Study On Secondary Metabolites Of Some Lichens And Endolichenic Fungi

Lichen is a sort of complex life that living in symbiotic relationship with fungi and algae,named by the mycobiont lichen-forming fungi taxonomically.Lichen is kind of worldwide distribution orgnanisms which able to living in many extreme environment conditions.A large amount of secondary metabolites with variety bio-activity were found in lichens(thulls), most of them are unique to lichen. Endolichenic fungi is sort of fungi that inhabit in the lichen thallus, in recent years, a lot of activities compounds were derived from the endolichenic fungi.In this paper some preliminary studies on the secondary metabolites of lichen-forming fungi and endolichenic fungi were carried out.Frist,we compare the two endolichenic fungi isolation method: cortex-scraping and the YAMAMOTO method,and result shows the cortex-scraping methods is more efficiency and productivity than the YAMAMOTO method,and the condition system of endolichenic fungi artificial culture is preliminary established. The EtOAc and the n-butanol extract of ENF-4 is apply to anti-tumor test,the result shows both the two part have anti-U2OS cell line activities,and the inhabitation activity of EtOAc phase is stronger.The chemical system pre-test is carried out to Lethariella zahlbruckneri, the result shows the main component of secondary metabolites of L.Zahlbrukneri are phenolics,glucide,coumarin,steriod terpenoide. And then screening for the most activity compounds by column chromatography on silica-gel G254, accompanied with anti-bacterial tests.Thallus of Lethariella zahlbruckneri was ultrasonic treated with methanol and then extract by EtOAc, n-Butanol,water respectively. Those three parts are applied to anti-bacterial activities test with five species of bacteria,according to the inhabitation activities ,the EtOAc extract is choosen for the further isolation. After column chromatography on silica-gel G-254, EtOAc extract is separated into 5 pats: F1,F2,F3,F4,F5,among of them,F1 has the strongest inhibition activities.F1 is divided into two parts through column chromatography, and then via Sephadex LH-20 colunm chromatography and semi-perparative HPLC, two compounds LE1,LE2 is obtained, they are proved to be pure compounds. Through physical&chemical quality analysis and organic spectrum determination,assisted with relevantpapers, identified the two pure compounds LE1 and LE2 as atranorin(Depsides)and norstictic acid(Depsidones),and both of them are not been reported for the frist time. The result of anti-bacterial experiment shows LE2 has obviously stronger inhibition activities than LE1.