Potential hypoglycemic constituents from coscinium fenestratum

Abstract

Dry powder extract from stems of Coscinium fenestratum (Gaertn.) Colebr. was dissolved in water at concentration 0.016 g/ml and treated with 4 M HCI to reach pH 2. The yellow precipitate (Cf) was separated and dried. The precipitate was dissolved in water (0.05 m g/ml) and applied on a silica gel 6 0 column, methanol : water : 25% NH3 (8: 1:1) was used as a mobile phase. Cf2 and Cf3 were separated. Cf2 was crystallized in methanol. Hypoglycemic effect of constituents of Coscinium fenestratum in normal male Wistar rats has been demonstrated. Cf2 -crystal fed at single doses of 20 and 60 mg/kg body weight and Cf3 fed at single doses of 20, 60 and 180 mg/kg body weight significantly (P< 0.05) decreased blood glucose concentration at 30 min after feeding of glucose 1 g/kg body weight. Blood glucose levels decreased 15.16, 14.16, 16.37, and 34.02%, respectively; as compared to the control group. Hypoglycemic activity of Cf2-crystal is not dose-related while of Cf3 is dose- dependent although not as a linear relationship. Structure analysis of Cf2 -crystal and Cf3 using spectroscopy t echnigue showed that Cf2-crystal is jatrorrhizine, while the major component of Cf3 is berberine.