Fungus Aspergillus sp., which was isolated from soft coral Sarcophyton tortuosum, was cultured in the GPY medium containing glucose 10 g/L, peptone 5 g/L, yeast extract 2 g/L, sea water 1 L, at pH=7.5. Four com pounds...Fungus Aspergillus sp., which was isolated from soft coral Sarcophyton tortuosum, was cultured in the GPY medium containing glucose 10 g/L, peptone 5 g/L, yeast extract 2 g/L, sea water 1 L, at pH=7.5. Four com pounds, 3,6-diisobutyl-2（1H）-pyrazinone（1）, 3-isobutyl-6-（1-hydroxy-2-methylpropyl）-2（1H）-pyrazinone（2）, 3-methoxy-4-methyl-2,4-dien-pentanoic acid（3） and penicillic acid（4） were obtained from the AcOEt extract of the culture broth. Their structures were elucidated mainly based on the NMR, HR-EI-MS and X-ray single crystal diffraction experimental data. Compound 3 is a new compound. Compound 1 was previously proposed to be the tautomer of flavacol（3,6-diisobutylpyrazin-2-ol, 5）. However, the evaluation of the NMR and X-ray single crystal diffraction experimental data permitted us to propose that compound 1 existed as amide form instead oftautomers. Compound 1 is stable both in solution and crystal due to strong intermolecular hydrogen bonds. Incidentally supplying anthracenone to the GPY medium with a dose of 100 mg/L, the yield of penicillic acid（4） in the culture broth of the strain Aspergillus sp. was increased dramatically from 6 mg/L to 57 mg/L.展开更多
Fungi isolated from mangrove rhizosphere soil of the South China Sea were investigated for the production of potential antifungal metabolites. With 28 fungal isolates, the strains Penicillium javanicum HK1-23 and P. j...Fungi isolated from mangrove rhizosphere soil of the South China Sea were investigated for the production of potential antifungal metabolites. With 28 fungal isolates, the strains Penicillium javanicum HK1-23 and P. janthinellum HK1-6 showed significant antifungal activities. A bioassay-guided investigation of the two fungal strains led to the isolation of two secondary metabolites, brefeldin A and penicillic acid, with high yields of 143 and 423 mg L^-1, respectively. Penicillic acid showed potent antifungal activities toward Rhizoctonia solani and R. cerealis, with 67.5% and 76% growth inhibition, respectively, at 50 μg mL^-1. Brefeldin A showed strong activity toward R. cerealis, with 56.4% growth inhibition at 50 μg mL^-1. The research highlights the importance of exploring microbes from mangrove rhizosphere soil for the identification of bioactive metabolites for future fungicide development.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.20502036 and 20602044)the Natural Science Founda-tion of Guangdong Province(No.05300667) the Fund for Innovative Chemical Experiment and Research of School of Chemi-stry and Chemical Engineering, Sun Yat-sen University, China
文摘Fungus Aspergillus sp., which was isolated from soft coral Sarcophyton tortuosum, was cultured in the GPY medium containing glucose 10 g/L, peptone 5 g/L, yeast extract 2 g/L, sea water 1 L, at pH=7.5. Four com pounds, 3,6-diisobutyl-2（1H）-pyrazinone（1）, 3-isobutyl-6-（1-hydroxy-2-methylpropyl）-2（1H）-pyrazinone（2）, 3-methoxy-4-methyl-2,4-dien-pentanoic acid（3） and penicillic acid（4） were obtained from the AcOEt extract of the culture broth. Their structures were elucidated mainly based on the NMR, HR-EI-MS and X-ray single crystal diffraction experimental data. Compound 3 is a new compound. Compound 1 was previously proposed to be the tautomer of flavacol（3,6-diisobutylpyrazin-2-ol, 5）. However, the evaluation of the NMR and X-ray single crystal diffraction experimental data permitted us to propose that compound 1 existed as amide form instead oftautomers. Compound 1 is stable both in solution and crystal due to strong intermolecular hydrogen bonds. Incidentally supplying anthracenone to the GPY medium with a dose of 100 mg/L, the yield of penicillic acid（4） in the culture broth of the strain Aspergillus sp. was increased dramatically from 6 mg/L to 57 mg/L.
基金supported by the National Natural Science Foundation of China (No.81703411)the Natural Science Foundation of Jiangsu Province (Nos.BK20180940, BK20180937)+1 种基金the Open Fund of CAS Key Laboratory of Marine Ecology and Environmental Sciences, Institute of Oceanology, Chinese Academy of Sciences (No.KLMEES201802)the Taishan Scholars Program, China。
文摘Fungi isolated from mangrove rhizosphere soil of the South China Sea were investigated for the production of potential antifungal metabolites. With 28 fungal isolates, the strains Penicillium javanicum HK1-23 and P. janthinellum HK1-6 showed significant antifungal activities. A bioassay-guided investigation of the two fungal strains led to the isolation of two secondary metabolites, brefeldin A and penicillic acid, with high yields of 143 and 423 mg L^-1, respectively. Penicillic acid showed potent antifungal activities toward Rhizoctonia solani and R. cerealis, with 67.5% and 76% growth inhibition, respectively, at 50 μg mL^-1. Brefeldin A showed strong activity toward R. cerealis, with 56.4% growth inhibition at 50 μg mL^-1. The research highlights the importance of exploring microbes from mangrove rhizosphere soil for the identification of bioactive metabolites for future fungicide development.
