Antifungal Macrocyclic Trichothecenes from the Insect-Associated Fungus .

Three new macrocyclic trichothecenes possessing rare 6'-ketal moieties, roridoxins A-C (), and five known compounds () were isolated from the insect-associated fungus . Their structures were confirmed by a combination of NMR and HRESIMS data, while their absolute configurations were unambiguously determined by single-crystal X-ray analysis and electronic circular dichroism experiments. Trichothecenes and showed potent antifungal activities against four strains of phytopathogenic fungi. In addition, , , , and were found to significantly inhibit the cell growth of with minimal inhibitory concentration values from 8.8 to 18.5 μg/mL. Moreover, they were able to inhibit the biofilm formation of better than the positive control.