title: Biomolecular Characterization of Putative Antidiabetic Herbal Extracts.
abstract: Induction of GLUT4 translocation in the absence of insulin is considered a key concept to decrease elevated blood glucose levels in diabetics. Due to the lack of pharmaceuticals that specifically increase the uptake of glucose from the blood circuit, application of natural compounds might be an alternative strategy. However, the effects and mechanisms of action remain unknown for many of those substances. For this study we investigated extracts prepared from seven different plants, which have been reported to exhibit anti-diabetic effects, for their GLUT4 translocation inducing properties. Quantitation of GLUT4 translocation was determined by total internal reflection fluorescence (TIRF) microscopy in insulin sensitive CHO-K1 cells and adipocytes. Two extracts prepared from purslane (Portulaca oleracea) and tindora (Coccinia grandis) were found to induce GLUT4 translocation, accompanied by an increase of intracellular glucose concentrations. Our results indicate that the PI3K pathway is mainly responsible for the respective translocation process. Atomic force microscopy was used to prove complete plasma membrane insertion. Furthermore, this approach suggested a compound mediated distribution of GLUT4 molecules in the plasma membrane similar to insulin stimulated conditions. Utilizing a fluorescent actin marker, TIRF measurements indicated an impact of purslane and tindora on actin remodeling as observed in insulin treated cells. Finally, in-ovo experiments suggested a significant reduction of blood glucose levels under tindora and purslane treated conditions in a living organism. In conclusion, this study confirms the anti-diabetic properties of tindora and purslane, which stimulate GLUT4 translocation in an insulin-like manner.
authors.affiliation: University of Applied Sciences Upper Austria, Wels, Austria.
authors.forename: Verena
authors.initials: V
authors.lastname: Stadlbauer
authors.affiliation: University of Applied Sciences Upper Austria, Wels, Austria.
authors.forename: Renate
authors.initials: R
authors.lastname: Haselgrübler
authors.affiliation: University of Applied Sciences Upper Austria, Wels, Austria.
authors.forename: Peter
authors.initials: P
authors.lastname: Lanzerstorfer
authors.affiliation: University of Applied Sciences Upper Austria, Linz, Austria.|Vienna University of Technology, Vienna, Austria.
authors.forename: Birgit
authors.initials: B
authors.lastname: Plochberger
authors.affiliation: University of Applied Sciences Upper Austria, Hagenberg, Austria.
authors.forename: Daniela
authors.initials: D
authors.lastname: Borgmann
authors.affiliation: University of Applied Sciences Upper Austria, Linz, Austria.
authors.forename: Jaroslaw
authors.initials: J
authors.lastname: Jacak
authors.affiliation: University of Applied Sciences Upper Austria, Hagenberg, Austria.
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Winkler
authors.affiliation: BioMed zet Life Science GmbH, Linz, Austria.
authors.forename: Klaus
authors.initials: K
authors.lastname: Schröder
authors.affiliation: University of Applied Sciences Upper Austria, Wels, Austria.
authors.forename: Otmar
authors.initials: O
authors.lastname: Höglinger
authors.affiliation: University of Applied Sciences Upper Austria, Wels, Austria.
authors.forename: Julian
authors.initials: J
authors.lastname: Weghuber
mesh_terms: D017667:Adipocytes / Q000187:drug effects / Q000378:metabolism; D000818:Animals; D016466:CHO Cells; D002642:Chick Embryo; D003412:Cricetulus; D019662:Cucurbitaceae / Q000737:chemistry*; D005947:Glucose / Q000378:metabolism*; D051275:Glucose Transporter Type 4 / Q000378:metabolism*; D007004:Hypoglycemic Agents / Q000737:chemistry / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D031822:Portulaca / Q000737:chemistry*; D021381:Protein Transport / Q000187:drug effects
chemical_list: D051275:Glucose Transporter Type 4; D007004:Hypoglycemic Agents; D010936:Plant Extracts; D019869:Phosphatidylinositol 3-Kinases; D005947:Glucose
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