Phytotoxic Hemiketal-Containing Polyketides from the Endophytic Fungus

Thirty highly oxidized hemiketal-containing polyketides, including 10 new ones (1-10) and 20 known analogues (11-30), were obtained from the endophytic fungus Trichoderma koningiopsis WZ-196 with the OSMAC strategy in combination with molecular network analysis. Their structures were elucidated through comprehensive spectroscopic analysis, together with NMR and ECD calculations. The phytotoxic activities of all compounds were evaluated using Arabidopsis thaliana (dicotyledonous) and Oryza sativa (monocotyledonous) as model systems. The results showed that most compounds exhibited significant inhibitory effects on seedling growth. Notably, compound 9 demonstrated the strongest phytotoxic activity against A. thaliana with an IC50 value of 8.09 μM, while 24 markedly suppressed the growth of O. sativa with an IC50 value of 9.42 μM, outperforming the commercial herbicide glyphosate under identical experimental conditions. These findings highlight the potential of hemiketal-containing polyketides derived from endophytic fungi as promising candidates for developing novel bioherbicides.