Chitosan oligosaccharide COS

Chitosan oligosaccharide (COS): An overview

The frequently studied polysaccharide, chitosan oligosaccharide/chitooligosaccharide (COS) is the major degradation product of chitosan/chitin via chemical hydrolysis or enzymatic degradation involving deacetylation and depolymerization processes. Innumerable studies have revealed in the recent decade that COS has various promising biomedical implications in the past analysis, current developments and potential applications in a biomedical, pharmaceutical and agricultural sector. Innovations into COS derivatization has broadened its application in cosmeceutical and nutraceutical productions as well as in water treatment and environmental safety. In relation to its parent biomaterials and other available polysaccharides, COS has low molecular weight (Mw), higher degree of deacetylation (DD), higher degree of polymerization (DP), less viscous and complete water solubility, which endowed it with significant biological properties like antimicrobial, antioxidant, anti-inflammatory and antihypertensive, as well as drug/DNA delivery ability. In addition, it is also revealed to exhibit antidiabetic, anti-obesity, anti-HIV-1, anti-Alzheimer's disease, hypocholesterolemic, calcium absorption and hemostatic effects. Furthermore, COS is shown to have higher cellular transduction and completely absorbable via intestinal epithelium due to its cationic sphere exposed on the more exposed shorter N-glucosamine (N-Glc) units. This paper narrates the recent developments in COS biomedical applications while paying considerable attention to its physicochemical properties and its chemical composition. Its pharmacokinetic aspects are also briefly discussed while highlighting potential overdose or lethal dosing. In addition, due to its multiple NGlc unit composition and vulnerability to degradation, its safety is given significant attention. Finally, a suggestion is made for extensive study on COS anti-HIV effects with well-refined batches.

Impacts of chitosan oligosaccharide (COS) on angiogenic activities

It has been proved that chitosan oligosaccharide (COS) has a more favorable therapeutic applications such as wound healing and anti-tumor treatment, and can affect angiogenesis. For better understanding the effect of COS on angiogenic activities at cellular level, COS with different concentration and degree of polymerization (DP) were used to culture human umbilical vein endothelial cells (HUVECs) in this work. Cell proliferation activity, cell morphology, cell migration and angiogenesis associated factor expression of HUVECs were evaluated. The results indicated that COS at a high concentration of 400 米g/mL (COS(400)) and DP of 6 (Chitinhexaose Hydrochloride, COS6) had inhibitory effect on angiogenic activities of HUVECs. Specifically, COS(400) and COS6 inhibited cell proliferation activity, cell migration, and vascular endothelial cell growth factor (VEGF) expression of HUVECs. While COS at a low concentration (<400 米g/mL) and suitable polymerization degrees (DP < 6) had little significant effect on cell proliferation, migration, and VEGF expression of HUVECs, showing dose-dependent effect. These findings provided insight for the potential use of COS, for broadening its future applications in biomedical fields and functional materials area. It also helped guide the design and synthesis of chitosan-based materials as an angiogenesis inhibitor for anti-angiogenic therapy.

Alginate-chitosan oligosaccharide-ZnO composite hydrogel for accelerating wound healing

Moist, breathable and antibacterial microenvironment can promote cell proliferation and migration, which is beneficial to wound healing. Here, we fabricated a novel sodium alginate-chitosan oligosaccharide?zinc oxide (SA-COS-ZnO) composite hydrogel by spontaneous Schiff base reaction, using aldehydated sodium alginate (SA), chitosan oligosaccharide (COS), and zinc oxide (ZnO) nanoparticles, which can provide a moist and antibacterial environment for wound healing. The porosity and swelling degree of SA-COS-ZnO hydrogel are 80% and 150%, respectively, and its water vapor permeability is 682 g/m²/24h. The composite hydrogel showed good biocompatibility to blood cells, 3T3 cells, and 293T cells, and significant antibacterial activity against Escherichia coli, Staphylococcus aureus, Candida albicans, and Bacillus subtilis. Moreover, the hydrogel showed a promoting effect on wound healing in a rat scald model. The present study suggests that marine carbohydrates composite hydrogels are promising in wound care management.

The protective effects of chitosan oligosaccharide (COS) on cadmium-induced neurotoxicity in Wistar rats

The aim of the study was to investigate the influence of chitosan oligosaccharide (COS) on some antioxidant and cytokine levels in the rat hippocampus as well as synaptophysin (SYP) immunoreactivity in the cerebral cortex of the cadmium (Cd) exposed rats. Thirty-two male albino Wistar rats were divided randomly into four equal groups as control (C; n = 8), Cd (n = 8), COS (n = 8), and Cd + COS (CdCOS; n = 8). The rats in the Cd and CdCOS groups received Cd chloride (CdCl₂) (2 mg/kg/d) orally by gastric gavage three times a week for 4 weeks. Besides, COS (200 mg/kg/d) was administered to COS and CdCOS groups five times a week for 4 weeks. Then, they were decapitated and hippocampal/cerebral cortex tissue samples were taken for measurement of GSH levels, CAT and SOD activities, MDA values, TNF-汐, IL-6, and IL-10 levels as well as SYP immunoreactivity. Although tissue GSH levels were determined the lowest in the Cd group, these values were attenuated with COS treatment in the CdCOS group (p < .01). In addition, TNF-汐 levels were alleviated by COS treatment in the CdCOS group when compared to Cd (p < .01). SYP-positive cells were investigated in the cerebral cortex and found mild in the CdCOS group. COS exhibits potential protective effects on Cd-induced neurotoxicity in rats.

A novel chitosan oligosaccharide derivative: Synthesis, antioxidant and antibacterial properties

A novel thioether chitosan oligosaccharide (COS-All-Tio) was prepared by the reaction of chitosan oligosaccharide (COS) with 3-bromopropene, followed by the coupling with tiopronin (Tio) using a thiol-ene reaction. The degree of substitution of COS-All-Tio reached 1.48. The structure of COS-All-Tio was identified by IR, NMR spectra. It was found that COS-All-Tio possessed more potent antioxidant activities than COS. The IC₅₀ values of COS-All-Tio for scavenging DPPH, ABTS⁺ and OH were 0.31, 0.39 and 0.73 mg/mL, respectively, while the corresponding values for COS were 0.66, 2.89 and 1.41 mg/mL, respectively. COS-All-Tio was also found to possess much stronger antibacterial effect than COS against five bacteria strains (Staphylococcus aureus, Bacillus subtilis, Listeria monocytogenes, Escherichia coli and Pseudomonas aeruginosa). Further, COS-All-Tio was found to be non-toxic to RAW264.7 macrophages and MRC-5 human lung cells. This work provides a convenient way to improve the antioxidant and antibacterial activities of COS.