Larvicidal and pediculicidal activity of synthesized TiO2 nanoparticles using Vitex negundo leaf extract against blood feeding parasites

Abstract

Insecticide resistance and inadequate attention to the application instructions of topical pediculicides are common reasons for treatment failure. Essential oils or plant extracts are good and safe alternatives due to their low toxicity to mammals and easy biodegradability. The present study was carried out to establish the larvicidal and the pediculicidal activity of synthesized titanium dioxide nanoparticles (TiO2 NPs) using the leaf aqueous extract of Vitex negundo (Verbenaceae) against the fourth instar larvae of the malaria vector, Anopheles subpictus Grassi and filariasis vector, Culex quinquefasciatus Say (Diptera: Culicidae) and the head louse, Pediculus humanus capitis De Geer (Phthiraptera: Pediculidae). The synthesized TiO2 NPs were characterized by UV, XRD, FTIR and SEM-EDX. The SEM analyses were clearly indicated that the spherical shape of the synthesized TiO2 NPs. Mosquito larvae and head lice were exposed to varying concentrations of the synthesized TiO2 NPs, V. negundo leaf aqueous extract and titanium tetrachloride (TiCl4) for 24h. The maximum activity was observed in the synthesized TiO2 NPs against A. subpictus, C. quinquefasciatus and lice, (LC50=7.52, 7.23 and 24.32mg/L; χ2=0.161, 2.678 and 4.495; r2=0.663, 0.742 and 0.924), respectively. The TiO2 NPs did not exhibit any noticeable toxicity on Poecilia reticulata after 24h of exposure. The findings revealed that the synthesized TiO2 NPs possess excellent mosquito larvicidal and anti-lice activity. These results suggest that the green synthesis of TiO2 NPs has the potential to be used as an ideal eco-friendly approach for the control of vectors and head lice.