Amphidinins C–F, Amphidinolide Q Analogues from Marine Dinoflagellate <i>Amphidinium</i> sp.

Abstract

Four new polyketides, amphidinins C–F (<b>1</b>–<b>4</b>), have been isolated from the culture broth of symbiotic dinoflagellate <i>Amphidinium</i> sp. The analysis of their spectral data revealed that amphidinins C–F (<b>1</b>–<b>4</b>) were 4,5-seco-analogues of amphidinolide Q (<b>5</b>). The absolute configurations of the new compounds were elucidated by the combination of <i>J</i>-based configuration analysis, modified Mosher’s method, and chemical derivatization. Amphidinins D (<b>2</b>) and F (<b>4</b>) are the first glycosides related to amphidinolides. Amphidinins C–F (<b>1</b>–<b>4</b>) showed antimicrobial activity against bacteria and/or fungi