Rapid synthesis of copper nanoparticles using Nepeta cataria leaves: An eco-friendly management of disease-causing vectors and bacterial pathogens

Abstract Insecticides kill mosquitoes but damage other animals including humans. Eco-friendly metal nanoparticles may be a plant-based pesticide for vector control. Here, the copper nanoparticles (Cu NPs) synthesized from Nepeta catarialeaves have been investigated for their antibacterial and larvicidal properties. Fourier transforms infrared spectroscopy demonstrated that biochemicals reduced and stabilized nanoparticles by shifting peaks from 1,049 to 1,492 cm−1, and ultraviolet–visible spectrometry proved that produced Cu NPs had a peak at 550 nm. Transmission electron microscopic and scanning electron microscope showed that the particles are spherical and 23–29 nm in size. X-ray diffraction analysis shows that Cu NPs are crystalline. At a 100 µg·mL−1 concentration, Cu NPs exhibited a higher percentage of inhibition in the order of Escherichia coli ≫ Enterococcus faecalis ≫ Staphylococcus aureus. The lethal concentration (LC50) of the Cu NPs against the larvae of Aedes aegypti, Anopheles stephensi, and Culex quinquefasciatus was determined to be 60.63, 56.58, and 54.32 µg·mL−1, respectively. This ground-breaking study describes the biological production of Cu NPs utilizing N. cataria leaf extract for the first time. Based on these findings, the bio-synthesized Cu NPs and the aqueous extract of N. cataria may provide a potential alternative method for managing these vector populations. Graphical abstract