Synthesis, Characterization, and Antifungal Activity of N-Quaternized and N-Diquaternized Chitin Derivatives

To improve the bioactivity of chitin (CT), novel N-quaternized (QCT), and N-diquaternized (DQCT) CT derivatives are synthesized through a series of reactions from CT. The derivatives are characterized using elemental analysis, FTIR, and C-13 NMR. In addition, the inhibitory effects of the compounds against three fungi (B. cinerea, F. oxysporum, and P. asparagi) are tested. The inhibitory indices of CT, QCT, and DQCT are 12-15%, 63-73%, and 74-89%, respectively, at 1.0 mg mL(-1). The antifungal activities are in the order of DQCT > QCT > CT, which correlated with the number of quaternized groups. Based on these results, it is concluded that the antifungal activity of CT is improved by the introduction of quaternized groups on CT backbone