Tersone A-G, New Pyridone Alkaloids from the Deep-Sea Fungus Phomopsis tersa

Abstract

Four phenylfuropyridone racemates, (±)-tersones A-C and E (<b>1</b>-<b>3</b>, <b>5</b>), one phenylpyridone racemate, (±)-tersone D (<b>4</b>), one new pyridine alkaloid, tersone F (<b>6</b>), single new phenylfuropyridone, tersone G (<b>7</b>) and two known analogs <b>8</b> and <b>9</b> were isolated from the deep-sea fungus <i>Phomopsis tersa</i>. Their structures and absolute configurations were characterized on the basis of comprehensive spectroscopic analyses, single-crystal X-ray diffraction experiments, and electronic circular dichroism (ECD) calculations. Moreover, compounds <b>1</b>-<b>9</b> were evaluated for in vitro antimicrobial and cytotoxic activity. Compounds <b>5b</b> and <b>8b</b> exhibited antibacterial activity against <i>S. aureus</i> with the MIC value of 31.5 μg/mL, while compound <b>5b</b> showed cytoxic activities against SF-268, MCF-7, HepG-2 and A549 cell lines with IC₅₀ values of 32.0, 29.5, 39.5 and 33.2 μM, respectively.