title: Antihyperglycemic Effect of Methanol Extract of Syzygium polyanthum (Wight.) Leaf in Streptozotocin-Induced Diabetic Rats.
abstract: Syzygium polyanthum (S. polyanthum), a plant belonging to Myrtaceae, is widely used in Indonesian and Malaysian cuisines. Diabetic patients in Indonesia also commonly use it as a traditional medicine. Hence, this study was conducted to investigate the antihyperglycemic effect of the methanol extract (ME) of S. polyanthum leaf and its possible mechanisms of action. To test for hypoglycemic activity, ME was administered orally to normal male Sprague Dawley rats after a 12-h fast. To further test for antihyperglycemic activity, the same treatment was administered to glucose-loaded (intraperitoneal glucose tolerance test, IPGTT) and streptozotocin (STZ)-induced diabetic rats, respectively. Hypoglycemic test in normal rats did not show significant reduction in blood glucose levels (BGLs) by the extract. Furthermore, IPGTT conducted on glucose-loaded normal rats also did not show significant reduction of BGLs. However, repeated administration of metformin and three doses of ME (250, 500 and 1000 mg/kg) for six days caused significant reduction of fasting BGLs in STZ-induced diabetic rats. The possible mechanisms of action of S. polyanthum antihyperglycemic activity were assessed by measurement of intestinal glucose absorption and glucose uptake by isolated rat abdominal muscle. It was found that the extract not only inhibited glucose absorption from the intestine but also significantly increased glucose uptake in muscle tissue. A preliminary phytochemical qualitative analysis of ME indicated the presence of tannins, glycosides, flavonoids, alkaloids and saponins. Additionally, Gas Chromatography-Mass Spectrometry (GC-MS) analysis detected squalene. In conclusion, S. polyanthum methanol leaf extract exerts its antihyperglycemic effect possibly by inhibiting glucose absorption from the intestine and promoting glucose uptake by the muscles.
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia. tw_rozan@yahoo.com.|Department of Pharmacology and Therapeutic, Medical Faculty, University of Sumatera Utara, Medan 20155, Indonesia. tw_rozan@yahoo.com.
authors.forename: Tri
authors.initials: T
authors.lastname: Widyawati
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia. noradlinyusoff@yahoo.com.|Integrative Medicine Cluster, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Penang 13200, Malaysia. noradlinyusoff@yahoo.com.
authors.forename: Nor Adlin
authors.initials: NA
authors.lastname: Yusoff
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia. mariam@usm.my.
authors.forename: Mohd Zaini
authors.initials: MZ
authors.lastname: Asmawi
authors.affiliation: School of Pharmaceutical Sciences, Universiti Sains Malaysia, Minden, Penang 11800, Malaysia. mariam@usm.my.
authors.forename: Mariam
authors.initials: M
authors.lastname: Ahmad
mesh_terms: D000009:Abdominal Muscles / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D000959:Antihypertensive Agents / Q000302:isolation & purification / Q000494:pharmacology*; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy*; D008401:Gas Chromatography-Mass Spectrometry; D007408:Intestinal Absorption / Q000187:drug effects; D007583:Jejunum / Q000187:drug effects / Q000378:metabolism; D008297:Male; D000432:Methanol / Q000737:chemistry*; D008517:Phytotherapy; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D018515:Plant Leaves; D010946:Plants, Medicinal; D017207:Rats, Sprague-Dawley; D012997:Solvents / Q000737:chemistry*; D027842:Syzygium / Q000737:chemistry; D013997:Time Factors
chemical_list: D000959:Antihypertensive Agents; D015415:Biomarkers; D001786:Blood Glucose; D010936:Plant Extracts; D012997:Solvents; D000432:Methanol
keywords: Syzygium polyanthum (Wight.); antihyperglycemic; leaf; methanol extract