Antifungal diterpenoid alkaloids from Delphinium denudatum

The roots of Delphinium denudatum have yielded a new diterpenoid alkaloid, 8-acetylheterophyllisine (1), in addition to the known alkaloids vilmorrianone (2), panicutine (3), denudatine (4), isotalatizidine (5), and condelphine (6), as well as 3-hydroxy-2-methyl-4H-pyran-4-one (7). Compounds 1, 3, and 7 have not been isolated from this plant previously. The structures of compounds 1, 3, and 7 were determined through spectral and X-ray diffraction analyses. Compounds 1-3 have shown antifungal activity against a number of human pathogenic fungi.