Evaluation of anti-vibriocidal, antioxidant properties and cytotoxicity of bio fabricated/green synthesized silver nanoparticles using Euphorbia hitra L. leaf extract

The increasing focus on combating antimicrobial resistance (AMR) in aquaculture sector is driving innovations and better improvements to save billions of dollars globally. Two gram- negative bacteria which cause vibriosis, Vibrio parahaemolytics and Vibrio harveyi, are now resistant to multiple antibiotics. Green technology has evolved to produce novel antimicrobials with reduced potential for AMR and sustainable synthesis. The present study utilized a one-pot biofabrication method to synthesize silver nanoparticles (AgNPs) using Euphorbia hitra leaf aqueous extract (EHLAE) through a bottom-up approach. The qualitative phytochemical examination of EHLAE confirmed the existence of diverse components including steroids, carbohydrates, alkaloids, flavonoids, tannins, terpenoids, saponins, glycosides, and phenols. These compounds have crucial role as reducing and capping AgNPs. The obtained gAgNPs were subjected to evaluate the physico-chemical properties such as Surface Plasmon Resonance (SPR), functional groups, and crystalline structure, were verified by UV-Vis spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), and X-ray diffraction (XRD). The morphology, elemental composition, and size distribution of the AgNPs synthesized using a green method were confirmed using advanced techniques including Field Emission Scanning Electron Microscope (FESEM) with Energy Dispersive X-ray spectroscopy (EDX), High-Resolution Transmission Electron Microscope (HRTEM), and Dynamic Light Scattering (DLS). The silver nanoparticles (AgNPs) shown potent anti-vibriocidal activity against both Vibrio parahaemolyticus and Vibrio harveyi and the Minimum Inhibitory Concentration (MIC) for both bacteria were consistently 31.25 µg mL⁻¹. The in vitro antioxidant tests showed effective results and the found IC₅₀ values are 306 µg mL⁻¹ for DPPH and 6.46 µg mL⁻¹ for FRAP assays. Furthermore, the assessment of in vitro cytotoxicity on Vero cell lines revealed minimal toxicity, as evidenced by an IC₅₀ value of 191.51 µg mL⁻¹. The results reveals that the green synthesized AgNPs using Euphorbia hitra leaf have the potential to be used as effective alternatives for therapeutic purposes in combating the increasing problem of antimicrobial resistance in the aquaculture industry.