Magnolia Polysaccharide Purification And Antibacterial, Anti-oxidative Activity Research

Flos magnoliae is the immature flower buds of Yulania Subgenus,Magnolia and Magnoliaceae.There are28species reported as medicine sources.Flos magnoliae is one of the best medicine for allergic rhinitis.It’s rich in a variety of biologically active components,such as volatile oils,lignans,alkaloids,etc.So it has the function of anti-allergic,immunological and anti-hypertensive.Now,The study for polysaccharides of Flos magnoliae is not reported.In this work,Flos magnoliae was choosed as raw material,the isolation,purification,structural analysis,in vitro antioxidant and antibacterial activity of the crude polysaccharides of Flos magnoliae were studied.The main conclusions are as follows:(1)The crude polysaccharides from Flos magnoliae was obtained by water extraction,ethanol precipitation,deproteinized Sevage method and hydrogen peroxide decolorization.On the base of single-factor experiments,response surface method was used to optimize the process.The relative polynomial model equationas was: Y=0.11+(6.087E-003)×A+(6.576E-003)×B+(1.458E-003)×C+(4.921E-003)×D-0.015×A×B+(1.250E-004)×A×C+(2.500E-004)×A×D+(9.125E-004)×B×C+(2.225E-003)×B×D+(3.838E-003)×C×D-0.022×A2-0.019×B2-0.013×C2-0.015×D2.The optimized extraction process parameters were as follows:water extraction time3.5h,extracted two times,solid-liquid ratio1:30,extraction temperature75℃. Under this condition,the extraction rate of polysaccharide from Flos magnoliae wss10.92%.(2)The crude polysaccharides from Flos magnoliae was separated by DEAE-52anion exchange chromatography and further purified by Sephadex G-100gel filtration chromatography to obtain two compenents,named WP andSP.The purity was identified by specific rotation and high performance liquid chromatography(HPLC).The result showed that they were both homogeneous.At the same time, the molecular weights of WP and SP werer2.357×105Da and1.824×106Da.(3)The configuration of WP and SP were determined by infrared spectroscopy(IR). In the3600cm-1,3200cm-1,2900cm-1,1700cm-1,1500cm-1,1000cm-1have absorption peak, these regions werer all charateristic absorption of polysaccharide. (4)Gas chromatography(GC) was used to dentermine the monosaccharide co mposition of WP and SP.WP was composed of five kinds of monosaccharides,n amely rhamnose,arabinose,mannose,glucose and galactose,SP was composed of fi ve kinds of monosaccharides,namely rhamnose,arabinose,mannose,glucose and gal actose.(5)The in vitro antioxidant activity of the crude polysaccharides from Flos magnoliae was studied.The redults showed that the crude polysaccharides from Flos magnoliae had strong reducing ability.In a certain concentration range,it had the ability of scavenging superoxide ion,hydroxyl radical and DPPH.The scavenging ability and the crude polysaccharides concentrations were related.(6)The crude polysaccharides from Flos magnoliae had inhibition ability of Escherichia coli,Baciltyphi murium,Staphylococcus aureus Aspergillus fumigatus and Aspergillus niger.The minimal inhibitory concentration(MIC) for Escherichia coli and Baciltyphi murium was5mg/mL.The MIC for Staphylococcus aureus,Aspergillus fumigatus and Aspergillus niger was2.5mg/mL.Hydrogen ion concentration(pH) and ultravioletlight(UV) irradiation had some impact on the antibacterial activity,and in the four to eight range of pH,the crude polysaccharides from Flos magnoliae showed good antibacterial activity.