The search for natural antibacterial agents to treat diseases caused by resistant microorganisms has been gaining increasing attention. Chitosan has been studied in several areas due to its particular properties. The grafting of hydrophobic chains into the chitosan molecule, turning it amphiphilic, may improve its antimicrobial activity by increasing electrostatic interaction with the bacterial cell wall. The objective of this work was to enhance the antimicrobial activity of chitosan by the reaction of N-acylation with maleic anhydride. For this purpose, molar ratios of 1:2, 1:5 and 1:10 chitosan: anhydride were investigated, and the obtained derivatives were characterized by elemental analysis, FTIR, thermal analysis and XRD where it was possible to prove the chemical modification of chitosan. The modified materials presented excellent antibacterial action against Staphylococcus aureus and Escherichia coli, evidencing no activity against the protozoan Leishmania amazonensis. Cytotoxicity assays by the MTT analysis and hemolysis indicated that the derivatives did not show toxicity in mammalian cells. The proposed modified chitosan compounds showed to be promising for biomedical applications since they allied excellent antibacterial activity and absence of cytotoxicity.
Keywords: Anhydride cytotoxicity; Antimicrobial activity; Chemical modification; Grafted chitosan.
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