[{"from": "human", "value": "Provide a description of this molecule. [C][C][C@@][Branch2][Ring2][=Branch1][C][=C][Branch1][#Branch1][C][O][C][Ring1][=Branch1][=O][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][=Branch1][O]"}, {"from": "gpt", "value": "The molecule is an alkaloid isolated from the stem wood of the Chinese tree, Camptotheca acuminata. This compound selectively inhibits the nuclear enzyme DNA topoisomerase, type I. Several semisynthetic analogs of camptothecin have demonstrated antitumor activity."}]