Novel Chitosan Polymer Design, Synthesis Using Mentha piperita of ZnO NPs as a Catalyst: Antibacterial Evaluation against Gram-Negative Multidrug-Resistant Pathogens

The goal of this research is to create a novel Schiff base of chitosan polymer derivatives 1a-1j. Nanotechnology is a promising field since it avoids the usage of hazardous chemicals while also saving time. Using the leaf extract of the pharmacologically valuable herb Mentha piperita, we described a green synthesis of ZnO NPs. Zinc oxide ions may be easily reduced into ZnO NPs using a Mentha piperita extract. ZnO NPs were employed as a phytocatalyst in this investigation to make chitosan derivatives. The synthetic procedure is straightforward, with a short reaction time and a high yield. Our newly synthesized compounds have been characterized by FTIR and nuclear magnetic resonance spectroscopy (1H NMR and 13C NMR), and morphology analysis was observed by XRD, SEM, and TEM. In addition, the antibacterial activity was also evaluated against gram-positive bacteria and gram-negative bacteria. Compound 1b is extremely active against gram-negative bacteria (4.0 μg/mL, E. coli), and compound 1h is highly active against gram-positive bacteria (6.0 μg/mL, S. aureus) compared with standard erythromycin and other chitosan derivatives. As a result, compounds 1b and 1h could be a high crucial molecule in the development of antibacterial drugs.