Hepatic Function Enzymes and Lipid Peroxidation in Streptozotocin-induced Diabetic Rats Fed Bitter Yam (dioscorea Polygonoides) Steroidal Sapogenin Extract

Diabetic male wistar rats (n=32) were fed diets supplemented with 1% bitter yam steroidal sapogenin extract or commercial diosgenin for three weeks. Thiobarbituric acid reactive substances (TBARS), conjugated dienes, lipid profile and the activities of alanine and aspartate transaminases and acid phosphatase were measured in the liver. Diabetic rats (groups B-D) lost weight significantly (p<0.05) compared with the normal group even though there was no significant difference (p<0.05) in their feed intake. There was no significant change (p<0.05) in liver weight. Test diets significantly lowered plasma glucose level. Total cholesterol and VLDL-cholesterol decreased significantly (p<0.05), while HDL-cholesterol levels increased significantly in group C and D rats compared to group B rats. There was no significant change in the levels of phospholipids and triglycerides. The feeding of commercial diosgenin and yam sapogenin extract resulted in a significant decrease in conjugated dienes and TBARS compared with the diabetic group fed normal diet and normal rats. Yam extract and commercial diosgenin also caused a significant decrease in the diabetesinduced increase in the activity of alanine transaminase. However, they had no effect on the aspartate and acid phosphatase levels. The study showed that the feeding of bitter yam steroidal sapogenin extract to diabetic rats may result in alterations in the lipid composition of the liver with subsequent reduction in lipid peroxidation. Data from this study also showed improvement in liver damage associated with diabetes.