Antifungal ergostane-type steroids from endophytic fungus Xylaria sp. VDL4

Three ergostane-type steroids, including one rare C-29 methylated xylarstane A ( 1 ) and one C22,23-epoxied xylarstane B ( 2 ), along with one reported compound 3 , were isolated from the endophytic fungus Xylaria sp. VDL4 harbored within the medicinal plant Vaccinium dunalianum . The structures of novel compounds were elucidated through comprehensive spectroscopic analysis, DP4 + -validated theoretical 13 C nuclear magnetic resonance (NMR) calculations, and electronic circular dichroism (ECD) calculations. The antifungal activities of the isolates against four phytopathogens were assessed in vitro. Compounds 1 and 3 exerted significant inhibition against Alternaria solani and Botrytis cinerea respectively, both with minimal inhibitory concentration (MIC) of 12.5 μg/mL, comparing with the positive control (Carbendazim and Thiabendazole, MICs = 12.5–25.0 μg/mL)