In vitro larvicidal, antioxidant, and DNA binding activity of biosynthesized zinc oxide nanoparticles conjugated with Andrographis paniculata aqueous extract

Abstract

Anopheles culicifacies is the major vector responsible for the transmission of human malarial parasite Plasmodium sp. The use of green synthesized nanoparticles has emerged as an interesting advancement for the development of plant-mediated insecticides that can be effective against widespread insecticide resistance. In the current study, we report on the larvicidal, antioxidant, H₂O₂ sensitivity, and hemolytic properties of green synthesized zinc oxide nanoparticles using Andrographis paniculata (ZnO-APNPs). The ZnO-APNPs were characterized using UV-Visible spectroscopy, FTIR, XRD, and TEM analysis. Crystalline and spherical NPs with an average particle size found to be ~17 nm were synthesized. The UV absorption spectra of the CT-DNA interaction with ZnO-APNPs revealed a bathochromic effect indicating groove binding. The ZnO-APNPs displayed lethality against A. culicifacies larvae after 24 h and 48 h of exposure. The LC₅₀ and LC₉₀values were 31.75±2.23 ppm and 189.56±2.44 ppm and 95.45±1.56 ppm, 432.36±1.34 ppm at different concentrations respectively. ZnO-APNPs offered complete larval mortality within 24 h and 48 h of exposure. Strong concentration-dependent antioxidant property with a free radical inhibition of 39.51±1.25 % was observed while the ZnO-APNPs were found to be non toxic in hemolysis assay. The strong potency of ZnO-APNPs in killing A. culicifacies larvae advocates their further development as potential natural, reliable and ecofriendly larvicides.