Submerged Fermentation Culture The Inonotus Obliquus Exopolysaccharide Chemical Nature, Structure And Antioxidant Activity

Inonotus obliquus (I. obliquus) belongs to Eumycota, Basidiomycotina,Hymenomy, Aphyllophorales, Polyporaceae, Poria. It is a rare edible andpharmaceutical fungus. Inonotus obliquus is an extremely cold resistant fungus andmainly distributes in the area the Northern Hemisp-herenorth latitude45°~50°.Several kinds of bioactive substances from Inonotus obliquus have shown variousbiological activities, thus the fungus has high value to be empoldered. Inonotusobliquus polysaccharides is an important bioactivity substance which has scavengingactivity against many kinds of reactive oxygen radical, immuno modulation,anti-caducity, reducing blood sugar, antitumor and so on. However, the naturalresources of Inonotus obliquus are scarce. It is cost to extract the bioactive substancesfrom natural fruitbody and disadvantageous for natural resources production. In thispaper, the exo-polysaccharide produced by submerged culture of I. obliquus, Wereported two different sources exo-polysaccharides in submerged cultures of I.obliquus, one is from the control medium (EPC), the other is from lignocellulosecontaining medium (EPL). The antioxidant effect and physical-chemical properties ofthe two different resources exo-polysacchareds from mycelial culture of Inonotusobliquus were comparatively studied.The experimental results show that,1. The deproteinated extracts from EPC and EPL were named as DEPC and DEPL.DEPC and DEPL were subjected to a DEAE-cellulose, four fractions from bothDEPC and DEPL were obtained. The first three fractions of DEPC1, DEPC2, DEPC3and DEPL1, DEPL2, DEPL3were concentrated, dialyzed and then lyophilized;2. The differences were more significant among the three fractions of DEPL than thefractions of DEPC in sugar and protein content. DEPL1had the higest sugar contentwas89.7%, and DEPL3had the highest protein content was38.3%;3. Compositional analysis of EP. The main monosaccharide content of DEPC andDEPL was galactose and mannose, respectively. The mannose content of DEPC3andDEPL3was49.8%and49.6%; 4. The order of antioxidant effect on hydroxyl radicals was, EPL＞EPC＞DEPL＞DEPC,DEPC3＞DEPC2＞DEPC1,DEPL3＞DEPL2＞DEPL1;5. Scavenging effect on DPPH radicals. The scavenging activity of EPL and DEPLwas almost similar, which was stronger than EPC and DEPC, the scavenging abilityorder of six purified fractions was, DEPC2＞DEPC3＞DEPC1,DEPL3＞DEPL2＞DEPL1;6. DEPL3had the most antioxidant effect and lowest IC50value in these six fractionsin the hydroxyl and DPPH radical scavenging assay;7. The six fractions were fractionated and purified further by a gel permeationchromatography technique over a Sephadex G-200. A single fraction from eachsample was collected and coded as PDEPC1, PDEPC2, PDEPC3and PDEPL1,PDEPL2, PDEPL3, respectively;8. The average molecular weights (MW) of PDEPC1, PDEPC2, PDEPC3andPDEPL1, PDEPL2, PDEPL3were determined as41,35,35kDa and44,33,29kDaby size exclusion chromatography with laser light scattering. The MW/MN(molecular size) value of PDEPC1was closer to1than the others, indicating morehomogeneous.In conclusion, that the exo-polysaccharides from the lignocellulose medium hadstronger antioxidant effects than the ones from the control medium may be attributedto the stimulation of lignocellulose for Inonotus obliquus in submerged fermentation,which results in a difference of chemical composition, molecular weight and so on.More analysis and evaluation such as chemical structure and chain conformation ofthe purified extracts will be required for further understanding the differences betweenthe exo-polysaccharide extracts from the two different mediums.