Herbicidal and Antibacterial Secondary Metabolites Isolated from the -Derived Endophytic Fungus TE-739D.

Endophytic fungi possess a unique ability to produce abundant secondary metabolites, which play an active role in the growth and development of host plants. In this study, chemical investigations on the endophytic fungus TE-739D derived from the cultivated tobacco ( L.) afforded two new polyketide derivatives, namely japoniones A () and B (), as well as four previously reported compounds -. Their chemical structures were elucidated by detailed spectroscopic analyses and quantum chemical calculations. In the herbicidal assays on the germination and radicle growth of L. and seeds, compound was found to inhibit the germ and radicle elongation. Notably, compound showed potent herbicidal activity against L. germ elongation, with an IC value of 43.6 μg/mL, even higher than the positive control glyphosate (IC = 76.0 μg/mL). Moreover, compound demonstrated strong antibacterial effects against the pathogens and , with a comparable MIC value of 16 μg/mL to the positive control chloramphenicol. These findings indicate that the endophytic fungus TE-739D holds significant metabolic potential to produce bioactive secondary metabolites, which are beneficial, providing survival value to the host plants.