Abstract: Seven compounds were isolated from the extract of the endophytic fungus Paraconiothyrium sp.YLHJ01,their structures were identified as one new compound,2-(1S,3R-dihydroxybutyl)benzene-1,4-diol (1) and six known compounds, 6-hydroxy-2S-methyl-4-chromanon (2),10-norparvulenone (3),(S)-7-hydroxy-3-((S)-1-hydroxyethyl)isobenzofuran-1(3H)-one (4),murranoic acid A (5),modiolide G (6),and uridine (7) by the analysis of spectroscopic data including NMR,ECD,IR and HR-ESI-MS.The cytotoxic activity in vitro assay indicated that none of the compounds showed cytotoxic activity on A549 and HepG2 cells. Antibacterial assay revealed that compounds 1 and 4 showed weak inhibitory activities against Staphylococcus aureus with minimum inhibitory concentrations (MICs) of 400 and 100 μg/mL,respectively,while compound 2 showed weak inhibition against S. aureus and Escherichia coli with MICs of 800 and 400 μg/mL,respectively.

Key words: Artemisia selengensis, Paraconiothyrium , sp., endophytic fungus, secondary metabolites, antibacterial activity