In vitro α-glucosidase and α-amylase inhibition, and in vivo anti-hyperglycemic effects of Psidium littorale Raddi leaf extract

Guava, belonging to family Myrtaceae, is widely grown in tropical countries. Different parts of guava are reported to have long been used in folk medicine. In this study, the in vitro and in vivo anti-hyperglycemic activities of Psidium littorale Raddi leaves extract were investigated. The results indicated that the leaf extract demonstrates relatively high intestinal α-glucosidase inhibitory activity in rats, twice as high as acarbose. In addition, the extract also induced lowering fasting blood glucose levels in streptozotocin- induced diabetic rats at the dose of 150 mg/kg body weight, and without any effect on normal rats. Moreover, the extract did not significantly induce body weight loss in rats. The results suggest that P. littorale Raddi may prove to be useful in treating diabetes in humans.