Camptotheca acuminata anticancer activity

Camptothecin was discovered as an active anticancer drug isolated from the bark of Camptotheca acuminata. The anticancer activity of camptothecin was discovered in the 1960s by the National Cancer Institute (NCI) as part of a systematic effort to screen for novel anticancer agents derived from natural products. Monroe Wall and Mansuhk Wani identified the chemical structure of camptothecin. They also identified the chemical structure of taxol, again under the auspices of the NCI. Susan Hoiwitz was contracted by the NCI to elucidate the anticancer mechanisms of camptothecin. She found in the early 1970s that camptothecin induced DNA breaks and attested DNA and RNA synthesis. However, it is approximately 12 years later, only after DNA topo-isomerase I (Topi) had been identified in human cells, that Leroy Liu and his coworkers found that Topi was the cellular target of camptothecin [reviewed in [1]. 

Camptothecin is a cytotoxic quinoline alkaloid, which inhibits the DNA enzyme topoisomerase I. It was discovered in 1966 in systematic screening of natural products for anticancer drugs. It was isolated from the bark and stem of the Chinese tree Camptotheca acuminata. Camptothecin showed remarkable anticancer activity. A fluorinated... 

Camptothecin, an alkaloid from the Tibetan shrub Camptotheca acuminata cleaves DNA in a way that the cell ligases can repair (Horowitz and Brayton, 1972). It has some selective anticancer (Kessel, 1971)5 and antiviral properties (Kelly, 1974). The molecule has five fused rings (Meyers et al. 1973)3 of which the active portion is a pyridine lactone (4.15). It is principally used as a biochemical reagent for inhibiting biosynthesis of ribosomal and messenger RNAs while permitting formation of mitochondrial RNA (Abelson and Penman, 1972). 

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