[{"from": "human", "value": "Provide a brief overview of this molecule. [C][C][C][Branch2][Ring2][Ring1][C][=C][Branch2][Ring1][N][C][=Branch1][C][=O][N][C][C][=C][C][=C][C][=C][C][=C][Ring1][=Branch1][N][=C][Ring1][#Branch2][C][Ring1][=N][=C][Ring2][Ring1][C][C][O][Branch1][=Branch1][C][=Branch1][C][=O][O][O]"}, {"from": "gpt", "value": "The molecule is the sodium salt of camptothecin, 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. The sodium salt of camptothecin is more water-soluble than the parent molecule. (NCI04)"}]