New Chaetoglobosins with Fungicidal Activity from sp. UJN-EF006 Endophytic in .

Nine chaetoglobosins (-) including five previously undescribed ones (-) were obtained from the culture broth of an endophytic fungus ( sp. UJN-EF006) isolated from the leaves of . The structures of these fungal metabolites were elucidated by spectroscopic methods including mass spectroscopy, nuclear magnetic resonance, single crystal X-ray crystallography, and electronic circular dichroism. To accelerate the development of novel fungicides, all of the isolated chaetoglobosins were evaluated for their antifungal activity against two crop pathogens, and . The assay results revealed that chaetoglobosins , , , and possessed a significant fungicidal effect against , with EC values all below 10 μg/mL. Particularly, the most potent compound, , was 175- and 96-fold as active as the commercially available fungicides carbendazim (EC 70.11 μg/mL) and azoxystrobin (EC 39.02 μg/mL), respectively. A further observation under scanning electron microscope indicated that compound could markedly impair the fungal hyphae of . The study demonstrates that the chaetoglobosins had excellent in vitro antifungal activities against .