Inhibition of metabolic disorders in vivo and in vitro by main constituent of Coreopsis tinctoria

Objective: To investigate the effects of the ethyl acetate extract of Coreopsis tinctoria (EAEC) on insulin resistance (IR) in rats fed a high-fat diet. Methods: Male Sprague-Dawley (SD) rats were fed a HFD (60% fat) supplemented with EAEC for 8 weeks. The administration of EAEC to the rats with HFD-induced insulin resistance reduced hyperglycemia, plasma levels of insulin, and steatosis in the liver. Metabolomic study was used to analyze the metabolic levels of the high glucose-treated cells, control cells and marein-treated cells. Results: High glucose and high fat conditions caused a significant increase in blood glucose, insulin, serum TC, TG and LDL-C levels, leading to abnormal IR in rats. However, treatment with EAEC protects against HFD-induced IR by improving the fasting serum glucose homeostasis and lipid homeostasis. The high glucose conditions significantly decreased glycogen synthesis and increased PEPCK, G6Pase and Krebs cycle-related enzyme protein levels, leading to an abnormal metabolic state in HepG2 cells. However, treatment with marein improved IR by increasing glucose uptake and glycogen synthesis and by downregulating PEPCK and G6Pase protein levels. The statistical analysis of the HPLC/MS data demonstrated that marein could restore the normal metabolic state. Conclusion: The results revealed that EAEC ameliorates IR in rats, and marein has the potential to improve IR by ameliorating glucose metabolism disorders. (C) 2018 Published by Elsevier B.V. on behalf of Tianjin Press of Chinese Herbal Medicines.