Synthesis and Antioxidant Activity of Cationic 1,2,3-Triazole Functionalized Starch Derivatives

In this study, starch was chemically modified to improve its antioxidant activity. Five novel cationic 1,2,3-triazole functionalized starch derivatives were synthesized by using "click" reaction and N-alkylation. A convenient method for pre-azidation of starch was developed. The structures of the derivatives were analyzed using FTIR and H-1 NMR. The radicals scavenging abilities of the derivatives against hydroxyl radicals, DPPH radicals, and superoxide radicals were tested in vitro in order to evaluate their antioxidant activity. Results revealed that all the cationic starch derivatives (2a-2e), as well as the precursor starch derivatives (1a-1e), had significantly improved antioxidant activity compared to native starch. In particular, the scavenging ability of the derivatives against superoxide radicals was extremely strong. The improved antioxidant activity benefited from the enhanced solubility and the added positive charges. The biocompatibility of the cationic derivatives was confirmed by the low hemolytic rate (<2%). The obtained derivatives in this study have great potential as antioxidant materials that can be applied in the fields of food and biomedicine

Novel 2-Hydroxypropyltrimethyl Ammonium Chitosan Derivatives: Synthesis, Characterization, Moisture Absorption and Retention Properties

Recent years have seen a steady increase in interest and demand for the use of humectants based on biodegradable natural polymers in many fields. The aim of this paper is to investigate the moisture absorption and retention properties of 2-hydroxypropyltrimethyl ammonium chitosan derivatives which were modified by anionic compounds via ion exchange. FTIR, 1H NMR, and 13C NMR spectroscopy were used to demonstrate the specific structures of chitosan derivatives. The degrees of substitution for objective products were calculated by the integral ratio of hydrogen atoms according to 1H NMR spectroscopy. Meanwhile, moisture absorption of specimens was assayed in a desiccator at different relative humidity (RH: 43% and 81%), and all target products exhibited enhanced moisture absorption. Furthermore, moisture retention measurement at different relative humidity (RH: 43%, 81%, and drier silica gel) was estimated, and all target products possessed obviously improved moisture retention property. Specifically, after 48 h later, the moisture retention property of HACBA at 81% RH was 372.34%, which was much higher than HA (180.04%). The present study provided a novel method to synthesize chitosan derivatives with significantly improved moisture absorption and retention properties that would serve as potential humectants in biomedical, food, medicine, and cosmetics fields

Modification of Hydroxypropyltrimethyl Ammonium Chitosan with Organic Acid: Synthesis, Characterization, and Antioxidant Activity

A novel and green method for the preparation of chitosan derivatives bearing organic acids was reported in this paper. In order to improve the antioxidant activity of chitosan, eight different hydroxypropyltrimethyl ammonium chitosan derivatives were successfully designed and synthesized via introducing of organic acids onto chitosan by mild and non-toxic ion exchange. The data of Fourier Transform Infrared (FTIR), C-13 Nuclear Magnetic Resonance (NMR), H-1 NMR, and elemental analysis for chitosan derivatives indicated the successful conjugation of organic acid salt with hydroxypropyltrimethyl ammonium chloride chitosan (HACC). Meanwhile, the antioxidant activity of the chitosan derivatives was evaluated in vitro. The results indicated that the chitosan derivatives possessed dramatic enhancements in DPPH-radical scavenging activity, superoxide-radical scavenging activity, hydroxyl radical scavenging ability, and reducing power. Furthermore, the cytotoxicity of the synthesized compounds was investigated in vitro on L929 cells and showed low cytotoxicity. Thus, the enhanced antioxidant property of all novel chitosan products might be a great advantage, while applied in a wide range of applications in the form of antioxidant in biomedical, food, and cosmetic industry

Highly efficient free radical-scavenging property of phenolic-functionalized chitosan derivatives: Chemicalmodification and activity assessment

Chitosan is an abundant and renewable polysaccharide, and chemical modification can be used to enhance the biological properties of chitosan. In this study, monophenol and ortho-diphenol were introduced to chitosan through chemical modification to get chitosan derivatives owned high antioxidant activity. Their free radical-scavenging activity against three free radicals and reduction ability was tested. Based on the four antioxidant assay, the antioxidant ability of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. The IC50 of inhibition of DPPH, hydroxyl ((OH)-O-center dot), and superoxide (O2 center dot-) radical-scavenging was 41-172, 10-89, and 14-38 mu g/mL, respectively. Meanwhile, ortho-diphenol was more efficient group than monophenol on the improvement of antioxidant ability of chitosan derivatives. The possible free radical-scavenging mechanism, including the number of the hydroxyl groups and the presence ortho-dihydroxy substitution for the antioxidant ability were discussed. In vitro studies demonstrated that the constructed chitosan derivatives have good biocompatibility, and good antioxidant capacity to reduce oxidative stress. Functionalization of chitosan with phenolic group allows the possible applications on the therapy of oxidative-related diseases. (C) 2020 Elsevier B.V. All rights reserved

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

Synthesis and characterization of alpha-lipoic acid grafted chitosan derivatives with antioxidant activity

Here, alpha-lipoic acid (LA) was grafted onto chitosan via EDC/NHS to improve the antioxidant effect. Chitosan acetate was innovatively used as precursor replaced pristine chitosan to synthesize alpha-lipoic acid grafted chitosan derivatives with different grafting ratios. The grafting ratio of LA-g-CS conjugates could be controlled by adjusting the reaction temperature, reaction time, and feed ratio of alpha-lipoic acid to anhydroglucose unit, and the feed ratio is the main factor on the grafting efficiency. The antioxidant results (superoxide anion, hydroxyl, and DPPH radicals scavenging activities, and reducing power) indicated that LA-g-CS displayed significantly enhanced antioxidant activity over pristine chitosan. Moreover, antioxidant efficiency of LA-g-CS showed an ascending tendency with the increasing of the grafting degree. The present study provided a novel synthesis strategy for preparation of alpha-lipoic acid grafted chitosan derivatives that could be a potential antioxidant biomaterial in food and biomedical industries

Novel 2-Hydroxypropyltrimethyl Ammonium Chitosan Derivatives: Synthesis, Characterization, Moisture Absorption and Retention Properties

Recent years have seen a steady increase in interest and demand for the use of humectants based on biodegradable natural polymers in many fields. The aim of this paper is to investigate the moisture absorption and retention properties of 2-hydroxypropyltrimethyl ammonium chitosan derivatives which were modified by anionic compounds via ion exchange. FTIR, H-1 NMR, and C-13 NMR spectroscopy were used to demonstrate the specific structures of chitosan derivatives. The degrees of substitution for objective products were calculated by the integral ratio of hydrogen atoms according to H-1 NMR spectroscopy. Meanwhile, moisture absorption of specimens was assayed in a desiccator at different relative humidity (RH: 43% and 81%), and all target products exhibited enhanced moisture absorption. Furthermore, moisture retention measurement at different relative humidity (RH: 43%, 81%, and drier silica gel) was estimated, and all target products possessed obviously improved moisture retention property. Specifically, after 48 h later, the moisture retention property of HACBA at 81% RH was 372.34%, which was much higher than HA (180.04%). The present study provided a novel method to synthesize chitosan derivatives with significantly improved moisture absorption and retention properties that would serve as potential humectants in biomedical, food, medicine, and cosmetics fields

Facile synthesis, characterization, antioxidant activity, and antibacterial activity of carboxymethyl inulin salt derivatives

A series of novel carboxymethyl inulin derivatives bearing thiosemicarbazide salts, aminoguanidine salts, and aniline salts were prepared via a facile method and employed to evaluate in vitro antioxidant activity and antibacterial activity. Their structures were characterized by Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The characterization results confirmed the successful synthesis of carboxymethyl inulin salt derivatives. The in vitro antioxidant activity evaluation results presented a significant improved superoxide radical scavenging ability, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, and reducing ability of carboxymethyl inulin salt derivatives as compared to inulin and carboxymethyl inulin. In particular, the series of carboxymethyl inulin derivatives containing thiosemicarbazide salts and aminoguanidine salts showed remarkable free radical scavenging ability and reducing ability. Moreover, the carboxymethyl inulin derivatives containing thiosemicarbazide salts and aniline salts displayed potential antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. The cytotoxicity assay was also carried out on L929 cells by CCK-8 method, and all samples showed weak cytotoxicity. Furthermore, hemolysis results showed no hemolytic activity of most prepared inulin derivatives. In summary, the inulin derivatives containing thiosemicarbazide salts exhibited outstanding antioxidant activity, antibacterial activity, and biocompatibility, and the all-inclusive properties highlighted their potential use in food and medical applications

pH sensitive adriamycin-incorporated nanoparticles self-assembled from amphiphilic chitosan derivatives with enhanced antioxidant and antitumor activities

Development of secure and efficient drug delivery systems to overcome physicochemical challenges in cancer clinical treatment is one of the most active fields, and novel drug carriers are actively sought. In this work, the successful synthesis of amphiphilic chitosan derivatives containing pyridine cations and folic acid (TMACMCF) was confirmed by FTIR and 1H NMR spectroscopy. The critical micelle concentration (CMC) of TMACMCF was studied, and the results indicated that it possessed a relatively low CMC (0.186 mg/mL). Self-assembled nanoparticles (TMACMCF-ADM NPs) for the entrapment and delivery of adriamycin (ADM) were synthesized based on TMACMCF, and the morphology, particle size, zeta potential, sustained release performance, antioxidant and antitumor activities, and cytotoxicity were investigated. The particle size of TMACMCF-ADM NPs was 163.79 ± 7.31 nm, and the morphology observed by SEM and TEM showed spherical or oval particles. TMACMCF-ADM NPs showed excellent entrapment of ADM with entrapment efficiency and drug loading efficiency of 65.04 ± 1.20 % and 22.73 ± 0.40 %, respectively. The release performance results showed that in vitro release profiles of ADM from NPs exhibited pH-sensitive controlled and sustained release properties. The assay of antioxidant activity exhibited that TMACMCF-ADM NPs possessed significantly improved scavenging ability against three kinds of radicals (Superoxide-radical, DPPH radical, and ABTS radical). Moreover, the assay of antitumor activity by CCK-8 test exhibited that nanoparticles led to statistically significant enhancement in inhibition index for four kinds of cancer cells (BGC-823, MCF-7, HEPG-2, and A549). This work provides a promising carrier for secure and effective entrapment and delivery of ADM

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 H-1 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