Antidiabetic potentials of ethanolic extract of Aristolochia ringens (Vahl.) roots

Ethnopharmacological importance: Oral administration of alcoholic decoctions of Aristolochia ringens is used extensively by Traditional Medicine Practitioners (TMP) of Yoruba heritage in South west, Nigeria for the management of diabetes and its associated complications. Aim of the study: To assess the potentials of root ethanolic extract of Aristolochia ringens V. (REAR) in the management of diabetes using chemical induced experimental animal model. Materials and methods: Qualitative and quantitative analyses were carried out to elucidate chemical constituents of the REAR extract using phytochemical analyses and gas chromatography-mass spectrometry (GC-MS) technique. Streptozotocin (STZ)-induced diabetic rats were orally administered with 75, 150 and 300 mg/kg body weight of the REAR, once a day and the blood glucose (GLU) levels were monitored for 14 days. Mechanisms of GLU lowering effect were investigated by performing oral glucose tolerance test (OGTT) and modulation of diabetes associated biomarkers including hepatic glycogen (GLY), GLU, alpha amylase (alpha AMY) and glucose-6-phosphate dehydrogenase (GPDH) by the extract. Results: Extraction from A. ringens roots using ethanol/water (70/30) yielded 10.25% w/w REAR extract. Preliminary phytochemical profiling of REAR extract revealed the presence of flavonoids (23.03%), phenols (19.15%), alkaloids (16.13%), tannins (4.21%), saponins (1.44%) and GC-MS analyses showed that bulk of the extract was constituted by aristolone (923%). Oral administration of 300 mg/kg b. wt. REAR extract caused significant reduction (> 90%) in hyperglycemia to normal GLU level (<= 120 mg/dl) after 11 days of treatment. Lower doses of 75 and 150 mg/kg b. wt. caused similar effect after 13 days. The extract also normalized postprandial GLU to baseline level within 90 - 120 min. Also, GLY concentrations and GPDH activity were significantly increased, whereas GLU levels and alpha AMY activity were reduced in the liver of diabetic rats treated with REAR extract compared to values in non-treated diabetic group. Conclusion: These findings revealed that ethanolic extract from A. ringens root possess antihyperglycemic activity and the data established its usage in folkloric decoctions for management of diabetes. (C) 2016 Elsevier Ireland Ltd. All rights reserved.