The Antioxidant and Antibacterial Activities of the Pyridine‐4‐Aldehyde Schiff Bases Grafted Chloracetyl Chitosan Oligosaccharide Derivatives

Abstract

As a reactive intermediate, chloracetyl chitosan oligosaccharide (CACS) can be nucleophilic substituted by some bioactive groups to give novel derivatives of chitosan oligosaccharide (COS). The Schiff bases of pyridine‐4‐aldehyde are grafted onto CACS to give four COS derivatives in this paper. Specific structural characterization is implemented by fourier‐transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The degree of substitution (DS) of COS derivatives is quantitatively calculated by ratio of hydrogen proton integral. Their antioxidant property is evaluated using free radical scavenging assay towards 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and superoxide anion radicals, and the antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) is also investigated. The results revealed that the pyridine‐4‐aldehyde Schiff bases grafted chloracetyl chitosan oligosaccharide derivatives showed better antioxidant activity as well as antibacterial activity than COS and CACS, which may be related to the positive charge of these derivatives. Among all final products, derivative BPCACS with the highest DS has the best bioactivity with scavenging rate of 91.49% for the DPPH assay and inhibition diameter of 39.25 mm for S. aureus inhibitory assay, respectively. These results indicated that COS derivatives with enhanced biological activities could serve as potential biomaterial for antioxidant and antibacterial applications.

Synthesis, biological evaluation and molecular docking of new triphenylamine-linked pyridine, thiazole and pyrazole analogues as anticancer agents

“…Thiazole substituted has a lot of interest due to its vast range of biological activity, such as anti-cancer [17][18][19], anti-bacterial [20], anti-inflammatory [21], anti-oxidant [22], and anti-epileptic [23]. On the other hand, the pyridine moiety also shows wide biological activities as anti-bacterial, anti-oxidant [24], and anticancer [25,26]. Pyridine represents the skeletal backbone of many therapeutic agents [27] (Fig.…”

Synthesis of Schiff Bases Containing Phenol Rings and Investigation of Their Antioxidant Capacity, Anticholinesterase, Butyrylcholinesterase, and Carbonic Anhydrase Inhibition Properties

“…In a recent study, many chitosan derivatives containing Schiff bases were synthesized. In this study, the structural characterization of chloracetyl chitosan oligosaccharide derivatives grafted with pyridine-4-aldehyde Schiff bases was performed, and their antioxidant activities against DPPH‧ radical and O 2 ‧– were determined [ 68 ]. Similarly, it was indicated that some chiral selenite ligands and their palladium complexes have antioxidant activity, which increased with concentration [ 69 ].…”

Strategies for the Preparation of Chitosan Derivatives for Antimicrobial, Drug Delivery, and Agricultural Applications: A Review

“…Recently, Tan et al synthesized CS-bearing pyridinium salt along with quaternary ammonium salt (DS: 35-97%) (3p) through a treat-ment between CS and narcotic acid, followed by a reaction with bromopropyl trialkyl ammonium bromides [115]. In another study, Guo et al also introduced CS derivatives that contain pyridine-bearing Schiff bases (3q, DS: 22.7-50%) [116] and heterocyclic scaffolds along with thiourea (3r, 3s; DS: 21-91%, 18-88%) [98,117]. In contrast with these conventional approaches, the Zincke reaction has been explored for the direct transformation of primary amines into N-aryl pyridinium salt [118].…”