Alkaloids from Trigonostemon lii and the Inhibitory Effects on Human NSCLC A549 Cells via Induction of Apoptosis

Trigonostemon lii is a medicinal plant used in Chinese folklore. Previous investigations have indicated some alkaloids in this plant showed significant cytotoxicity to human non-small cell lung cancer (NSCLC) A549 cells. In our interests to search novel therapy for the treatment of NSCLC, we have investigated alkaloids from Trigonostemon lii, which led to the identification of five alkaloids including trigonostemine A (1), trigonostemine B (2), trigonostemonines C (3), trigonostemonine D (4), and trigonostemonine E (5). Biological evaluation on these compounds has shown trigonostemine A, trigonostemine B and trigonostemonines C possessed inhibitory effects on the survival of A549 cells, and especially trigonostemine B afforded the most potent activity. Further mechanisms for trigonostemine B have unraveled it could induce apoptosis of A549 cells via a mitochondria-mediated pathway. These results can provide evidence for the application of Trigonostemon lii in clinical practice and the discovery of novel therapy for the treatment of NSCLC.