This review describes the most common methods for recovery of chitin from marine organisms. In depth, both enzymatic and chemical treatments for the step of deproteinization are compared, as well as different conditions for demineralization. The conditions of chitosan preparation are also discussed, since they significantly impact the synthesis of chitosan with varying degree of acetylation (DA) and molecular weight (MW). In addition, the main characterization techniques applied for chitin and chitosan are recalled, pointing out the role of their solubility in relation with the chemical structure (mainly the acetyl group distribution along the backbone). Biological activities are also presented, such as: antibacterial, antifungal, antitumor and antioxidant. Interestingly, the relationship between chemical structure and biological activity is demonstrated for chitosan molecules with different DA and MW and homogeneous distribution of acetyl groups for the first time. In the end, several selected pharmaceutical and biomedical applications are presented, in which chitin and chitosan are recognized as new biomaterials taking advantage of their biocompatibility and biodegradability.

/pdf/chitin-and-chitosan-preparation-from-marine-sources-395brtgt7i.pdf

Chitin and Chitosan Preparation from Marine Sources. Structure, Properties and Applications

Perspectives for chitosan based antimicrobial films in food applications

Chitosan is a natural polycationic linear polysaccharide derived from chitin. The low solubility of chitosan in neutral and alkaline solution limits its application. Nevertheless, chemical modification into composites or hydrogels brings to it new functional properties for different applications. Chitosans are recognized as versatile biomaterials because of their non-toxicity, low allergenicity, biocompatibility and biodegradability. This review presents the recent research, trends and prospects in chitosan. Some special pharmaceutical and biomedical applications are also highlighted.

/pdf/chitosan-an-update-on-potential-biomedical-and-1on5gom49q.pdf

Chitosan: An Update on Potential Biomedical and Pharmaceutical Applications.

During the past decade, there was an increasing interest to develop and use bio-based active films which are characterized by antimicrobial and antifungal activities in order to improve food preservation and to reduce the use of chemical preservatives. Biologically active bio-molecules such as chitosan and its derivatives have a significant potential in the food industry in view of contaminations associated with food products and the increasing concerns in relation with the negative environmental impact of conventional packaging materials such as plastics. Chitosan offers real potential for applications in the food industry due to its particular physico-chemical properties, short time biodegradability, biocompatibility with human tissues, antimicrobial an antifungal activities, and non-toxicity. Thus, chitosan-based films have attracted serious attention in food preservation and packaging technology. This is mainly due to a fact that chitosan exhibits high antimicrobial activity against pathogenic and spoilage micro-organisms, including fungi, and both Gram-positive and Gram-negative bacteria. The aim of the present review was to summarize the most important information on chitosan from its bioactivity point of view and to highlight various preparative methods used for chitosan-based active bio-films and their potential for applications in the food preservation and packaging technology.

Chitosan application for active bio-based films production and potential in the food industry: Review

Biological activities of chitosan and chitooligosaccharides

Study on antimicrobial activity of chitosan with different molecular weights

OBJECTIVE
To reveal the possible effects of decursin on viability, oxidative stress, and inflammatory response in lipopolysaccharide (LPS)-treated human bronchial epithelial cells-2B (BEAS-2B) and human pulmonary artery endothelial cells (HPAEC) cells, and revealed the potential mechanisms.


METHODS
LPS was used to induce acute lung injury (ALI) in normal human lung epithelial cells, including BEAS-2B and HPAEC cells. Cell viability and apoptosis in response to LPS and decursin in BEAS-2B and HPAEC cells were, respectively, evaluated by MTT colorimetric and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assays. The oxidative stress and inflammatory response in LPS-treated BEAS-2B and HPAEC cells were detected by enzyme-linked-immunosorbent serologic assay. In addition, the role of decursin in nuclear -factor-kappa B (NF-κB) activation was analyzed by immunoblot and immunofluorescence assays.


RESULTS
Our data revealed that decursin could alleviate the viability of LPS-induced BEAS-2B and HPAEC cells. Decursin could also reduce LPS-induced oxidative stress in BEAS-2B and HPAEC cells. In addition, it could reduce LPS-induced inflammation in BEAS-2B and HPAEC cells. Mechanically, decursin suppressed the activation of NF-κB pathway.


CONCLUSION
Decursin suppressed NF-κB pathway, and therefore alleviated ALI.

Decursin alleviates LPS-induced lung epithelial cell injury by inhibiting NF-κB pathway activation.

Purpose: To determine the effect of γ-mangostin on myocardial ischemia (MI) -induced injury of myocardial cells, and the possible involvement of SIRT3 in myocardial cell apoptosis in Sprague-Dawley rats after ischemia-reperfusion (I/R). 
Methods: Ischemic reperfusion (I/R) model of rat was established, followed by TTC staining. The serum levels of CK-MB and LDH were also assessed. In addition, inflammatory response and oxidative stress were evaluated by quantitative PCR and enzyme linked immunosorbent assay (ELISA), while cell apoptosis was assessed using TdT-mediated dUTP nick end labeling (TUNEL) assay and western blot. The mechanism of action of γ-mangostin by which it mediated improvement in cardiac injury was investigated by ELISA and western blot. 
Results: γ-Mangostin attenuated myocardial injury and reduced myocardial inflammation in I/R rats (p < 0.05). In addition, it alleviated oxidative stress in I/R rat myocardial tissues and suppressed apoptosis. Furthermore, γ-mangostin improved myocardial injury probably by targeting SIRT3 (p < 0.05). 
Conclusion: γ-Mangostin has potentials for use as a therapeutic agent for the treatment of myocardial I/R injury. However, there is a need for clinical trials on the compound.

Jiang-Feng Zhu

Papers

Study on antimicrobial activity of chitosan with different molecular weights

Decursin alleviates LPS-induced lung epithelial cell injury by inhibiting NF-κB pathway activation.

γ-Mangostin alleviates myocardial ischemia-reperfusion injury by up-regulating SIRT3