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Open AccessArticle Novel Water Soluble Chitosan Derivatives with 1,2,3-Triazolium and Their Free Radical-Scavenging Activity

by Qing Li, Xueqi Sun, Guodong Gu and Zhanyong Guo

Mar. Drugs 2018, 16(4), 107; https://doi.org/10.3390/md16040107

Received: 9 February 2018 / Revised: 14 March 2018 / Accepted: 24 March 2018 / Published: 28 March 2018

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Abstract

Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium

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Chitosan is an abundant and renewable polysaccharide, which exhibits attractive bioactivities and natural properties. Improvement such as chemical modification of chitosan is often performed for its potential of providing high bioactivity and good water solubility. A new class of chitosan derivatives possessing 1,2,3-triazolium charged units by associating “click reaction” with efficient 1,2,3-triazole quaternization were designed and synthesized. Their free radical-scavenging activity against three free radicals was tested. The inhibitory property and water solubility of the synthesized chitosan derivatives exhibited a remarkable improvement over chitosan. It is hypothesized that triazole or triazolium groups enable the synthesized chitosan to possess obviously better radical-scavenging activity. Moreover, the scavenging activity against superoxide radical of chitosan derivatives with triazolium (IC₅₀ < 0.01 mg mL⁻¹) was more efficient than that of derivatives with triazole and Vitamin C. In the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical-scavenging assay, the same pattern were observed, which should be related to the triazolium grafted at the periphery of molecular chains. Full article

(This article belongs to the Special Issue Marine Chitin)

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Open AccessArticle First Report on Chitin in a Non-Verongiid Marine Demosponge: The Mycale euplectellioides Case

by Sonia Żółtowska-Aksamitowska, Lamiaa A. Shaala, Diaa T. A. Youssef, Sameh S. Elhady, Mikhail V. Tsurkan, Iaroslav Petrenko, Marcin Wysokowski, Konstantin Tabachnick, Heike Meissner, Viatcheslav N. Ivanenko, Nicole Bechmann, Yvonne Joseph, Teofil Jesionowski and Hermann Ehrlich

Mar. Drugs 2018, 16(2), 68; https://doi.org/10.3390/md16020068

Received: 7 January 2018 / Revised: 8 February 2018 / Accepted: 16 February 2018 / Published: 20 February 2018

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Abstract

Sponges (Porifera) are recognized as aquatic multicellular organisms which developed an effective biochemical pathway over millions of years of evolution to produce both biologically active secondary metabolites and biopolymer-based skeletal structures. Among marine demosponges, only representatives of the Verongiida order are known to

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Sponges (Porifera) are recognized as aquatic multicellular organisms which developed an effective biochemical pathway over millions of years of evolution to produce both biologically active secondary metabolites and biopolymer-based skeletal structures. Among marine demosponges, only representatives of the Verongiida order are known to synthetize biologically active substances as well as skeletons made of structural polysaccharide chitin. The unique three-dimensional (3D) architecture of such chitinous skeletons opens the widow for their recent applications as adsorbents, as well as scaffolds for tissue engineering and biomimetics. This study has the ambitious goal of monitoring other orders beyond Verongiida demosponges and finding alternative sources of naturally prestructured chitinous scaffolds; especially in those demosponge species which can be cultivated at large scales using marine farming conditions. Special attention has been paid to the demosponge Mycale euplectellioides (Heteroscleromorpha: Poecilosclerida: Mycalidae) collected in the Red Sea. For the first time, we present here a detailed study of the isolation of chitin from the skeleton of this sponge, as well as its identification using diverse bioanalytical tools. Calcofluor white staining, Fourier-transform Infrared Spcetcroscopy (FTIR), electrospray ionization mass spectrometry (ESI-MS), scanning electron microscopy (SEM), and fluorescence microscopy, as well as a chitinase digestion assay were applied in order to confirm with strong evidence the finding of a-chitin in the skeleton of M. euplectellioides. We suggest that the discovery of chitin within representatives of the Mycale genus is a promising step in their evaluation of these globally distributed sponges as new renewable sources for both biologically active metabolites and chitin, which are of prospective use for pharmacology and biomaterials oriented biomedicine, respectively. Full article

(This article belongs to the Special Issue Marine Chitin)

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Open AccessArticle Low Molecular Weight Chitosan-Insulin Complexes Solubilized in a Mixture of Self-Assembled Labrosol and Plurol Oleaque and Their Glucose Reduction Activity in Rats

by Amani M. Elsayed, Aseel H. Khaled, Mayyas M. Al Remawi, Nidal A. Qinna, Hussam Abu Farsakh and Adnan A. Badwan

Mar. Drugs 2018, 16(1), 32; https://doi.org/10.3390/md16010032

Received: 10 December 2017 / Revised: 4 January 2018 / Accepted: 10 January 2018 / Published: 16 January 2018

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Abstract

Oral insulin delivery that better mimics physiological pathways is a necessity as it ensures patient comfort and compliance. A system which is based on a vehicle of nano order where positively charged chitosan interacts with negatively charged insulin and forms a polyelectrolyte complex

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Oral insulin delivery that better mimics physiological pathways is a necessity as it ensures patient comfort and compliance. A system which is based on a vehicle of nano order where positively charged chitosan interacts with negatively charged insulin and forms a polyelectrolyte complex (PEC) solubilizate, which is then solubilized into an oily phase of oleic acid, labrasol, and plurol oleaque-protects insulin against enzymatic gastrointestinal reduction. The use of an anionic fatty acid in the oily phase, such as oleic acid, is thought to allow an interaction with cationic chitosan, hence reducing particle size. Formulations were assessed based on their hypoglycaemic capacities in diabetic rats as compared to conventional subcutaneous dosage forms. 50 IU/kg oral insulin strength could only induce blood glucose reduction equivalent to that of 5 IU/kg (1 International unit = 0.0347 mg of human insulin). Parameters that influence the pharmacological availability were evaluated. A preliminary investigation of the mechanism of absorption suggests the involvement of the lymphatic route. Full article

(This article belongs to the Special Issue Marine Chitin)

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Open AccessArticle Determination of the Deacetylation Degree of Chitooligosaccharides

by Yao Jiang, Chuhan Fu, Sihui Wu, Guihua Liu, Jiao Guo and Zhengquan Su

Mar. Drugs 2017, 15(11), 332; https://doi.org/10.3390/md15110332

Received: 25 August 2017 / Revised: 12 October 2017 / Accepted: 23 October 2017 / Published: 25 October 2017

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Abstract

The methods for determination of chitosan content recommended in the Chinese Pharmacopoeia and the European Pharmacopoeia are not applicable for evaluation of the extent of deacetylation (deacetylation degree, DD) in chitooligosaccharides (COS). This study explores two different methods for assessment of DD in

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The methods for determination of chitosan content recommended in the Chinese Pharmacopoeia and the European Pharmacopoeia are not applicable for evaluation of the extent of deacetylation (deacetylation degree, DD) in chitooligosaccharides (COS). This study explores two different methods for assessment of DD in COS having relatively high and low molecular weights: an acid-base titration with bromocresol green indicator and a first order derivative UV spectrophotometric method for assessment of DD in COS. The accuracy of both methods as a function of molecular weight was also investigated and compared to results obtained using ¹H NMR spectroscopy. Our study demonstrates two simple, fast, widely adaptable, highly precise, accurate, and inexpensive methods for the effective determination of DD in COS, which have the potential for widespread commercial applications in developing country. Full article

(This article belongs to the Special Issue Marine Chitin)

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Open AccessArticle Effect of Protonation State and N-Acetylation of Chitosan on Its Interaction with Xanthan Gum: A Molecular Dynamics Simulation Study

by Suha M. Dadou, Musa I. El-Barghouthi, Samer K. Alabdallah, Adnan A. Badwan, Milan D. Antonijevic and Babur Z. Chowdhry

Mar. Drugs 2017, 15(10), 298; https://doi.org/10.3390/md15100298

Received: 17 August 2017 / Revised: 17 September 2017 / Accepted: 20 September 2017 / Published: 25 September 2017

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Abstract

Hydrophilic matrices composed of chitosan (CS) and xanthan gum (XG) complexes are of pharmaceutical interest in relation to drug delivery due to their ability to control the release of active ingredients. Molecular dynamics simulations (MDs) have been performed in order to obtain information

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Hydrophilic matrices composed of chitosan (CS) and xanthan gum (XG) complexes are of pharmaceutical interest in relation to drug delivery due to their ability to control the release of active ingredients. Molecular dynamics simulations (MDs) have been performed in order to obtain information pertaining to the effect of the state of protonation and degree of N-acetylation (DA) on the molecular conformation of chitosan and its ability to interact with xanthan gum in aqueous solutions. The conformational flexibility of CS was found to be highly dependent on its state of protonation. Upon complexation with XG, a substantial restriction in free rotation around the glycosidic bond was noticed in protonated CS dimers regardless of their DA, whereas deprotonated molecules preserved their free mobility. Calculated values for the free energy of binding between CS and XG revealed the dominant contribution of electrostatic forces on the formation of complexes and that the most stable complexes were formed when CS was at least half-protonated and the DA was ≤50%. The results obtained provide an insight into the main factors governing the interaction between CS and XG, such that they can be manipulated accordingly to produce complexes with the desired controlled-release effect. Full article

(This article belongs to the Special Issue Marine Chitin)

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Open AccessArticle Production of Chitin from Penaeus vannamei By-Products to Pilot Plant Scale Using a Combination of Enzymatic and Chemical Processes and Subsequent Optimization of the Chemical Production of Chitosan by Response Surface Methodology

by José A. Vázquez, Patrícia Ramos, Jesús Mirón, Jesus Valcarcel, Carmen G. Sotelo and Ricardo I. Pérez-Martín

Mar. Drugs 2017, 15(6), 180; https://doi.org/10.3390/md15060180

Received: 12 May 2017 / Revised: 5 June 2017 / Accepted: 9 June 2017 / Published: 16 June 2017

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Abstract

The waste generated from shrimp processing contains valuable materials such as protein, carotenoids, and chitin. The present study describes a process at pilot plant scale to recover chitin from the cephalothorax of Penaeus vannamei using mild conditions. The application of a sequential enzymatic–acid–alkaline

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The waste generated from shrimp processing contains valuable materials such as protein, carotenoids, and chitin. The present study describes a process at pilot plant scale to recover chitin from the cephalothorax of Penaeus vannamei using mild conditions. The application of a sequential enzymatic–acid–alkaline treatment yields 30% chitin of comparable purity to commercial sources. Effluents from the process are rich in protein and astaxanthin, and represent inputs for further by-product recovery. As a last step, chitin is deacetylated to produce chitosan; the optimal conditions are established by applying a response surface methodology (RSM). Under these conditions, deacetylation reaches 92% as determined by Proton Nuclear Magnetic Resonance (¹H-NMR), and the molecular weight (Mw) of chitosan is estimated at 82 KDa by gel permeation chromatography (GPC). Chitin and chitosan microstructures are characterized by Scanning Electron Microscopy (SEM). Full article

(This article belongs to the Special Issue Marine Chitin)

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Open AccessArticle Preparation and Characterization of Chitosan Obtained from Shells of Shrimp (Litopenaeus vannamei Boone)

by Rayane Santa Cruz Martins de Queiroz Antonino, Bianca Rosa Paschoal Lia Fook, Vítor Alexandre de Oliveira Lima, Raid Ícaro de Farias Rached, Eunice Paloma Nascimento Lima, Rodrigo José da Silva Lima, Carlos Andrés Peniche Covas and Marcus Vinícius Lia Fook

Mar. Drugs 2017, 15(5), 141; https://doi.org/10.3390/md15050141

Received: 5 April 2017 / Revised: 3 May 2017 / Accepted: 8 May 2017 / Published: 15 May 2017

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Abstract

The main source of commercial chitosan is the extensive deacetylation of its parent polymer chitin. It is present in green algae, the cell walls or fungi and in the exoskeleton of crustaceans. A novel procedure for preparing chitosan from shrimp shells was developed.

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The main source of commercial chitosan is the extensive deacetylation of its parent polymer chitin. It is present in green algae, the cell walls or fungi and in the exoskeleton of crustaceans. A novel procedure for preparing chitosan from shrimp shells was developed. The procedure involves two 10-minutes bleaching steps with ethanol after the usual demineralization and deproteinization processes. Before deacetylation, chitin was immersed in 12.5 M NaOH, cooled down and kept frozen for 24 h. The obtained chitosan was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), UV, X-ray diffraction (XRD) and viscosimetry. Samples of white chitosan with acetylation degrees below

9 %

were obtained, as determined by FTIR and UV-first derivative spectroscopy. The change in the morphology of samples was followed by SEM. The ash content of chitosan samples were all below

0.063 %

. Chitosan was soluble in

1 %

acetic acid with insoluble contents of

0.62 %

or less. XRD patterns exhibited the characteristic peaks of chitosan centered at 10 and 20 degrees in

2 θ

. The molecular weight of chitosan was between 2.3 and 2.8

\times 10^{5}

g/mol. It is concluded that the procedure developed in the present work allowed obtaining chitosans with physical and chemical properties suitable for pharmaceutical applications. Full article

(This article belongs to the Special Issue Marine Chitin)

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Open AccessArticle Bioresponsive Materials for Drug Delivery Based on Carboxymethyl Chitosan/Poly(γ-Glutamic Acid) Composite Microparticles

by Xiaoting Yan, Zongrui Tong, Yu Chen, Yanghe Mo, Huaiyu Feng, Peng Li, Xiaosai Qu and Shaohua Jin

Mar. Drugs 2017, 15(5), 127; https://doi.org/10.3390/md15050127

Received: 27 March 2017 / Revised: 14 April 2017 / Accepted: 17 April 2017 / Published: 28 April 2017

Cited by 5 | PDF Full-text (11958 KB) | HTML Full-text | XML Full-text | Supplementary Files

Abstract

Carboxymethyl chitosan (CMCS) microparticles are a potential candidate for hemostatic wound dressing. However, its low swelling property limits its hemostatic performance. Poly(γ-glutamic acid) (PGA) is a natural polymer with excellent hydrophilicity. In the current study, a novel CMCS/PGA composite microparticles with a dual-network

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Carboxymethyl chitosan (CMCS) microparticles are a potential candidate for hemostatic wound dressing. However, its low swelling property limits its hemostatic performance. Poly(γ-glutamic acid) (PGA) is a natural polymer with excellent hydrophilicity. In the current study, a novel CMCS/PGA composite microparticles with a dual-network structure was prepared by the emulsification/internal gelation method. The structure and thermal stability of the composite were determined by Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The effects of preparation conditions on the swelling behavior of the composite were investigated. The results indicate that the swelling property of CMCS/PGA composite microparticles is pH sensitive. Levofloxacin (LFX) was immobilized in the composite microparticles as a model drug to evaluate the drug delivery performance of the composite. The release kinetics of LFX from the composite microparticles with different structures was determined. The results suggest that the CMCS/PGA composite microparticles are an excellent candidate carrier for drug delivery. Full article

(This article belongs to the Special Issue Marine Chitin)

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