New α-pyranone derivatives from Diaporthe sp. WLM-Y1

From the ethyl acetate extract of solid-state cultures of the endophytic fungus Diaporthe sp. WLM-Y1 (isolated from the leaves of Cayratia japonica (Thunb.) Gagnep.), we characterised three previously undescribed α-pyranones, wodiaporones A-C (1-3), together with eleven known metabolites (4-14). Structures were clarified by an integrated analysis of 1D/2D NMR and high-resolution MS datasets. In preliminary screening assays, all isolated metabolites (1-14) were evaluated at 50 μg/mL against the phytopathogens Ralstonia solanacearum (ATCC 11696), Fusarium oxysporum (ATCC 48112), and Alternaria alternata (ATCC 6663). Several metabolites showed measurable inhibition, with the most pronounced effect observed for compound 13 against R. solanacearum (27.74% inhibition at 50 μg/mL). Compound 11 displayed the highest activity against F. oxysporum (25.55%), whereas only compounds 1, 11-13 showed detectable inhibition towards A. alternata (3.69%-8.93%). These findings expand the α-pyranone chemical space from Diaporthe and provide leads for further evaluation of plant-pathogen control.