Study On Secondary Metabolites Of Two Endophytic Fungi And Two Streptomycete Stranins

In this thesis, the secondary metabolites and their bioactivities of two endophytic fungi and two streptomycete strains had been studied. A total of34compounds were obtained by various column chromatography on silica gel, RP-18and Sephadex LH-20. Among them, the structures of31compounds were established on the basis of extensive spectroscopic analyses including1D and2D NMR experiments, along with MS, UV and IR spectra. The anti-influenza virus, antitumor and antimicrobial activities of some compounds were evaluated. The results are concluded as follows:1. During our previous study, two endophytic fungal strains, Phomopsis sp. YE3708and Nigrospora sp. YE3033were found to possess anti-H5N1pseudovirus and antimicrobial activities. The chemical constituents from the culture broth of these two strains were studies in this paper. Eight compounds were obtained from the fermentation extracts of the strain YE3708. Their structures were identified to be16-acetoxycytosporone (1),4-methyl-5-(1-methyl-3-oxo-octa-1,4,6-trienyl)-1,2-dihydro-pyrazol-3-one (2), dankasteroneB (3),3β,5α,9α-Trihydroxy-(22E,24R)-ergosta-7,22-dien-6-one (4), cerevisterol (5), cyclonerodiol oxide (6), convolvulol (7), nicotinic acid (8). Compounds1and2are new, belonging to polyketide and alkaloid, respectively. Seven compounds were obtained from the fermentation extracts of the strain YE3033, which are mainly belonging to quinones. The structures were identified to be1,2,3,6,8-pentahydroxy-3-methyl-1,2,3,4-tetrahydro-anthraquinone (9),7-demethyl-macrosporin (10),1,2,8-trihydroxyanthraquinone (11), isozyganein (12),1-acetyl-4,5-dihydroxyanthra quinone (13), cis-4-hydroxyscytalone (14), cerebroside B (15), Compound9is a new anthraquinone.2. The anti-influenza virus and antimicrobial active screening,as well as TLC chemical screening of nine streptomycetes are performed. Two strains YIM121234and YIM12075were selected for further expansive fermentation. Thirteen compounds were obtained from the fermentation extracts of the strain YM121234. They were identified to be endophenazine A (16), endophenazine B (17), cyclo(phe-tyr)(18), cyclo(leu-tyr)(19), cyclo(L-pro-L-val)(20), cyclo(gly-phe)(21), dihydrouracil (22),5-methyl-uracil (23), uracil (24),5,6-dihydrothymine (25),4-hydroxy-benzaldehyde (26), cyclo(leu-val)(27),2,3-dihydroxypropyl acetate (28), respectively. Compounds16and17are belonging to phenazines. Six compounds were obtained from the fermentation extracts of the strain YIM120754, three of them were identified to be leucine (29), indole-3-carboxylic acid (30), and hydroxybenzoic acid (31), respectively.3. Parts of compounds were preliminarily evaluated for their biological activities. Compounds1,2and4showed moderate antifungal activities against Candida albicans with MIC values of32,64and64μg/ml, respectively. Compounds16and17showed anti-H5N1pseudovirusand cytotoxic activities.They inhibited the growth of MCF-7cell line with IC50of20.23±1.37and28.98±1.58μg/mL, respectively.In this paper, the chemical constituents and their bioactivities from fermentation extracts of two endophytic fungi and two streptomycetes were studied. The chemical structural types of the secondary metabolites from these four strains were clarified. Three new compounds, two antitumor and three antimicrobial active compounds were obtained. The current research could provide chemical substance basis for further study on these bioactive strains.