Chitooligosaccharide Derivatives Research Articles

Chitooligosaccharide Derivatives with Aromatic Ring Conjugated Intercalation Function Disperse Asphaltene to Reduce the Viscosity of Heavy Oil

Chitooligosaccharide Derivatives with Aromatic Ring Conjugated Intercalation Function Disperse Asphaltene to Reduce the Viscosity of Heavy Oil

Preparation, characterization, antioxidant, and antifungal activity of phenyl/indolyl-acyl chitooligosaccharides

In this study, carboxylic acids compounds were grafted onto chitooligosaccharides to prepare seven phenyl/indolyl-acyl chitooligosaccharides derivatives. The structures of the derivatives were characterized by IR spectroscopy, 13C NMR and elemental analysis. Meanwhile, antioxidant activities in vitro of the novel derivatives were analyzed. Compared to COS and carboxylic acid, the derivatives showed higher scavenging capacity for superoxide anion and DPPH radicals, with scavenging rates of 59.39% and 94.86%, respectively. The hydroxyl radical scavenging ability of the derivatives was only 18.89%. The antifungal activities of chitooligosaccharide derivatives against Diaporthe batatas and Phytophthora capsici were studied by the growth rate method. Compared with chitooligosaccharide itself, derivatives were inhibited by 97.77% and 100%. The above results showed that chitooligosaccharide derivatives have good biocompatibility and can be used in food, agriculture and medicine.

Caffeic acid-grafted chitooligosaccharides downregulate MAPK and NF-kB in RAW264.7 cells.

Chitooligosaccharide (COS) is a derivative of chitosan, which is a natural macromolecular compound. COS has been shown effects in an inflammatory response. Recent reports show that COS derivatives have enhanced anti-inflammatory activity by inhibiting intracellular signals. Evaluation of the anti-inflammatory effect of caffeic acid conjugated COS chain (CA-COS) was performed in this study. The effects of CA-COS on the inflammatory response were demonstrated in lipopolysaccharide-stimulated RAW264.7 macrophages. The results showed that CA-COS inhibited nitric oxide (NO) production and downregulated the gene expression of nitric oxide synthase (iNOS), and cytokines such as tumor necrosis factor-alpha (TNF-α), IL-1β, and IL-6 without cytotoxic effect. In addition, western blot analysis showed that CA-COS inhibits the protein expression of iNOS and nuclear factor kappa B (NF-kB), including p50 and p65, and mitogen-activated protein kinase (MAPK) signaling pathways. Collectively, these results provide clear evidence for the anti-inflammatory mechanism of CA-COS that show great potential as a novel agent for the prevention and therapy of inflammatory diseases.

Phenolic Acid Functional Quaternized Chitooligosaccharide Derivatives: Preparation, Characterization, Antioxidant, Antibacterial, and Antifungal Activity.

As a promising biological material, chitooligosaccharide (COS) has attracted increasing attention because of its unique biological activities. In this study, fourteen novel phenolic acid functional COS derivatives were successfully prepared using two facile methods. The structures of derivatives were characterized by FT-IR and 1H NMR spectra. The in vitro antioxidant activity experiment results demonstrated that the derivatives presented stronger 1,1-Diphenyl-2-picryl-hydrazyl (DPPH), superoxide, hydroxyl radical scavenging activity and reducing power, especially the N,N,N-trimethylated chitooligosaccharide gallic acid salt (GLTMC), gallic acid esterified N,N,N-trimethylated chitooligosaccharide (GL-TMC) and caffeic acid N,N,N-trimethylated chitooligosaccharide (CFTMC) derivatives. Furthermore, the antifungal assay was carried out and the results indicated that the salicylic acid esterified N,N,N-trimethylated chitooligosaccharide (SY-TMC) had much better inhibitory activity against Botrytis cinerea and Fusarium graminearum. Additionally, the results of the bacteriostasis experiment showed that the caffeic acid esterified N,N,N-trimethylated chitooligosaccharide (CF-TMC) had the potential ability to inhibit Escherichia coli and Staphylococcus aureus bacteria. Altogether, this study may provide a neoteric method to produce COS derivatives with significantly increased biological activities, which have potential use in food, medicine, and health care products and other related industries.

Spraying phenolic acid-modifiedchitooligosaccharide derivatives improves anthocyanin accumulation in grape.

Herein, four chitooligosaccharide derivatives (COS-RA, COS-FA, COS-VA, COS-GA) were prepared by laccase-catalyzed chitooligosaccharide modification with rosmarinic acid (RA), ferulic acid (FA), gallic acid (GA), and vanillic acid (VA), and structures were characterized. RA and FA resulted in higher amino-substitution in the chitooligosaccharides than GA and VA. COS-RA and COS-FA had greater DPPH scavenging rates than COS-GA and COS-VA. Compared with COS treatment, spraying 250mg L-1 COS-RA or COS-VA 6 times (once per 7days) increased soluble sugar and anthocyanin content by 18.6%-23.2% and 41.7%-46.7%, respectively, from the fruit expansion to harvest stage. COS-RA and COS-VA also enhanced gene expression related to anthocyanin synthesis (PAL, F3H, F3'5'H, DFR, and UFGT) and monomeric anthocyanin accumulation (Mal-3-O-glu, Petu-3-O-ace-glu, Del-3-O-glu). Therefore, chitooligosaccharide derivatives may improve grape fruit anthocyanin accumulation by regulating antioxidant systems, improving the photosynthetic rate and inducing gene expression related to anthocyanin synthesis.

Water-soluble fluorine-functionalized chitooligosaccharide derivatives: Synthesis, characterization and antimicrobial activity

In this work, a series of water-soluble fluorine-functionalized chitooligosaccharide derivatives were synthesized by conjugating nicotinic acid to chitooligosaccharide via nicotinylation reaction, followed by nucleophilic reaction with ethyl bromide, benzyl bromide and fluorobenzyl bromides. Synthesized derivatives were identified structurally by Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance. In addition, the antibacterial activities of chitooligosaccharide derivatives against several disease-causing bacteria were assessed by the broth dilution method and Kirby-Bauer method, the mycelium growth rate method was used to assessing the antifungal properties of samples against three plant-threatening fungi. Among the chitooligosaccharide derivatives, those containing benzyl or fluorobenzyl exhibited noteworthy antimicrobial activity. Specifically, the chitooligosaccharide derivative containing 2,3,4-trifluorobenzyl displayed remarkable antimicrobial activity, with an inhibition index of 84.35% against Botryis cinerea at a concentration of 1.0 mg/mL. Additionally, its MIC value against Staphylococcus aureus was found to be 0.03125 mg/mL, while the MBC value was determined to be 0.0625 mg/mL. The findings of the study revealed that the incorporation of pyridinium cations and fluorine into the chitooligosaccharide backbone may play a critical role in strengthening its ability to combat harmful microorganisms. Furthermore, the cytotoxicities of chitooligosaccharide derivatives against Huvec cells were evaluated through MTT assay, and all samples were not toxic. As a consequence, the water-soluble fluorine-functionalized chitooligosaccharide derivatives possessed rapid microbicidal properties and good biocompatibility, which provided promising prospects for the development of a more effective and environmentally friendly antimicrobial agent.

Efficient and versatile formation of glycosidic bonds via catalytic strain-release glycosylation with glycosyl ortho−2,2-dimethoxycarbonylcyclopropylbenzoate donors

Catalytic glycosylation is a vital transformation in synthetic carbohydrate chemistry due to its ability to expediate the large-scale oligosaccharide synthesis for glycobiology studies with the consumption of minimal amounts of promoters. Herein we introduce a facile and efficient catalytic glycosylation employing glycosyl ortho−2,2-dimethoxycarbonylcyclopropylbenzoates (CCBz) promoted by a readily accessible and non-toxic Sc(III) catalyst system. The glycosylation reaction involves a novel activation mode of glycosyl esters driven by the ring-strain release of an intramolecularly incorporated donor-acceptor cyclopropane (DAC). The versatile glycosyl CCBz donor enables highly efficient construction of O-, S-, and N-glycosidic bonds under mild conditions, as exemplified by the convenient preparation of the synthetically challenging chitooligosaccharide derivatives. Of note, a gram-scale synthesis of tetrasaccharide corresponding to Lipid IV with modifiable handles is achieved using the catalytic strain-release glycosylation. These attractive features promise this donor to be the prototype for developing next generation of catalytic glycosylation.

Preparation of cationic chitooligosaccharide derivatives bearing N-halogenated benzyl pyridinium and assessment of their antimicrobial activities

Preparation of cationic chitooligosaccharide derivatives bearing N-halogenated benzyl pyridinium and assessment of their antimicrobial activities

Cationic Chitooligosaccharide Derivatives Bearing Pyridinium and Trialkyl Ammonium: Preparation, Characterization and Antimicrobial Activities.

In this study, chitooligosaccharide-niacin acid conjugate was designed and synthesized through the reaction of chitooligosaccharide and nicotinic acid with the aid of N,N'-carbonyldiimidazole. Its cationic derivatives were prepared by the further nucleophilic substitution reaction between the chitooligosaccharide-niacin acid conjugate and bromopropyl trialkyl ammonium bromide with different alkyl chain lengths. The specific structural characterization of all derivatives was identified using Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR), and the degree of substitution was obtained using the integral area ratio of the hydrogen signals. Specifically, the antibacterial activities against Escherichia coli, Staphylococcus aureus, Pseudoalteromonas citrea and Vibrio harveyi were evaluated using broth dilution methods. In addition, their antifungal activities, including Botrytis cinerea, Glomerella cingulate and Fusarium oxysporum f. sp. cubense were assayed in vitro using the mycelium growth rate method. Experimental data proved that the samples showed antibacterial activity against four pathogenic bacteria (MIC = 1-0.125 mg/mL, MBC = 8-0.5 mg/mL) and enhanced antifungal activity (50.30-68.48% at 1.0 mg/mL) against Botrytis cinerea. In particular, of all chitooligosaccharide derivatives, the chitooligosaccharide derivative containing pyridinium and tri-n-butylamine showed the strongest antibacterial capacity against all of the test pathogenic bacteria; the MIC against Vibrio harveyi was 0.125 mg/mL and the MBC was 1 mg/mL. The experimental results above showed that the introduction of pyridinium salt and quaternary ammonium salt bearing trialkyl enhanced the antimicrobial activity. In addition, the cytotoxicity against L929 cells of the chitooligosaccharide derivatives was evaluated, and the compounds exhibited slight cytotoxicity. Specifically, the cell viability was greater than 91.80% at all test concentrations. The results suggested that the cationic chitooligosaccharide derivatives bearing pyridinium and trialkyl ammonium possessed better antimicrobial activity than pure chitooligosaccharide, indicating their potential as antimicrobial agents in food, medicine, cosmetics and other fields.

Bioeconomic production of high-quality chitobiose from chitin food wastes using an in-house chitinase from Vibrio campbellii

Marine Vibrio species are natural degraders of chitin and usually secrete high levels of chitinolytic enzymes to digest recalcitrant chitin to chitooligosaccharides. This study used an endochitinase (VhChiA) from Vibrio campbellii to produce high-quality chitobiose from crustacean chitins. The enzyme was shown to be fully active and stable over 24 h when BSA was used as an additive. When different chitin sources were tested, VhChiA preferentially digested shrimp and squid (α) chitins compared to crab (β) chitin and did not utilize non-chitin substrates. The overall yields of chitobiose obtained from small-scale production using a single-step reaction was 96% from shrimp, and 91% from squid pen and crab-shell chitins. Larger-scale production yielded 200 mg of chitobiose, with > 99% purity after a desalting and purification step using preparative HPLC. In conclusion, we report the employment of an in-house produced chitinase as an effective biocatalyst to rapidly convert chitin food wastes to chitobiose, in a quantity and quality suitable for use in research and commercial purposes. Chitobiose production by this economical and eco-friendly approach can be easily scaled up to obtain multi-gram quantities of chitobiose for chemo-enzymic synthesis of rare chitooligosaccharide derivatives and long chain chitooligosaccharides, as well as preparation of sugar-based functionalized nanomaterials.Graphical

Synthesis, Characterization, and the Antioxidant Activity of Phenolic Acid Chitooligosaccharide Derivatives.

A series of phenolic acid chitooligosaccharide (COS) derivatives synthesized by two mild and green methods were illuminated in this paper. Seven phenolic acids were selected to combine two kinds of COS derivatives: the phenolic acid chitooligosaccharide salt derivatives and the phenolic-acid-acylated chitooligosaccharide derivatives. The structures of the derivatives were characterized by FT-IR and 1H NMR spectra. The antioxidant experiment results in vitro (including DPPH-radical scavenging activity, superoxide-radical scavenging activity, hydroxyl-radical scavenging ability, and reducing power) demonstrated that the derivatives exhibited significantly enhanced antioxidant activity compared to COS. Moreover, the study showed that the phenolic acid chitooligosaccharide salts had stronger antioxidant activity than phenolic-acid-acylated chitooligosaccharide. The cytotoxicity assay of L929 cells in vitro indicated that the derivatives had low cytotoxicity and good biocompatibility. In conclusion, this study provides a possible synthetic method for developing novel and nontoxic antioxidant agents which can be used in the food and cosmetics industry.

Preparation, characterization, and antifungal evaluation of a new type of aminourea chitooligosaccharide derivatives

Phytopathogenic fungi cause heavy negative impact on the agricultural economy, but most existing fungicides are toxic and pose a threat to both human health and environments. A green and efficient fungicide is urgently needed. Chitooligosaccharides (COSs), the degradation products of natural polysaccharide chitosan, are nontoxic and biodegradable antifungal substances. In this study, a novel type of aminourea chitooligosaccharide derivatives (AUCOS) was synthesized by successively grafting a hydrazine group and an amine-carbonyl group onto a chitooligosaccharide backbone to enhance the antifungal capability of COSs. The structures of the target compounds were identified by FTIR, 1 H NMR, and 13 C NMR, and the degree of substitution of each product was calculated from the results of the elemental analysis. The antifungal activities of the prepared chitooligosaccharide derivatives against Fusarium solani, Verticillium albo-atrum and Phytophthora capsici were tested in vitro. The AUCOSs had better inhibitory efficiencies against the three plant pathogen fungi than that of chitooligosaccharide, of which aminourea chitooligosaccharide 2 (AUCOS2) was the most promising antifungal compound, whose highest inhibition rates were 60.12%, 82.95%, and 85.23% against F. solani, V. albo-atrum and P. capsici, respectively. The synthesized derivatives have good application prospects in crop protection and deserve further research.

Inhibition Behavior of Chitooligosaccharide Derivatives for Carbon Steel in 3.5% NaCl Solution

Inhibition Behavior of Chitooligosaccharide Derivatives for Carbon Steel in 3.5% NaCl Solution

Angiotensin-I-Converting Enzyme (ACE) Inhibitors from Marine Resources: Prospects in the Pharmaceutical Industry

Hypertension or high blood pressure is one of the major independent risk factors for cardiovascular diseases. Angiotensin-I-converting enzyme (EC 3.4.15.1; ACE) plays an important physiological role in regulation of blood pressure by converting angiotensin I to angiotensin II, a potent vasoconstrictor. Therefore, the inhibition of ACE activity is a major target in the prevention of hypertension. Recently, the search for natural ACE inhibitors as alternatives to synthetic drugs is of great interest to prevent several side effects and a number of novel compounds such as bioactive peptides, chitooligosaccharide derivatives (COS) and phlorotannins have been derived from marine organisms as potential ACE inhibitors. These inhibitory derivatives can be developed as nutraceuticals and pharmaceuticals with potential to prevent hypertension. Hence, the aim of this review is to discuss the marine-derived ACE inhibitors and their future prospects as novel therapeutic drug candidates for treat hypertension.

Acetylcholinesterase inhibitory activity of novel chitooligosaccharide derivatives

In this study, three kinds of chitooligosaccharides (COS) with different substitution groups, including aminoethyl (AE), dimethylaminoethyl (DMEM) and diethylaminoethyl (DEAE) groups, were evaluated for their inhibitory activities against cholinesterase (acetylcholinesterase and butyrylcholinesterase). These COS derivatives were synthesized and their structures were characterized as AE-COS, DMAE-COS and DEAE-COS, respectively; the structures were elucidated via spectroscopic techniques ( 1H NMR). Of these, DMAE- and DEAE-COS were synthesized for the first time in this work. These COS derivatives evidenced potent acetylcholinesterase (AChE) inhibitory activities with IC 50 values of 56.5 ± 0.26, 24.1 ± 0.39 and 9.2 ± 0.33 μg/ml, respectively; however, these compounds exhibited no activity against butyrylcholinesterase. These were further analyzed for their inhibitory pattern on AChE via Lineweaver–Burk plots. AE-COS showed non-competition type inhibition, and DMAE-COS and DEAE-COS exhibited competition type inhibition against AChE. In this study, we suggested that COS derivatives have potential as AChE inhibitors for preventing Alzheimer’s disease.

Synthesis and Characterization of Amino Acid Modified Chitooligosaccharides

AbstractAmino acid modified chitooligosaccharides were synthesized by the new synthetic route. The chloroacetyl‐chitooliogosaccharide intermediates were prepared under a mild condition via a reaction between chitooligosaccharide (COS) and chloroacetic anhydride. The intermediates were subsequently reacted with a variety of amino acids, e.g., glycine, aspartic acid, alanine, arginine, and serine, under a basic condition, yielding amino acid modified COS products. The degree of chloroacetylation was calculated based on new 1H NMR absorption peaks at 3.80 and 3.94 ppm, corresponding to NHCOCH2Cl and OCOCH2Cl, respectively. The degrees of chloroacetylation determined were 0.40, 0.44, 0.62, and 0.93 when the mole ratios of chloroacetic anhydride to COS were 0.5, 1, 2, and 4, respectively. The chemical structures of the COS derivatives were also determined using 1H NMR spectroscopy. The biological properties of the derivatives were evaluated. Cytotoxicity of the derivatives was assessed by a direct contact, using L929 cells. An MTT assay was a method of choice to evaluate the efficacy of the derivatives to enhance the proliferation of L929 cells.

Determination of lysozyme activities in a microplate format

-glucose)inmureins(microbialcell wall polysaccharides consisting of GlcNAc andmuramicacid)[1],butisalsocapableofdegradingchitin(GlcNAcb1–4GlcNAcpolymer).Lysozymeisknowntobepresentinsuchplacesaschickeneggwhite[1],humantears [1,2], fish serum [3], and insect saliva [4] and isfound to be an effective antifungal and antibacterialagent [5,6]. Recently it was found that the urinary ly-sozyme present in a human gonadotropin preparationexhibits anti-HIV activity [7]. Lysozyme also has beenused for synthesis of chito-oligosaccharide derivatives[8].MostofthecurrentlyavailablemethodsforanalysisoflysozymeactivityusetheapproachoffollowinglysisofMicrococcuslysodeikticuscells[7,9],bymeasuringthedecreaseinturbidity.However,thistypeofassaymustbecarriedoutunderstringentconditionswithrespecttoconcentration of bacterial suspension and the range ofabsorbance decrease, as well as pH and temperature.These restrictions pose serious problems when a largenumberofsamplesaretobeassayed.However,withtheadvent of more efficient microplate readers as well asfaster data collection systems and software for man-agement of data, these problems can be alleviated.Currentmicroplatereadersareusuallycapableofrapidreading of absorbance (e.g., ca. 10s/96 wells) and pro-videconvenientmethodsofdatastorage(e.g.,inExcelformat)amenabletoimmediateplottingandregressionanalysis. We have utilized such microplate technologyanddevelopedaneffectivemethodforlysozymeassayofmultiplesamples.Itwassuccessfulduringtheisolationofpigeoneggwhitelysozymebycolumnchromatogra-phy and was used to measure the lysozyme level inTilapia(fish)serum.MethodsMaterials and instrumentation. M. lysodeiktikus cellswerepurchasedfromSigmaChemical(St.Louis,MO).Chickeneggwhitelysozyme(10,000units/mg)wasfromWorthington Biochemical (Lakewood, NJ). A micro-platereader(ModelBenchmark)anditsaccompanyingsoftware, Microplate Manager, version 5.1, were fromBio-Rad Laboratories (Richmond, CA). Nunc micro-plates of 96 flat-bottom wells (Cat. No. 269620) werefrom Fisher Scientific (Pittsburgh, PA). A Shimadzuspectrophotometer (Model UV1600) with a cell posi-tioner(CPS240)wasusedforconventionalmethod oflysozyme assay [10]. A gel-filtration medium based oncellulose, Spherilose GCL-300, was purchased fromISCO(Lincoln,NE).Procedure. Cells of Micrococcus (9mg) were sus-pended in 30ml of 100mM potassium phosphate, pH7.0,shortlybeforetheassay.Ineachofthemicroplatewellswasplaced50llsample,and200lloftheMicro-coccuscellsuspensionwasadded.Theplatewasgentlyshaken for 1min. Measurement of A

New glycolipids (chitooligosaccharide derivatives) possessing immunostimulating and antitumor activities

New glycolipids, derived from chitooligosaccharides of dp 2–4 and containing both free and acylated amino groups, were synthesized. The structure of the key compounds (di-, tri-, and tetra-saccharides acylated with different fatty acids) were elucidated by 13C NMR spectroscopy. Only the amino group of the reducing end of the chitooligosaccharides was found to be acylated when equimolecular amounts of reagents were used. The compounds obtained were shown to possess a low toxicity and certain immunostimulatory and antitumor activities. An induction of interleukin-1 and tumor necrosis factor by the immunocompetent cells and an augmentation by 140–180% of the mean life of mice with the Erlich carcinoma were observed.

Thermotropic Liquid Crystals Based on Chito-Oligosaccharides. 1. Synthesis of Chitobiose Octaalkanoates and Chitotriose Undecaalkanoates and Their Thermal Properties

Abstract This paper deals with the preparation of two series of chito-oligosaccharide derivatives, chitobiose octaalkanoates, and chitotriose undecaalkanoates, in which the amino- and hydroxyl groups were blocked with alkyl pendants of differing lengths via an ester linkage. By differential scanning calorimetry(DSC) and optical microscopic observations, these compounds were found to exhibit an enantiotropic mesophase at temperatures ranging from ca. 50 °C to ca. 200 °C. The texture of the mesophases were similar to those of the discotic columnar liquid crystals formed by the cellobiose and cellotriose equivalents. However, the amido group in the chito-derivatives seems to stabilize the mesophase to an appreciable extent, bringing about higher temperatures and a longer temperature span of the mesophase than those of the cello-equivalents.

Synthesis of Chitooligosaccharide Derivatives by Condensation Polymerization

Abstract Oligomerization of mono- and oligosaccharide units can be an interesting methodology for synthesis of homooligosaccharides and oligosaccharides having repeating units, respectively. Recently, chitooligosaccharides, especially the hexamer, were shown to have an antitumor effect,2 suppress metastasis3 and protect against microbial infection.4 For the synthesis of these oligomers the ring-opening polymerization of such monomers as 1,6-anhydro5 and 1,2-cyano-ethylidene6 derivatives, which are the effective monomers for polycondensation, cannot be used.