Camptothecin is a
quinoline-based
alkaloid found in the barks of the
Chinese camptotheca tree and the Asian nothapodytes tree. It and its close chemical relatives (aminocamptothecin, CPT-11
irinotecan, DX-8951f, and
topotecan) are the only known naturally-occurring
DNA topoisomerase I inhibitors. It's one of the newer
chemotherapy drugs, and as such cancer researchers are really interested in it, but some incarnations of the drug aren't FDA-approved yet (it and some of its chemical relatives are in clinical trials to treat
breast cancers,
ovarian cancers,
colon cancers, malignant
melanoma, small-cell
lung cancer, and
leukemia).
The major side effects of camptothecin drugs are potentially severe diarrhea, nausea, hair loss, anemia, and lowered leukocyte (white blood cell) counts. The drug may also damage bone marrow.