Oxidative stress induced by camptothecin and hydroxyl-camptothecin in IOZCAS-Spex-II cells of Spodoptera exigua Hübner.

Camptothecin (CPT) and its derivatives show potential insecticidal activities against various insect species due to target at DNA-Topoisomerase I complex and induce apoptosis death of insect cells. Oxidative stress resulted from excessive production of reactive oxygen species (ROS) has been proved to be an important component of the mechanism of pesticide toxicity. The aim of the present study was to investigate whether CPTs promote the increasing of intracellular oxidative stress by enhancing accumulation of intracellular ROS in IOZCAS-Spex-II cells derived from Spodoptera exigua Hübner. Results demonstrated that there was a significant increase in the level of intracellular ROS accompanied by markedly increased DNA damage, lipid peroxidation and protein carbonylation after exposing to CPT and hydroxyl-camptothecin (HCPT) in IOZCAS-Spex-II cells. These results documented ROS generation induced by CPT and HCPT played an essential role in toxicity and mode of action of CPTs against insects. This research will throw new light on the critical roles of oxidative stress in CPTs- induced toxicity against insects, as well as on the exploration of using CPTs as a kind of insecticide with unique mode of action in the future.