Phomopchalasins A and B, Two Cytochalasans with Polycyclic-Fused Skeletons from the Endophytic Fungus <i>Phomopsis</i> sp. shj2

Phomopchalasins A (<b>1</b>) and B (<b>2</b>), two novel cytochalasans with unprecedented carbon skeletons, and phomopchalasin C (<b>3</b>), containing a rare hydroperoxyl motif, were obtained from the endophytic fungus <i>Phomopsis</i> sp. shj2, which was first isolated from the <i>Isodon eriocalyx var. laxiflora</i>. Their structures were elucidated by extensive spectroscopic analyses, electronic circular dichroism (ECD) calculation, and X-ray crystallographic analysis. Notably, <b>1</b> possessed an unprecedented 5/6/5/8-fused tetracyclic ring system, and <b>2</b> featured a novel 5/6/6/7/5-fused pentacyclic skeleton. The cytotoxic, anti-inflammatory, and antimigratory activities of <b>1</b>–<b>3</b> were evaluated in vitro.