Isochamaejasmin induces toxic effects on Helicoverpa zea via DNA damage and mitochondria-associated apoptosis

Background: Stellera chamaejasme L. is a poisonous plant with rich resources and is thus highly valuable in terms of new pesticide development. Isochamaejasmin (ICM), one of the main ingredients in S. chamaejasme has drawn much attention owing to its antitumour properties. However, the toxicity and mode of action of ICM on insects are still not clear. In this article, the larva and neuronal cell (AW1) of Helicoverpa zea were used to clarify the insecticidal activity of ICM as well as its toxic mechanism at the cellular level.

Results: The results confirmed that ICM has potential toxicity against H. zea both in vivo and in vitro via time- and dose-dependent manners. Moreover, we found that ICM caused DNA damage and increased the levels of γH2AX and OGG1 in AW1 cells. Results also showed decline in the mitochondrial membrane potential (MMP), upregulation of Bax/Bcl-2 expression resulting in the release of cytochrome c into the cytosol, activation of Caspase-3/9, and cleavage of poly ADP-ribose polymerase (PARP) as a result of exposure to ICM. Additionally, a dose-dependent rise in the Reactive Oxygen Species (ROS) levels, accumulation of a lipid peroxidation product, and inactivation of antioxidant Enzymes were found in ICM-treated cells.

Conclusion: These findings confirmed the insecticidal activity of ICM. Furthermore, the results revealed that ICM could cause DNA damage and induce Apoptosis via the mitochondrial pathway in AW1 cells. This study provides the basic information needed to understand the toxicity and mechanisms of action of ICM, which could potentially be used to develop it as a new insecticide.

DNA damage; Helicoverpa zea; Stellera chamaejasme L.; apoptosis; isochamaejasmin; mitochondrial dysfunction.