碩士 / 國立臺灣大學 / 生化學研究所 / 89 / Chitosan is the deacetylated product of chitin, an ubiquitous biopolymer found in the exoskeleton of insects and marine invertebrates or the cell wall of fungi. Althought chitosan has been found to have some physiological and biological activities such as hypocholesterolemic activity, wound dressing and blood anticoagulant, little is known about the utility of chitosan in anti-lipid peroxidation effect.
In this study, we examined the effects of water-soluble carboxylmethyl chitosan (CM-chitosan) on antioxidant activities and its possible mechanism of action. We used water-soluble CM-chitosan derived from shrimp or crab as material to make following experiments. Percent inhibition of the lipid peroxidation was used as an index of the antioxidant effect. The products of lipid peroxidation were measured as malondialdehyde-thiobarbituric acid (MDA-TBA). Ferrous ion content was analyzed by the indicator 1,10-phenanthroline. We found that CM-chitosan could significantly reduce iron-induced lipid peroxidation at the initial and propagation stages in rat liver microsomes. The IC50 for shrimp CM-chitosan, crab CM-chitosan and trolox were 54.09, 58.88 and 64.09 μg/ml, respectively. And its antioxidant activities were mediated by chelating iron. We also test whether CM-chitosan has antioxidant activities on scavenging superoxide anion, hydrogen peroxide or free radicals produced by 2,2′-azobis (2-amidino-propane) dihydrochloride (ABAP) or tert-butyl hydroperoxide, CM-chitosan has no effect on them. We then used rat red blood cells to evaluate the effects of CM-chitosan on cell membrane lipid peroxidation induced by ferrous ion. It was found that CM-chitosan could prevent cell membrane from lipid peroxidation induced by ferrous ion. In HL-60 promyelocytic leukemia cell line experimemts, we used ferrous ion to cause cell membrane damage, induce cell to produce reactive oxygen species (ROS), and make mitochondrial membrane potential decreasing. CM-chitosan could protect those cells from oxidative stress. Taken together these observations, CM-chitosan may have potential use as an antioxidant for the decrease of lipid peroxidation by chelating iron.
| Identifer | oai:union.ndltd.org:TW/089NTU01104009 |
| Date | January 2001 |
| Creators | I-Ching Tieng, 田依靜 |
| Contributors | Fung-Jou Lu, 呂鋒洲 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 76 |
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