Hypoglycemic activity of polygonati rhizoma in normal and diabetic mice

The hypoglycemic effect of different dose of Polygonati Rhizoma, i.e., "Ousei", was investigated in both normal and streptozotocin-induced diabetic mice. The methanol extract of Polygonati Rhizoma (OM) (800 mg/kg) reduced the blood glucose of normal mice from 202 +/- 7 to 144 +/- 13 mg/100 ml 4 h after intraperitoneal administration (p < 0.01), and also lowered significantly the blood glucose of streptozotocin-induced diabetic mice from 589 +/- 34 to 396 +/- 15 mg/100 ml under similar conditions (p < 0.001). However, the hypoglycemic effects were not accompanied by any alteration in the serum insulin in these mice. OM also suppressed epinephrine-induced hyperglycemia in mice. These results support, therefore, the use of Polygonati Rhizoma in patients with diabetes and confirm its role as a traditional medicine. In addition, one of the active components of OM was identified as a spirostanol glycoside (PO-2).