Antifungal and α-Glucosidase Inhibitory Metabolites from Xylaria sp. VDL4 Endophyte of Vaccinium dunalianum

Phytochemical investigation of the ethyl acetate extract from Xylaria sp. VDL4, an endophytic fungus isolated from Vaccinium dunalianum Wight (Ericaceae), resulted in the isolation and structural characterization of a novel sesquiterpenoid, (3 S ,10 S ,6 E )-2,10-dihydroxy-2,6,10-trimethyldodeca-6,11-dien-3-ylacetate, named xylarnoid A ( 1 ), along with five known secondary metabolites ( 2–6 ). Their structures were elucidated through integrated spectroscopic analysis and electronic circular dichroism calculations. In vitro antifungal evaluation against phytopathogens ( Fusarium oxysporum , Botrytis cinerea , Phytophthora capsici , and Fusarium solani ) demonstrated significant inhibitory activities for selected compounds. Additionally, 2 , 3 , and 6 exhibited notable α -glucosidase inhibitory potential.