Hydroxyl radicals scavenging activity of N-substituted chitosan and quaternized chitosan (original) (raw)
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Synthesis and hydroxyl radicals scavenging activity of quaternized carboxymethyl chitosan
Carbohydrate Polymers, 2008
In order to determine the effect of the forms of the amido groups of chitosan on antioxidant activity, quaternized carboxymethyl chitosan (QCMC) derivatives were prepared with a degree of quaternization ranging from 34.3% to 59.5%. The antioxidant activity of QCMCs against hydroxyl radicals was assessed. The results indicated that QCMCs have better hydroxyl radicals scavenging activity than that of carboxymethyl chitosan, as a result of the positive charge of the quaternized chitosan.
Food Hydrocolloids, 2013
Different low molecular weight chitosan (LMWC) and chitoooligosaccharide (COS) derivatives were obtained by the introduction of lactobionic acid (LA) through amide formation, obtaining different complexes COS-LA and LMWC-LA (1-5), with a degree of substitution (DS) between 3 and 16%. The synthesis of these derivatives was monitored by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), High-Performance Liquid Chromatography-Size Exclusion Chromatography (HPLC-SEC) and proton Nuclear Magnetic Resonance (1 H-NMR) analyses. Different functional properties, solubility, water binding capacity (WBC) and fat binding capacity (FBC), as well as the antioxidant activity (DPPH radical scavenging activity) of these derivatives were evaluated. Solubility, WBC and FBC increased in all of the chitosan derivatives respect to those of the native LMWC or COS. The most substituted chitosan derivative (LMWC-LA1, DS 15%) presented the highest value of solubility (14.4 mg mL-1) while the highest levels of WBC and FBC were obtained for the derivative with a DS of 3% (LMWC-LA5; 4730% and 7100%, respectively). COS-LA showed a similar DPPH radical scavenging activity to that of COS in all concentrations tested (16.7-20.9% and 18.0-20.4%, respectively). An inverse relationship between the DS of chitosan derivatives and the antioxidant activity was observed. LMWC-LA5 (3% DS) was the chitosan derivative with the highest DPPH radical scavenging activity, being higher than LMWC in all the concentrations assayed (10.2-14.3% and 6.9-13.7%, respectively). Due to their enhanced functional properties, these chitosan derivatives could be considered as very promising for their future use as additives in the food industry (i.e. to bind fat and cholesterol or avoid hardening of foods).
Effects of chitosan molecular weight on its antioxidant and antimutagenic properties
A B S T R A C T Chitosan (300.0 kDa) was enzymatically degraded to obtain six degraded chitosans with molecular weights (MWs) of 156.0, 72.1, 29.2, 7.1, 3.3, and 2.2 kDa. The antioxidant and antimutagenic properties of all seven chitosan samples were evaluated in vitro. The antioxidant scavenging activities of chitosans on hydrogen per-oxide and 2, 2-diphenyl-1-picryl hydrazyl radical, and on chelating ferrous ion were significantly increased with chitosan's decreasing MW, with 2.2-kDa chitosan have the highest impact. All seven chitosan samples exhibited strong anitmutagenic effects against direct (4-nitroquinoline 1-oxide) and indirect (benzo[α]pyrene) mutagens in the presence of rat liver enzyme S9 mix in Salmonella typhimurium TA 98 and TA 100. The effect of MW on antimutagenicity was similar to that on antioxidant activity. The underlying mechanism for chitosan anti-mutagenicity proved to be its desmutagenic effect on mutagens.
Analysis of Antioxidant Properties of Chitosan
Oral treatment with chitosan with a molecular weight ~105, but not its oligomer, reduced plasma content of free-radical oxidation products in normal rats and animals treated for the bone marrow form of radiation sickness and stimulated the recovery processes in involved bone marrow and peripheral blood.
SYNTHESIS OF QUERCETIN FUNCTIONALIZED CHITOSAN AND DETERMINATION OF ANTIOXIDANT PROPERTIES
Chemistry Journal of Moldova, 2023
This paper is dedicated to the synthesis of a copolymer with reducing properties obtained by functionalizing chitosan with quercetin and determining the antioxidant activity of the derivatives obtained depending on the molar mass of the polymer. For this purpose, low molecular weight chitosan was obtained by oxidizing commercial chitosan with hydrogen peroxide and further functionalization with quercetin by the covalent grafting method. The functionalization process was performed through the following steps: functionalization of chitosan with ethyl chloroformate to increase the reactivity of the amine group to the hydroxyl group of quercetin and grafting the quercetin molecule to the synthesized intermediate. The comparative antioxidant properties of the composite obtained by grafting technical chitosan with quercetin and by grafting low molecular weight chitosan were studied by the DPPH (2,2-diphenyl-1-picrylhydrazyl radical) method. The obtained results indicate that a decrease in the molecular weight of chitosan contributed to its grafting with quercetin. As a result, the functionalized polymer composite acquired a higher antioxidant activity and can be successfully used to inhibit the oxidation of various organic substrates in the cosmetic, food and pharmaceutical industries.
Journal of Nepal Chemical Society, 2021
High molecular weight nanocrystalline chitosan (HMWNC) with M w of 350 kDa and 66.92% DDA was prepared by alkaline N-deacetylation of chitin that was abundantly obtained after demineralization and deproteinization of pulverized crab shells, and commercially available chitosan oligosaccharide (COS) with average M w < 3000 Da and 87% DDA was encapsulated with HMWNC. The encapsulation of COS as a pharmaceutical ingredient into HMWC was hypothesized to enhance the bioavailability of COS in target cells. The HMWNC encapsulated chitosan oligosaccharide (COS-HMWNC) showed in vitro antioxidant activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals (IC 50 = 512.6±14.4 μg/mL) while others showed less than 50% inhibition at 1000 μg/mL. The lower the molecular weight of chitosan, the higher was the antioxidant activity. The study showed that the encapsulation of COS molecules in HMWNC could be used as a simple and effective way of enhancing the antioxidant activity of COS.
Chitosans are naturally occurring biologically safe and non-toxic polymer of polysaccharides. In the present study, Chitosan [(1-4) 2-amino-2-deoxy--D-glucan] was extracted from the exoskeleton of Black Tiger (Penaeus monodon) shrimp shells by alkaline deacetylation of chitin. Three different chitosan extracts, coded as Chito A (3.33 % w/w), Chito B (4.01 % w/w) and Chito C (3.45 % w/w) were extracted using 3 %, 4 % and 5% w/v concentrations of HCl as decalcifiers respectively. Physicochemical properties such as appearance, odor, insolubility and pH of all the extracts were found to comply with the compendial specifications of pharmaceutical grade chitosan. Qualitative identification of the samples was carried out using Infrared (IR) spectroscopy. Major peaks of the extracts matched with reference IR spectrum of standard chitosan. Extracted chitosans were found lacking cytotoxicity in brine shrimp lethality bioassay. All the extracts showed strong antioxidant activity in DPPH free radical scavenging assay and the IC50 values were found to be 37 ± 2 μg/mL (Chito A), 35 ± 1 μg/mL (Chito B) and 30 ± 2 μg/mL (Chito C) while the standard antioxidant Quercetin showed an IC50 value of 15 ± 2 μg/mL .
Effectuality of chitosan biopolymer and its derivatives during antioxidant applications
International Journal of Biological Macromolecules, 2020
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Stamford Journal of Pharmaceutical Sciences, 2010
Chitosans are naturally occurring biologically safe and non-toxic polymer of polysaccharides. In the present study, Chitosan [(1-4) 2-amino-2-deoxy-β-D-glucan] was extracted from the exoskeleton of Black Tiger (Penaeus monodon) shrimp shells by alkaline deacetylation of chitin. Three different chitosan extracts, coded as Chito A (3.33 % w/w), Chito B (4.01 % w/w) and Chito C (3.45 % w/w) were extracted using 3 %, 4 % and 5% w/v concentrations of HCl as decalcifiers respectively. Physicochemical properties such as appearance, odor, insolubility and pH of all the extracts were found to comply with the compendial specifications of pharmaceutical grade chitosan. Qualitative identification of the samples was carried out using Infrared (IR) spectroscopy. Major peaks of the extracts matched with reference IR spectrum of standard chitosan. Extracted chitosans were found lacking cytotoxicity in brine shrimp lethality bioassay. All the extracts showed strong antioxidant activity in DPPH free radical scavenging assay and the IC50 values were found to be 37 ± 2 µg/mL (Chito A), 35 ± 1 µg/mL (Chito B) and 30 ± 2 µg/mL (Chito C) while the standard antioxidant Quercetin showed an IC50 value of 15 ± 2 µg/mL .