Lycocasine A, a Alkaloid from and Its Acid-Sensing Ion Channel 1a Inhibitory Activity.

A novel alkaloid, lycocasine A (), and seven known alkaloids (-), were isolated from . Their structures were determined through NMR, HRESIMS, and X-ray diffraction analysis. Compound features an unprecedented 5/6/6 tricyclic skeleton, highlighted by a 5-aza-tricyclic[6,3,1,0]dodecane motif. In bioactivity assays, compound demonstrated weak inhibitory activity against acid-sensing ion channel 1a.