Water-soluble Chitin Derivative Research Articles

Exclusion liquid chromatography of carboxymethylchitin and carboxymethylchitosan from crustacean <i>Artemia Parthenogenetica</i> of the Aral Sea

The article deals with the synthesis of water-soluble derivatives of chitin and chitosan from cysts of crustaceans of the genus Artemia Parthenogenetica of the Aral Sea by carboxymethylation of OH and NH2 groups of their chains. The elution, viscosity and polyelectrolyte properties in size exclusion liquid chromatography of carboxymethylchitin and carboxymethylchitosan were studied. The suppression of electrostatic effects and the implementation of the exclusion mechanism for the separation of these polysaccharides were achieved by using an aqueous solution of sodium nitrate with a concentration of 0.1 mol/l as an eluent, which was recommended for determining molecular weight characteristics.

Synthesis of Water-Soluble Sulfonated Chitin Derivatives for Potential Antioxidant and Antifungal Activity.

Chitin is a natural renewable and useful biopolymer limited by its insolubility; chemical derivatization can enhance the solubility and bioactivity of chitin. The purpose of this study was to synthesize novel water-soluble chitin derivatives, sulfo-chitin (SCT) and sulfopropyl-chitin (SPCT), as antioxidant and antifungal agents. The target derivatives were characterized by means of elemental analysis, FTIR, 13C NMR, TGA and XRD. Furthermore, the antioxidant activity of the chitin derivatives was estimated by free radical scavenging ability (against DPPH-radical, hydroxyl-radical and superoxide-radical) and ferric reducing power. In addition, inhibitory effects against four fungi were also tested. The findings show that antioxidant abilities and antifungal properties were in order of SPCT > SCT > CT. On the basis of the results obtained, we confirmed that the introduction of sulfonated groups on the CT backbone would help improve the antioxidant and antifungal activity of CT. Moreover, its efficacy as an antioxidant and antifungal agent increased as the chain length of the substituents increased. This derivatization strategy might provide a feasible way to broaden the utilization of chitin. It is of great significance to minimize waste and realize the high-value utilization of aquatic product wastes.

Efficacy of a Chitin-Based Water-Soluble Derivative in Inducing Purpureocillium lilacinum against Nematode Disease (Meloidogyne incognita).

Plant-parasitic nematodes cause severe economic losses annually which has been a persistent problem worldwide. As current nematicides are highly toxic, prone to drug resistance, and have poor stability, there is an urgent need to develop safe, efficient, and green strategies. Natural active polysaccharides such as chitin and chitosan with good biocompatibility and biodegradability and inducing plant disease resistance have attracted much attention, but their application is limited due to their poor solubility. Here, we prepared 6-oxychitin with good water solubility by introducing carboxylic acid groups based on retaining the original skeleton of chitin and evaluated its potential for nematode control. The results showed that 6-oxychitin is a better promoter of the nematicidal potential of Purpureocillium lilacinum than other water-soluble chitin derivatives. After treatment, the movement of J2s and egg hatching were obviously inhibited. Further plant experiments found that it can destroy the accumulation and invasion of nematodes, and has a growth-promoting effect. Therefore, 6-oxychitin has great application potential in the nematode control area.

New water-soluble chitin derivative with high antibacterial properties for potential application in active food coatings

The synthesis of new chitin derivatives through ultrasound-assisted treatment of the chitin with 1-azido-3-chloropropan-2-ol under Green Chemistry conditions is described. This is the first example of ultrasound-assisted polymer analogues transformation of chitin unaccompanied by noticeable backbone degradation or deacetylation. The obtained water-soluble azido chitin derivatives are characterized by high antibacterial activity, which is comparable with that of commercial antibiotics ampicillin and gentamicin. At the same time, they were demonstrated almost identical in vitro toxicity as unmodified chitin and chitosan. The antibacterial activity of the obtained polymers is mainly provided by azido moiety in their macromolecules. The conjugation of azido moiety to chitin backbone strongly diminishes the toxicity of the azido pharmacophore, but preserves its antibacterial properties. The most potent chitin derivative was used for the film coating of Ricotta cheese samples. This food coating proved to be efficient for the prolongation of shelf life of Ricotta cheese.

New water-soluble derivatives of chitin and their based nanoparticles: Antibacterial and catalytic activity

A facile route towards new chitin derivatives with both catalytical and biological activities is proposed in the course of methodology development aimed at the design of polyfunctional materials on the basis of renewable and accessible natural polysaccharides. Ultrasound-promoted and Cu(I)-catalyzed azido-alkyne click cycloaddition of the propargylic ester of nicotinic acid and its N-methylated analogue to the azido chitin derivative allowed us to obtain previously unknown non-toxic water-soluble derivatives of chitin. The obtained polymers and their based nanoparticles demonstrated a high antibacterial activity in vitro, which is comparable or even superior to that of commercial antibiotics ampicillin and gentamicin. New derivatives of chitin were also shown to be highly efficient and reusable (at least for 10 times) green catalysts for the aldol reaction in water. The catalysts can be easily separated from the reaction mixture by their precipitation with ethanol. The results obtained highlight prospects of further studies on chitin's application in the rational design of novel functional materials with valuable properties.

Adsorption of sodium dodecylsulfate on modified carbon adsorbents

The adsorption of anionic surfactants on carbon adsorbents modified with water-soluble derivatives of natural polymers, cellulose and chitin, is considered with sodium dodecylsulfate taken as an example. It is shown that such modification leads to changes in the adsorption structural characteristics and the particle size distribution of carbon-water suspensions of the original adsorbent, and to the emergence of new functional groups on its surface that are able to interact selectively with adsorbate molecules. It is assumed that adsorption of anionic surfactant on carbon adsorbents under equilibrium conditions proceeds via stepwise filling of the carbon’s porous structure: we first observe volume filling of micropores according to their sizes, and then the formation of a surfactant’s monolayer in mesopores and on the outer surface of the adsorbate. It is established by thermal analysis that the thermal stability of carbon adsorbents is enhanced through the preferential localization of anionic surfactants in micropores. The filling of mesopores and the outer carbon surface by surfactant molecules leads to a regular decrease in thermal stability and an increase in the adsorbent surface’s hydrophilicity.

Aggregation of some water-soluble derivatives of chitin in aqueous solutions: Role of the degree of acetylation and effect of hydrogen bond breaker.

By dynamic light scattering in combination with fluorescence spectroscopy and TEM it was shown that aggregation in aqueous solutions is inherent not only to chitosan, but also to two other water-soluble derivatives of chitin: O-carboxymethylchitin and di-N,N-carboxymethylchitosan. Aggregation is observed even for the samples without N-acetyl-d-glucosamine units, which remain upon incomplete chemical modification of chitin, indicating that specific interactions between residual chitin repeat units cannot be the main reason for the aggregation. At the same time, 7M urea weakens the aggregation, thus testifying that hydrogen bonding and/or hydrophobic interactions are partially responsible for this phenomenon. The incomplete disruption of aggregates in 7M urea may arise from crystallization of junction zones between different macromolecules, which makes some hydrogen bonds inaccessible for urea or too stable for breaking by this agent.

A simple colorimetric determination of the free amino groups in water soluble chitin derivatives using genipin

A colorimetric method for quantitative measurement of free amino groups of water soluble chitin derivatives is described. The method utilizes genipin as a natural and specific reagent for determining the concentration of free amino groups in samples of water soluble chitin derivatives. The blue color adduct (complex) formed during genipin reaction with free amino groups was measured at about 589 nm and Beer-Lambert’s law obeyed over the concentration range of 50 to 300 mg/L. Parameters of analytical conditions were considered and kept constant during the experimental procedure. Highly acetylated water soluble chitin derivatives can be differentiated from water soluble chitosan using this genipin method. The colorimetric method with genipin was proved to be a rapid and efficient technique to determine the free amino groups in water soluble chitin derivatives. This method can also be applied for the detection of the enzymatic activity of chitindeacetylase.

Carboxymethylations of chitosan and chitin inhibit MMP expression and ROS scavenging in human fibrosarcoma cells

The water-soluble derivatives of chitosan and chitin, carboxymethyl-chitosan (CM-chitosan) and carboxymethyl-chitin (CM-chitin), were synthesised by means of carboxymethylation reaction. Their antioxidative and matrix metalloproteinase-2 and -9 (MMP-2 and -9) inhibitory effects were investigated in HT1080 human fibrosarcoma cells. Treatment with CM-chitosan and CM-chitin suppressed the formation of intracellular reactive oxygen species (ROS), protein oxidation and lipid peroxidation in a concentration-dependent manner. In addition, a protective effect against oxidative damage of purified genomic DNA was observed in the presence of CM-chitosan and CM-chitin. Moreover, CM-chitosan and CM-chitin reduced the expression levels of MMP-2 and -9 in gelatin zymography, RT-PCR and western blot analysis without any cytotoxic influence. CM-chitin exhibited a higher MMP inhibitory effect than CM-chitosan through transcriptional down-regulations of activator protein-1 (AP-1) and nuclear factor κB (NF-κB). Findings from the present study underscore the nutraceutical value of CM-chitosan and CM-chitin as a potent antioxidant and MMP inhibitor via alleviations of radical-induced oxidative damage.

The control of wheat defense responses during infection with Bipolaris sorokiniana by chitooligosaccharides

We studied the effects of low-molecular-weight water-soluble derivatives of chitin, chitooligsaccharides (ChOS) with a mol wt of 5–10 kD and the degree of acetylation of 65% on expression and molecular heterogeneity of peroxidase and the content of phytohormones in wheat plants differing in their resistance to the causal agents of root rots. Plant infection or their treatment with ChOS induced expression of the gene for anionic peroxidase and enhanced enzyme activity, and these processes depended on the degree of wheat resistance. They were more intense in the resistant cultivar. Treatment of susceptible plants with ChOS prevented a pathogen-induced drop in the cytokinin level, thus simulating defensive responses, which are characteristic of the resistant plants.

Antioxidant activity of novel chitin derivative

Novel water-soluble chitin derivative was prepared by chemical modification to evaluate antioxidant activities by free radical scavenging potential using electron spin resonance spin trapping technique. Aminoethyl-chitin (AEC) exhibited free radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, superoxide, and peroxyl radicals. AEC quenched DPPH and peroxyl radical over 55% and 59% at 4 mg/mL, and also suppressed superoixde radical over 58% at 2 mg/mL. Especially, AEC was more active against hydroxyl radical, and scavenging ratio was 92.2% at 0.12 mg/mL. These results suggested that free amino group in the –CH 2CH 2NH 2 plays an important role in the free radical scavenging activity. In addition, cytotoxic effect of AEC was assessed using human lung fibroblast (MRC-5) cell line, and AEC showed less toxic against MRC-5.

Interactions of enzymes and a lectin with a chitin-based graft copolymer having polysarcosine side chains.

The molecular-recognition abilities of a water-soluble chitin derivative, chitin-graft-polysarcosine (2) were investigated using chitinase, lysozyme, and wheat germ agglutinin (WGA). The enzymatic degradabilities of 2 were evaluated using chitinase and lysozyme. The molecular weight of those compounds of 2 with a higher affinity toward water decreased rapidly, as compared with partially deacetylated chitin (1). The 1H NMR spectrum of the low-molecular-weight fraction, yielded after lysozymic hydrolysis, indicated that saccharide residues in the chitinous backbone were specifically recognized by the lysozyme, then beta-glycosidic linkages in the backbone were selectively hydrolyzed. Furthermore, the molecular-recognition ability of the chitinous backbone of graft copolymer 2 toward the lectin WGA was elucidated by the enzyme-linked lectin-binding assay (ELLA). It was revealed that the graft copolymer with a lower degree of substitution (DS) value efficiently interacted with WGA. Interestingly, a graft copolymer having longer polysarcosine side chains showed higher recognition ability toward WGA than that having short side chains.

Diethylaminoethylation of Chitin and the Adsorption of Acid Dyes onto the Resulting Polymer

Water-soluble chitin derivatives have been synthesized by the diethylaminoethylation (DEAE) reaction and the adsorption characteristics of the resulting polymeric adsorbents towards two acid dyes (CI Acid Orange 7 and CI Acid Red 88) were studied. The adsorption behaviours towards these dyes were also compared with those exhibited by two water-insoluble commercially available derivatives. The conventional water-insoluble DEAE-chitins showed a high adsorptive capacity towards CI Acid Orange 7 compared to that on untreated chitin and alkali-treated chitin. A similar trend was also found for CI Acid Red 88 dye, where the increase in adsorption was characterized more clearly. However, the adsorption capacities towards both dyes exhibited by the water-soluble DEAE-chitins were increased significantly at a particular free dye concentration, with the adsorptive power also being increased both with the degree of DEAE substitution and the hydrophobicity of the dyes.

ChemInform Abstract: Synthesis and Properties of Water‐Soluble Derivatives of Chitin.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis and properties of water-soluble derivatives of chitin. A review

Concepts were formulated concerning the correlation of the structure and properties of an important class of biopolymers—aminopolysaccharides in aquatic organisms. Improved methods of obtaining water-soluble derivatives of chitin were developed, and their structure, physicochemical, and functional properties were characterized, including in the form of drugs, SF-PEC, and films.

Preparation and characterization of water-soluble chitin and chitosan derivatives

Chitosan was modified with poly(ethylene glycol)-aldehyde (PEG-aldehyde) of various molecular weights under the various molar ratios of PEG-aldehyde to chitosan. Then the prepared chitosan-PEG hybrid was converted to chitin-PEG hybrid by the acetylation with acetic anhydride. The solubility of various derivatives was investigated in three buffers of various pH. Some of these derivatives were soluble in 0.01 M phosphate buffer saline (PBS, pH = 7.2). The solubility in PBS was dependent on the degree of PEG substitution, the degree of acetylation, the molecular weight of PEG, and the weight ratio of PEG in chitin/chitosan-PEG hybrid.

Surface activity of water soluble amphiphilic chitin derivatives

Chitin was derivatized to extend its applications in the field of water soluble systems. It was first carboxymethylated and then alkylated. Two technics were used for that purpose: ionic surfactants playing the role of counterions form an electrostatic complex, and covalent derivatization. The difference between covalent alkylation and dynamic association (SPEC) is discussed in relation with the length of the alkyl chain and the density of alkylation.

Synthesis and Antibacterial Activity of Water-soluble Chitin Derivatives

Diethylaminoethyl–chitin (DEAE–chitin) was synthesized by introducing DEAE groups onto the C(6)–OH in chitin. DEAE–chitin was N-deacetylated by heating in aqueous 10% sodium hydroxide containing sodium borohydride to prepare the diethylaminoethyl–chitosan (DEAE–chitosan). In addition, DEAE–chitin was quaternized with ethyl halide to produce triethylaminoethyl–chitin (TEAE–chitin). Their antibacterial activities were evaluated by using colony count against Staphylococcus aureus and Escherichia coli by means of shake flask method. The antibacterial activity was found to increase in order of DEAE–chitin, DEAE–chitosan, TEAE–chitin. DEAE–chitin was hydrolyzed by enzymes to investigate the effect of molecular weight on its antibacterial activities. The antibacterial activity was dependent on the structure, particularly on the molecular weight of chitin derivatives. © 1997 John Wiley & Sons, Ltd.

Enzymatic hydrolysis reaction of water-soluble chitin derivatives with egg white lysozyme

Hydrolysis reactions using two kinds of water-soluble chitin derivatives and egg white lysozyme were carried out. The optimum pHs of the lysozyme were 5.0 and 3.8 for CM- and DHP-chitin, respectively. There were large differences in the reactivities, that is, in the case of DHP-chitin the reactivity was 7.9–10% of that for CM-chitin.

Three extracellular chitinases in suspension-cultured rice cells elicited by N-acetylchitooligosaccharides.

In rice suspension culture, a large part (about 90% of total activity in the culture) of the chitinase activity was found in the medium. Two extracellular chitinases (which we named RCH-A and -B) were separated from the cell suspension by DEAE-cellulofine column chromatography. When cells were treated with N-acetylchitooligosaccharides (chitin oligosaccharides) for 3 days, extracellular chitinase activity increased about 3-fold over the control culture. After the treatment, another extracellular chitinase (named RCH-C) appeared in addition to increases in the levels of RCH-A and -B. Partial amino acid sequences of these enzymes indicated that RCH-A (33.5 kDa) and -B (34 kDa) were class Ib chitinases but RCH-C (27 kDa) was a class III chitinase. RCH-A and -B were capable of actively degrading water-insoluble chitin with high affinities, while RCH-C had less affinity for the substrate. However, when a water-soluble chitin derivative, 6-O-hydroxyethylchitin (glycolchitin) was used, RCH-C as well as RCH-A and -B degraded actively with a high affinity. A synergistic effect was observed when these three chitinases acted simultaneously in the hydrolysis of chitin.