EVALUATION OF ANTIDIABETIC AND INSULINTROPIC POTENTIAL OF NIGELLA SATIVA SEEDS WATER EXTRACT AND /OR ALPHALIPOIC ACID IN TYPE 2 DIABETIC RATS

The objective of this study was to evaluate the possible antidiabetic and insulin tropic effect of nigella sativa seeds water extract and/or lipoic acid. For this purpose, Forty male Wistar strain albino rats were divided into five groups (8 rat /group), group 1; control group, group2; normal rats fed on basal diet and received 21% fructose in drinking water for four weeks then injected intraperitoneally by a single streptozotocin (STZ) dose (40 mg/kg) to induce type2 diabetes and served as diabetic control group , group3; diabetic rats orally administrated water extract of nigella sativa (1ml/kg daily for 6 weeks), group4; diabetic rats orally administrated lipoic acid (100 mg/kg daily for 6 weeks), group5;diabetic rats orally administrated aqueous extract of nigella sativa and lipoic acid daily simultaneously at the previous tested doses for 6 weeks. Untreated diabetic group showed a significant increase in serum glucose, total cholesterol, triacylglycerols, transforming growth factor beta (TGF- β)and leptin. Also, hepatic total lipids, total cholesterol, alcohol dehydrogenase (AD) activity were significantly elevated in untreated diabetic group as compared to normal control. Whereas, serum insulin, C-peptide, insulin like growth factor -1(IGF-1), hepatic glycogen and NADPH were significantly reduced in untreated diabetic group as compared to normal control. Moreover, the activities of hepatic enzymes cytochrome p450 reductase, glucose-6-phosphate dehydrogenase (G-6-P-D), Glyoxalase I and II were significantly reduced in untreated diabetic rat as compared to normal control group (p<0.05). Oral administration of nigella sativa seeds water extract and /or lipoic acid restored all these altered biochemical parameters to near normal levels. Conclusion the ameliorative effect of water extract of nigella sativa and /or lipoic acid on altered carbohydrate , lipid and oxidative stress variables in type 2 diabetic rats , may be attributed to their insulin releasing capacity, lipid lowering effect and antioxidative effect.