Role of pectin from cucumber (Cucumis sativus) in modulation of protein kinase C activity and regulation of glycogen metabolism in rats.

The regulatory role of protein kinase C (PKC) in glycogen metabolism in pectin fed rats was investigated. Administration of pectin (5 g/kg body wt/day) from cucumber (Cucumis sativius L.) led to inhibitory effects on PKC activity in the liver of rats. In the brain and pancreas, PKC activity was significantly higher in pectin-treated rats as compared to the control group. Level of blood glucose was significantly lowered and the level of glycogen in the liver was significantly increased in pectin-administered rats. Glycogen synthase activity was enhanced, while glycogen phosphorylase enzyme showed inhibition in pectin-treated rats. Results indicated that pectin administration might have caused an increase in the secretion of the insulin, which, in turn, had a stimulatory effect on the PKC activity in the pancreas. The decreased PKC activity in the liver and increased PKC activity in the brain and pancreas on pectin administration indicated enhanced glycogenesis and reduced glycogenolysis.

Effect of catechin on carbohydrate metabolism.

Effect of varying concentrations of catechin on blood glucose levels was examined in male rats. Catechin exerted maximum hypoglycemic action at a dose of 10 mg/kg BW/day. Above this dose, the activity decreased gradually and blood sugar returned to almost normal levels at a concentration of 100 mg/kg BW/day. At optimum dose of catechin there was increase in the hepatic glycogen levels. Incorporation of [14C] glucose into glycogen in vitro was also increased. Glycogen synthase activity was found increased significantly whereas glycogen phosphorylase showed a decrease showing that hypoglycemic effect of catechin is due to increased glycogenesis and decreased glycogenolysis.