A review of the preparation, derivatization and functions of glucosamine and N-acetyl-glucosamine from chitin

Chitin is a valuable and renewable carbohydrate. It is the second abundant but underexploited carbohydrate polymer. Its monomers, glucosamine (GlcN) and N-acetyl-glucosamine (NAG), are widely used in food, cosmetic, and pharmaceutical fields owing to their high biocompatibility and other properties. Therefore, conversion of chitin to highly hydrophilic and active GlcN and NAG can enhance its utility. In this review, we summarize the design strategies, reaction conditions for the preparation of GlcN and NAG from chitin and the synthesis of derivatives from GlcN/NAG. Moreover, we discuss the advantages of physicochemical properties and active advantages of GlcN derivatives formed by active compounds when they are conjugated with GlcN/NAG. Based on these experiences, we finally proposed a novel strategy for GlcN derivatization, which is expected to yield highly active GlcN derivatives that can be applied in pharmaceutical or food fields.