(±)-Talaroindolenes A and B: Spiro-Ergot Alkaloid Enantiomers with a 5/6/6/6/5/5 Hexacyclic System and Cardioprotective Activity from <i>Talaromyces</i> sp. TJ403-AL05

Chemical investigation of fungus <i>Talaromyces</i> sp. TJ403-AL05 led to the isolation of (±)-talaroindolenes A (<b>1a</b>/<b>1b</b>) and B (<b>2a</b>/<b>2b</b>), two pairs of spiro-ergot alkaloid enantiomers featuring a 5/6/6/6/5/5 hexacyclic skeleton defined by a spiro[2-oxa-7,15-diaza-pentacyclo[12.2.1.1^1,8.0^3,7.0^12,18]octadecane-13,1'-[2]oxacyclopentane] core. Extensive spectroscopic analysis, X-ray crystallography and ECD calculation were used to determine the structure and absolute configuration of each enantiomer after chiral resolution. Additionally, <b>2b</b> exhibited significant cardioprotective effect on oxygen-glucose deprivation (OGD)-damaged H9C2 cells by preserving mitochondrial membrane potential and modulating the mRNA levels of Bax and Bcl-2.