Phyto-mechanochemical Synthesis, Pesticidal and Antimicrobial Applications of Iron Oxide Nanoparticles Using Polygonum Paronychioides.

Abstract

New developments in nanotechnology have provided an effective method for addressing insect pest problems that affect critical commodities. This research represents the first report on the phyto-mechanochemical synthesis of iron oxide (Fe3O4) nanoparticles (NPs) using Polygonum paronychioides (PP) extract to determine the pesticidal potential against two crop pests, Tribolium castaneum (TC) and Oryzaephilus surinamensis (OS). The PP extract was analyzed using liquid chromatography-tandem mass spectrometry (LC-MS) to determine the presence of phytochemicals that act as reducing agents. The influence of parameters such as salt concentration, stirring time, temperature, and pH was optimized using the central composite design (CCD) of response surface methodology (RSM). The PP/Fe3O4 NPs were characterized by UV-visible spectrophotometer, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Zeta sizer, and X-ray diffraction technique (XRD). The PP/Fe3O4 NPs give an absorbance peak at 237 nm in the UV-visible spectrum, with an average size of 87.43 nm in Zetasizer. The FTIR spectra also showed the existence of phenolic compounds in PP leaf extract and bond stretching of Fe-O, O-H, N-H, CN, and C═O. The Ames test revealed that the PP/Fe3O4 NPs were not cytotoxic. The pesticidal potential of PP/Fe3O4 NPs was determined using the mortality rates of two crop pests, TC and OS. Results were obtained after 24, 48, and 72 hours. Maximum results were obtained by OS (88 ± 4) rather than TC (80 ± 4). The pesticide activity was enhanced by enhancing the concentration of PP extract and the Fe3O4 NPs. The PP/Fe3O4 NPs were also tested against multiple bacteria and fungi. The antibacterial activity of PP/Fe3O4 NPs was tested against two bacterial strains Pseudomonas syringe and Clavibacter michiganensis. Clavibacter michiganensis's inhibition zone (34.4±0.2) is more significant than Pseudomonas syringe (32.2±0.1). The antifungal test of PP/Fe3O4 NPs was assessed against two fungal strains: Alternaria alternata and Aspergillus niger. The zone of inhibition of Aspergillus niger (28±0.1) is more significant than Alternaria alternata (27±0.5). Results revealed that PP/Fe3O4 NPs could be used against pathogens. To our knowledge, PP extract has never been used for the phyto-mechanochemical synthesis of Fe3O4 NPs.