Study On The Active Metabolites Of Endophytic Fungi From Glycyrrhiza Uralensis Fisch

Endophytes are microorganisms that live within plants for at least a part of their life cycle without causing any visible manifestation of disease. Their enormous biological diversity, such as antimicrobial, antioxidant, antitumor, etc. coupled with their capability to biosynthesize bioactive secondary metabolites especially those exclusive to heir host plants has provided the impetus for a number of investigations on endophytes.In this work, an endophytic fungi named RP4 which isolated from the root of Glycyrrhiza uralensis was chosen as the research object, and the species relationship of strain RP4 was determined. Then, the active secondary metabolites of RP4 were seperation and identified by modern analytical technology and their antibacterial activities were also screened The main conclusions are as follows:1. The endophytic fungi RP4 was identified as Acremonium dichromosporum by morphological characteristics and ITS sequence analysis.2. The endophytic fungi RP4 were fermented in large scale, then the bioacitivity compounds in the fermentation broth were isolated by liquid-liquid extraction, silica gel column chromatography, TLC and other methods. Three compounds were obtained, they are Crystal 1, Crystal 2 and Crystal 3.3. The structures of three compounds were analyzed by means of HPLC,’H-NMR, 13C-NMR, IR and HPLC/MS and Crystal 1 was Glycyrrhetinic acid, but the structure of Crystal 2 and Crystal 3 can not be determined for little amount.4.11 strains of microbes were selected as the indicators and antimicrobial tests of Crystal 1, Crystal 2 and Crystal 3 were carried out by paper disc diffusion method. Among these three crystals, Crystal 1 showed the different antimicrobial activity against of 7 human pathogenic microbes; Crystal 2 showed the different antimicrobial activity against of 6 human pathogenic microbes, especially Staphylococcus aureus; Crystal 3 showed the different antimicrobial activity against of 8 human pathogenic microbes, and also showed strong activity to Staphylococcus aureus.The active metabolites of endophytic fungi RP4 were isolated and purified for the first time. The fungus appears to produce the same bioactive ingredient, glycyrrhetinic acid, as the host plant. The current research indicates that a glycyrrhetinic acid-producing endophytic fungus RP4 isolated from Glycyrrhiza uralensis was got.