Use of natural biopolymers for diversified applications in life sciences has several advantages, such as availability from replenishable agricultural or marine food resources, biocompatibility, biodegradability, therefore leading to ecological safety and the possibility of preparing a variety of chemically or enzymatically modified derivatives for specific end uses. Polysaccharides, as a class of natural macromolecules, have the tendency to be extremely bioactive, and are generally derived from agricultural feedstock or crustacean shell wastes. Cellulose, starch, pectin, etc. are the biopolymers derived from the former while chitin and chitosan are obtained from the latter. In terms of availability, chitin is next to cellulose, available to the extent of over 10 gigatons annually. The application potential of chitosan, a deacetylated derivative of chitin, is multidimensional, such as in food and nutrition, biotechnology, material science, drugs and pharmaceuticals, agriculture and environmental protection, and recently in gene therapy too. The net cationicity as well as the presence of multiple reactive functional groups in the molecule make chitosan a sought-after biomolecule. The latter offers scope for manipulation for preparing a broad spectrum of derivatives for specific end use applications in diversified areas. The biomedical and therapeutic significance of chitin/chitosan derivatives is a subject of significant concern to many all over the world. An attempt is made in this overview to consolidate some of the recent findings on the biorelated application potential of chitosan and its derivatives.

Chitin/chitosan: modifications and their unlimited application potential—an overview

Homeostasis, Inflammation, and Disease Susceptibility

Biological activities of chitosan and chitooligosaccharides

It is estimated that nearly one-third of all cancer deaths in the United States could be prevented through appropriate dietary modification. Various dietary antioxidants have shown considerable promise as effective agents for cancer prevention by reducing oxidative stress which has been implicated in the development of many diseases, including cancer. Therefore, for reducing the incidence of cancer, modifications in dietary habits, especially by increasing consumption of fruits and vegetables rich in antioxidants, are increasingly advocated. Accumulating research evidence suggests that many dietary factors may be used alone or in combination with traditional chemotherapeutic agents to prevent the occurrence of cancer, their metastatic spread, or even to treat cancer. The reduced cancer risk and lack of toxicity associated with high intake of fruits and vegetables suggest that specific concentrations of antioxidant agents from these dietary sources may produce cancer chemopreventive effects without causing...

Cancer chemoprevention through dietary antioxidants: progress and promise.

AIM: Five representative waterborne pathogens were used to illustrate the relationship between chitosan’s antibacterial activity and the surface characteristics of the bacterial cell wall. METHODS: Chitosan was prepared with averaged 75 % or 95 % deacetylated degree to examine its antibacterial activity against waterborne pathogens. Fresh microbial inoculants for the antibacterial assessment were prepared on nutrient agar at 37 oC for 24 h. The evaluation items of antibacterial mechanism included hydrophilicity and negative charge analysis of cell surface, and adsorptive characteristics of chitosan to bacterial cell. All the experiments were applied in triplicate tests at least. RESULTS: Although cell wall hydrophilicity was similar among Gram-negative bacteria, the distribution of negative charge on their cell surfaces was quite different. More negatively charged cell surfaces had a greater interaction with chitosan, a phenomenon further confirmed by transmission electron micrography (TEM). CONCLUSION: Results showed the hydrophilicity in Gram-negative bacteria was much higher than in Gram-positive ones. The correlation coefficient 0.988 between the amount of absorbed chitosan and its inhibition efficiency indicated a close relationship.

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Relationship between antibacterial activity of chitosan and surface characteristics of cell wall.

Antimutagenicity and induction of anticarcinogenic phase II enzymes by basidiomycetes.

The present study investigated the antimetastatic property of chitosan oligosaccharides (COS) by evaluating motility, invasion, and the amount and activity of MMP-9 in MDA-MB-231 human breast carcinoma cells. Treatment of MDA-MB-231 cells with increasing concentrations of COS led to a concentration-dependent decrease in cell migration. COS significantly inhibited the invasion of MDA-MB-231 cells through a Matrigel-coated membrane. The treatment of MDA-MB-231 cells with COS reduced the amounts of secreted MMP-9. The activity and amount of MMP-9 protein in MDA-MB-231 cells were decreased by treatment with COS and occurred in a concentration-dependent manner. Our data indicated that COS can serve as a potential novel therapeutic candidate for the treatment of metastatic breast cancer.

Suppression of metastasis of human breast cancer cells by chitosan oligosaccharides.

The effect of chitosan oligosaccharide (COS, 1 kDa <MW<3 kDa) on proinflammatory cytokines-induced nitric oxide (NO) production and invasiveness of human colorectal adenocarcinoma HT-29 cells was investigated. COS (0.1-5mg/ ml) suppressed the NO production induced by proinflammatory cytokines (100 U/ml IFN-gamma, 10 ng/ml IL-1alpha, and 25 ng/ml TNF-alpha) in HT-29 cells. Inducible nitric oxide synthase (iNOS) expression induced by these cytokines was inhibited by COS. COS pretreatment inhibited the invasiveness of cytokines-treated HT-29 cells through Matrigel-coated membrane in a dose-dependent manner. COS also inhibited cytokines-induced matrix metalloproteinase (MMP)-2 activity. This study shows that proinflammatory cytokines induce NO production, iNOS expression, and invasiveness of human colorectal adenocarcinoma HT-29 cells. COS pretreatment inhibited cytokines-mediated NO production, iNOS expression, and invasiveness of HT-29 cells. These results provide sufficient information for the further development of COS as an antitumor metastatic agent for the treatment of colon cancer.

http://www.koreascience.or.kr:80/article/JAKO200709906360449.pdf

Inhibition of Proinflammatory Cytokine-induced Invasiveness of HT-29 Cells by Chitosan Oligosaccharide

Chitosan oligosaccharide (COS, 3 kDa<MW<5 kDa) was tested for colon cancer chemoprevention by measuring the activities of quinine reductase (QR) and glutathione-S-transferase (GST), glutathione (GSH) levels, ornithine decarboxylase (ODC) activity, and cyclooxygenase (COX)-2 expression in HT-29 cells treated with COS. COS induced QR activity in a dose-dependent manner over a concentration range of 0.1-4.0 mg/ml. GST activity was also induced in HT-29 cells treated with COS. In addition, GSH levels were increased 1.3-, 1.4-, and 1.5-fold with COS at 2, 3, and 4 mg/ml, respectively. ODC activity induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) was inhibited by 33% and 39% with 3 and 4 mg/ml of COS, respectively. COS also inhibited the expression of TPA-induced COX-2 protein in HT-29 cells. These results suggest that COS has colon cancer chemopreventive activity by increasing QR and GST activities and GSH levels and by inhibiting ODC activity and COX-2 expression in vitro.

Kyung-Soo Nam

Papers

Antimutagenicity and induction of anticarcinogenic phase II enzymes by basidiomycetes.

Suppression of metastasis of human breast cancer cells by chitosan oligosaccharides.

Inhibition of Proinflammatory Cytokine-induced Invasiveness of HT-29 Cells by Chitosan Oligosaccharide

Chemopreventive effect of chitosan oligosaccharide against colon carcinogenesis.

Large-scale and effective screening of Korean medicinal plants for inhibitory activity on matrix metalloproteinase-9.