Abstract

Fruits of Phaleria macrocarpa are used in the traditional health system of the Indonesians and lower course of Malaysia, as effective remedy and management for diabetes mellitus. This study therefore investigated the hypoglycemic and anti-hyperglycemic effects of P. macrocarpa extracts in normal and diabetic rats, respectively. The fruits were sequentially extracted in petroleum ether, methanol and water to obtained 3 extracts. Blood glucose response to acute dose of the extracts (1 g/kg b.w.) and intra-peritoneal glucose tolerance test (IPGTT) was performed in normal rats and a 12-day anti-hyperglycemic activity study was carried out in diabetic rats. The extracts exerted no effect in acute dose study. However, the methanol and water extracts showed a non significant blood glucose lowering effect between the 30 and 120 min in IPGTT, compared with the normal control. In diabetic rats, methanol extract only, lowered blood glucose by 56.25 and 58.33% (P<0.05) after a 12-day treatment compared with diabetic control (DC) and pre-treatment values, respectively; an effect similar to metformin, glibenclamide and insulin treated groups. Plasma insulin measured in the methanol extract-treated group was found to decrease by 75 and 50% compared with DC and pre-treatment values, respectively (P<0.05). This later effect only compared with the insulin-treated control with respective reductions of 65 and 30% (P<0.05). Phytochemical thin layer chromatography (TLC) spray test of the methanol extract indicated the presence in abundance of flavonoids, terpenoids and tannins. The antidiabetic activity ofP. macrocarpa was validated and this action which resides in the methanol fraction may be exerted by extra-pancreatic means.

Key words: Phaleria macrocarpa, plasma insulin, blood glucose, IPGTT, streptozotocin-induced diabetes.