Abstract: A new amide metabolite,(2E,7Z)-9-hydroxy-4,6,8-trimethylnona-2,7-dienamide (1),together with two known manumycin-type compounds,antibiotic U-62162 (2) and salternamide C (3) were obtained from the fermentation broth of endophytic Plantactinospora sp.NEAU-gxj3.Their structures were determined on the basis of spectroscopic analysis,including 1D and 2D NMR as well as ESI-MS and comparison with literature data.Bioassay of cytotoxic activities results showed that 2 demonstrated potent cytotoxic activity against human leukemia cell line K562,human lung adenocarcinoma cell line A549 and human liver hepatocellular carcinoma cell line HepG2 with an IC50 value of 6.8,32 μg/mL and 19 μg/mL,respectively.