Chitosan, a polysaccharide made up of b-1,4-linked D-glucosamine residues, is produced by deacetylation of chitin obtained from crab and prawn shells. This polysaccharide is not specifically hydrolyzed by mammalian digestive enzymes, and only limited hydrolysis may occur by the action of enzymes produced by bacterial flora. In recent years, chitosan has attracted much attention as a new biomedical material owing to its unique antibacterial, 1,2) hypoglycemic, [3][4][5] wound-healing, 6,7) and hypocholesterolemic [8][9][10] activities as well as others.11) Even though chitosan has various biologically important properties, its high molecular weight and insolubility in the neutral pH region may restrict its use in vivo. In addition, although the toxicity of chitosan is known to be low, 11) some adverse effects have been reported, including excessive excretion of essential fatty acids 12) and decreased absorption of fat-soluble vitamins and minerals. 13) We consider that it is worthwhile to study the functional properties of the oligosaccharides made from chitosan, because these oligosaccharides, as distinct from chitosan itself, have lower viscosity and are soluble in neutral aqueous solutions. In addition, their toxicity is very low. The biological activities of each of the chitooligosaccharides, however, remain to be studied further.In the present paper, the antioxidant activities of several chitooligosaccharides, especially chitobiose and chitotriose, were studied in different in vitro systems. MATERIALS AND METHODS MaterialsPhenazine methosulfate, nitro blue tetrazolium, pyridoxamine dihydrochloride, D-glucosamine hydrochloride, Trolox (2-carboxy-2,5,7,8-tetramethyl-6-chromanol, a water-soluble a-tocopherol analogue), aminoguanidine hydrochloride, and horseradish peroxidase (Type XII) were obtained from Sigma-Aldrich (St. Louis, MO, U.S.A.). A series of chitooligosaccharide hydrochlorides, di-N-acetylchitobiose, and tri-N-acetylchitotriose were purchased from Seikagaku (Tokyo, Japan). Chelex-100 was obtained from Nippon Bio-Rad (Yokohama, Japan).Inhibition of H 2 O 2 -Induced Hydroxylation of Benzoate Hydroxylation of benzoate by H 2 O 2 was measured by the method of Giardino et al. 22) except that CuSO 4 was supplemented to the reaction mixture. Briefly, 100 mM sodium phosphate buffer (pH 7.4) containing 30 mM sodium benzoate, 10 mM H 2 O 2 , and 0.1 mM CuSO 4 was incubated for 16 h at 37°C in the presence and absence of a test compound. Then the amount of salicylate formed by the reaction was determined by HPLC with a TSK gel ODS-80TM column (150ϫ4.6 mm, 5 mm; Tosoh, Tokyo, Japan). The mobile phase was 10% (v/v) acetonitrile containing 20 mM potassium dihydrogen phosphate, and chromatography was performed at a flow rate of 1.0 ml/min and at a column temperature of 37°C. Salicylate was monitored by measuring fluorescence at excitation and emission wavelengths of 308 and 410 nm, respectively. Scavenging of Hydroxyl Radicals Produced by Photolysis of Zinc OxideThe hydroxyl radical-scavenging activities of tes...
Chitooligosaccharides, which are oligosaccharides made up of b-1,4-linked D-glucosamine residues, have attracted much attention as new biomedical materials. Mixtures of chitooligosaccharides have been reported to have various biologic activities in vitro including antibacterial, 1,2) antifungal, 3) antioxidant, 4,5) antimutagenic, 6) and leukemia cell differentiation-inducing activities.7) The in vivo antioxidant activity of a mixture of chitooligosaccharides (3 kDaϽMWϽ5 kDa) was also reported. 8) Our recent study has revealed that chitobiose and chitotriose ( Fig. 1) showed higher antioxidant activities in vitro than other chitooligosaccharides in various assay systems.9) The biologic activity in vivo and biologic availability of each chitooligosaccharide remain to be studied.In the present study, we investigated the absorbability of several chitooligosaccharides from the rat gastrointestinal tract and also the pharmacokinetics of chitobiose and chitotriose administered intravenously or orally to rats. MATERIALS AND METHODS MaterialsWistar strain male rats (7 weeks old) were obtained from Clea Japan (Tokyo, Japan). The body weight of the rats at the time of usage ranged from 165 to 185 g. A series of chitooligosaccharides as hydrochlorides and a 4-aminobenzoyl ethyl ester (ABEE) labeling kit for the derivatization of chitooligosaccharides were purchased from Seikagaku Corp. (Tokyo, Japan). Based on HPLC analysis by the manufacturer, the purity of all chitooligosaccharides was approximately 100%.Intravenous and Oral Administration Rats were fasted overnight (12 to 14 h) prior to experiments, but were allowed free access to water. Chitooligosaccharide solutions (1.0 ml/kg) in saline were administered intravenously through a tail vein or orally by gavage. Each rat was then left free in a metabolic cage for urine collection. Blood samples (about 150 ml) were taken with heparinized syringes from a tail vein at 0, 10, 20, 40, 60, 120, and 240 min postdosing and then immediately centrifuged to obtain plasma samples.HPLC Analysis of Saccharides Saccharides in the plasma and urine were converted to fluorescent derivatives with an ABEE labeling kit as described by Yasuno et al. 10)Aliquots (40 ml) of the ABEE reagent solution were added to 10 ml of samples, and the mixtures were then incubated at 80°C for 1 h. After cooling to room temperature, 0.2 ml of distilled water and 0.2 ml of chloroform were added to the test tubes. The mixtures were vigorously vortexed and then centrifuged to separate them into two layers. Aliquots (10 ml) of the upper aqueous layer were used for HPLC analysis with a Honenpak C18 column (75ϫ4.6 mm, Seikagaku Corp.). Solvents A and B used for HPLC were 0.02% trifluoroacetic acid solutions containing 3% and 50% acetonitrile, respectively. Solvent A was passed through the column for 40 min for separation, and then the column was washed for 5 min with solvent B. Chromatography was performed at a flow rate of 1.0 ml/min and at a column temperature of 45°C. Chitooligosaccharides have attracted much at...
The purpose of the present study was to examine whether chitobiose and chitotriose can protect rats from CCl 4 -induced hepatic toxicity when given orally. We studied the effects of the 2 chitooligosaccharides given orally to rats on the acute hepatotoxicity induced by CCl 4 -dependent lipid peroxidation. The increase in the sum of malondialdehyde and 4-hydroxy-2-alkenals, a marker of lipid peroxidation, in both plasma and liver of CCl 4 -treated rats was suppressed by oral administration of chitobiose or chitotriose. The elevation in the levels of plasma aspartate transaminase and alanine transaminase activities, markers of hepatic injury, induced by CCl 4 intoxication was also counteracted by oral administration of either chitooligosaccharide. The results indicate that chitobiose and chitotriose have the ability to exert a protective action against CCl 4 -induced acute hepatoxicity, probably by their antioxidant activity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.