In southern China, where Camptotheca acuminata is native, people call these big-leafed trees "Happy Trees." Chinese herbalists have been prescribing medicine from the leaves for centuries to treat various ailments, including leukemia. In the 1950s, National Cancer Institute researchers in the U.S. isolated the alkaloid camptothecin from the leaves, and today, several drugs derived from camptothecin help treat ovarian and colon cancer.
(Podcast: The Plant Detective, 8/16/14)