Valentina Guzman-Perez, Christiane Bumke-Vogt, Monika Schreiner, Inga Mewis, Andrea Borchert and Andreas F H Pfeiffer
Pontificia Universidad Javeriana, Colombia
German Institute of Human Nutrition, Germany
Leibniz-Institute of Vegetable and Ornamental Crops Gro√?¬?beeren/Erfurt e.V., Germany
Posters & Accepted Abstracts: J Nutr Food Sci
The consumption of vegetables is related with the prevention of type-2 diabetes (T2D). Nasturtium (Tropaeolum majus) possesses high contents of nitrogen sulfur compounds (glucosinolates and isothiocyanates) associated with the prevention of diabetes complications. In this study using stably transfected human osteosarcoma cells (U-2 OS) with constitutive expression of FOXO1 protein labeled with GFP (green fluorescent protein) and human hepatoma cells (HepG2) cultures, the ability of hydrolyzed benzyl glucosinolate (BITC) deriving from Nasturtium to modulate, the insulin signaling pathway, the intracellular localization of FOXO1 and the expression of proteins involved in glucose metabolism, ROS detoxification, cell cycle arrest and DNA damage repair was evaluated. BITC induced a dose-dependent nuclear translocation of FOXO1- GFP in U-2 OS cells. In HepG2 cells an inhibition of protein kinase B (AKT/PKB) and FOXO1-phosphorylation was observed. BITC up regulated the antioxidant and detoxification enzymes Superoxide Dismutase (MnSOD2), Sulfiredoxin 1 (SRXN1), NAD(P)H dehydrogenase (quinone1) (NQO1) and Glutathione peroxidase 2 (GPX2); induced a significant reduction of gluconeogenic enzymes Glucose-6-Phosphatase (G6Pase) and Phosphoenolpyruvate carboxykinase (PEPCK) and promoted an up regulation of the cyclin dependent kinase inhibitor (p21CIP) and Growth Arrest/DNA Damage Repair (GADD45). Except for the nuclear factor (erythroid derived)-like 2 (NRF2) and its influence on gene expression of detoxification enzymes, all of the observed effects were independent from FOXO1, AKT and NAD-dependent deacetylase sirtuin-1 (SIRT1) shown by siRNA knockdown. Besides an anticarcinogenic potential of isothiocyanates BITC enhances the antioxidative response, promotes longevity and potentially down regulates the hepatic glucose production, suggesting a role in T2D prevention and treatment.
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