Anti-hyperglycemic effect of 11-hydroxypalmatine, a palmatine derivative from Stephania glabra tubers.

A palmatine derivative, named 11-hydroxypalmatine (4), has been isolated from the tubers of Stephania glabra, together with three known alkaloids, palmatine (1), dehydrocorydalmine (2), and stepharanine (3). The structures of the compounds were elucidated by means of spectroscopic analysis including 2D NMR experiments. The hypoglycemic activity of 4 was evaluated against alloxan-induced diabetic mice. The test compound was administered at doses of 25, 50, and 100 mg/kg, p.o., 36 h after alloxan injection (60 mg/kg, i.v.). The alloxan-induced diabetic mice showed significant reduction in blood glucose after treatment with the test compound by 52% as compared to the positive control glibenclamide (54%) and the diabetic control (27%).