A new chitosan-thymine conjugate: synthesis, characterization and biological activity.

Conjugation of chitosan with nucleobases is expected to expand its not only antimicrobial activity but also anti-cancer activity. Here, we report the synthesis of a novel chitosan-thymine conjugate by the reaction between chitosan and thymine-1-yl-acetic acid followed by acylation. The synthesized conjugate was characterized by FTIR, XRD, (1)H NMR, TGA and SEM. The microbiological screening results demonstrated the antimicrobial activity of the conjugate against bacteria viz., Escherichia coli, Staphylococcus aureus, and fungi viz., Aspergillus niger. The chitosan-thymine conjugate also inhibited (p<0.05) the proliferation of human liver cancer cells (HepG2) in a dose-dependent manner but had no cellular toxicity in non-cancerous mouse embryonal fibroblast cells (NIH 3T3). Thus, the chitosan-nucleobase conjugate may open a new perspective in biomedical applications.