Study On Secondary Metabolites Of One Strain Of Endophytic Fungus

Lichen is a reciprocal symbiotic complex which is composed of fungi and algae or cyanobacteria,is classified as fungi in taxonomy.Most of the algaes are chlorellas,fungi are ascomecetes and basidiomycetes.And lichen is named by the mycobiont lichen-forming fungi taxonomically.However,those endolichen fungi refers to living in health lichen piant tissue clearance,mainly in the medullary layer,which won't cause any direct or indirect damage to the lichen.Lichen is a kind of worldwide distribution organisms wich can adapt to many extreme environment conditions,such as alpine,permafrost,strong acid-base salt,the north and south poles and so on.Thus,it is speculated are of rich species diversity.There are increasing number of reports on secondary metabolites of endolichenic fungi,since 2007.The results showed there are many kinds of secondary metabolites in endophytic fungi,meanwhile some of them are with cxcellent biological activities.Thus,they can be used as lead compounds for drug research and development,with potential development value.In this experiment,we made isolation and culture of endophytic fungi by Scraping cortex,using 49 kinds of lichen as the experimental material collected from Jilin and Xinjiang Province,such as Parmelia sp.?Nephromopsis sp.?Physcia sp.?Cladonia sp.?Parmotrema sp.and so on.The result showed that 162 strains of endophytic fungi were isolated and cultured.In order to test biological activity of their secondary metabolites,the 162 strains of endophytic fungi were subjected to a small amount of fermentation,and be soaked into ethyl acetate one month later.We test the minimal inhibitory concentration(MIC)with cell culture method of 96-well plates and antitumor activity screening with MTT method.9 strains of endophytic fungi showe strong antagonistic effect to the growth of Candida albicans,and the MIC value of 20140207 b is 4 ug/ml.32 strains of them have different cytotoxicityon on human breast cancer cells HCC1428.Among them,15 strains present stronger cytotoxicity,the antitumor activity of 20140225 a is first-rate and it's IC50 value can attain to 3.22.Based on the comprehensive analysis,20140207 d and 20140790 d were selected as experimental materials.The endophytic fungi 20140790 d and 20140207 d isolated from Xanthoria sp.Physcia sp.respectively were fermented in rice culture medium and then extracted with ethyl acetate to obtain a large amount of crude extract.The crude extract was extracted by ethyl acetate-methanol-water system and then purificated ethyl acetate fraction by silica gel column chromatography,SephadexLH-20,ODS column chromatography and RP-HPLC.Finally,eight compounds are obtained from 20140207 d and six compounds are obtained from 201400790 d.Mass spectrometry(MS)and nuclear magnetic resonance(NMR)techniques are employed to elaborate the structure of the compounds,including cyclic peptides,coumarins and p-Hydroxybenzoic acid.