A. V. Il’ina

[Chitosan-based polyelectrolyte complexes: a review].

This review focuses on the formation of polyelectrolyte chitosan complexes with biologically active compounds and the prospects of use thereof. The possibility of obtaining low-molecular-weight, water-soluble batches of chitosan, which differ in their degree of acetylation, is discussed, with emphasis on their use for binding nucleic acids into complexes.

Effect of the molecular weight of chitosan on its antiviral activity in plants

The effect of the molecular weight of chitosan on its ability to suppress systemic infection of bean mild mosaic virus in bean (Phaseolus vulgaris L.) plants was studied. The enzymatic hydrolysate of low-molecular-weight chitosan was successively fractionated by ultrafiltration through membranes with decreasing pore size. In total, four chitosan fractions with a weight-average molecular weight varying from 1.2 to 40.4 kDa were obtained. It was shown that the treatments of bean plants with these fractions (chitosan concentration, 10 or 100 μg/ml) inhibited virus accumulation and systemic propagation. The degree of chitosan-induced antiviral resistance increased as the molecular weight of chitosan decreased. The monomers comprising the chitosan molecule—glucosamine and N-acetylglucosamine—exhibited no antiviral activity.

Antibacterial Activity of Alkylated and Acylated Derivatives of Low–Molecular Weight Chitosan

A number of alkylated (quaternized) and acylated derivatives of low–molecular weight chitosan were obtained. The structure and composition of the compounds were confirmed by the results of IR and PMR spectroscopy, as well as conductometric titration. The effect of the acyl substituent and the degree of substitution of N-(2-hydroxy-3-trimethylammonium) propyl fragment appended to amino groups of the C2 atom of polymer chains on antibacterial activity against typical representatives of gram-positive and gramnegative microorganisms (Staphylococcus epidermidis and Escherichia coli) was studied. The highest activity was in the case of N-[(2-hydroxy-3-trimethylammonium)propyl]chitosan chloride (HTCC) with the maximal substitution (98%). The minimal inhibitory concentration of the derivative was 0.48 μg/mL and 3.90 μg/mL for S. epidermis and E. coli, respectively.

[Obtaining and study of monosaccharide derivatives of low-molecular-weight chitosan].

The possibility of obtaining monosaccharide derivatives of low-molecular-weight chitosan with the use of the Maillard reaction was studied. Chitosan derivatives (molecular weight, 24 and 5 kDa) obtained with glucosamine, N-acetyl galactosamine, galactose, and mannose with a substitution degree of 4–14% and a yield of 60–80% were obtained. Some physicochemical and biological properties of these derivatives were studied. We showed that monosaccharide derivatives of low-molecular-weight chitosan exhibited antibacterial activity. Chitosan at a concentration of 0.01% caused 100% death of bacteria B. subtilis and E. coli. The strongest antibacterial effect was exhibited by 24-kDa derivatives: only 0.02–0.08% of cells survived. These derivatives were two orders of magnitude more effective than the 5-kDa chitosan modified with galactose.

Nanoparticles based on succinylchitosan with doxorubicin: Preparation and properties

The conditions of succinylchitosan-based nanostructures with doxorubicin preparation were optimized. Nanoparticles were obtained using a precipitation conservation method for the first time, and the particles were further used to prepare noncovalent complexes with doxorubicin. The physicochemical and biological properties of the studied structures were investigated. It was shown that the average size of the obtained nanostructures is 200–250 nm and their ζ-potential was determined as negative (−20 to −25 mV). Nanoparticles loaded with doxorubicin were shown to demonstrate a positive cytotoxic effect in vitro. Doxorubicin sorbtion on nanoparticles resulted in no changes in the properties of the drug, which may make it possible to lower its toxicity in vivo.

Galactosylated derivatives of low-molecular-weight chitosan: Obtaining and properties

Chitosan, a binary heteropolysaccharide consisting of 2-acetamide-2-deoxy-β-D-glucopyranose and 2-amino-2-deoxy-β-D-glucopyranose residues linked in different proportions via β-glycosidic bonds. The presence of a primary amino group in the chitosan structure allows for the synthesis of various derivatives. The procedure of obtaining activated N-hydroxysuccinimide esters with the use of lactobionic acid was applied to obtain galactosylated derivatives of low-molecular-weight chitosan with a substitution degree varying from 8 to 23%. The properties of these derivatives (viscosity, solubility, and biodegradability) were studied. These derivatives are well soluble at pH values greater than the acidity constant of amino groups of chitosan (6.5). Broadening the pH range towards increase and the presence of galactose residues allows these derivatives to be used in working with biological objects.

Chitin and chitosan derivatives as elicitors of potato resistance to late blight

Water-soluble low-molecular-weight (3–10 kDa) chitosan obtained by enzymatic degradation of high-molecular-weight chitosan, as well as its deaminated derivatives, can be used as elicitors of resistance to late blight in potato.

Neutralization of reactive oxygen species by chitosan and its derivatives in vitro/in vivo (Review)

The review considers recent data that indicate the ability of chitosan and its derivatives to bind reactive oxygen species. The analysis of the results of these studies will promote the selection of a promising natural antioxidant for applications in the cosmetics, food, pharmaceutical, and other industries.

Immunomodulating activity of chitosan derivatives with salicylic acid and its fragments

A study of biological activity of the derivatives of the chitin-chitosan oligomer with salicylic acid and its fragments showed that chitosan salicylate actively protected potato tubers against Phytophthora infestans but sharply inhibited reparation of potato tissues. N-(2-hydroxybenzyl)chitosan exhibited good protective properties but did not influence wound reparation. N-(2-hydroxy-3-methoxybenzyl)-N-pyridoxchitosan, which contained the pyridoxal and 2-hydroxy-3-methoxy fragments, was the most efficient, stimulating both defense against late blight and wound reparation in potato tissues.

In vitro Antitumor Activity of Heterochitooligosaccharides (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.