Development of novel vanillylidene acetonyl chitosan Schiff base using click chemistry: antibacterial and antioxidant characters

There is increased interest in developing new eco-friendly materials with antibacterial and antioxidant properties for various technological applications. This study prepared a new chitosan phenolic derivative with a hydroxyl group via a click reaction between chitosan (Ch) and vanillylidene acetone to form the corresponding vanillylidene acetonyl chitosan Schiff base (Va.Ch.SB). Detailed structural characterization was carried out using FTIR, UV-Vis, and 1H-NMR spectroscopy. The substitution degree calculated as 8.81%, according to 1H-NMR analysis. The obtained results confirm the formulation of imine Schiff base bond between chitosan amino groups react and vanillylidene acetone. Furthermore, the thermo-gravimetric analysis indicates that the decomposition behaviour of both chitosan and its vanillylidene acetonyl chitosan Schiff base derivative is nearly identical, with a slight enhancement of the SB derivative. The Va.Ch.SB exhibited duple antioxidant activity of the Va.Ch.SB. The comparative analysis reveals that the antimicrobial properties exhibited efficacy against two strains of gram-positive bacteria, namely Staphylococcus aureus and Staphylococcus haemolyticus, as three strains of gram-negative bacteria, namely Escherichia coli, Pseudomonas aeruginosa, and Klebsiella pneumoniae. These findings suggest that the Va.Ch.SB has the capability to apply in different medical and environmental contexts.