Coptidis Rhizoma: a comprehensive review of its traditional uses, botany, phytochemistry, pharmacology and toxicology

Wang, Jin; Wang, Lin; Lou, Guan-Hua; Zeng, Hai-Rong; Hu, Ju; Huang, Qin-Wan; Peng, Wei; Yang, Xiang-Bo

The expression of the glucose transporter protein (GLUT) is a key factor in the intracellular transport of glucose and is closely linked to cellular energy metabolism (Huang 2013) . A previous report revealed that after treatment with berberine, the glucose uptake in L929 fibroblast cells, a cell line that express only GLUT1, reached maximum stimulation. Moreover, significant activation was observed within 5 min and reached a maximum at 30 min, which was attributed to the acute activation of the transport activity of GLUT1 (Cok et al. 2011) . The level of GLUT1 protein was increased in 3T3-L1 cells, which was stated to be associated with the activation of AMPK stimulation ). The upregulation of GLUT4 expression and downregulation of Retinol-binding protein 4 (RBP4) are also involved in glucose uptake (Zhang et al. 2008) . HepG2 and bTC3 cell lines were used to test glucose consumption and insulin release, respectively. The results showed that glucose consumption by HepG2 cells was increased from 32% to 60% by berberine, which was insulin independent but had no influence on insulin secretion . Another study showed the GnRH-glucagon-like peptide-1 (GLP-1) and MAPK pathways in the intestines might be involved in the mechanisms of berberine to modulate glucose metabolism .