Phytochemical and chemotaxonomic investigations on the aerial parts of Cynanchum auriculatum Royle ex Wight

A phytochemical investigation on the aerial parts of Cynanchum auriculatum Royle ex Wight (C. auriculatum) resulted in the isolation of sixteen compounds, including alkaloids (1-6), coumarins (7-9), lignans (10-12), phenolic acids (13 and 14), and flavonoids (15 and 16). Their chemical structures have been elucidated by NMR and MS analyses, as well as by comparison of the published data. Among them, four compounds (1, 3, 4, and 5) were first isolated from the family Apocynaceae; two compounds (8 and 12) were first separated from the genus Cynanchum; and six compounds (2, 6, 7, and 14-16) were first yielded from C. auriculatum. Furthermore, the chemotaxonomic significance of yielded compounds was also discussed.