Abstract Chemical pesticides have been used as a reliable method of controlling pests on crops. However, their applications have led to the development of resistance, environmental problems, and risks to human health. Therefore, new chemicals in nanoform such as chlorophyll derivatives could be a good choice for pest control through the induction of reactive oxygen species, liberating singlet oxygen when they are excited by photo exposure. The present work evaluated the toxicity of magnesium chlorophyllin (Mg-Chl) and magnesium chlorophyllin zinc oxide (Mg-Chl–ZnO NC) nanocomposite on Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) . Additionally, the biochemical changes of detoxifying enzymes, such as carboxylesterases (CXEs) and glutathione- S -transferases (GSTs), were investigated. In silico, molecular docking analysis was also performed to assess the binding affinities of the tested compounds to CXE22 and SfGSTe9 . Thus, the evaluation of potential photosensitizers against the second instar larvae of Chrysoperla carnea Stephens, as non-target insect and active predator of aphids, was conducted. The results showed that both Mg-Chl and Mg-Chl–ZnO NC have a high potency against S. frugiperda with LC 50 = 0.59 and 0.49 mg L −1 , respectively, after 12-h dark incubation and 5-h light exposure, while after 24 h, LC 50 values after dark incubation were 0.51 and 0.31 mg L −1 , respectively. Both tested compounds exhibited a strong binding affinity to CXE22 and SfGSTe9 , leading to significant alterations in CXEs activity and GSTs activity in correspondence with the oxidative stress and contributing to larval mortality. In parallel, both compounds exhibited very low toxicity on C. carnea . Overall, these findings support that Mg-Chl and Mg-Chl–ZnO NC could be used as alternative approaches to synthetic pesticides for the management of S. frugiperda .
Elshemy et al. (Sat,) studied this question.