Identification of secondary metabolites of Aspergillus flavipes ASD and their fungicidal activities

In this work, the antibacterial substances in Aspergillus flavipesASD isolated from soil were identified and the biological activities of its secondary metabolites were evaluated. The crude dichloromethane extract from ASD fermentation broth was purified by silica gel column chromatography, gel column chromatography and semi-prepared high performance liquid chromatography. The isolated pure compounds were characterized by nuclear magnetic resonance spectrum and high resolution mass spectrometry and were compared with literature reported data. The structures were further confirmed by X-ray single crystal diffraction data. The fungicidal activities of the compounds against 9 pathogenic fungi, such as Phytophthora capsici, Exserohilum turcicum and Colletatrichum graminicola, etc, were determined by the method of pesticide plate dilution and mycelial growth rate. The results show that sulochrin and 4,5-dimethyl resorcinol were isolated from ASD. Sullocrin has a good control effect on P. capsici, E. turcicum and C. graminicola. 4,5-Dimethyl resorcinol has good control effect onP. capsici. They had no obvious effect or no inhibitory effect on 6 strains, such as Botrytis cinerea, Cercospora zeae-maydisand Curvularia lunata.