Nigroepocins A-D: Antifungal Polyketides from Nigrospora sp. SN56127 with Activity against Fusarium graminearum

Nigroepocins A-D (1-4), along with one known compound clavatol (5), were isolated from the fermentation broth of Nigrospora sp. SN56127. Their structures, including absolute configurations, were determined by NMR, MS, and single-crystal X-ray diffraction analyses. Each of the four compounds (1-4) possesses a three-membered epoxy ring, which is rare in other compounds isolated from Nigrospora. All compounds (1-5) were evaluated for their antifungal activities against Fusarium graminearum, and nigroepocin A (1) exhibited inhibition with EC50 values of 110 and 23.1 μM against mycelial growth and conidial germination, respectively.