Anti-hyperglycaemic effect of an extract of Myrtus communis in streptozotocin-induced diabetes in mice.

Intraperitoneal injection of streptozotocin (150 mg/kg) in mice produced an initial transient hyperglycaemia at 2 h followed by a second hyperglycaemic phase after 48-72 h which persisted throughout the 7-day observation period. An ethanol-water extract of Myrtus communis (2 g/kg) administered intragastrically 30 min before streptozotocin abolished the initial hyperglycaemic without affecting the second phase. Myrtus extract given prior to streptozotocin and repeated at 24 h and 30 h, did not allow hyperglycaemia to develop until after 48 h. Administration of Myrtus extract 48 h after streptozotocin significantly reduced the hyperglycaemia and this effect was maintained by its repeated administration. Myrtus extract had no effect on the blood glucose level of normal mice. These studies confirm the "folk-medicine" indication of Myrtus extract as potentially useful in the treatment of diabetes mellitus.