A novel spirocyclic triterpenoid and a new taraxerane triterpenoid from Teucrium viscidum

Two new triterpenoids, teuviscins A (1) and B (2), were isolated from the whole plants of Teucrium viscidum. Compound 1 possessed a rare 7(8→9)abeo-9R-D:C-friedo-B′:A′-neo-gammacerane skeleton, and compound 2 is a taraxerane triterpene acid. Their structures were characterized by extensive spectroscopic methods (HR-ESI-MS, 1D and 2D NMR), and the absolute configurations of 1 and 2 were secured by single-crystal X-ray diffraction analyses using Cu Kα radiation. Compound 2 showed anti-AD bioactivity which delayed animals paralysis of transgenic AD Caenorhabditis elegans.