[Hypoglycemic effects of Siamese Momordica charantia and Phyllanthus urinaria extracts in streptozotocin-induced diabetic rats (the 1st report)].

Hypoglycemic effects of the extracts of two Siamese plants, Momordica charantia (M.c.) and Phyllanthus urinaria (P.u.), were examined in streptozotocin-induced diabetic rats. Oral administration of a 50% methanol extract (30 mg/kg) of M.c. and P.u. decreased the blood glucose levels (BGL) by 25% and 24%, respectively, at 3 hr after administration. Among other fractions such as the ethyl ether or water soluble fractions, the 10 and 30 mg/kg n-butanol soluble fraction from M.c. extract was most effective in lowering BGL by 26% and 34%, respectively. Similarly with M.c., the n-butanol fraction from P.u. extract decreased BGL by 23% and 39% at the doses of 10 and 30 mg/kg, respectively. In the oral glucose tolerance test, n-butanol fractions from M.c. and P.u. (30 mg/kg, p.o.) both inhibited the initial increase in BGL to the same degree. In the intraperitoneal glucose tolerance test the n-butanol fraction of M.c. inhibited the increase of BGL prominently, but the n-butanol fraction of P.u. did not. These plants generally contain moderately non-polar hypoglycemic compound(s) soluble in n-butanol; and specifically, with regards to the hypoglycemic mechanism, the M.c. extract seems to act like insulin or via insulin secretion from the pancreas, like the action of sulfonyl ureas, and the P.u. extract may act via facilitation of glucose metabolism and/or the inhibition of glucose absorption in the gut like the action of biguanides.