Camptothecin is a naturally occurring compound derived from the Chinese tree Camptotheca acuminata. It was discovered in the 1960s and has since been studied extensively for its potent anticancer properties. The compound works by inhibiting the enzyme topoisomerase I, which is essential for DNA replication and transcription. By interfering with this enzyme, camptothecin causes DNA damage that leads to cell death, particularly in rapidly dividing cancer cells.