Evaluation of Catharanthus roseus leaf extract-mediated biosynthesis of titanium dioxide nanoparticles against Hippobosca maculata and Bovicola ovis

The purpose of the present study was based on assessments of the antiparasitic activities of synthesized titanium dioxide nanoparticles (TiO2 NPs) utilizing leaf aqueous extract of Catharanthus roseus against the adults of hematophagous fly, Hippobosca maculata Leach (Diptera: Hippoboscidae), and sheep-biting louse, Bovicola ovis Schrank (Phthiraptera: Trichodectidae). The synthesized TiO2 NPs were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The formation of the TiO2 NPs synthesized from the XRD spectrum compared with the standard confirmed spectrum of titanium particles formed in the present experiments were in the form of nanocrystals, as evidenced by the peaks at 2 theta values of 27.43A degrees, 36.03A degrees, and 54.32A degrees. The FTIR spectra of TiO2 NPs exhibited prominent peaks at 714 (Ti-O-O bond), 1,076 (C-N stretch aliphatic amines), 1,172 (C-O stretching vibrations in alcoholic groups), 1,642 (N-H bend bond), and 3,426 (O-H stretching due to alcoholic group). SEM analysis of the synthesized TiO2 NPs clearly showed the clustered and irregular shapes, mostly aggregated and having the size of 25-110 nm. By Bragg's law and Scherrer's constant, it is proved that the mean size of synthesized TiO2 NPs was 65 nm. The AFM obviously depicts the formation of the rutile and anatase forms in the TiO2 NPs and also, the surface morphology of the particles is uneven due to the presence of some of the aggregates and individual particles. Adulticidal parasitic activity was observed in varying concentrations of aqueous leaf extract of C. roseus, TiO2 solution, and synthesized TiO2 NPs for 24 h. The maximum parasitic activity was observed in aqueous crude leaf extracts of C. roseus against the adults of H. maculata and B. ovis with LD50 values of 36.17 and 30.35 mg/L, and r (2) values of 0.948 and 0.908, respectively. The highest efficacy was reported in 5 mM TiO2 solution against H. maculata and B. ovis (LD50 = 33.40 and 34.74 mg/L; r (2) = 0.786 and 0.873), respectively, and the maximum activity was observed in the synthesized TiO2 NPs against H. maculata and B. ovis with LD50 values of LD50 = 7.09 and 6.56 mg/L, and r (2) values of 0.880 and 0.913, respectively. This method is considered as an innovative alternative approach to control the hematophagous fly and sheep-biting louse.