title: Sclerocarya birrea (Anacardiaceae) stem-bark extract corrects glycaemia in diabetic rats and acts on beta-cells by enhancing glucose-stimulated insulin secretion.
abstract: Sclerocarya birrea is a plant widely used as traditional medication for the treatment of diabetes in sub-Saharan regions. However, the mechanism of action is unknown and only hypoglycaemic effects of S. birrea extract (SBE) in diabetic rats have been reported to date. Here, we tested aqueous extracts of S. birrea on insulin-secreting INS-1E cells and isolated rat islets. Following 24 h of treatment at 5 microg/ml, the extract markedly potentiated glucose-stimulated insulin secretion. Neither basal insulin release nor non-nutrient stimulation was affected. The potentiation of the secretory response at stimulatory glucose appeared after 12 h of treatment. No acute effects were observed and, at the effective concentration, SBE was safe regarding cell integrity and differentiation. The mechanism of action of the SBE was related to glucose metabolism as both ATP generation and glucose oxidation were enhanced following the 24-h treatment. In streptozotocin-induced diabetic rats, SBE administration corrected glycaemia and restored plasma insulin levels after 2 weeks of treatment. These data show direct action of S. birrea on insulin-secreting cells and favour further delineation for use of the plant in the management of diabetes.
authors.affiliation: Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, 1 rue Michel-Servet, Geneva 4, Switzerland.
authors.forename: Ivonne Gisèle
authors.initials: IG
authors.lastname: Makom Ndifossap
authors.forename: Francesca
authors.initials: F
authors.lastname: Frigerio
authors.forename: Marina
authors.initials: M
authors.lastname: Casimir
authors.forename: Florence
authors.initials: F
authors.lastname: Ngueguim Tsofack
authors.forename: Etienne
authors.initials: E
authors.lastname: Dongo
authors.forename: Pierre
authors.initials: P
authors.lastname: Kamtchouing
authors.forename: Théophile
authors.initials: T
authors.lastname: Dimo
authors.forename: Pierre
authors.initials: P
authors.lastname: Maechler
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D027926:Anacardiaceae; D000818:Animals; D045744:Cell Line, Tumor; D003921:Diabetes Mellitus, Experimental / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D004195:Disease Models, Animal; D005947:Glucose / Q000378:metabolism / Q000494:pharmacology*; D006943:Hyperglycemia / Q000188:drug therapy* / Q000378:metabolism; D007328:Insulin / Q000378:metabolism*; D050417:Insulin-Secreting Cells / Q000187:drug effects / Q000378:metabolism*; D007340:Insulinoma / Q000378:metabolism / Q000473:pathology; D008297:Male; D010190:Pancreatic Neoplasms / Q000378:metabolism / Q000473:pathology; D024301:Plant Bark; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D018547:Plant Stems; D051381:Rats; D017208:Rats, Wistar; D013311:Streptozocin
chemical_list: D007328:Insulin; D010936:Plant Extracts; D013311:Streptozocin; D000255:Adenosine Triphosphate; D005947:Glucose