201
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Chen H, Hu W, Li S, Wang M. Direct determination of Cd and Pb in gel forming konjac samples by enzymatic hydrolysis assisted slurry sampling graphite furnace atomic absorption spectrometry. Mikrochim Acta 2007. [DOI: 10.1007/s00604-007-0883-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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202
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Wen X, Wang T, Wang Z, Li L, Zhao C. Preparation of konjac glucomannan hydrogels as DNA-controlled release matrix. Int J Biol Macromol 2007; 42:256-63. [PMID: 18190958 DOI: 10.1016/j.ijbiomac.2007.11.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2007] [Revised: 11/24/2007] [Accepted: 11/26/2007] [Indexed: 11/29/2022]
Abstract
In this study, hydrogels for DNA-controlled release was prepared with konjac glucomannan (KGM), a water-soluble non-ionic polysaccharide, by means of deacetylated reaction and physically cross-linking method under mild conditions. The properties of the KGM hydrogels were analyzed by FTIR spectra and scanning electron microscopy (SEM). The integrality of the released DNA was investigated by circular dichroism (CD). The DNA release kinetics was performed using the DNA-loaded KGM gels in buffer solutions of pH 7.4 at 37+/-0.5 degrees C. Peppas model and Higuchi model were used to analysis the DNA release mechanism; the data indicated that the DNA release can be controlled by changing the preparation conditions and the structure parameters of the gels. This study suggested that the KGM hydrogels have a potential use for advanced controlled release.
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Affiliation(s)
- Xian Wen
- College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610065, PR China
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203
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Prawitwong P, Takigami S, Phillips GO. Effects of γ-irradiation on molar mass and properties of Konjac mannan. Food Hydrocoll 2007. [DOI: 10.1016/j.foodhyd.2006.10.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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204
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Xu Z, Sun Y, Yang Y, Ding J, Pang J. Effect of γ-irradiation on some physiochemical properties of konjac glucomannan. Carbohydr Polym 2007. [DOI: 10.1016/j.carbpol.2007.05.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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205
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Effect of ultrasound on enzymatic acylation of konjac glucomannan. Bioprocess Biosyst Eng 2007; 31:351-6. [DOI: 10.1007/s00449-007-0171-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2007] [Accepted: 10/14/2007] [Indexed: 11/26/2022]
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206
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Rheological properties of aqueous konjac glucomannan dispersions and its mixtures with soybean protein isolate. ACTA ACUST UNITED AC 2007. [DOI: 10.1007/s11771-007-0314-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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207
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208
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Hrmova M, Burton R, Biely P, Lahnstein J, Fincher G. Hydrolysis of (1,4)-beta-D-mannans in barley (Hordeum vulgare L.) is mediated by the concerted action of (1,4)-beta-D-mannan endohydrolase and beta-D-mannosidase. Biochem J 2006; 399:77-90. [PMID: 16771710 PMCID: PMC1570163 DOI: 10.1042/bj20060170] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A family GH5 (family 5 glycoside hydrolase) (1,4)-beta-D-mannan endohydrolase or beta-D-mannanase (EC 3.2.1.78), designated HvMAN1, has been purified 300-fold from extracts of 10-day-old barley (Hordeum vulgare L.) seedlings using ammonium sulfate fractional precipitation, followed by ion exchange, hydrophobic interaction and size-exclusion chromatography. The purified HvMAN1 is a relatively unstable enzyme with an apparent molecular mass of 43 kDa, a pI of 7.8 and a pH optimum of 4.75. The HvMAN1 releases Man (mannose or D-mannopyranose)-containing oligosaccharides of degree of polymerization 2-6 from mannans, galactomannans and glucomannans. With locust-bean galactomannan and mannopentaitol as substrates, the enzyme has K(m) constants of 0.16 mg x ml(-1) and 5.3 mM and kcat constants of 12.9 and 3.9 s(-1) respectively. Product analyses indicate that transglycosylation reactions occur during hydrolysis of (1,4)-beta-D-manno-oligosaccharides. The complete sequence of 374 amino acid residues of the mature enzyme has been deduced from the nucleotide sequence of a near full-length cDNA, and has allowed a three-dimensional model of the HvMAN1 to be constructed. The barley HvMAN1 gene is a member of a small (1,4)-beta-D-mannan endohydrolase family of at least six genes, and is transcribed at low levels in a number of organs, including the developing endosperm, but also in the basal region of young roots and in leaf tips. A second barley enzyme that participates in mannan depolymerization through its ability to hydrolyse (1,4)-beta-D-manno-oligosaccharides to Man is a family GH1 beta-D-mannosidase, now designated HvbetaMANNOS1, but previously identified as a beta-D-glucosidase [Hrmova, MacGregor, Biely, Stewart and Fincher (1998) J. Biol. Chem. 273, 11134-11143], which hydrolyses 4NP (4-nitrophenyl) beta-D-mannoside three times faster than 4NP beta-D-glucoside, and has an action pattern typical of a (1,4)-beta-D-mannan exohydrolase.
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Affiliation(s)
- Maria Hrmova
- *School of Agriculture, Food and Wine, University of Adelaide and Australian Centre for Plant Functional Genomics, Waite Campus, Glen Osmond, SA 5064, Australia
- Correspondence may be addressed to either of these authors (email or )
| | - Rachel A. Burton
- *School of Agriculture, Food and Wine, University of Adelaide and Australian Centre for Plant Functional Genomics, Waite Campus, Glen Osmond, SA 5064, Australia
| | - Peter Biely
- †Institute of Chemistry, Slovak Academy of Sciences, Bratislava, Slovak Republic
| | - Jelle Lahnstein
- *School of Agriculture, Food and Wine, University of Adelaide and Australian Centre for Plant Functional Genomics, Waite Campus, Glen Osmond, SA 5064, Australia
| | - Geoffrey B. Fincher
- *School of Agriculture, Food and Wine, University of Adelaide and Australian Centre for Plant Functional Genomics, Waite Campus, Glen Osmond, SA 5064, Australia
- Correspondence may be addressed to either of these authors (email or )
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209
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210
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Alvarez-Manceñido F, Braeckmans K, De Smedt SC, Demeester J, Landin M, Martínez-Pacheco R. Characterization of diffusion of macromolecules in konjac glucomannan solutions and gels by fluorescence recovery after photobleaching technique. Int J Pharm 2006; 316:37-46. [PMID: 16574355 DOI: 10.1016/j.ijpharm.2006.02.029] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2005] [Revised: 02/14/2006] [Accepted: 02/15/2006] [Indexed: 10/24/2022]
Abstract
Konjac glucomannan (KGM) is a neutral polysaccharide with interesting properties as gelling agent and thickener. Its peculiar biodegradability, being not degradable in the small intestine but degradable by the anaerobic human intestinal bacteria, turn it into a promising candidate for colonic drug delivery systems. In this study aqueous systems (0.5%, w/v,) of KGM from three different origins and their mixtures with xanthan gum (XG) (1:1) were evaluated as regards their rheological properties and the diffusion coefficients and mobile fraction of macromolecules (dextrans of different molecular weight). Rheological data illustrate the synergism between KGM and XG at a stoichiometric relationship 1:1. Moreover, fluorescence recovery after photobleaching (FRAP) data indicate that diffusion of probes through the polysaccharide systems cannot be completely explained by the macroscopic properties of the medium but it is related to their molecular size and as a consequence to a sieving mechanism. The strong differences between KGM from different suppliers suggest the convenience of establishing specifications for this material in order to use it as pharmaceutical excipient.
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Affiliation(s)
- Felipe Alvarez-Manceñido
- Departamento Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
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211
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212
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Ratcliffe I, Williams PA, Viebke C, Meadows J. Physicochemical Characterization of Konjac Glucomannan. Biomacromolecules 2005; 6:1977-86. [PMID: 16004435 DOI: 10.1021/bm0492226] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Four commercial konjac glucomannan (KGM) samples and a glucomannan derived from yeast were characterized by aqueous gel permeation chromatography coupled with multi angle laser light scattering (GPC-MALLS). Disaggregation of aqueous glucomannan solutions through controlled use of a microwave bomb facilitated reproducible molar mass distribution determination alleviating the need for derivatization of the polymer or the use of aggressive solvents. Further characterization was undertaken by use of capillary viscometry and photon correlation spectroscopy (PCS). The weight average molecular masses (M(w)) determined were in the region of 9.0 +/- 1.0 x 10(5) g mol(-1) for KGM samples and 1.3 +/- 0.4 x 10(5) g mol(-1) for the yeast glucomannan. The values determined for KGM in aqueous solution are in agreement with those reported for KGM in aqueous cadoxen. The degradation of samples observed upon autoclaving has been quantified by GPC-MALLS and intrinsic viscosity determination, allowing comparison with reported Mark-Houwink parameters. Shear flow experiments were undertaken for a range of KGM solutions of concentration 0.05 to 2.0% using a combination of controlled stress and controlled strain rheometers. The concentration dependence of the zero shear specific viscosity was determined by analysis of the data using the Ellis model. The dependence of the zero shear specific viscosity on the coil overlap parameter was defined and interpretation discussed in terms of the Martin and Tuinier equations.
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Affiliation(s)
- Ian Ratcliffe
- Centre for Water Soluble Polymers, The North East Wales Institute, Mold Road, Wrexham, United Kingdom LL11 2AW
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213
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Zhang YQ, Xie BJ, Gan X. Advance in the applications of konjac glucomannan and its derivatives. Carbohydr Polym 2005. [DOI: 10.1016/j.carbpol.2004.11.003] [Citation(s) in RCA: 215] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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214
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Gao S, Nishinari K. Effect of deacetylation rate on gelation kinetics of konjac glucomannan. Colloids Surf B Biointerfaces 2004; 38:241-9. [PMID: 15542332 DOI: 10.1016/j.colsurfb.2004.02.026] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Accepted: 02/02/2004] [Indexed: 11/23/2022]
Abstract
Effect of deacetylation rate on the gelation behaviors on addition of sodium carbonate for native and acetylated konjac glucomannan (KGM) samples with a degree of acetylation (DA) range of 1.38-10.1 wt.% synthesized using acetic anhydride in the presence of pyridine as catalyst was studied by dynamic viscoelastic measurements. At a fixed alkaline concentration (C(Na)), both the critical gelation times (t(cr)) and the plateau values of storage moduli (G'(sat)) of the KGM gels increased with increasing DA. While at a fixed ratio of alkaline concentrations to values of DA (C(Na)/DA), the similar t(cr) and (G'(sat)) values independent of DA were observed. On the whole, increasing KGM concentration or temperature shortened the gelation time and enhanced the elastic modulus for KGM gel. The effect of deacetylation rate related to the C(Na)/DA on the gelation kinetics of the KGM samples were discussed.
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Affiliation(s)
- Shanjun Gao
- Graduate School of Human Life Science, Osaka City University Sugimoto, Sumiyoshi, Osaka 558-8585, Japan.
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215
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Hua YF, Zhang M, Fu CX, Chen ZH, Chan GYS. Structural characterization of a 2-O-acetylglucomannan from Dendrobium officinale stem. Carbohydr Res 2004; 339:2219-24. [PMID: 15337449 DOI: 10.1016/j.carres.2004.05.034] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2003] [Accepted: 05/10/2004] [Indexed: 11/13/2022]
Abstract
A heteropolysaccharide obtained from an aqueous extract of dried stem of Dendrobium officinale Kimura and Migo by anion-exchange chromatography and gel-permeation chromatography, was investigated by chemical techniques and NMR spectroscopy, and is demonstrated to be a 2-O-acetylglucomannan, composed of mannose, glucose, and arabinose in 40.2:8.4:1 molar ratios. It has a backbone of (1-->4)-linked beta-d-mannopyranosyl residues and beta-d-glucopyranosyl residues, with branches at O-6 consisting of terminal and (1-->3)-linked Manp, (1-->3)-linked Glcp, and a small proportion of arabinofuranosyl residues at the terminal position. The acetyl groups are substituted at O-2 of (1-->4)-linked Manp and Glcp. The main repeating unit of the polysaccharides is reported.
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Affiliation(s)
- Yun-Fen Hua
- Lab of Plant Systematic Evolution and Biodiversity, College of Life Sciences, Zhejiang University, Hangzhou 310029, China
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216
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Gao S, Nishinari K. Effect of Degree of Acetylation on Gelation of Konjac Glucomannan. Biomacromolecules 2003; 5:175-85. [PMID: 14715024 DOI: 10.1021/bm034302f] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Effect of the degree of acetylation (DA) on the gelation behaviors on addition of sodium carbonate for native and acetylated konjac glucomannan (KGM) samples with a DA range from 1.38 to 10.1 wt % synthesized using acetic anhydride in the presence of pyridine as catalyst was studied by dynamic viscoelastic measurements. At a fixed alkaline concentration (CNa), both the critical gelation times (tcr) and the plateau values of storage moduli (G'sat) of the KGM gels increased with increasing DA, while at a fixed ratio of alkaline concentrations to values of DA (CNa/DA), similar tcr and values independent of DA were observed. On the whole, increasing KGM concentration or temperature shortened the gelation time and enhanced the elastic modulus for KGM gel. The effect of deacetylation rate related to the CNa/DA on the gelation kinetics of the KGM samples was discussed.
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Affiliation(s)
- Shanjun Gao
- Department of Food and Human Health Sciences, Graduate School of Human Life Science, Osaka City University, Sugimoto, Sumiyoshi, Osaka 558-8585, Japan.
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217
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Current awareness in phytochemical analysis. PHYTOCHEMICAL ANALYSIS : PCA 2003; 14:328-335. [PMID: 14627054 DOI: 10.1002/pca.680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
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