Secondary Metabolites And Antimicrobial Activity Of Endophytic Fungus From Cephalotaxus Fortunei

Endophytic fungi have many species that are widely distributed inplants. Research results showed that endophytic fungi can producevarious novel structures and bioactive substances. In the rescent, theresearch of antimicrobial activity of the metabolites becomes more andmore important, and there is vast prospect to develop new antimicrobialnatural medicines from the endophytic fungi. So, endophytic fungi fromCephalotaxus fortunei was selected, in order to get the compounds withgood antimicrobial activity.In this paper, we selected the endophytic fungi from Cephalotaxusfortunei isolated from Shaanxi Province, Qinling area.There are61strains of Endophytic fungi, which were isolated from the seed coat,stem and leaf of Cephalotaxus fortunei by tissue-culture method,52sporulated strains were identified to9genera,5families and3orders bymorphological method. Penicillium sp., Penicillium sp. and Alternariasp. were dominant endophytic fungi which occupy49.18%in totalstrains. An endophytic fungus Se01with strong inhibitory activity wasanalyzed by morphological characteristics and18S rDNA sequences, theresults showed that strain Se01was Aspergillus piperis.Antimicrobial activities of61strains endophytic fungi and theirsecondary metabolites were screened against six kinds of bacteria andnine kinds of plant pathogenic fungi. It was found that three strains(Se01, St16and St24) with strong inhibitory activity against six kindsof bacteria and nine kinds of plant pathogenic fungi, and averagediameter of the antibiotic circle is13~27mm. Finally, We chose Se01astarget strain.Se01strain was fermented in solid culture medium, the ethylacetatephaseand extracted to get98.33g crude extract. The structures with the secondary metabolites of Se01were elucidated throughphysicochemical properties and spectral data analyses. Finally,7compounds were identified as gliotoxin (1), emodin8-O-methylether(2), monomethylsulochrin (3),1,5-dimethyl citrate (4),5α,8α-epidioxyergosterol (5), ergosterol (6), D-mannitol (7).The minimal inhibition concentration (MIC) of seven kinds ofcompounds against six kinds of bacteria and nine kinds of plantpathogenic fungi were tested. The results showed that compound1,2,3and4had good antimicrobial activity against bacteria and plantpathogenic fungi, and compound1,3,4,5and6had betterantimicrobial activity against bacteria than plant pathogenic fungi.Compound1and3had high antimicrobial activity, which coincidedwith positive control.