Cochliomycin G, a 14-membered resorcylic acid lactone from a marine-derived fungus <i>Cochliobolus lunatus</i>

Abstract

Cochliomycin G (<b>1</b>), a new 14-membered resorcylic acid lactone, together with six known analogues (<b>2</b>-<b>7</b>), was isolated from the culture broth of a marine-derived fungus <i>Cochliobolus lunatus</i>. The planar structure of <b>1</b> was established by extensive NMR spectroscopy, and the absolute configuration was elucidated by the combination of empirical rules, CD data, and ¹³C chemical shift calculations. Compound <b>1</b> exhibited potent antifouling activity against <i>Chlorella vulgaris</i>, <i>Chaetoceros socialis</i>, and <i>Navicula exigua</i>, with EC₅₀ values of 1.09, 0.92, and 0.61 <i>μ</i>g/mL, respectively.