title: Tartary buckwheat flavonoids protect hepatic cells against high glucose-induced oxidative stress and insulin resistance via MAPK signaling pathways.
abstract: Oxidative stress plays a crucial role in chronic complication of diabetes. In this study, the protective effect of purified tartary buckwheat flavonoids (TBF) fraction against oxidative stress induced by a high-glucose challenge, which causes insulin resistance, was investigated on hepatic HepG2 cells. Oxidative status, phosphorylated mitogen-activated protein kinases (MAPKs), nuclear factor E2 related factor 2 (Nrf2) and p-(Ser307)-IRS-1 expression, and glucose uptake were evaluated. Results suggest that treatment of HepG2 cells with TBF alone improved glucose uptake and antioxidant enzymes, and activated Nrf2, and attenuated the IRS-1 Ser307 phosphorylation, and enhanced total levels of IRS-1. Furthermore, the high glucose-induced changes in antioxidant defences, Nrf2, p-MAPKs, p-IRS1 Ser307, and IRS-1 levels, and glucose uptake were also significantly inhibited by pre-treatment with TBF. Interestingly, the selective MAPK inhibitors significantly enhanced the TBF-mediated protection by inducing changes in the redox status, glucose uptake, p-(Ser307) and total IRS-1 levels. This report firstly showed that TBF could recover the redox status of insulin-resistant HepG2 cells, suggesting that TBF significantly protected the cells against high glucose-induced oxidative stress, and these beneficial effects of TBF on redox balance and insulin resistance were mediated by targeting MAPKs.
authors.affiliation: College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi'an 710062, China. xbyang@snnu.edu.cn.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Department of Aerospace Medicine, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Zuoxu
authors.initials: Z
authors.lastname: Hou
authors.affiliation: The First Brigade of Cadets, Fourth Military Medical University, Xi'an 710032, China.
authors.forename: Dongyang
authors.initials: D
authors.lastname: Liu
authors.affiliation: College of Food Engineering and Nutritional Science, Shaanxi Normal University, Xi'an 710062, China. xbyang@snnu.edu.cn.
authors.forename: Xingbin
authors.initials: X
authors.lastname: Yang
mesh_terms: D019612:Fagopyrum / Q000737:chemistry*; D005419:Flavonoids / Q000494:pharmacology*; D005947:Glucose / Q000009:adverse effects* / Q000378:metabolism; D056945:Hep G2 Cells; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D055504:Insulin Receptor Substrate Proteins / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D020011:Protective Agents / Q000494:pharmacology*; D051057:Proto-Oncogene Proteins c-akt / Q000235:genetics / Q000378:metabolism
chemical_list: D005419:Flavonoids; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; D051267:NF-E2-Related Factor 2; D010936:Plant Extracts; D020011:Protective Agents; D051057:Proto-Oncogene Proteins c-akt; D005947:Glucose