Enhanced mosquitocidal efficacy of pyrethroid insecticides by nanometric emulsion preparation towards Culex pipiens larvae with biochemical and molecular docking studies

Abstract

Background The growing threat of vector-borne diseases and environmental pollution with conventional pesticides has led to the search for nanotechnology applications to prepare alternative products. Methods In the current study, four pyrethroid insecticides include alpha-cypermethrin, deltamethrin, lambda-cyhalothrin, and permethrin were incorporated into stable nanoemulsions. The optimization of nanoemulsions is designed based on the active ingredient, solvent, surfactant, sonication time, sonication cycle, and sonication energy by factorial analysis. The nanoscale emulsions’ droplet size and morphology were measured by dynamic light scattering (DLS) and transmission electron microscopy (TEM), respectively. The toxicity of nanoemulsions against Culex pipiens larvae was evaluated and compared with the technical and commercial formulations. The in vitro assay of adenosine triphosphatase (ATPase), carboxylesterase (CaE), and glutathione-S-transferase (GST) were also investigated. Furthermore, molecular docking was examined to assess the binding interactions between the tested pyrethroids and the target enzymes. Also, an ecotoxicological assessment of potential effects of the tested products on the freshwater alga Raphidocelis subcapitata was determined according to OECD and EPA methods. The emulsifible concentration (EC50) and NOEC (no observed effect concentration) values were estimated for each insecticide and graded according to the GHS to determine the risk profile in aquatic life. Results The mean droplet diameter and zeta potential of the prepared pyrethroid nanoemulsions were found to be in the range of 72.00–172.00 nm and − 0.539 to − 15.40 mV, respectively. All insecticides’ nanoemulsions showed significantly high toxicity (1.5–2-fold) against C. pipiens larvae compared to the technical and EC. The biochemical activity data proved that all products significantly inhibited ATPase. However, GST and CaE were significantly activated. Docking results proved that the pyrethroids exhibited a higher binding affinity with CaE and GST than ATPase. The docking scores ranged from − 4.33 to − 10.01 kcal/mol. Further, the biosafety studies of the nanopesticides in comparison with the active ingredient and commercial EC were carried out against the freshwater alga R. subcapitata and the mosquitocidal concentration of nanopesticides was found to be non-toxic. Conclusion The mosquitocidal efficacy of nano-pyrethroids formulated in a greener approach could become an alternative to using conventional pesticide application in an environmentally friendly manner.

The in-vivo and in-vitro Effectiveness of Three Insecticides Types for Eradication of The Tick Rhipicephalus sanguineus in Dogs

“…The animals were handled in human manners, considering all the national and international ethical guidelines in treating the animals. The synchronization in the selected dogs was important to minimize the influences of the physiological variation between the members of each group on the responses to the insecticides used for the treatments ( Taktak et al , 2021 ). Dogs on their arrival were double-checked for their physical conditions and fitness, as well as some random blood samples were collected in a human manner using a local anesthetic to check any signs of internal or external parasitism.…”

Insecticidal Efficacy and Safety of Phoxim and Influence on Hematological, Biochemical, and Antioxidant Profiles in German Shepherd Dogs

“…Usually, after exerting its action, it is excreted in urine and feces. Phoxim ® can act as contact, stomach, and fumigant poison ( Taktak et al ., 2021 ).…”

“…Twenty German Shepherd male dogs at one year old and 44.0 kg body weight were picked up from a pet shop in Ismailia governorate, Egypt. All the picked-up dogs were nearly similar to overcome the individual biological variation in response to the Phoxim ® treatment ( Taktak et al, 2021 ). Dogs were divided randomly on their arrival into four groups of five dogs in four separate Kennels.…”

Development and characterization of nanoemulsions loaded with essential oil and β‐cypermethrin and their bioefficacy on insect pest of economic and medical importance

“…NEs formulated with ⊎-CP, methyl oleate (solvent), and polyoxyethylene castor oil ether (surfactant) showed a mean droplet size of 166 nm and a PDI value of 0.160. 31 Taktak et al 32 formulated NEs with 0.5% CP, 44% solvent (dimethyl sulfoxide), 15% surfactant (Tween 80), and 40.5% water using ultrasound, which had a mean droplet size of 90.3 nm and a PDI value of 0.377, with a transparent visual appearance. It should be noted that there is a relationship between the visual appearance and size of NEs and their interaction with light.…”