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

Some studies reported that berberine could promote the secretion of insulin by increasing GLP-1 release or by stimulating pancreatic cells . Intragastric administration of berberine restored the damage to pancreas tissues and reversed the decreased in the number of islets in rats with DM (Tang et al. 2006; Chueh and Lin 2011) . Berberine significantly downregulated the ratio of BAX/BCL-2 to block streptozotocin (STZ)-induced apoptosis in mouse pancreatic islets (Chueh and Lin 2012) . Berberine and CRE exerted similar protective effect on islet b cells by improving islet b cell proliferation and the protein level of PARP1 . Inflammation and oxidation are closely associated with DM. After treatment with berberine, decrease levels of proinflammatory cytokines, such as TNF-a, IL-6, iNOS, MCP-1 and COX-2, were observed (Jeong et al. 2009; Lou et al. 2011) , while IL-10 levels were elevated in diabetic animals, in related cells, and in patients . The levels of AR, SOD, GSH-px and GSH increased, while MDA decreased, indicating that oxidation was inhibited (Zhou and Zhou 2011; Lao-Ong et al. 2012) . Multiple cellular kinases, as well as signalling pathways (such as MAPKs, AMPK, Nrf2/HO, NF-jB, and Rho GTPase pathways) were verified to be pivotal for berberine's activity in reducing oxidative stress and inflammation to treat DM Xie et al. 2013; Mo et al. 2014) . However, some studies showed that berberine could decrease hyperglycaemia and improve impaired glucose tolerance but did not increase insulin release and synthesis (Yin et al. 2002; Chen et al. 2010) . In addition to berberine, recent studies showed that polysaccharides in CR increased glucose uptake, recovered glucose tolerance, inhibited the formation of advanced glycation end products, and reduced oxidation (Jiang et al. 2015; Cui et al. 2016; Yang Y et al. 2016) .