Trichothecroamides A‒F, antifungal amides from potato associated fungus Trichothecium crotocinigenum.

Potato is the most important non-cereal food crop in the world. Phytophthora infestans and Rhizoctonia solani are responsible for the cause of late blight and black scurf of potato, respectively, which take a decline of potato production and serious economic loss to the producers. As a continuation of the search of natural fungicides from the secondary metabolites of potato associated fungus Trichothecium crotocinigenum, five previously undescribed amide derivatives trichothecroamides A‒E, one previously undescribed cyclopeptide trichothecroamide F, together with three known cyclopeptides, have been obtained. Their structures were established by extensive spectroscopic analysis, as well as quantum chemistry calculations on ECD. Trichothecroamide A and two known cyclopeptides showed moderate antifungal activities against P. infestans and R. solani with MIC values of 16-64 μg/mL, which could be applied as potential anti-pathogenic agents for potato fungal diseases.