Study on secondary metabolites of Nigrospora oryzae isolated from loquat and their inhibitions of pathogenic fungus from host plant

The fungi were isolated from the bark, stem and leaf of Loquat in the Wancui Garden of Yunnan University of Chenggong, of which Nigrospora oryzae and Alternaria alternata were dominant fungi. To explore the secondary metabolites of Nigrospora oryzae for their inhibitions of pathogenic fungus Alternaria alternata from host plant, Nigrospora oryzae were fermented by sloid mice medium. Ten compounds were isolated from solid rice fermentation of N. oryzae and their structures were identified as: R-mevalonolactone（1）, (4R,5S)-5-hydroxyhexan-4-olide（2）, (4R,5R)-5-hydroxyhexan-4-olide（3）, 1-phenyl-1,2-ethanediol（4）, p-hydroxyphenethylalcohol（5）, orcinol（6）, (2R,3S)-1,2,3-butanetriol（7）, (2R,3R)-1,2,3-butanetriol（8）, (5R,7R,9R)-7,9-dihydroxy-5-decanolide（9）and ethyl-α-D-glucopyranoside（10）. The ten compounds for antifungal assays against plant pathogens Alternaria alternata in the host plant were the first time. Compounds 4, 6 and 7/8 exhibited significant inhibitory activities. This study provided the reference for the development of biocontrol agents.