Facile synthesis and antibacterial activity of geraniol conjugated chitosan oligosaccharide derivatives

A new chitosan oligosaccharide derivative (COS-N-Ger), based on geraniol (Ger) modificated onto the NH 2 position of chitosan oligosaccharide (COS) via a facile method, was prepared and employed to evaluate in vitro antibacterial activity. The structures of COS-N-Ger derivatives were confirmed by FT-IR, 1 H, 13 C NMR, and elemental analysis. The characterization results showed successful synthesis of derivatives and the degrees of substitution (DS) of COS-N-Ger1-3 were from 0.260 to 0.283 with the yields up to 78 %. The in vitro antibacterial activity evaluation results presented a significant inhibition effect of COS-N-Ger1-3 derivatives on Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) as compared to COS. Moreover, their antibacterial activities were dose-dependent and more sensitive to S. aureus than E. coli . The results provide reliable theoretical supports for exploring the application of COS derivatives in the food industry as new potential antibacterial agents.