3-Decalinoyltetramic acids from kiwi-associated fungus <i>Zopfiella</i> sp. and their antibacterial activity against <i>Pseudomonas syringae</i>

Abstract

Four rare 3-decalinoyltetramic acid derivatives, zofielliamides A-D (1-4), were obtained from cultures of kiwi-associated fungus <i>Zopfiella</i> sp. Their structures with absolute configurations were established by extensive spectroscopic methods and single crystal X-ray diffraction. The compounds possessed rare pentacyclic systems that might derive from a polyene precursor <i>via</i> [4 + 2] intramolecular Diels-Alder reactions. Compounds 1, 2, and 4 showed antibacterial activity against plant pathogen <i>Pseudomonas syringae</i> with MIC values of 64, 32, and 64 μg mL^-1, respectively.