Coccinia grandis has been used in tribal populations of India both as food and medicine, but it has been not reported to be a neuroprotective agent yet. The present study was designed to evaluate the protective effects of Coccinia grandis leaf extract on diabetes induced brain damage of Wistar rats. This study reports the protective effect of methanolic leaf extract of Coccinia grandis against STZ induced diabetes in rats. Metformin (150mg/kg body wt.) was used as a reference drug. The enzymes of the polyol pathway and its related substrates were studied in the brain tissue. The effect of Coccinia on Cyclooxygenase (COX) and Prostaglandin peroxidise (PG) was also studied. Diabetes induced rats showed a significantly increased activity of Aldose reductase, Sorbitol dehydrogenase, Glucose-6-phosphodehydrogenase, whereas the decreased activity of Hexokinase. The content of Glucose, Sorbitol significantly increased in rat brain. Sodium potassium ATPase activity was also decreased in diabetic rats. COX, PG peroxidase was increased. Histological alternations were induced in the hippocampus of STZ treated diabetic rats. Oral administration of Coccinia leaf extract (200mg/kg) of body weight to diabetic rats for 21 days efficiently attenuated the parameters studied. A decreased activity of brain AR, sorbitol dehydrogenase, glucose-6-dehydrogenase was observed along with the increase in Hexokinase and Sodium potassium ATPase activity. It also showed decreased content of glucose and Sorbitol. Diabetes induced brain damage in the hippocampus and cerebral cortex was restored with Coccinia treatment. Decreased COX and PG peroxidase suggest its protection against inflammation. The current results suggest that Coccinia grandis leaf extract exerts the potential ability to reverse the progression of hyperglycemia and its concomitant induced brain damage.

The aim of the present study was to evaluate the protective effect of methanol garlic extract on the enzymes related with polyol pathway, advanced glycation end products, markers of oxidative stress and antioxidant status in brain of streptozotocin induced diabetic rats. Antioxidant capability of methanol extract of garlic was evaluated by 2,2-diphenyl-2-picrylhydrazyl hydrate radical and FOX (ferrous ion oxidation-xylenol orange) H2O2 scavenging test. Diabetes was induced by single i.p injection of STZ (32mg/kg per body Wt.,). Blood glucose levels and body wt, were measured on every 7th day over a period of 30 days. The diabetic rats treated with garlic extract at two doses 250mg/kg and 500mg/kg body wt., by oral administration. Diabetic rats showed significant increase in food and water intake, decrease in blood glucose levels, body weights, but could not show any recovery by garlic treatment. Garlic treatment significantly decreased aldose reductase (AR); sorbitol dehydrogenase (SD) and glutathione S-transferase (GST) enzyme activities. A decrease of malndialdehyde (MDA), Protein carbonyls (PC), Pentosidine advance oxidation protein products (AOPP), Advanced glycation end products (AGEs) was also observed. Additionally garlic administration produced a restoration of brain superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and reduced glutathione (GSH) in diabetic rats. Garlic treatment also reduced the free radical formation and progression of hyperglycemia induced diabetic complications by decreasing influx of glucose into the polyol pathway and increased activity of antioxidant enzymes. The current study reveals exerts, efficiently, an attenuating effect of methanol garlic extract exterted antihyperlgycemic, antioxidant and anti-glycating effects in a dose dependent manner in diabetic rats.