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Abstract.We have shown that separate dose of tetrahydrocurcumin (THC) at a dose of 80 mg/kg body weight (b.w.) and chlorogenic acid (CGA) at a dose of 5 mg/kg b.w. exerts antidiabetic potential in streptozotocin (STZ) (45 mg/kg b.w.) nicotinamide induced diabetic rats. In the present study we have attempted to compare the antihyperglycemic activity exerted by the combined treatment of THC/CGA with THC and CGA alone treated diabetic rats. After the experimental period of 45 days we observed that supplementation with combined dose of THC/CGA significantly decreased glycosylated hemoglobin (HbA 1C ) and increased the levels of plasma insulin, C-peptide, hemoglobin and glycogen which were decreased upon STZ treatment and also significantly reversed the altered activities of gluconeogenic enzymes such as glucose-6-phosphatase, fructose-1,6-bisphosphatase, and of glycolytic enzymes such as glucokinase and hexokinase in the tissues of experimental rats as compared to their individual supplementation. Thus our results substantiate that though THC and CGA alone found to exert hypoglycemic activity the maximum hypoglycemic effect was always observed in diabetic rats treated THC/CGA and this summed effect seems to have a promising value for the development of a potent phytomedicine for diabetes.

Caffeic acid is a well-known phenolic compound mainly present in plants. In this study, caffeic acid was evaluated for its protective effect against chronic ethanol-induced biochemical changes in male Wistar rats. Administration of ethanol (7.9 g/kg/day) for 45 days induced liver and kidney damage as manifested by a significant increase in the levels of serum hepatic and renal markers namely aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), gamma glutamyl transferase (GGT), bilirubin, urea, creatinine, and a significant decrease in creatinine clearance and levels of hemoglobin. Plasma thiobarbituric acid-reactive substances and hydroperoxide were significantly elevated where as the levels of nonenzymic antioxidants [reduced glutathione, vitamin E and vitamin C] were significantly decreased in alcohol-intoxicated rats. Administration of caffeic acid along with alcohol significantly decreased the serum levels of liver and kidney markers to near-normal levels. In addition, administration of caffeic acid significantly decreased the levels of lipid peroxidation markers while the levels of antioxidants were significantly increased in circulation of alcohol-fed rats. All these results were accompanied by histological observations in liver. The results demonstrate that caffeic acid has a beneficial effect in reducing the adverse effect of alcohol.

Chlorogenic acidStreptozotocin Tetrahydrocurcumin A B S T R A C TThe present study was undertaken to investigate the protective effect of tetrahydrocurcumin (THC) and chlorogenic acid (CGA) against streptozotocin (STZ)-nicotinamide (NA)-induced type 2 diabetes in adult Wistar rats. Diabetes was induced in experimental rats weighing 180-220 g, by a single intraperitoneal (i.p.) injection of STZ (45 mg/kg BW), 15 min after the (i.p.) administration of NA (110 mg/kg BW). THC (80 mg/kg BW) and CGA (5 mg/kg BW) were orally administered to diabetic rats for a period of 45 days. Fasting plasma glucose, glycosylated haemoglobin (HbA 1C ), thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LOOH) were significantly increased, whereas insulin, total haemoglobin (Hb), non-enzymic antioxidants (reduced glutathione (GSH), vitamin C, vitamin E and ceruloplasmin) were decreased significantly in diabetic rats. Though the diabetic rats treated with THC and CGA individual exerts beneficial effects in all the biochemical parameters in (STZ)-induced diabetic rats. The combined treatment with THC and CGA normalized all the above-mentioned biochemical parameters in STZ-induced diabetic rats.Normal pancreatic histological architecture in THC and CGA treated diabetic rats revealed that these phytochemical exert higher degree of protection when administered in combination than single treatment of individual compounds.

The present study evaluates the combined effect of tetrahydrocurcumin and chlorogenic acid on oxidative stress in streptozotocin-nicotinamide-induced diabetic rats. Rats were rendered diabetic by a single intraperitoneal injection (i.p) of streptozotocin (45 mg/kg BW), 15 min after an i.p injection of nicotinamide (110 mg/kg BW). The levels of fasting plasma glucose and insulin were estimated. As an index of oxidative stress, the levels of enzymic antioxidants and lipid peroxidation products were analyzed in liver and kidney. Diabetic rats showed an increase in the levels of fasting plasma glucose, lipid peroxidative products such as thiobarbituric acid reactive substances and lipid hydroperoxides and a decrease in plasma insulin, and enzymic antioxidants viz., superoxide dismutase, catalase, glutathione peroxidase and glutathione-S-transferase. Combined administration of tetrahydrocurcumin (80 mg/kg BW) and chlorogenic acid (5 mg/kg BW) to diabetic rats for 45 days, reversed the biochemical changes to near normal. The above findings were supported by histological observations of the liver and kidney. Together the present study clearly reflects that combined dosage of tetrahydrocurcumin and chlorogenic acid augments enzymic antioxidants with a concomitant decrease in lipid peroxidation and protects against streptozotocin-nicotinamide-induced type 2 diabetes in experimental rats.