Ergosterol,(1→3)-α-D-glucan and chitosan are important biomaterials.In this research,a process has been developed to integratively extract ergosterol,(1→3)-α-D-glucan,and chitosan from Penicillium chrysongenum myc...Ergosterol,(1→3)-α-D-glucan and chitosan are important biomaterials.In this research,a process has been developed to integratively extract ergosterol,(1→3)-α-D-glucan,and chitosan from Penicillium chrysongenum mycelium.First,the mycelia are pretreated with 0.1mol·L-1 of NaOH.After recovery by centrifugation,the solid portion is made to undergo saponification and deacetylation reactions by addition of 2mol·L-1 NaOH and ethanol. After reaction,extraction is carried out by addition of petroleum ether,which separates the reaction mixture into two phases.The upper layer of petroleum ether contains extracted ergosterol,and the bottom layer of NaOH solu-tion contains(1→3)-α-D-glucan;the chitosan is on the mycelia residuum.After isolation,the recovery yield of er-gosterol is 0.52%of dry mycelium.That of(1→3)-α-D-glucan is about 8.2%;and chitosan is 5.7%with 86% deacetylation.The compositions have been characterized by IR,HPLC analyses.展开更多
Fractions of a water insoluble α-(1→3)-D-glucan (GL) extracted from Ganoderma lucidum were carboxy-methylated (CM) to obtain water-soluble carboxymethylated derivatives (CM-GL) having a degree of substitution (DS) o...Fractions of a water insoluble α-(1→3)-D-glucan (GL) extracted from Ganoderma lucidum were carboxy-methylated (CM) to obtain water-soluble carboxymethylated derivatives (CM-GL) having a degree of substitution (DS) of0.38～0.51. Weight-average molecular weight M_w and intrinsic viscosity [η] of the samples CM-GL were measured by gelpermeation chromatography combined with laser light scattering (GPC-LLS) and viscometry. The CM-GL exhibits a stifferchain in aqueous solution at 25℃ than the original glucan, The antitumor activities against Ehrlich ascites carcinoma (EAC,5×10~6) of the carboxymethylated derivatives from the α-glucan and curdlan, a β-glucan, are significantly higher than thoseof the original glucans. The effects of the relatively low molecular weight, expanded chains and better water-solubility of theCM-GL on the enhancement of antitumor activity could not be neglected. The chain stiffness decreased speedily withincrease of temperature from 40 to 60℃ or NaOH concentration from 0.1 to 0.4 in the solution, respectively, and the changeof the chain stiffness is reversible.展开更多
Critical concentrations of α-(1→3)-D-glucan L-FV-Ⅱ from Lentinus edodes were studied by viscometry andfluorescence probe techniques. The dependence of the reduced viscosity on concentration of the glucan in 0.5 mol...Critical concentrations of α-(1→3)-D-glucan L-FV-Ⅱ from Lentinus edodes were studied by viscometry andfluorescence probe techniques. The dependence of the reduced viscosity on concentration of the glucan in 0.5 mol/L NaOHaqueous solutions with or without urea showed two turning points corresponding to the dynamic contact concentration c_s andthe overlap concentration c~* of the polymer. The values of c_s and c~* were found to be 1×10^(-3) g cm^(-3) and 1.1×10^(-2) g cm^(-3),respectively, for L-FV-Ⅱ in 0.5 mol/L NaOH aqueous solutions. The two critical concentrations of L-FV-Ⅱ in 0.5 mol/LNaOH aqueous solutions were also found to be 1.2×10^(-3) g cm^(-3) fbr c_s and 9.2×10^(-3) g cm^(-3) for c~* from the concentrationdependence of phenanthrene fluorescence intensities. The overlap concentration c~* of L-FV-Ⅱ in 0.5 mol/L NaOH aqueoussolutions was lower than that of polystyrene with same molecular weight in benzene, owing to the fact that polysaccharidetends to undergo aggregation caused by intermolecular hydrogen bonding. A normal viscosity behavior of L-FV-Ⅱ in 0.5 mol/L urea/0.5 mol/L NaOH aqueous solutions can still be observed in an extremely low concentration range at 25℃.展开更多
基金Supported by the National Natural Science Foundation of China （No.20636010, No.50373003, No.20406002）, Beijing Natural Science Foundation （No.2071002）, and the Special Funds for Major State Basic Research Program of China （973 Program, No.2007CB714305）.
文摘Ergosterol,(1→3)-α-D-glucan and chitosan are important biomaterials.In this research,a process has been developed to integratively extract ergosterol,(1→3)-α-D-glucan,and chitosan from Penicillium chrysongenum mycelium.First,the mycelia are pretreated with 0.1mol·L-1 of NaOH.After recovery by centrifugation,the solid portion is made to undergo saponification and deacetylation reactions by addition of 2mol·L-1 NaOH and ethanol. After reaction,extraction is carried out by addition of petroleum ether,which separates the reaction mixture into two phases.The upper layer of petroleum ether contains extracted ergosterol,and the bottom layer of NaOH solu-tion contains(1→3)-α-D-glucan;the chitosan is on the mycelia residuum.After isolation,the recovery yield of er-gosterol is 0.52%of dry mycelium.That of(1→3)-α-D-glucan is about 8.2%;and chitosan is 5.7%with 86% deacetylation.The compositions have been characterized by IR,HPLC analyses.
基金This work was financially supported by the Research Fund for the Doctoral program of Higher Education (RFDP) and the National Natural Science Foundation of China (No. 20074025)
文摘Fractions of a water insoluble α-(1→3)-D-glucan (GL) extracted from Ganoderma lucidum were carboxy-methylated (CM) to obtain water-soluble carboxymethylated derivatives (CM-GL) having a degree of substitution (DS) of0.38～0.51. Weight-average molecular weight M_w and intrinsic viscosity [η] of the samples CM-GL were measured by gelpermeation chromatography combined with laser light scattering (GPC-LLS) and viscometry. The CM-GL exhibits a stifferchain in aqueous solution at 25℃ than the original glucan, The antitumor activities against Ehrlich ascites carcinoma (EAC,5×10~6) of the carboxymethylated derivatives from the α-glucan and curdlan, a β-glucan, are significantly higher than thoseof the original glucans. The effects of the relatively low molecular weight, expanded chains and better water-solubility of theCM-GL on the enhancement of antitumor activity could not be neglected. The chain stiffness decreased speedily withincrease of temperature from 40 to 60℃ or NaOH concentration from 0.1 to 0.4 in the solution, respectively, and the changeof the chain stiffness is reversible.
基金This work was supported by the National Natural Science Foundation of China (No. 29374170) and the Research Grant Council of Hong Kong Government Earmarked Grant (CUHK 4161/99M).
文摘Critical concentrations of α-(1→3)-D-glucan L-FV-Ⅱ from Lentinus edodes were studied by viscometry andfluorescence probe techniques. The dependence of the reduced viscosity on concentration of the glucan in 0.5 mol/L NaOHaqueous solutions with or without urea showed two turning points corresponding to the dynamic contact concentration c_s andthe overlap concentration c~* of the polymer. The values of c_s and c~* were found to be 1×10^(-3) g cm^(-3) and 1.1×10^(-2) g cm^(-3),respectively, for L-FV-Ⅱ in 0.5 mol/L NaOH aqueous solutions. The two critical concentrations of L-FV-Ⅱ in 0.5 mol/LNaOH aqueous solutions were also found to be 1.2×10^(-3) g cm^(-3) fbr c_s and 9.2×10^(-3) g cm^(-3) for c~* from the concentrationdependence of phenanthrene fluorescence intensities. The overlap concentration c~* of L-FV-Ⅱ in 0.5 mol/L NaOH aqueoussolutions was lower than that of polystyrene with same molecular weight in benzene, owing to the fact that polysaccharidetends to undergo aggregation caused by intermolecular hydrogen bonding. A normal viscosity behavior of L-FV-Ⅱ in 0.5 mol/L urea/0.5 mol/L NaOH aqueous solutions can still be observed in an extremely low concentration range at 25℃.
