Synthesis of novel chitosan-Schiff bases nanoparticles for high efficiency Helicobacter pylori inhibition

Two chitosan Schiff bases were synthesized by condensation of chitosan with 2-(4-formylphenoxy)-N-phenylacetamide and N-(4-bromophenyl)-2-(4-formylphenoxy) acetamide denoted as Cs-SBA and Cs-SBBr, respectively. The molecular structures of the resulting chitosan derivatives were characterized using FTIR and ¹HNMR and their thermal properties were investigated by TGA. These derivatives were treated with sodium tripolyphosphate (TPP) to produce Cs Schiff base nanoparticles. The nanoparticles physicochemical properties were determined by FTIR, XRD, TEM, and zeta potential analysis. The antimicrobial action against Helicobacter pylori (H. pylori) was evaluated and the results indicated that the anti-H. pylori activity had minimal inhibitory concentration MIC values of 15.62 ± 0.05 and 3.9 ± 0.03 μg/mL for Cs-SBA and Cs-SBBr nanoparticles (Cs-SBA NPs and Cs-SBBr NPs), respectively. The better biologically active nanoparticles, Cs-SBBr NPs, were tested for their cyclooxygenases (COX-1 and COX-2) inhibitory potential. Cs-SBBr NPs demonstrated COX enzyme inhibition activity against COX-2 (IC₅₀ 4.5 ± 0.165 μg/mL) higher than the conventional Indomethacin (IC₅₀ 0.08 ± 0.003 μg/mL), and Celecoxib (IC₅₀ 0.79 ± 0.029 μg/mL). Additionally, the cytotoxicity test of Cs-SBBr NPs showed cytotoxic effect on Vero cells (CCL-81) with IC₅₀ = 17.95 ± 0.12 μg/mL which is regarded as a safe compound. Therefore, Cs-SBBr NPs may become an alternative to cure H. pylori and prevent gastric cancer.