Study On The Active Constitutes Of Several Lichens And Endolichenic Fungi

Lichen is a special symbiotic of cyanobacteria and filamentous fungi. at present, there are 26000 species of belongs to 525 families. Most of the fungi are ascomycete, account for 98% of the amount of fungi. The lichens are widespread from the north and south poles to equator, from the mountains to the plain, from the forest to desert.The metabolisms of lichens include polyols and carbohydrates,xanthones and bis- xanthones,aromatic,dibenzofuranes,chromanes and chromones,depsides,depsidones,cleavage products of depsides and depsidones. To the present, more than 700 lichen compounds have been identified, most of them show good bio-activity.There are a few reports about the isolation and the metabolism of endolichenic fungi. Most of the research about the chemical constitutes of endolichenic fungi is from Yongsheng Che, from the first report about endolichenic in 2007 by Priyani A. Paranagama. The structure of constitutes is very novel and they show modest antitumor and antifungal activities.This thesis studied the metabolisms of two species of lichens Evernia divaricata (L.) Ach. and Lethariella zahlbruckneri (Dr.) Krog., from which we afford 11 compounds , and we identified their structure by spectrum and Single crystal X-ray, most of which belongs to depsides,dibenzofuranes and cleavage products of depsides and depsidones. Two of the isolates (usnic acid and divaric acid) showed potent antibacterial activity against four bacterial.The method of scraping cortex was adapted to isolate endolichenic fungi from Laojun Mountain, Yunnan Province, and 263 strains of fungi was afford from 21 families. 51 strains of fungi's classic position were determined by ITS analysis, nine of which were selected for antibiotic activity and HPLC analysis, 4 strains were selected for further chemical study.We isolated and identified 19 compounds from the EtOAc extract of strain of 20081189 by semi-prepared HPLC and silica gel column chromatograph, including 6 new compounds:1,8a-dihydro-7,8-dihydro-7,8-dihydroxy-3,7-dimethyl-2-benzopyra n-6-one (7),5-chloro-7,8-dihydro-7,8-dihydroxy-3,7-dimethyl-2-benzopyran-6-one (8),2,3-dihydro-2-n-butyloxyanhydrofulvic acid (13),2,3-dihydro-2-methoxyanhydroful vic acid (14),13-decarboxylanhydrofulvic acid (15),12-dehydroxylcitromycetin (19). The bio-activity assay of compounds 8-19 show: compounds 19 and 13 exhibit modest cytotoxicity against human leukemia cell line K562, with IC50 is 20.0 and 32.2μM respectively. Compounds 9,10,11 show modest inhibitory on Candida albicans (sc5314), with the MIC value is 128μg/ml respectively.We isolated and identified 3 compounds from the strain of 20102595A with the methods of semi-prepared HPLC and silica gel column chromatograph. All of the isolates showed modest antifungal activity against C. albicans.