Avaliação do potencial antimicrobiano e antiparasitário de oligossacarídeos de quitosana

Abstract

The increase in outbreaks of infectious diseases, the worldwide progression of microbial resistance and the high impact of neglected tropical diseases reinforces the search for new molecules with antimicrobial potential. Chitosan is a copolymer formed of D-glucosamine and N-acetyl-glucosamine, obtained by partial deacetylation of chitin. The chitosan hydrolysis generates chitosoligosaccharides (COS) and monosaccharides. COS have a greater advantage over chitosan due to greater solubility and lower viscosity. Allied to these parameters, research demonstrates the vast biological potential of COS with antimicrobial, anti-inflammatory, antioxidant and anti-tumor properties. Despite the knowledge of the biological effects of COS, the antiparasitic activity of these molecules is poorly studied. Thus, the objectives of this study were to obtain COS from the enzymatic hydrolysis of chitosan by chitosanases from Bacillus toyonensis, to characterize the oligomers and to evaluate their cytotoxic, antimicrobial and antiparasitic effects in vitro. The mixture of COS produced by enzymatic hydrolysis in the 5- and 10-min reaction times were characterized by ¹H and ¹³C NMR, uni and bidimensional, and mass spectrometry. Both oligomers evaluated did not demonstrate cytotoxicity on cancer cells and non-cancer cells up to 2 mg / mL. The COS revealed an antimicrobial effect similar to chitosan against bacteria and yeasts. In the antiparasitic assay, the COS showed time-dependent antiparasitic activity on the Trypanosoma cruzi and Leishmania amazonensis with inhibition rates of about 30% and above 50%, respectively. The possibility of obtaining a molecule of high biotechnological interest from shrimp residues, resulting in a decrease in ecological impact, highlights the importance of the study and use of chitooligosaccharides to obtain new pharmacological agents.