A new extracellular polysaccharide (EPS-I) isolated and purified from Z_ 222 ,a strain of Lactic acid bacteria has been investigated. Sugar composition analysis,methylation analysis and 1H NMR and 13 C NM...A new extracellular polysaccharide (EPS-I) isolated and purified from Z_ 222 ,a strain of Lactic acid bacteria has been investigated. Sugar composition analysis,methylation analysis and 1H NMR and 13 C NMR spectroscopy reveal that the EPS-I is composed of a pentasaccharide repeating unit. The sequence of sugar residue was determined by using two-dimensional NMR spectroscopy,including heteronuclear multiple-bond correlation (HMBC) and nuclear overhauser effect spectroscopy (NOESY).展开更多
A polysaccharide of Thea sinensis, TSA, has been isolated from the fresh leaves as a major fraction of polysaccharides. The mol. wt. was estimated to be 850,000 with [α]_D^(15)+ 25.5°(c=0.75, H_2O). The componen...A polysaccharide of Thea sinensis, TSA, has been isolated from the fresh leaves as a major fraction of polysaccharides. The mol. wt. was estimated to be 850,000 with [α]_D^(15)+ 25.5°(c=0.75, H_2O). The component sugars were determined as L-rhamnose, L-arabinose, and D-galactose in molar ratio of 0.54: 1.0: 0.94. The O-acetyl groups locating on galactose residues position 2 were also iden- tified and the content was 3.8％. The ^(13)C NMR spectrum and CrO_3 oxidation of TSA indicated the Rhamnose, Arabinose and Galactose to be in α-, α- and β-configurations, respectively. Me- thylation analysis, periodate oxidation, partial hydrolysis and ^(13) C NMR. spectrum showed that TSA. is a branched galactoarabinan.展开更多
Compression coated tablets for oral colon specific delivery systems were developed with a mixture polysaccharide of konjac glucomannan(KGM)and xanthan gum(XG)as the compression coat.Diffusion of cimetidine from compre...Compression coated tablets for oral colon specific delivery systems were developed with a mixture polysaccharide of konjac glucomannan(KGM)and xanthan gum(XG)as the compression coat.Diffusion of cimetidine from compression coated tablets was investigated by release experiment in Vitro.0.22U/mLβ-mannanase was applied in the mimic colon solution.The structure of the mixture polysaccharide was studied by an atomic force microscope(AFM).The experimental results indicate that a KGM70 tablet with a 0.4 g coat is of good design,due to a less than 5%drug loss in the mimic upper gastrointestinal solution by the synergistic interaction between XG and KGM,and due to about 50%cumulative release in the mimic colon solution by degradation after 24 hours.The release mechanism and model are discussed based on different periods of drug release including the delay of the drug,the constant release without an enzyme and the delay of degradation.Under hydrolysis byβ-mannanase,drug release from the tablet with KGM coat shows an exponential increase,while that from the dosage with the mixture polysaccharide coat is an approximately zero-order process in which the constant release rate relates to the release velocity of a non-degraded system,the content of KGM within the coat and the average molecular weight ratio of KGM to XG.It was found that XG was the framework of the polysaccharide mixtures by AFM,which is similar to the analysis results from experiments on drug release.展开更多
文摘A new extracellular polysaccharide (EPS-I) isolated and purified from Z_ 222 ,a strain of Lactic acid bacteria has been investigated. Sugar composition analysis,methylation analysis and 1H NMR and 13 C NMR spectroscopy reveal that the EPS-I is composed of a pentasaccharide repeating unit. The sequence of sugar residue was determined by using two-dimensional NMR spectroscopy,including heteronuclear multiple-bond correlation (HMBC) and nuclear overhauser effect spectroscopy (NOESY).
文摘A polysaccharide of Thea sinensis, TSA, has been isolated from the fresh leaves as a major fraction of polysaccharides. The mol. wt. was estimated to be 850,000 with [α]_D^(15)+ 25.5°(c=0.75, H_2O). The component sugars were determined as L-rhamnose, L-arabinose, and D-galactose in molar ratio of 0.54: 1.0: 0.94. The O-acetyl groups locating on galactose residues position 2 were also iden- tified and the content was 3.8％. The ^(13)C NMR spectrum and CrO_3 oxidation of TSA indicated the Rhamnose, Arabinose and Galactose to be in α-, α- and β-configurations, respectively. Me- thylation analysis, periodate oxidation, partial hydrolysis and ^(13) C NMR. spectrum showed that TSA. is a branched galactoarabinan.
基金the financial support from Grand project of Tianjin City,China(No.07ZCZDGX19600).
文摘Compression coated tablets for oral colon specific delivery systems were developed with a mixture polysaccharide of konjac glucomannan(KGM)and xanthan gum(XG)as the compression coat.Diffusion of cimetidine from compression coated tablets was investigated by release experiment in Vitro.0.22U/mLβ-mannanase was applied in the mimic colon solution.The structure of the mixture polysaccharide was studied by an atomic force microscope(AFM).The experimental results indicate that a KGM70 tablet with a 0.4 g coat is of good design,due to a less than 5%drug loss in the mimic upper gastrointestinal solution by the synergistic interaction between XG and KGM,and due to about 50%cumulative release in the mimic colon solution by degradation after 24 hours.The release mechanism and model are discussed based on different periods of drug release including the delay of the drug,the constant release without an enzyme and the delay of degradation.Under hydrolysis byβ-mannanase,drug release from the tablet with KGM coat shows an exponential increase,while that from the dosage with the mixture polysaccharide coat is an approximately zero-order process in which the constant release rate relates to the release velocity of a non-degraded system,the content of KGM within the coat and the average molecular weight ratio of KGM to XG.It was found that XG was the framework of the polysaccharide mixtures by AFM,which is similar to the analysis results from experiments on drug release.
