Secondary metabolites produced by marine actinomycete <i>Micromonospora</i> sp. A258

<jats:title>Abstract</jats:title><jats:p>In the course of our screening program, the EtOAc extract of <jats:italic>Micromonospora</jats:italic> sp. A258 from the sponge <jats:italic>Haliclona oculata</jats:italic> exhibited antimicrobial activity against both gram positive <jats:italic>S.aureus</jats:italic> ATCC25923 and gram‐negative <jats:italic>E.coli</jats:italic> ATCC25922, <jats:italic>S.enterica</jats:italic> ATCC13076. This paper reports the isolation and structural elucidation of eight secondary metabolites including bacilsubteramide A (<jats:bold>1</jats:bold>), 4,9‐dihydroxy‐3‐isobutyl‐2,3,4,5‐tetrahydrobenzo‐azepin‐1‐one (<jats:bold>2</jats:bold>), indole‐3‐carboxylic acid (<jats:bold>3</jats:bold>), <jats:italic>N</jats:italic>‐acetyltryptamine (<jats:bold>4</jats:bold>), <jats:italic>N</jats:italic>‐(4‐hydroxyphenyl)ethyl‐methylbutanamide) (<jats:bold>5</jats:bold>), <jats:italic>N</jats:italic>‐phenyl‐acetamide (<jats:bold>6</jats:bold>), 2‐[(5‐methyl‐1,4‐dioxan‐2‐yl)methoxy]ethanol (<jats:bold>7</jats:bold>), (2<jats:italic>R</jats:italic>,3<jats:italic>S</jats:italic>)‐butane‐2,3‐diol (<jats:bold>8</jats:bold>) from the culture broth of <jats:italic>Micromonospora</jats:italic> sp. A258. Their structures were determined by spectroscopic analysis including MS, 1D NMR and 2D NMR, as well as comparison with literature data.</jats:p>