Separation and identification of secondary metabolites from Xenorhabdus nematophila SN313 and the biological activity against Meloidogyne incognita

This study isolated four secondary metabolites from Xenorhabdus nematophila SN313 and evaluated their nematicidal activity. Secondary metabolites were isolated and purified from X. nematophila SN313 using techniques including silica gel column chromatography, gel column chromatography, and HPLC. Their toxicity against second-stage juveniles (J2) of the Meloidogyne incognita was subsequently determined using a 24-well plate assay. The results demonstrated the isolation and purification of four compounds. Comprehensive analysis through HRMS, ¹H NMR, ¹³C NMR, comparison with literature data, and X-ray single-crystal diffraction established their structures. compound 1 was identified as a novel nitro-containing amide, designated xenornemamide. compounds 2−4 were determined to be known tryptamine derivatives. Nematicidal activity assays revealed that compounds 1, 3, and 4 exhibited significant activity against M. incognita, with LC₅₀ values of 31.62, 36.89, and 39.05 µg/mL, respectively. These results indicate their potential for further investigation.