Secondary Metabolites From Two Endophytic Fungi Associated With Sapindus Mukorossi Gaertn. And Their Antimicrobial Effect

Microorganism is a rich source of biologically active metabolites.Especially the endophyte has attract more and more attention as more and more metabolites were isolated from them.This thesis study on the bioactive secondary metabolites from three endophytic fungi firstly isolated from the healthy leaves of Sapindus mukorossi Gaertn.,including screening bioactive endophyte,identification and fermentation of three active strains,separation of active ingredients and structure identification and evaluation of the biological activity of the compounds.Two endophytic fungi named HY11-1,ye5 were screened from 6endophyte(HY11-1?HY11-2?ye5?ye4?P11?O)isolated from the leaves of Sapindus mukorossi Gaertn.through the antimicrobial test and chemical composition prediction.After morphological observation and18 S rDNA sequence analysis,strain HY11-1 was identificatied asAlternaria alternate because it was clustered in the same branch of the strain Alternaria alternate(No.HM165489.1)and displayed the similar growth status in plate and morphology under the microscope with Alternaria alternate;strain ye5 was identificatied as Aspergillus ochraceus because it was clustered in the same branch of the strain Aspergillus ochraceus(No.AF548065.1)and displayed the similar growth status in plate and morphology under the microscope with Aspergillus ochraceus.Strain HY11-1 and ye5 were cultured in czapek's,and the extract of their metabolites were got through extraction.Ten compounds were isolated from the extract of the two endophyte by UV-HPLC and their structure were identified by spectroscopic techniques(NMR,MS etc).Six compounds named tricycloalternarenes3a(1),di-isobutyl phthalate(2),tricyclo-alternarenes 3b(3),ACTG toxins F(4),tricycloalternarene 2b(5),tricycloalternarene 14b(6)were isolated from the extract of strain HY11-1;and four compounds named circumdatin C(7),circumdatin G(8),10-hydroxyl-3,4-dihydro-3-methyl-1H-1,4-benzo-diazepine-2,5-dione(9)and cyclo-try-pro(10)were isolated from the extract of strain ye5.And compound 6 is a new compound.Ten compounds were evaluated for their antimicrobial activities against three human pathogenic strains(Escherichia coli AB 94012,Staphyloccocus aureus AB 2010021 and Candida albicans AY 204006)by microbroth dilution method in 96-well culture plates.The results indicated that all the compounds had weak to no activity.Compound 4showed the strongest activity against C.albicans with the MIC value of15.63 ?M.Compounds 1-3 showed modern activity against C.albicans with the MIC value of 31.25?M and compound 5 and 9 showed the MIC value of 62.5 ?M;Compounds 1,3 and 7-9 showed certain antibacterial activity aganist E.coli with a MIC value of 62.5 ?M,while compound 10 showed weak activity against E.coli with the MIC value of 125 ?M.