New α-pyranone derivatives from <i>Diaporthe</i> sp. WLM-Y1

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