Triterpene from Tithonia Diversifolia Potentiate Insulin Release: Invitro and in silico Approach

Presentation Number: SAT 582
Date of Presentation: April 1st, 2017

Ejelonu Oluwamodupe Cecilia*1, Adanlawo Isaac Gbadura2, Elekofehinti Olusola Olalekan3 and Rakesh Kundu4
1Adekunle Ajasin University.Akungba Akoko. Ondo State .Nigeria, Akungb Akoko, Nigeria, 2Ekiti State University Ado Ekiti Ekiti State. Nigeria, Ado Ekiti, Nigeria, 3Federal University of Technology, Akure. Ondo State. Nigeria, 4Visva Bharati university Santiniketan India, India

Abstract

Takeda G protein Bile acid receptor (TGR5) is a membrane receptor for bile acids (GBAR). Its activation increases energy expenditure and controls blood glucose through secretion of GLP1 in enteroendocrine L cells.TGR5 is activated by Cholic acid (CA) which potentiate insulin release via GLP1 secretion. Concoction of Tithonia diversifolia (TD) leaf is used in traditional medicine as antidiabetic remedy and very abundant in Nigeria. Saponins especially Triterpenoids have being indicated as the antidiabetic agents in plants. The objective of this experiment is to extract and isolate Triterpene from TD leaves and investigate its insulin secretory ability in MIN6 cell line and measure GLP1 secretion in the enteroendocrine L-cells treated with triterpene a structural analogue of CA (TGR5 agonist) using invitro and in silico approach. Triterpene was extracted, isolated, and characterized from TD via,TLC, column chromatography, LCMS, FTIR, and NMR. Insulin secretion was measured in MIN6-cells line a pancreatic beta cell incubated with TD triterpene, and treatments were compared to CA (10mM), and Metformin (50mM) incubation at (25, 50 and 75) µg/ml using insulin ELISA. GLP1 secretion was evaluated from enteroendocrine intestinal L-cell from a primary cell culture treated with (25, 50, and 75) µg/ml dosage of the TD triterpene and CA using GLP1 ELISA. A molecular docking of TD triterpene and CA with TGR5 respectively were performed. Validation of docking was done by comparing docking scores with experimental data. Structural elucidation shows that chloroform/methanol/water 30:70:10 fraction is a triterpene which was further proving by LCMS and NMR(1H&13C) with MW=484.2g/mol. Dose dependent increase in insulin secretion was observed in (25,50 and 75)µg/ml dosage of TD triterpene (2.06±0.02, 2.45±0.023,2.97±0.022 ) µg insulin secreted/1X106 cells respectively, while treatment with 10Mm CA gives 1.77 µg and 50mM Metformin 1.24 µg. Treatment with the primary L-cell culture from the intestine of mice at (25,50 and 75) µg/ml concentration dosage shows GLP1 secretion by TD triterpene higher than CA (0.72±0.05, 0.82±0.09, 0.84±0.06)µg/ml by TD triterpene treatment and (0.35±0.005, 0.45±001, 0.54±003) µg/ml by CA treatment. The molecular docking result also shows TD triterpene higher binding affinity at the active site of TGR5 when compared with CA (-7.2 kcal/mol). Triterpene from TD activate TGR5, thereby causing secretion of GLP1 which potentiate release of insulin. Therefore we propose that enhancing GLP-1 secretion via TGR5 agonist from plant source may represent a promising treatment strategy for type 2 diabetic mellitus

 

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