Chitosan of Peppery Milky Cap Fungi (Lactarius Pergamenus (Fr.) Fr): Isolation, Study of Physico-Chemical Properties and Biological Activity

Chitosan is widely used in biology and medicine. Usually, it is isolated from chitin of crustaceans, while chitosan of the basidiomycetes fungi is poorly studied. The purpose of this study was: 1) to develop a method for isolation of chitosan from dried pomace of the peppery milky cap (Lactarius pergamenus); 2) to study of physico-chemical and biological properties of the isolated chitosan. As tradicionally, chitosan was obtained by the alkaline hydrolysis of chitin. The determination of its molecular mass was performed using the viscometric method and further analyzed by disk electrophoresis (pH 5.0). The anti-microbial and cytotoxic activities were measured spectrophoto metrically as a convertion of MTT dye to formazan, while the antifungal activity was evaluated using by counting colony-forming units (CFU). Chitosan of L. pergamenus fungi was shown to have lower molecular mass and a lower degree of deacetylation compared to shrimp chitosan. A yield of chitosan from a pomace of L. pergamenus was 6.27%. A heterogeneous product was obtained with an average molecular mass of 72 kDa and a degree of deacetylation equal - 87.1%. In 10 mg/ml dose, it inhibited by 29% the growth of gram-positive of Staphylococcus aureus (ATCC25923) bacteria and inhibited growth of gram-negative Echerichia coli dH5a - by 86% and Pseudomonas aeruginosa (ATCC9027) bacteria by 55%. Approximately 50 and 90 % of Candida albicans (pat.) cells were killed at the action of chitosan in doses of 0.025 mg/mL and 0.1 mg/mL correspondingly. It should be noted that this chitosan preparation did not affect a growth of human embryonic kidney pseudonormal cells of HEK 293 line and human breast carcinoma cells of MCF7 line.