Research On The Method Of Isolation And Purification Of Lentinan From Lentinus Edodes

Lentinus Edodes is commonly known as "Xiang-Gu" for both functional food and medicine in China.Lentinan is one of the effective constituents isolated from L.Edodes and has various biological activities such as anti tumor,anti virus.This dissertation focused on the isolation and purification of lentinan by the integrated utilization of membrane separation technology,High Speed Counter Current Chromatography(HSCCC),Sephacryl-column Chromatograghy and so on.The main conclusions were as follows:1.Membrane separation technology for the isolation of lentinan.The crude polysaccharide was subjected to MWCO 10K and 3.5k polyethersulfone membrane to afford three fractions(Fr.A～Fr.C).To obtain preffered membrane separation effect,the dilution times were studied with the help of High Performance Liquid Chromatograph,and it suggested that 3 times was the best.2.HSCCC for the isolation of lentinan.In order to obtain a better separation,the long chain ionic liquid C18 mim·Br was added into the solvent system of HSCCC.The result showed that the long chain ionic liquid,to some extent,had a positive effect on the purification of lentinan.Subsequently,the solvent systems(n-butyl alcohol-ethyl acetate-water systems,5:4:10 and 7:2:10,v/v)were adopted in the HSCCC experiment to purification of the fractions(Fr.A～Fr.C).The result showed that HSCCC technology was helpful for the purification of lentinan and can reduce the difficulty for the following gel purification3.Sephacryl gel filtration for the crude polysaccharide.The crude polysaccharide,which had been separated by membrane and HSCCC,were further purified by Sephacryl S 100-200 gel filtration,and obtained two lentinans(len 1-2 and len 2-1).The dissertation provided an efficient method for separation and purification of lentinan,laid a solid foundation for the follow-up resarchs of the structure identification and biological activities of lentinan,offered useful information for the industrialized production of lentinan.Moreover,a review on the progress of the isolation and purification of lentinan was presented.