Antihyperglycemic effects of gymnemic acid IV, a compound derived from Gymnema sylvestre leaves in streptozotocin-diabetic mice.
We investigated the antihyperglycemic action of a crude saponin fraction and five triterpene glycosides (gymnemic acids I-IV and gymnemasaponin V) derived from the methanol extract of leaves of Gymnema sylvestre R. BR. (Asclepiadaceae) in streptozotocin (STZ)-diabetic mice. The saponin fraction (60mg/kg) reduced blood glucose levels 2 4h after the intraperitoneal administration. Gymnemic acid IV, not the other 4 glycosides at doses of 3.4-13.4mg/kg reduced the blood glucose levels by 13.5-60.0% 6h after the administration comparable to the potency of glibenclamide, and did not change the blood glucose levels of normal mice. Gymnemic acid IV at 13.4 mg/kg increased plasma insulin levels in STZ-diabetic mice. Gymnemic acid IV (1 mg/mL) did not inhibit alpha-glycosidase activity in the brush border membrane vesicles of normal rat small intestines. These results indicate that insulin-releasing action of gymnemic acid IV may contribute to the antihyperglycemic effect by the leaves of G. sylvestre. Gymnemic acid IV may be an anti-obese and antihyperglycemic pro-drug.
Department of Chemical Pharmacology, Toyama Medical and Pharmaceutical University, Sugitani, Japan.
Y
Y
Sugihara
H
H
Nojima
H
H
Matsuda
T
T
Murakami
M
M
Yoshikawa
I
I
Kimura
D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000097:blood; D007422:Intestines / Q000187:drug effects / Q000201:enzymology; D008297:Male; D051379:Mice; D010946:Plants, Medicinal / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D012503:Saponins; D014315:Triterpenes / Q000627:therapeutic use*
D001786:Blood Glucose; D065089:Glycoside Hydrolase Inhibitors; D007004:Hypoglycemic Agents; D007328:Insulin; D012503:Saponins; D014315:Triterpenes; C007898:gymnemic acid