Vicinal Diol Sesquiterpenes from Cinnamomum migao with Neuroprotective Effects in PC12 Cells

In the ongoing search for new vicinal diol natural products, four new (Migaones A-D, <b>1</b>-<b>4</b>) and four known (<b>5</b>-<b>8</b>) vicinal diol sesquiterpenoids were isolated from the branches and leaves of <i>Cinnamomum migao</i>. Their structures were unequivocally determined by comprehensive spectroscopic analyses (HRESIMS, 1D, and 2D NMR), single-crystal X-ray diffraction, electronic circular dichroism calculations, and comparison with existing literature data. All compounds isolated from <i>C. migao</i> possess vicinal diol structural units except compound <b>2</b>. The newly isolated compounds (<b>1</b>-<b>4</b>) were evaluated for their neuroprotective activity using the PC12 cell injury model induced by <i>N</i>-methyl-daspartate acid (NMDA) and compounds <b>1</b>-<b>2</b> showing moderate neuroprotective activity against NMDA-induced neurotoxicity. Furthermore, molecular docking studies indicated that the most active compound <b>2</b> binds to the active site of the NMDA receptor via hydrogen bonds and hydrophobic interactions.