Antibiotic and Antimalarial Quinones from Fungus-Growing Ant-Associated <i>Pseudonocardia</i> sp.

Abstract

Three new members of the angucycline class of antibiotics, pseudonocardones A–C (<b>1</b>–<b>3</b>), along with the known antibiotics 6-deoxy-8-<i>O</i>-methylrabelomycin (<b>4</b>) and X-14881 E (<b>5</b>) have been isolated from the culture of a <i>Pseudonocardia</i> strain associated with the fungus-growing ant <i>Apterostigma dentigerum</i>. Compounds <b>4</b> and <b>5</b> showed antibiotic activity against <i>Bacillus subtilis</i> 3610 and liver-stage <i>Plasmodium berghei</i>, while <b>1</b>–<b>3</b> were inactive or only weakly active in a variety of biological assays. Compound <b>5</b> also showed moderate cytotoxicity against HepG2 cells