Hypoglycemic effects and mechanisms of Portulaca oleracea L. in alloxan-induced diabetic rats

Portulaca oleracea L. (POL) has been used as one of the traditional oriental medicines to treat bacteria, virus, antherasis, caducity, diabetes and for enhancing immunity. This study aims at revealing effects of POL on alloxan-induced diabetic rats and its mechanisms. According to thin layer chromatography assay, the main compounds of POL included organic acid, flavonoids, alkaloids, terpene ansteroid, hydroxybenzene, saponin and polysaccharide. The rats were divided into four groups: normal control (NC), diabetes control (DC), diabetes + POL high dose (400 mg/kg), diabetes + POL low dose (200 mg/kg). The diabetic rats were administrated with POL or dH(2)O daily for 28 days. The POL treatment resulted in significant decreases of fasting blood glucose, total cholesterol and triglycerides. POL also showed a tendency of improvement body weight gain on diabetic rats. Furthermore, the DC group had low serum insulin level comparing with that of NC group, at the same time, the insulin levels were dose-dependently raised in the POL-treated groups than that of DC group. According to single cell gel electrophoresis and LD50 analysis, POL was proved to be nontoxic to the animals. The results indicate that POL would alleviate the blood glucose and lipid rising associated with diabetes, and improve the abnormal glucose metabolism and increase insulin secretion by restoring the impaired pancrease beta cells in alloxan-induced diabetic rats, which suggest that POL has the hypoglycemic potential and could be useful on the diabetes therapy.