Lyonin A, a New 9,10‐Secograyanotoxin from Lyonia ovalifolia

Phytochemical studies on the branches and leaves of Lyonia ovalifolia yielded a new grayanane diterpenoid, lyonin A ( 1 ), together with two known compounds, secorhodomollolides A and D ( 2 and 3 , resp.). The structure of 1 was elucidated by combination of 1D‐ and 2D‐NMR, and MS analyses. Compound 1 turned out to be a new, highly O ‐acylated grayanane diterpenoid, of which ring B has undergone an oxidative cleavage between C(9) and C(10), yielding a system differing from the previously reported grayanane type with a 5/7/6/5 ring system. Results of the cAMP regulation activity assay showed that compounds 2 and 3 at 50 μ M induced a significantly decreased cAMP level in N1E‐115 neuroblastoma cells ( p <0.001), indicating neuropharmacological potential.