E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Special Issue "Marine Chitin and Chitosan"

Quicklinks

A special issue of Marine Drugs (ISSN 1660-3397).

Deadline for manuscript submissions: closed (28 February 2010)

Special Issue Editor

Guest Editor
Prof. Dr. Riccardo A. A. Muzzarelli (Website)

Via Volterra, 7, 60123 Ancona, Italy
Phone: +39 071 36206/220 6068
Fax: +39-071-36206

Special Issue Information

Dear Colleagues,

Chitin can be interpreted as the most abundant organic compound of nitrogen. Current sources are the crustacean shells isolated as by-products of canning / freezing operations in marine food factories. Mechanical peeling and enzyme inactivation are pre-requisites for treating the chitin-bearing biomass. Immediately after isolation, chitin is transformed into chitosans of various grades. Chemical, physical and enzymatic deacetylation methods are available for the production of chitosan, the sole abundantly accessible cationic polysaccharide. Manipulation of the molecular weight leads to water-soluble chitosans: the randomly 50 % deacetylated, and the partially depolymerized chitosans are water-soluble. Advanced water-soluble modified chitosans are also available, as well as new solvent systems. Purification methods from proteins, carotenoids and inorganics enable to produce chitosans of technical, food, pharmaceutical and medical grades, that are officially recognized as safe in a large number of countries. The industrial production of N-acetylglucosamine and glucosamine is based on the depolymerization of chitosan from marine crustaceans. Due to different crystallinity, chitosan obtained from squid chitin is more prone to chemical modification because the nanofibrillar structure of chitin and chitosan has a certain technical significance. Chitosans in novel physico-chemical forms include composites, electrospun nanofibers, polyelectrolyte complexes, blends with neutral polysaccharides (cellulose, starch...), silylated and otherwise cross-linked chitosans, metal ion chelates, and films for marine food protection. Chitin and chitosan are not drugs sensu stricto, but exhibit peculiar characteristics that recently qualified them in the biomedical field, for example as carriers for drug delivery, chitosan being the best DNA vector for gene therapy. Chitosan exerts immuno-stimulating effects, and it is not seen as a foreign body by human cells. The antimicrobial activity of chitosans has been elucidated for numerous bacteria and some fungi. This special issue is expected to encourage a wider exploitation of the marine chitin resources, and the scaling-up of certain applications, particularly in the pharmaceutical area.

Prof. Dr. Riccardo A.A. Muzzarelli
Guest Editor

Keywords

  • chitin
  • chitosan
  • crustaceans
  • squid
  • quality assessment
  • N-acetylglucosamine
  • glucosamine
  • pharmaceuticals
  • antimicrobials
  • drug carriers

Related Special Issues

Published Papers (14 papers)

View options order results:
result details:
Displaying articles 1-14
Export citation of selected articles as:

Research

Jump to: Review

Open AccessArticle Preparation and Characterization of Chitosan Poly(acrylic acid) Magnetic Microspheres
Mar. Drugs 2010, 8(7), 2212-2222; doi:10.3390/md8072212
Received: 16 June 2010 / Revised: 3 July 2010 / Accepted: 7 July 2010 / Published: 23 July 2010
Cited by 26 | PDF Full-text (340 KB) | HTML Full-text | XML Full-text
Abstract
Spherical microparticles, capable of responding to magnetic fields, were prepared by encapsulating dextran-coated Fe3O4 nanoparticles into chitosan poly(acrylic acid) (PAA) microspheres template. The obtained magnetic microspheres were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning [...] Read more.
Spherical microparticles, capable of responding to magnetic fields, were prepared by encapsulating dextran-coated Fe3O4 nanoparticles into chitosan poly(acrylic acid) (PAA) microspheres template. The obtained magnetic microspheres were characterized by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray powder diffraction (XRD), and thermogravimetry (TG). The results showed that the microspheres were formed and demonstrated magnetic behavior in an applied magnetic field. In addition, magnetite particles were well encapsulated and the composite particles have high magnetite content, which was more than 40%. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessArticle Chitosan-Genipin Microspheres for the Controlled Release of Drugs: Clarithromycin, Tramadol and Heparin
Mar. Drugs 2010, 8(6), 1750-1762; doi:10.3390/md8061750
Received: 10 March 2010 / Revised: 23 April 2010 / Accepted: 17 May 2010 / Published: 26 May 2010
Cited by 31 | PDF Full-text (378 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this study was to first evaluate whether the chitosan hydrochloride-genipin crosslinking reaction is influenced by factors such as time, and polymer/genipin concentration, and second, to develop crosslinked drug loaded microspheres to improve the control over drug release. Once the [...] Read more.
The aim of this study was to first evaluate whether the chitosan hydrochloride-genipin crosslinking reaction is influenced by factors such as time, and polymer/genipin concentration, and second, to develop crosslinked drug loaded microspheres to improve the control over drug release. Once the crosslinking process was characterized as a function of the factors mentioned above, drug loaded hydrochloride chitosan microspheres with different degrees of crosslinking were obtained. Microspheres were characterized in terms of size, morphology, drug content, surface charge and capacity to control in vitro drug release. Clarithromycin, tramadol hydrochloride, and low molecular weight heparin (LMWH) were used as model drugs. The obtained particles were spherical, positively charged, with a diameter of 1–10 μm. X-Ray diffraction showed that there was an interaction of genipin and each drug with chitosan in the microspheres. In relation to the release profiles, a higher degree of crosslinking led to more control of drug release in the case of clarithromycin and tramadol. For these drugs, optimal release profiles were obtained for microspheres crosslinked with 1 mM genipin at 50 ºC for 5 h and with 5 mM genipin at 50 ºC for 5 h, respectively. In LMWH microspheres, the best release profile corresponded to 0.5 mM genipin, 50 ºC, 5 h. In conclusion, genipin showed to be eligible as a chemical-crosslinking agent delaying the outflow of drugs from the microspheres. However, more studies in vitro and in vivo must be carried out to determine adequate crosslinking conditions for different drugs. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessArticle Evaluation of Three Chitin Metal Silicate Co-Precipitates as a Potential Multifunctional Single Excipient in Tablet Formulations
Mar. Drugs 2010, 8(5), 1699-1715; doi:10.3390/md8051699
Received: 9 March 2010 / Revised: 15 April 2010 / Accepted: 26 April 2010 / Published: 25 May 2010
Cited by 7 | PDF Full-text (168 KB) | HTML Full-text | XML Full-text
Abstract
The performance of the novel chitin metal silicate (CMS) co-precipitates as a single multifunctional excipient in tablet formulation using direct compression and wet granulation methods is evaluated. The neutral, acidic, and basic drugs Spironolactone (SPL), ibuprofen (IBU) and metronidazole (MET), respectively, were used as model drugs. Commercial Aldactone®, Fleximex® and Dumazole® tablets containing SPL, IBU and MET, respectively, and tablets made using Avicel® 200, were used in the study for comparison purposes. Tablets of acceptable crushing strength (>40 N) were obtained using CMS. The friability values for all tablets were well below the maximum 1% USP tolerance limit. CMS produced superdisintegrating tablets (disintegration time < 1 min) with the three model drugs. Regarding the dissolution rate, the sequence was as follow: CMS > Fleximex® > Avicel® 200, CMS > Avicel® 200 > Dumazole® and Aldactone® > Avicel® 200 > CMS for IBU, MET and SPL, respectively. Compressional properties of formulations were analyzed using density measurements and the compression Kawakita equation as assessment parameters. On the basis of DSC results, CMS co precipitates were found to be compatible with the tested drugs. Conclusively, the CMS co-precipitates have the potential to be used as filler, binder, and superdisintegrant, all-in-one, in the design of tablets by the direct compression as well as wet granulation methods. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessArticle Bioadhesive Controlled Metronidazole Release Matrix Based on Chitosan and Xanthan Gum
Mar. Drugs 2010, 8(5), 1716-1730; doi:10.3390/md8051716
Received: 9 March 2010 / Revised: 23 March 2010 / Accepted: 6 April 2010 / Published: 25 May 2010
Cited by 16 | PDF Full-text (205 KB) | HTML Full-text | XML Full-text
Abstract
Metronidazole, a common antibacterial drug, was incorporated into a hydrophilic polymer matrix composed of chitosan xanthan gum mixture. Hydrogel formation of this binary chitosan-xanthan gum combination was tested for its ability to control the release of metronidazole as a drug model. This [...] Read more.
Metronidazole, a common antibacterial drug, was incorporated into a hydrophilic polymer matrix composed of chitosan xanthan gum mixture. Hydrogel formation of this binary chitosan-xanthan gum combination was tested for its ability to control the release of metronidazole as a drug model. This preparation (MZ-CR) was characterized by in vitro, ex vivo bioadhesion and in vivo bioavailability study. For comparison purposes a commercial extended release formulation of metronidazole (CMZ) was used as a reference. The in vitro drug-release profiles of metronidazole preparation and CMZ were similar in 0.1 M HCl and phosphate buffer pH 6.8. Moreover, metronidazole preparation and CMZ showed a similar detachment force to sheep stomach mucosa, while the bioadhesion of the metronidazole preparation was higher three times than CMZ to sheep duodenum. The results of in vivo study indicated that the absorption of metronidazole from the preparation was faster than that of CMZ. Also, MZ-CR leads to higher metronidazole Cmax and AUC relative to that of the CMZ. This increase in bioavailability might be explained by the bioadhesion of the preparation at the upper part of the small intestine that could result in an increase in the overall intestinal transit time. As a conclusion, formulating chitosan-xanthan gum mixture as a hydrophilic polymer matrix resulted in a superior pharmacokinetic parameters translated by better rate and extent of absorption of metronidazole. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)

Review

Jump to: Research

Open AccessReview N-Acetylglucosamine: Production and Applications
Mar. Drugs 2010, 8(9), 2493-2516; doi:10.3390/md8092493
Received: 22 March 2010 / Revised: 19 April 2010 / Accepted: 23 April 2010 / Published: 15 September 2010
Cited by 63 | PDF Full-text (427 KB) | HTML Full-text | XML Full-text
Abstract
N-Acetylglucosamine (GlcNAc) is a monosaccharide that usually polymerizes linearly through (1,4)-β-linkages. GlcNAc is the monomeric unit of the polymer chitin, the second most abundant carbohydrate after cellulose. In addition to serving as a component of this homogeneous polysaccharide, GlcNAc is also [...] Read more.
N-Acetylglucosamine (GlcNAc) is a monosaccharide that usually polymerizes linearly through (1,4)-β-linkages. GlcNAc is the monomeric unit of the polymer chitin, the second most abundant carbohydrate after cellulose. In addition to serving as a component of this homogeneous polysaccharide, GlcNAc is also a basic component of hyaluronic acid and keratin sulfate on the cell surface. In this review, we discuss the industrial production of GlcNAc, using chitin as a substrate, by chemical, enzymatic and biotransformation methods. Also, newly developed methods to obtain GlcNAc using glucose as a substrate in genetically modified microorganisms are introduced. Moreover, GlcNAc has generated interest not only as an underutilized resource but also as a new functional material with high potential in various fields. Here we also take a closer look at the current applications of GlcNAc, and several new and cutting edge approaches in this fascinating area are thoroughly discussed. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Chitin Research Revisited
Mar. Drugs 2010, 8(7), 1988-2012; doi:10.3390/md8071988
Received: 2 May 2010 / Revised: 24 May 2010 / Accepted: 8 June 2010 / Published: 28 June 2010
Cited by 78 | PDF Full-text (268 KB) | HTML Full-text | XML Full-text
Abstract
Two centuries after the discovery of chitin, it is widely accepted that this biopolymer is an important biomaterial in many aspects. Numerous studies on chitin have focused on its biomedical applications. In this review, various aspects of chitin research including sources, structure, [...] Read more.
Two centuries after the discovery of chitin, it is widely accepted that this biopolymer is an important biomaterial in many aspects. Numerous studies on chitin have focused on its biomedical applications. In this review, various aspects of chitin research including sources, structure, biosynthesis, chitinolytic enzyme, chitin binding protein, genetic engineering approach to produce chitin, chitin and evolution, and a wide range of applications in bio- and nanotechnology will be dealt with. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Chitosan Modification and Pharmaceutical/Biomedical Applications
Mar. Drugs 2010, 8(7), 1962-1987; doi:10.3390/md8071962
Received: 20 April 2010 / Revised: 29 May 2010 / Accepted: 9 June 2010 / Published: 25 June 2010
Cited by 102 | PDF Full-text (310 KB) | HTML Full-text | XML Full-text
Abstract
Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the [...] Read more.
Chitosan has received much attention as a functional biopolymer for diverse applications, especially in pharmaceutics and medicine. Our recent efforts focused on the chemical and biological modification of chitosan in order to increase its solubility in aqueous solutions and absorbability in the in vivo system, thus for a better use of chitosan. This review summarizes chitosan modification and its pharmaceutical/biomedical applications based on our achievements as well as the domestic and overseas developments: (1) enzymatic preparation of low molecular weight chitosans/chitooligosaccharides with their hypocholesterolemic and immuno-modulating effects; (2) the effects of chitin, chitosan and their derivatives on blood hemostasis; and (3) synthesis of a non-toxic ion ligand—D-Glucosaminic acid from Oxidation of D-Glucosamine for cancer and diabetes therapy. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Application of Spectroscopic Methods for Structural Analysis of Chitin and Chitosan
Mar. Drugs 2010, 8(5), 1567-1636; doi:10.3390/md8051567
Received: 8 March 2010 / Revised: 30 March 2010 / Accepted: 27 April 2010 / Published: 29 April 2010
Cited by 154 | PDF Full-text (1140 KB) | HTML Full-text | XML Full-text
Abstract
Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this [...] Read more.
Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Figures

Open AccessReview Chitin and Chitosan as Multipurpose Natural Polymers for Groundwater Arsenic Removal and As2O3 Delivery in Tumor Therapy
Mar. Drugs 2010, 8(5), 1518-1525; doi:10.3390/md8051518
Received: 27 March 2010 / Revised: 23 April 2010 / Accepted: 26 April 2010 / Published: 28 April 2010
Cited by 16 | PDF Full-text (137 KB) | HTML Full-text | XML Full-text
Abstract
Chitin and chitosan are natural polysaccharide polymers. These polymers have been used in several agricultural, food protection and nutraceutical applications. Moreover, chitin and chitosan have been also used in biomedical and biotechnological applications as drug delivery systems or in pharmaceutical formulations. So [...] Read more.
Chitin and chitosan are natural polysaccharide polymers. These polymers have been used in several agricultural, food protection and nutraceutical applications. Moreover, chitin and chitosan have been also used in biomedical and biotechnological applications as drug delivery systems or in pharmaceutical formulations. So far, there are only few studies dealing with arsenic (As) removal from groundwater using chitin or chitosan and no evidence of the use of these natural polymers for arsenic trioxide (As2O3) delivery in tumor therapy. Here we suggest that chitin and/or chitosan might have the right properties to be employed as efficient polymers for such applications. Besides, nanotechnology offers suitable tools for the fabrication of novel nanostructured materials of natural origin. Since different nanostructured materials have already been employed successfully in various multidisciplinary fields, we expect that the integration of nanotechnology and natural polymer chemistry will further lead to innovative applications for environment and medicine. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Figures

Open AccessReview Production of Chitooligosaccharides and Their Potential Applications in Medicine
Mar. Drugs 2010, 8(5), 1482-1517; doi:10.3390/md8051482
Received: 5 March 2010 / Revised: 14 April 2010 / Accepted: 23 April 2010 / Published: 27 April 2010
Cited by 143 | PDF Full-text (1047 KB) | HTML Full-text | XML Full-text
Abstract
Chitooligosaccharides (CHOS) are homo- or heterooligomers of N-acetylglucosamine and D-glucosamine. CHOS can be produced using chitin or chitosan as a starting material, using enzymatic conversions, chemical methods or combinations thereof. Production of well-defined CHOS-mixtures, or even pure CHOS, is of [...] Read more.
Chitooligosaccharides (CHOS) are homo- or heterooligomers of N-acetylglucosamine and D-glucosamine. CHOS can be produced using chitin or chitosan as a starting material, using enzymatic conversions, chemical methods or combinations thereof. Production of well-defined CHOS-mixtures, or even pure CHOS, is of great interest since these oligosaccharides are thought to have several interesting bioactivities. Understanding the mechanisms underlying these bioactivities is of major importance. However, so far in-depth knowledge on the mode-of-action of CHOS is scarce, one major reason being that most published studies are done with badly characterized heterogeneous mixtures of CHOS. Production of CHOS that are well-defined in terms of length, degree of N-acetylation, and sequence is not straightforward. Here we provide an overview of techniques that may be used to produce and characterize reasonably well-defined CHOS fractions. We also present possible medical applications of CHOS, including tumor growth inhibition and inhibition of TH2-induced inflammation in asthma, as well as use as a bone-strengthener in osteoporosis, a vector for gene delivery, an antibacterial agent, an antifungal agent, an anti-malaria agent, or a hemostatic agent in wound-dressings. By using well-defined CHOS-mixtures it will become possible to obtain a better understanding of the mechanisms underlying these bioactivities. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Chitosan Based Polyelectrolyte Complexes as Potential Carrier Materials in Drug Delivery Systems
Mar. Drugs 2010, 8(4), 1305-1322; doi:10.3390/md8041305
Received: 9 February 2010 / Revised: 17 March 2010 / Accepted: 22 March 2010 / Published: 19 April 2010
Cited by 140 | PDF Full-text (385 KB) | HTML Full-text | XML Full-text
Abstract
Chitosan has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. However, one [...] Read more.
Chitosan has been the subject of interest for its use as a polymeric drug carrier material in dosage form design due to its appealing properties such as biocompatibility, biodegradability, low toxicity and relatively low production cost from abundant natural sources. However, one drawback of using this natural polysaccharide in modified release dosage forms for oral administration is its fast dissolution rate in the stomach. Since chitosan is positively charged at low pH values (below its pKa value), it spontaneously associates with negatively charged polyions in solution to form polyelectrolyte complexes. These chitosan based polyelectrolyte complexes exhibit favourable physicochemical properties with preservation of chitosan’s biocompatible characteristics. These complexes are therefore good candidate excipient materials for the design of different types of dosage forms. It is the aim of this review to describe complexation of chitosan with selected natural and synthetic polyanions and to indicate some of the factors that influence the formation and stability of these polyelectrolyte complexes. Furthermore, recent investigations into the use of these complexes as excipients in drug delivery systems such as nano- and microparticles, beads, fibers, sponges and matrix type tablets are briefly described. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Chitosan in Plant Protection
Mar. Drugs 2010, 8(4), 968-987; doi:10.3390/md8040968
Received: 12 March 2010 / Revised: 24 March 2010 / Accepted: 29 March 2010 / Published: 30 March 2010
Cited by 94 | PDF Full-text (134 KB) | HTML Full-text | XML Full-text
Abstract
Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. [...] Read more.
Chitin and chitosan are naturally-occurring compounds that have potential in agriculture with regard to controlling plant diseases. These molecules were shown to display toxicity and inhibit fungal growth and development. They were reported to be active against viruses, bacteria and other pests. Fragments from chitin and chitosan are known to have eliciting activities leading to a variety of defense responses in host plants in response to microbial infections, including the accumulation of phytoalexins, pathogen-related (PR) proteins and proteinase inhibitors, lignin synthesis, and callose formation. Based on these and other proprieties that help strengthen host plant defenses, interest has been growing in using them in agricultural systems to reduce the negative impact of diseases on yield and quality of crops. This review recapitulates the properties and uses of chitin, chitosan, and their derivatives, and will focus on their applications and mechanisms of action during plant-pathogen interactions. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Chitins and Chitosans as Immunoadjuvants and Non-Allergenic Drug Carriers
Mar. Drugs 2010, 8(2), 292-312; doi:10.3390/md8020292
Received: 27 January 2010 / Accepted: 20 February 2010 / Published: 21 February 2010
Cited by 169 | PDF Full-text (161 KB) | HTML Full-text | XML Full-text
Abstract
Due to the fact that some individuals are allergic to crustaceans, the presumed relationship between allergy and the presence of chitin in crustaceans has been investigated. In vivo, chitin is part of complex structures with other organic and inorganic compounds: in [...] Read more.
Due to the fact that some individuals are allergic to crustaceans, the presumed relationship between allergy and the presence of chitin in crustaceans has been investigated. In vivo, chitin is part of complex structures with other organic and inorganic compounds: in arthropods chitin is covalently linked to proteins and tanned by quinones, in fungi it is covalently linked to glucans, while in bacteria chitin is diversely combined according to Gram(+/-) classification. On the other hand, isolated, purified chitin is a plain polysaccharide that, at the nano level, presents itself as a highly associated structure, recently refined in terms of regularity, nature of bonds, crystallinity degree and unusual colloidal behavior. Chitins and modified chitins exert a number of beneficial actions, i.e., (i) they stimulate macrophages by interacting with receptors on the macrophage surface that mediate the internalization of chitin particles to be degraded by lysozyme and N-acetyl-β-glucosaminidase (such as Nod-like, Toll-like, lectin, Dectin-1, leukotriene 134 and mannose receptors); (ii) the macrophages produce cytokines and other compounds that confer non-specific host resistance against bacterial and viral infections, and anti-tumor activity; (iii) chitin is a strong Th1 adjuvant that up-regulates Th1 immunity induced by heat-killed Mycobacterium bovis, while down- regulating Th2 immunity induced by mycobacterial protein; (iv) direct intranasal application of chitin microparticles into the lung was also able to significantly down-regulate allergic response to Dermatophagoids pteronyssinus and Aspergillus fumigatus in a murine model of allergy; (v) chitin microparticles had a beneficial effect in preventing and treating histopathologic changes in the airways of asthmatic mice; (vi) authors support the fact that chitin depresses the development of adaptive type 2 allergic responses. Since the expression of chitinases, chitrotriosidase and chitinase-like proteins is greatly amplified during many infections and diseases, the common feature of chitinase-like proteins and chitinase activity in all organisms appears to be the biochemical defense of the host. Unfortunately, conceptual and methodological errors are present in certain recent articles dealing with chitin and allergy, i.e., (1) omitted consideration of mammalian chitinase and/or chitotriosidase secretion, accompanied by inactive chitinase-like proteins, as an ancestral defensive means against invasion, capable to prevent the insurgence of allergy; (2) omitted consideration of the fact that the mammalian organism recognizes more promptly the secreted water soluble chitinase produced by a pathogen, rather than the insoluble and well protected chitin within the pathogen itself; (3) superficial and incomplete reports and investigations on chitin as an allergen, without mentioning the potent allergen from crustacean flesh, tropomyosine; (4) limited perception of the importance of the chemical/biochemical characteristics of the isolated chitin or chitosan for the replication of experiments and optimization of results; and (5) lack of interdisciplinarity. There is quite a large body of knowledge today on the use of chitosans as biomaterials, and more specifically as drug carriers for a variety of applications: the delivery routes being the same as those adopted for the immunological studies. Said articles, that devote attention to the safety and biocompatibility aspects, never reported intolerance or allergy in individuals and animals, even when the quantities of chitosan used in single experiments were quite large. Therefore, it is concluded that crab, shrimp, prawn and lobster chitins, as well as chitosans of all grades, once purified, should not be considered as "crustacean derivatives", because the isolation procedures have removed proteins, fats and other contaminants to such an extent as to allow them to be classified as chemicals regardless of their origin. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Open AccessReview Chitin Deacetylases: Properties and Applications
Mar. Drugs 2010, 8(1), 24-46; doi:10.3390/md8010024
Received: 24 December 2009 / Revised: 8 January 2010 / Accepted: 11 January 2010 / Published: 14 January 2010
Cited by 74 | PDF Full-text (271 KB) | HTML Full-text | XML Full-text
Abstract
Chitin deacetylases, occurring in marine bacteria, several fungi and a few insects, catalyze the deacetylation of chitin, a structural biopolymer found in countless forms of marine life, fungal cell and spore walls as well as insect cuticle and peritrophic matrices. The deacetylases [...] Read more.
Chitin deacetylases, occurring in marine bacteria, several fungi and a few insects, catalyze the deacetylation of chitin, a structural biopolymer found in countless forms of marine life, fungal cell and spore walls as well as insect cuticle and peritrophic matrices. The deacetylases recognize a sequence of four GlcNAc units in the substrate, one of which undergoes deacetylation: the resulting chitosan has a more regular deacetylation pattern than a chitosan treated with hot NaOH. Nevertheless plain chitin is a poor substrate, but glycolated, reprecipitated or depolymerized chitins are good ones. The marine Vibrio sp. colonize the chitin particles and decompose the chitin thanks to the concerted action of chitinases and deacetylases, otherwise they could not tolerate chitosan, a recognized antibacterial biopolymer. In fact, chitosan is used to prevent infections in fishes and crustaceans. Considering that chitin deacetylases play very important roles in the biological attack and defense systems, they may find applications for the biological control of fungal plant pathogens or insect pests in agriculture and for the biocontrol of opportunistic fungal human pathogens. Full article
(This article belongs to the Special Issue Marine Chitin and Chitosan)
Figures

Journal Contact

MDPI AG
Marine Drugs Editorial Office
St. Alban-Anlage 66, 4052 Basel, Switzerland
marinedrugs@mdpi.com
Tel. +41 61 683 77 34
Fax: +41 61 302 89 18
Editorial Board
Contact Details Submit to Marine Drugs
Back to Top