase activities in the liver were assessed. The diabetic rats and the groups fed extracts of yam, dasheen and linamarin supplements lost weight significantly despite the non-significantly difference in their food intake. Liver weights were significantly (p<0.05> reduced in these groups compared to the healthy control rats fed a similar diet without the appropriate supplements (p<0.05>. The groups fed yam and dasheen extracts had significantly lower liver weights when compared to the diabetic group fed regular rat diet (p<0.05), and the diabetic group fed normal rat diet plus commercial linamarin additive (p<0.05). Rats fed dasheen organic extract supplement had significantly lower blood glucose levels (13.18 ñ 3.53 mmol/l) compared to the diabetic group fed normal rat diet (19.50 ñ 5.16 mmol/l) at p<0.05. Rats fed dasheen organic extract supplement had significantly lower blood triglyceride levels (2.29 ñ 0.16 mmol/l) with respect to the normal; 9.85 ñ 0.57 mmol; p<0.05, while yam extract (9.57 ñ 0.55 mmol/l) and linamarin (10.63 ñ 0.46 mmol/l) fed groups did not show significant changes in blood triglyceride levels. Blood total cholesterol level was reduced from 9.71 ñ 0.23 mmol/l in the diabetic state to 6.14 ñ 0.05 mmol/l and 6.66 ñ 0.65 mmol/l by feeding supplements of yam and dasheen extracts, respectively. The diabetic condition did not significantly affect the integrity of the liver as measured by alanine and asparate transaminase activities in this short term study.(AU)