Flavonoids from Camellia sinensis (L.) O. Kuntze seed ameliorates TNF-α induced insulin resistance in HepG2 cells

Abstract

The aim of this study is to discuss the non-catechin flavonoids (NCF) from Camellia sinensis (L.) O. Kuntze seed improving TNF-α impaired insulin stimulated glucose uptake and insulin signaling. Flavonoids had anti-metabolic syndrome and anti-inflammatory properties. It had widely been known for biological activity of catechins in tea, but very few research reports discussed the biological activity of non-catechin flavonoids in tea seed. We used HepG2 cell to treat with 5 μM insulin or with 5 μM insulin + 30 ng/ml TNF-α. Detecting the glucose concentration of medium, insulin decreased the glucose levels of medium meant that insulin promoted glucose uptake into cells, but TNF-α inhibited the glucose uptake effect of insulin. Furthermore, insulin increased the protein expressions of IR, IRS-1, IRS-2, PI3K-α, Akt/PKB, GLUT-2, AMPK, GCK, pyruvate kinase, and PPAR-γ. TNF-α activated p65 and MAPKs (p38, JNK1/2 and ERK1/2), iNOS and COX-2 which worsened the insulin signaling expressions of IR, IRS-1, IRS-2, PI3K-α, Akt/PKB, GLUT-2, AMPK, GCK, pyruvate kinase, and PPAR-γ. We added NCF (500, 1000, 2000 ppm) to cell with insulin and TNF-α. Not only glucose levels of medium were lowered, and the protein expressions of insulin signaling were increased, but p38, JNK1/2, iNOS and COX-2 were also reduced. NCF could ameliorate TNF-α induced insulin resistance through inhibiting p38, JNK1/2, iNOS and COX-2, and suggested that it might be used in the future to help control insulin resistance. This finding is the first report to present the discovery.

Protective Role of Nutritional Plants Containing Flavonoids in Hair Follicle Disruption: A Review

“…Actually, some reports have demonstrated that catechins are the major components in leaves that acted as agonists of the nuclear receptor protein peroxisome proliferator-activated receptor gamma (PPAR-c); therefore, they could be considered as current pharmacological targets for the treatment of type 2 diabetes mellitus (T2DM) [85]. The rich saponins and catechins in Camellia sinensis (L.) Kuntze seeds have been known to lower body weight and serum lipid levels [86,87]. Camellia sinensis (L.) Kuntze leaves contain catechins, such as epigallocatechin-3-gallate, as well as quercetin, the aflavins, the arubigins, the anine, caffeine, chlorogenic acid, and gallic acid.…”

Facile production of chlorophyllides using recombinant CrCLH1 and their cytotoxicity towards multidrug resistant breast cancer cell lines

“…The identification of chlorophyllides was performed by ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS/MS, Waters Co., Massachusetts, USA) [ 24 ]. Before the analysis, the sample solution was prepared by diluting it in 90% acetone.…”

Combination of white tea and peppermint demonstrated synergistic antibacterial and anti‐inflammatory activities

“…TPA‐induced ear edema is used as a classical model of animal acute inflammation for anti‐inflammatory activity evaluation 29 . To investigate the anti‐inflammatory effects of white tea and/or peppermint, TPA‐induced mouse ear edema was established in this study.…”