Dimeric Diarylheptanoids with Neuroprotective Activities from Rhizomes of <i>Alpinia officinarum</i>

Abstract

Two novel dimeric diarylheptanoids, alpinidinoids A [(±)-<b>1</b>] and B (<b>2</b>), with two unusual coupling patterns, together with a new naturally occurring diarylheptanoid dimer possessing a rare pyridine ring linkage (alpinidinoid C, <b>3</b>), were isolated from the rhizomes of <i>Alpinia officinarum</i>. Their structures including absolute configurations were determined by extensive spectroscopic methods and theoretical calculations. All isolates were examined for their neuroprotective activities against oxygen-glucose deprivation and reoxygenation (OGD/R) damage in primary cortical neurons. Remarkably, the dextrorotatory enantiomer of alpinidinoid A [(+)-<b>1</b>] significantly ameliorated OGD/R-induced neuronal apoptosis, which was dependent on the activation of the AKT/mTOR signaling pathway.