Triterpenes from Agarista Mexicana as potential antidiabetic agents

Hypoglycaemic activity‐guided fractionation together with chemical analysis led to the isolation of 12‐ursene and a novel triterpene 23,24 dimethyl‐24‐ethyl‐stigmast‐25‐ene from the chloroform extract of the dried stem of A. mexicana . Identification was based on spectroscopic methods. The isolated triterpenes were tested for hypoglycaemic activity in normal and alloxman‐diabetic CD1 mice 25–30 g at a dose of 50 mg/kg body weight. The blood glucose levels were determined before and 1.5, 3, 4.5 and 24 h after intraperitoneal drug administration. The results showed that the triterpenes produced a significant hypoglycaemic effect in normal as well as in diabetic mice. Comparison was made between the action of the triterpenes and a known hypoglycaemic drug, tolbutamide (50 mg/kg). The 12‐ursene was found to be slow and less effective than tolbutamide, and the 23,24 dimethyl‐24‐ethyl‐stigmast‐25‐ene was shown to be more effective than tolbutamide. Copyright © 2002 John Wiley & Sons, Ltd.