Chitosan and Chitooligosaccharide: The Promising Non-Plant-Derived Prebiotics with Multiple Biological Activities

Abstract

Biodegradable chitin is the second-most abundant natural polysaccharide, widely existing in the exoskeletons of crabs, shrimps, insects, and the cell walls of fungi. Chitosan and chitooligosaccharide (COS, also named chitosan oligosaccharide) are the two most important deacetylated derivatives of chitin. Compared with chitin, chitosan and COS not only have more satisfactory physicochemical properties but also exhibit additional biological activities, which cause them to be widely applied in the fields of food, medicine, and agriculture. Additionally, due to their significant ability to improve gut microbiota, chitosan and COS are deemed prospective prebiotics. Here, we introduced the production, physicochemical properties, applications, and pharmacokinetic characteristics of chitosan and COS. Furthermore, we summarized the latest research on their antioxidant, anti-inflammatory, and antimicrobial activities. Research progress on the prebiotic functions of chitosan and COS is particularly reviewed. We creatively analyzed and discussed the mechanisms and correlations underlying these activities of chitosan and COS and their physicochemical properties. Our work enriched people's understanding of these non-plant-derived prebiotics. Based on this review, the future directions of research on chitosan and COS are explored. Collectively, optimizing the production technology of chitin derivatives and enriching understanding of their biological functions will shed more light on their capability to improve human health.

Keywords: anti-inflammatory activity; antimicrobial activity; antioxidant activity; chitooligosaccharide; chitosan; prebiotic.

Figure 1

Schematic diagrams of the structures of chitin, chitosan, and COS and the process for producing chitosan and COS from chitin. (a) Schematic diagram of the structure of chitin. DP: degree of polymerization, DA: degree of acetylation. (b) Schematic diagram of the structures of chitosan and COS. DD: degree of deacetylation. (c) Schematic diagram of the process for producing chitosan and COS from chitin.

Figure 2

Schematic diagram of the pharmacokinetic process of chitosan and COS.

Figure 3

Summary and comparison of engineering applications and physiological functions of chitosan and COS. The straight line indicates that one has more application value or better activity than the other. The dash-dotted line indicates that one has equal application value or activity with the other. The dotted line indicates that one has less application value or lower activity than the other. No line indicates that one has little related application value or activity.