ANTI-DIABETIC ACTIVITY OF SYZYGIUM POLYANTHUM (WIGHT) LEAF EXTRACT, THE MOST COMMONLY USED HERB AMONG DIABETIC PATIENTS IN MEDAN, NORTH SUMATERA, INDONESIA

Ethnopharmacological relevance: A preliminary ethnobotanical survey of diabetic patients in Health Community Centre Sering, Medan, North Sumatera, Indonesia from 2010-2011 revealed Syzygium polyanthum (Wight) as the most commonly used herb in the traditional management of diabetes mellitus. Yet, no substantial pharmacological evidences are available to validate this claim. Material and methods: A survey on the traditional herbs used among 264 diabetic outpatients attending the Health Community Centre Sering, Medan, North Sumatera, Indonesia was carried out from January 2010-April 2011.  The most commonly used herb was then extracted serially with petroleum ether (PEE), chloroform (CE), methanol (ME) and water (WE); and the extracts were used for detailed anti-diabetic evaluation in both non-diabetic rats (NDR) and streptozotocin-induced diabetic rats (SDR).  Results: The most commonly used herb was Syzygium polyanthum (Wight) leaf. In NDR, the increasing on blood glucose levels (BGLs) of intraperitoneal glucose-loaded rats (1g/kg) were not significantly altered by PEE, CE, and ME (1 g/kg) within 120 minutes after glucose loading. However, the BGL in WE group was significantly altered at 30 minutes after glucose loading (P < 0.05), meanwhile metformin significantly altered the BGL in 90 minutes (P<0.01), and 120 minutes (P<0.05) compared with control group. In SDR, anti-hyperglycaemic test with single dose administration of the extracts demonstrated that metformin- and ME-treated group significantly reduced the BGL.  Conclusion: The methanol extract of S. polyanthum (Wight) leaf proved to be the most effective anti-hyperglycaemic preparation.