THE EFFECTS OF FISETIN ON GLYCOGENOLYSIS AND GLYCOLYSIS IN THE RAT LIVER

Abstract

Flavonoids have been proposed to exert beneficial effects in a multitude of disease states, including cancer, cardiovascular disease, and neurodegenerative disorders. The most known biological effects of the flavonoids, is no doubt their antioxidant action, which represents protection of tissues against the action of free-radicals and diminution of lipid peroxidation. Fisetin is a flavonoid found in the smoke tree (Cotinus coggyria) and is also widely distributed in fruits and vegetables such as strawberry, apple, persimmon, grape, onion, and cucumber. It has been reported to suppress the proliferation of tumor cells, such as prostate cancer, liver cancer, colon cancer, and leukemia. The present work was planned to investigate if fisetin affects glycogenolysis and glycolysis in the rat liver. Male Wistar rats, weighing 200 to 280 g, were utilized in all experiments. The isolated liver was perfused in the non-recirculating system. The perfusion fluid was Krebs/Henseleit-bicarbonate buffer (pH 7.4), saturated with a mixture of O2 and CO2 (95:5). For measuring glycogen catabolism (glycogenolysis and glycolysis) livers from ad libitum fed rats were utilized. Fisetin inhibited glycogenolysis, as revealed by the decrease of glucose, lactate and pyruvate release from endogenous glycogen. Lactate and pyruvate productions from endogenous glycogen (glycolysis) were diminished by fisetin, the diminution in pyruvate production being less pronounced. Overall, the inhibition of glycogenolysis indicates that fisetin could be potentially useful as an antidiabetic agent, although further studies are needed to validate its therapeutic use.