GCG and diabetes mellitus: Among them, the hypoglycemic function of berberine is mainly to promote the regeneration of islet cells, inhibit hepatic gluconeogenesis, and increase the level of glucagon-like peptide-1, serum insulin and the number of islet beta cells in the intestine.[32–34] The active ingredient of Cinnamomum cassia Presl is also one of the hot researches in the treatment of diabetes in recent years.