Modulating efficacy of Rebaudioside A, a diterpenoid on antioxidant and circulatory lipids in experimental diabetic rats.

The present study was to evaluate the protective effects of Rebaudioside A (Reb A) on antioxidant status and lipid profile in streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in Wistar rats by a single intraperitoneal administration of STZ (40mg/kg b.w). Diabetic rats showed significantly increased levels of plasma glucose, thiobarbituric acid reactive substances, hydroperoxides and decreased levels of insulin. The activity of enzymatic antioxidants (superoxide dismutase, catalase and glutathione peroxidase) and the levels of non enzymatic antioxidants (vitamin C, vitamin E and reduced glutathione) were decreased in diabetic rats. The levels of total cholesterol (TC), triglycerides (TGs), free fatty acids (FFAs), phospholipids (PLs), low density lipoproteins (LDL-cholesterol) and very low-density lipoproteins (VLDL-cholesterol) in the plasma significantly increased, while plasma high-density lipoproteins (HDL-cholesterol) were significantly decreased in diabetic rats. Oral administration of Reb A (200mg/kg b.w) brought back plasma glucose, insulin, lipid peroxidation products, enzymatic, non-enzymatic antioxidants and lipid profile levels to near normal. The results of the present investigation suggests that Reb A, a natural sweetener exhibits antilipid peroxidative, antihyperlipidemic and antioxidant properties.

Saravanan R ，Ramachandran V 《-》

Antioxidative and hypolipidemic efficacy of alcoholic seed extract of Swietenia macrophylla in streptozotocin diabetic rats.

Kalpana K ，Pugalendi KV 《-》

Protective effect of esculetin on hyperglycemia-mediated oxidative damage in the hepatic and renal tissues of experimental diabetic rats.

Diabetes mellitus is the most common serious metabolic disorder and it is considered to be one of the five leading causes of death in the world. Hyperglycemia-mediated oxidative stress plays a crucial role in diabetic complications. Hence, this study was undertaken to evaluate the protective effect of esculetin on the plasma glucose, insulin levels, tissue antioxidant defense system and lipid peroxidative status in streptozotocin-induced diabetic rats. Diabetic rats exhibited increased blood glucose with significant decrease in plasma insulin levels. Extent of oxidative stress was assessed by the elevation in the levels of lipid peroxidation markers such as thiobarbituric acid reactive substances (TBARS), lipid hydroperoxides (HP) and conjugated dienes (CD); reduction in the enzymic antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST); nonenzymic antioxidants Vitamin C, E and reduced glutathione (GSH) were observed in the liver and kidney tissues of diabetic control rats as compared to control rats. Oral supplementation of esculetin to diabetic rats for 45 days significantly brought back lipid peroxidation markers, enzymic and nonenzymic antioxidants to near normalcy. Moreover, the histological observations evidenced that esculetin effectively rescues the hepatocytes and kidney from hyperglycemia mediated oxidative damage without affecting its cellular function and structural integrity. These findings suggest that esculetin (40 mg/kg BW) treatment exerts a protective effect in diabetes by attenuating hyperglycemia-mediated oxidative stress and antioxidant competence in hepatic and renal tissues. Further, detailed studies are in progress to elucidate the molecular mechanism by which esculetin elicits its modulatory effects in insulin signaling pathway.

Prabakaran D ，Ashokkumar N 《-》

Isopulegol Mitigates Hyperglycemia Mediated Oxidative and Endoplasmic Reticulum Stress in HFD/STZ Induced Diabetic Rats.

Oxidative and endoplasmic reticulum stresses contribute to the pathogenesis of β-cell dysfunction in diabetes mellitus. This study investigates the effect of isopulegol on the above stresses in HFD/STZ induced diabetic rats. Animals in group I and II were placed in normal pellet diet and group II was treated with isopulegol at 200 mg/kg b.w. Animals in groups III-V were placed in HFD for 4 weeks and made diabetic with single intraperitoneal injection of STZ (35 mg/kg b.w) in 0.1 M citrate buffer (pH 4.5). Group III served as diabetic control while animals in group IV and V were treated with isopulegol (100 mg/kg b.w) and metformin (25 mg/kg b.w) respectively for 28 d. The activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione sulphur transferase (GST), glutathione reductase (GR) and the levels of vitamin-E, vitamin-C, reduced glutathione (GSH) were significantly (p <0.05) decreased in plasma and tissues of diabetic rats. Thiobarbituric acid reactive acid substances (TBARS) and lipid hydroperoxides (LHP), indices of lipid peroxidation were also significantly (p <0.05) increased in diabetic rats. In pancreatic tissue ER stress markers PERK, elf2α, ATF4 and in hepatic tissue oxidative stress marker UCP-2 expression was significantly (p <1.0) increased in diabetic rats. Administration of isopulegol significantly improved antioxidant status and decreased oxidative and ER stress markers in diabetic treated rats. Histopathological studies on liver and kidney supported the above findings. The results are comparable with the standard drug metformin. Isopulegol a naturally occurring monoterpene alcohol attenuated oxidative and ER stress in HFD/STZ induced diabetic rats.

Sankaranarayanan C ，Kalaivani K 《-》

Erythrocyte redox status in streptozotocin diabetic rats: effect of Casearia esculenta root extract.

Prakasam A ，Sethupathy S ，Pugalendi KV 《PHARMAZIE》