Hot water extract of mature jak leaves ( Artocarpus heterophyllus
) is recommended by Ayurvedic and traditional medical practitioners as a treatment for diabetes mellitus. The leaf extract caused the hypoglyceamic effect at a dose of 50 mg/Kg, both in normal and alloxan-diabetic rats. The hypoglycaemic effect was at its maximum 2 h after flavonoid fraction administration, and multiple dosing maintained the activity for a week. The hypoglycaemic effect of the flavonoid fraction of leaf (49%) is higher than that of tolbutamide (27.0%), a sulphonyl urea drug commonly used for treatment of hyperglycaemia. Administering the flavonoid fraction for 3 months had no significant effects on liver function while the histology of liver, kidney and heart revealed no damage. These results indicate that the total flavonoid content of A. heterophyllus
leaf exhibited a non-toxic and significant hypoglycaemic activity in male Wistar rats and may therefore be responsible for the previously reported antidiabetic activity.