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International Journal of Endocrinology
Volume 2018, Article ID 3189879, 7 pages
https://doi.org/10.1155/2018/3189879
Research Article

Stevia Nonsweetener Fraction Displays an Insulinotropic Effect Involving Neurotransmission in Pancreatic Islets

1Department of Physiology Sciences, Universidade Estadual de Maringá, Maringá, PR, Brazil
2Department of Cell Biology and Genetics, Universidade Estadual de Maringá, Maringá, PR, Brazil
3Department of Biochemistry, Universidade Estadual de Maringá, Maringá, PR, Brazil

Correspondence should be addressed to Silvano Piovan; moc.liamg@32navoiponavlis

Received 15 January 2018; Accepted 26 March 2018; Published 29 April 2018

Academic Editor: Rosaria Meccariello

Copyright © 2018 Silvano Piovan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Stevia rebaudiana (Bert.) Bertoni besides being a source of noncaloric sweeteners is also an important source of bioactive molecules. Many plant extracts, mostly obtained with ethyl acetate solvent, are rich in polyphenol compounds that present insulinotropic effects. To investigate whether the nonsweetener fraction, which is rich in phenolic compounds isolated from Stevia rebaudiana with the solvent ethyl acetate (EAF), has an insulinotropic effect, including interference at the terminals of the autonomic nervous system of the pancreatic islets of rats. Pancreatic islets were isolated from Wistar rats and incubated with EAF and inhibitory or stimulatory substances of insulin secretion, including cholinergic and adrenergic agonists and antagonists. EAF potentiates glucose-stimulated insulin secretion (GSIS) only in the presence of high glucose and calcium-dependent concentrations. EAF increased muscarinic insulinotropic effects in pancreatic islets, interfering with the muscarinic receptor subfamily M3. Adrenergic inhibitory effects on GSIS were attenuated in the presence of EAF, which interfered with the adrenergic α2 receptor. Results suggest that EAF isolated from stevia leaves is a potential therapy for treating type 2 diabetes mellitus by stimulating insulin secretion only in high glucose concentrations, enhancing parasympathetic signal transduction and inhibiting sympathetic signal transduction in beta cells.