• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1439-1447
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• 1998

Antimicrobial activity of chitosan and chitosan oligosaccharides on the microorganism related to Kimchi was investigated. 5 kinds of chitosan, which have different deacetylation degrees and molecular weights were prepared and its effect on the organoleptic characteristics, pH and titrable acidity of Kimchi in the storage time were examined. C-4 and C-5 chitosan (D.A.:$92{\sim}99%$, M.W.: $16,000{\sim}32,000)$ recorded high score in the texture and showed pH 4.9 and titrable acidity 0.35%, compared with control (pH 4.1, titrarable acidity 0.50 %) evaluated to optimal ripening time. The chitosan oligosaccharides containing relatively large amount of $pentamer{\sim}heptamer$ were chosen from C-4 chitosan hydrolyzates. Antimicrobial activity of C-4 and chitosan oligosaccharides against B. subtilis, B. cereus, Pse. fluorescens, E. coli, Lac. plantarum, Leu. mesenteroides, Lac. brevis, Ent. faecalis and 3 kinds of microflora from Kimchi were examined. The clear zone against microorganism were $9{\sim}20mm$ at 3.0% C-4 chitosan and $8{\sim}24mm$ at 5.0% chitosan oligosaccharides, and MIC of chitosan and chitosan oligosaccharides was shown $0.01{\sim}0.05%$ and $0.05{\sim}0.2%$, respectively. The antimicrobial effect of chitosan and chitosan oligosaccharides was also observed in 3 kinds of total microflora from Kimchi and was most strong in the microflora from the ripening stage of Kimchi, suggesting C-4 chitosan and chitosan oligosaccharides could be applicable to extending shelf-life of Kimchi.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.23 no.2
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• pp.48-62
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• 1997

Chitosan oligosaccharides having aldehyde group at reducing end were prepared by oxidative-deamination reaction of chitosan by using sodium nitrite, and the resulting aldehyde group was reduced to 2, 5-anhydro-D-mannitol group. The obtained chitosan oligosaccharides showed an average degree of polymerization 2~3 by gel permeation chromatography analysis. It was highly soluble in hydrophilic solvents and thermally stable. N, N-diacyl, O-acyl chitosan oligosaccharides were obtained from the reaction between chitosan oligosaccharides and acyl chloried under dimethylaminopyridine. From differential scanning calorimetric measurement, N, N-dilauroyl, O-lauroyl chitosan oligosaccharides showed mesophase region, which was confirmed by polarized microscope as a thermotropic liquid crystalline state. X-ray diffraction pattern revealed that N, N-dilauroyl, O-lauroyl chitosan oligosaccharedes were highly crystalline, whereas chitosan oligosaccharides were not.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.317-323
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• 2004

This study was performed to investigate the antimicrobial effects of hetero-chitosans and their oligosaccharides against three Gram-negative bacteria and five Gram-positive bacteria. Nine classes of hetero-chitosan oligosaccharides consisted of partially deacetylated chitosans; 90％, 75％, and 50％ deacetylated chitosans. Based on molecular weight, they were prepared using an ultrafiltration membrane reactor system. Seventy-five percent deacetylated chitosan showed the highest antimicrobial acitivity as compared with the 90％ and 50％ deacetylated chitosan, and the activity was dependent on their molecular weights. It was apparent that the growth of Gram-negative bacteria is less inhibited in the presence of the heterochitosans and their oligosaccharides than Gram-positive bacteria. These results revealed that the antimicrobial effects of hetero-chitosans and their oligosaccharides depend on the degree of deacetylation, and their molecular weights.

• Journal of Microbiology and Biotechnology
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• v.14 no.1
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• pp.41-47
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• 2004

This study was performed to investigate the antimicrobial effects of hetero-chitosans and their oligosaccharides on the halophilic bacterium, Vibrio parahaemolyticus. Nine classes of hetero-chitosan oligosaccharides were prepared based on their molecular weights, using an ultrafiltration membrane reactor system with chitosanase and celluase, from partially different deacetylated chitosans, 90%, 75%, and 50% deacetylated chitosan, respectively. Thirty-two strains of V. parahaemolyticus were isolated from various marine organisms such as shellfish, shrimps, octopus, and seabirds. Seventy-five percent deacetylated chitosan showed the highest antimicrobial acitivity. The minimal inhibitory concentration (MIC) was 0.5 mg/ml on 14 strains of V. parahaemolyticus, and MIC of the rest strains (18 strains) was 1.0 mg/ml. In addition, MIC of most hetero-chitosan oligosaccharides was 8.0 mg/ml. The results revealed that the antimicrobial effects of hetero-chitosans and their oligosaccharides against V. parahaemolyticus depend on the degree of deacetylation, their molecular weights, and strains tested.

• Korean Journal of Food Science and Technology
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• v.30 no.6
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• pp.1476-1479
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• 1998

Effect of chitosan oligosaccharides on the ACE (angiotensin I converting enzyme) inhibition and antihypertension in SHR (Spontaneously hypertensive rat) was examined. The ACE inhibition activity was observed in all the chitosan oligosaccharides used in this study, and chitosan trimer exhibited the highest inhibitory activity $(IC_{50}=0.9{\mu}M)$ compared with other chitosan oligosaccharides $(IC_{50}\;:\;2.4{\sim}100\;{\mu}M)$. The results suggested that chitosan trimer was a good inhibitor of ACE in molecular level. When the single oral dose (2.14 mg/kg, similar to dose level of Captopril, known as strong ACE inhibitor) of chitosan trimer was given to 8 or 21 week aged SHR, the blood pressure reduction of both SHRs in 4hrs were $27{\pm}4.8\;mmHg\;and\;36{\pm}4.3\;mmHg$, respectively. Therefore, it was suggested that chitosan trimer could be applicable as natural ACE inhibitor related to antihypertension.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.416-417
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• 2000

Chitin, a poly $\beta$-(1longrightarrow14)-N-acetyl-D-glucosamine, is best known as a cell wall component of fungi and as a skeletal materials of invertebrates. Chitosan is derived from chitin by deacetylation in the presence of alkali. Chitosan has been developed as new physiological materials since it possesses antibacterial activity, hypocholesterolemic activity and antihypertensive action. However, the actions of chitosan in vivo still remain ambiguous as the physiological functional properties because most animal intestines, especially the human gastrointestinal tract, do not possess enzyme such as chitosanase which directly degrade the $\beta$-glucosidic linkage in chitosan, and consequently the unbroken polymers may be poorly absorbed into the human intestine. Therefore, recent studies as chitosan have attracted interest for chitosan oligosaccharides, because the oligosaccharides process not only water-soluble property but also versatile functional properties such as antitumor activity, immune-enhancing effects, enhancement of protective effects against infection with some pathogens in mice and antimicrobial activity (Kingsnorth et al., 1983, Mori et al., 1997). (omitted)

• Journal of Life Science
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• v.7 no.2
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• pp.149-159
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• 1997

Chitin, a linked polysaccharide composed of 2-acetamido-2-deoxy-$\beta$-D-glucopytanose residues, is distributed widely in nature. It has been utilized on various application field due to the development of chitin derivatives such as chitosan, partial deacetylated chitin, carboxylmethyl chitin, sulfated chitin, and so on. Chitin and chitosan have been recently interested in antitumor and antimicrobial activities, because of a powerful tumor inhibitory effect against experimental mouse tumors. Especially, the oligosaccharides obtained by partial degradation of them exhibited a remarkable antitumor effect against sarcoma 180, MM 48 and Meth Asolid tumors and antimetastatic effect against Lewis lung carcinoma in mice. This review describes on antitumor effects of chitin, chitosan and their oligosaccharides by their mechanism of action involving enhancement of immunological system.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.241-242
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• 2001

Chitosan, a deacetylated derivative of chitin, is one of the abundant resources, and its biological properties such as antibactierial activity, hypocholesterolemic activity, and hypertensive action are remarked. However, increasing attention has recently been yen to converting chitosan to its oligosaccharides because they possess various functional properties like antitumor activity, immune-enhancing effects, enhancing protective effects against infection with some pathogens in mice, antifungal activity, and antimicrobial activity (Jeon et al., 2001). (omitted)

• Journal of Microbiology and Biotechnology
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• v.19 no.6
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• pp.629-633
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• 2009

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.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.245-252
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• 1998

The chitosanolytic capabilities of cellulases, glucosidases, proteases and commercial enzymes were evaluated, and effective chitosanolytic cellulases from T. viride, T. reesei and Celluclast, a commercial enzyme from T. reesei were characterized. The reaction of cellulase from T. viride, T. reesei and Celluclast was optimal at pH 5. 0 and $45{\sim}55^{\circ}C$. Max. chitosanolytic activities of cellulases from both T. viride and T. reesei were observed at the enzyme/chitosan ratio=0.1 and chitosan concentration=3.0%. For the possible application of commercial Celluclast to chitosan oligosaccharides production, 3%(w/v) chitosan was reacted with 1%(v/v) Celluclast at pH 5.0 and $55^{\circ}C$. The apparent viscosity decreased by 98% within 30 minutes reaction and Max. contents of 50% EtOH solubles were 70% at 15 hrs reaction. Total reducing sugars were also increased with reaction time and maintained approx. 13.5% after 2hrs reaction. In 15 hrs treated chitosan hydrolyzates, various kinds of chitosan oligosaccharides were produced and contents of chitosan hexamer, known for its antitumor activities, were about 8.0%, about 4 times higher values compared with acid hydrolysis method. The results suggested that chitosan oligosaccharides could be produced with low-cost cellulases from T. reesei.