Camptothecin

**Semantic type:** Organic Chemical|Pharmacologic Substance

**Definition:** An alkaloid isolated from the Chinese tree Camptotheca acuminata, with antineoplastic activity. During the S phase of the cell cycle, camptothecin selectively stabilizes topoisomerase I-DNA covalent complexes, thereby inhibiting religation of topoisomerase I-mediated single-strand DNA breaks and producing potentially lethal double-strand DNA breaks when encountered by the DNA replication machinery. (NCI)

**Synonyms:** - (+)-Camptothecin - (+)-Camptothecin - (S)-4-ethyl-4-hydroxy-1H-pyrano-[3',4':6,7]indolozino[1,2-b]quinoline-3,14(4H,12H)-dione - 1H-Pyrano[3',3'.6,7]indolizino[1,2-b]quinoline-3,14(4H,12H)-dione, 4-ethyl-4hydroxy-(S)-(9CI) - 20(S)-Camptothecine - 20-(S)-camptothecine - 21, 22-Secocamptothecin-21-oic acid lactone - 21, 22-secocamptothecin-21-oic acid lactone - CAMPTOTHECIN - camptothecin - camptothecine