Camptotheca acuminata is a tree in the family
Nyssaceae (the
tupelo family) and is native only to
China and
Tibet, where it is known as xi shu ("happy tree").
Camptotheca is of scientific interest mainly because it contains an anti-cancer ingredient (a quinoline alkaloid) called camptothecin. Camptothecin has in turn has been modified to create a host of other anti-cancer drugs, including irinotecan, topotecan, 9-aminocamptothecin, and CPT-11. Camptothecin and its analogs are being investigated to treat a wide variety of cancers, but the compounds are also quite poisonous.
Western researchers (Dr. Monroe E. Wall of the USDA and Jonathon Hartwell of the National Cancer Institute) first discovered Camptotheca's anticancer properties in 1958. In 1966, after Wall joined the Research Triangle Institute, he and other researchers isolated camptothecin. A camptothecin analog (camptothecin sodium) was tested on gastrointestinal cancer patients in the early 1970s, but the clinical trials were discontinued because the patients suffered severe side effects. Researchers continued to investigate camptothecin to develop drugs with fewer side effects, and their work began to bear fruit in the late 1980s. In China, camptothecin has been used to treat leukemia and cancers (carcinomas) of the stomach and liver.
References:
http://www.rti.org/patents/camptothecin.cfm
Duke, James A., and Edward S. Ayensu. 1985. Medicinal Plants of
China. Algonac, MI, Reference Publications, Inc.