Novel sulfoxide chitosan derivative: synthesis, characterization, antimicrobial, antioxidant and anti-cancer study and comparison with sulfone counterpart

Novel sulfoxide based chitosan conjugate with potential applications has been synthesized and characterized by FT-IR and 1H NMR spectroscopy and X-ray diffraction (XRD) analyses. Surface morphology and elements present in the derivative were determined by FE-SEM and EDX analyses respectively. Agar well diffusion method was employed to study the antimicrobial property of the synthesized conjugate which exhibited enhanced antimicrobial activity against gram-negative bacteria Escherichia coli (E. coli), gram positive bacteria Bacillus subtilis (B. subtilis) and fungi Aspergillus niger (A. niger) in comparison to chitosan. The synthesized derivative was also tested for the antioxidant property using DPPH radical scavenging method and was found to possess better antioxidant activity (37.0 ± 1.2%) as compared to that of native chitosan (9.5 ± 0.9%). It also showed anticancer property (tested for HepG2 cells) with 53.6 ± 1.3% cell viability. Moreover, it also showed low cytotoxicity when tested against PBMCs (peripheral blood mononuclear cells) using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Further, synthesis of a sulfone based chitosan derivative was also carried out via a novel route. This derivative was also studied for the aforementioned properties and applications and a comparative study of the results obtained is reported herein.