Isoquinoline-derived alkaloids and one terpene lactone from the leaves of Duguetia pycnastera (Annonaceae)

Abstract The phytochemical investigation from the leaves of Duguetia pycnastera Sandwith (Annonaceae) led to the isolation and identification of ten compounds: nine isoquinoline-derived alkaloids, including five aporphines, anonaine, isopiline, O-methylisopiline, nornuciferine, and norstephalagine; three oxoaporphines, O-methylmoschatoline, liriodenine, and lysicamine; and one tetrahydroprotoberberine, isocorypalmine; in addition, one C11-terpene lactone known as loliolide. The isolated compounds (except for O-methylmochatoline and lysicamine) are described for the first time in the species and their chemophenetics relationships were discussed. The occurrence of loliolide is reported for the first time in the Duguetia. The structure elucidation of these compounds was established by extensive analyzes of 1D and 2D NMR spectroscopy in combination with MS. The NMR spectroscopic data for norstephalagine and isocorypalmine were reviewed.