Camptothecin

Description

Camptothecin is an alkaloid derived from the chinese tree Camptotheca acuminata Decne. Camptothecin and its derivatives are unique in their ability to inhibit DNA Topoisomerase I, by stabilizing a covalent reaction intermediate termed the cleavable complex which ultimately causes tumor cell death. In clinical it is widely believed that camptothecin analogs exhibited remarkable anti-tumour and anti-leukaemia activity. Topoisomerase is a basilic enzyme in the process of DNA replication, it is responsible for the winding / unwinding of the supercoiled DNA composing the chromosomes. If the chromosomes cannot be unwound, transcription of DNA message cannot occur and the protein cannot be synthesized, it ultimately causes cell death. Application of camptothecin in clinic is limited due to serious side effects and poor water-solubility. At present, some camptothecin analogs, either semi-synthetic or synthetic drug based on camptothecin, have been applied cancerous therapy such as topotecan and irinotecan while others have been obtained satisfying curative effects in clinic.