The Secondary Metabolites Of Two Endophytic Fungi From Cephalotaxus Fortunei

Pharmacological ingredient in organisms has attracted much attention due to the varied medicine efficacy. The natural medicinal plants and the endophytic fungi of medicinal plants became an important source of finding a pharmacological active ingredient. The endophytic fungi of medicinal plants are better than medicinal plants due to small volume, fast reproduction, strong adaptability, etc. The purpose of the research is obtained novel structure and highly active compounds, and known to be a promising reservoir of antimicrobial medicines.In this paper, two endophytic fungi from Cephalotaxus fortunei were selected. The endophytic fungi S19 and S16 were identified by morphological characteristics and molecular biology characteristics. The results showed that the strain S19 was Aspergillus flavus and the S16 was Aspergillus fumigatus. Compounds were isolated from fermentation of the endophytic fungi S19 and S16 by chromatography and recrystallization. The structures of compounds 1-11 were determined by spectroscopic data interpretation. Nine compounds, 5-(hydroxymethyl) furan-3-carboxylic acid(1), 5-acetoxymethylfuran-3-carboxylic acid(2), ergosterol(3), β-sitosterol(4), stigmasta-7,22-diene-3β,5α,6α-triol(5), daucosterol(6), succinic acid(7), tuberoside(8) and sterigmatocystin(9), were isolated from the fermentation of strain S19. Among them, compound 2 is a new compound. Two compounds, gliotoxin(10) and 3β, 22-Dihydroxyhopane(11), were isolated from the fermentation broth of strain S16.The antimicrobial activities of eleven compounds were tested. Compounds 1 and 2 showed inhibitory effect against plant pathogens and bacteria, especially a strong inhibitory action against Gram positive bacteria. The minimum inhibitory concentration(MIC) value of compound 2 aginst Staphylococcus aureus was 15.6 μg/m L. Compounds 10 and 11 showed potent activity against bacteria and plant pathogens. Compound 10 showed high activity against Pseudomonas aeruginosa with MIC value of 1.95 μg/m L, and against Valsa Mali, Alternaria alternate and Alternaria brassicae with MIC value of 15.6 μg/m L. Compound 11 inhibited the growth of Escherichia coli and Pseudomonas aeruginosa with MIC value of 0.98 μg/m L, against Botrytis cinerea and Valsa mali with MIC value of 7.81 μg/m L.The antioxidant activities of compounds were tested. The compounds 1 and 10 showed antioxidant activity with IC50 values of 130.47 μg/m L and 132.83 μg/m L, separately. Compound 2 showed weak antioxidant activity with IC50 value of 543.47 μg/m L.A new compound, 5-acetoxymethylfuran-3-carboxylic acid(2) showed good antibacteria activity against gram negative bacteria. And 5-(hydroxymethyl) furan-3-carboxylic acid(1), with the weight of 120 g, is abundant. The compounds, gliotoxin(10) and 3β, 22-Dihydroxyhopane(11), showed potent antimicrobial activity against gram positive bacteria, gram negative bacteria and plant pathogens. The study showed endophytic fungi have an important significance on developing drugs and obtaining new structural compounds.