[In vitro antitumor activity of heterochitooligosaccharides (a review)]

This review presents an analysis of the literature data over the last decade in order to reveal the relationship between the structure and composition of chitin/chitosan oligomers and their antitumor activity. Oligosaccharides consisting of N-acetylglucosamine and/or glucosamine units connected to each other by β-1,4-O-glycoside bond are generally called chitooligosaccharides. Homochitooligosaccharides are the oligomers of N-acetylglucosamine (AGA) or glucosamine (GA). Heterooligosaccharides are a mixture of various oligomers differing in the degree of polymerization (DP), acetylation (DA), or deacetylation (DD), as well as in the location of N-acetyl residues in the oligomer chain. Heterochitooligomers with a polymerization degree of no more than 10 are usually water soluble. The solubility of chitooligosaccharides with a DP of more than 10 depends on the DA and pH of a solution. The pharmaceutical and food industries, as well as scientists engaged in basic research, are interested in the use of heterochitooligosaccharides. This is explained by their unique properties, such as good water solubility; minimal toxicity; biocompatibility; the ability to penetrate cell membranes, resulting in a high degree of absorption (unlike chitin and chitosan); and their biological activity. Therefore, in the last decade, researchers have focused their attention on studying the relationship of the structure of oligosaccharides and their specific activity, such as antitumor, antimicrobial, antioxidant, immunemodulatory, and other activities. This is shown by the number of publications, which has doubled compared to the number in 2001.