Functional benefits of mulberry leaf tea or extracts to alleviate metabolic diseases: Current opinion and perspectives

Mulberry leaf can be used as supplements and functional foods to prevent and alleviate metabolic diseases. Metabolic diseases include obesity, type 2 diabetes, cardiovascular diseases, and non-alcoholic fatty liver diseases. Metabolic diseases may cluster in an individual and are associated with myriad complications and comorbidities. Mulberry leaf is consumed as tea, powder, or extracts to treat and manage health conditions, particularly hyperglycemia and type 2 diabetes. Alkaloids, polyphenols, phytoalexins, polysaccharides, and fibers are the main bioactive compounds in mulberry leaf and they are associated with hypoglycemic, lipid, and urate-lowering activities important for the prevention and managing metabolic diseases. 1-deoxynojirimycin and fagomine are among the alkaloids in mulberry leaf, which exhibit α-glucosidase inhibitory activity and enhance insulin sensitivity important for glucose homeostasis and hypoglycemic effect. Also, mulberry leaf bioactive compounds provide prebiotic functions to the gut microbiota and are converted into beneficial metabolites in multiple dimensions. This review presents the recent findings on the application of mulberry leaf as a functional food in preventing and alleviating metabolic diseases when consumed as tea or extract.