Topical Analgesic and Anti-Inflammatory Properties of Bioengineered Juglans regia L. Silver Nanoparticles.

<b>Background and Objective:</b> Research has demonstrated the antibacterial, anti-angiogenetic, antiviral, anti-inflammatory, anticancer and antioxidant properties of colloidal silver due to its biological, optical and electrical properties. The aim of this study was the anti-inflammatory effect of the silver bioengineered nanoparticles by using the acetonitrile-unripe fruit extract of <i>Juglans regia</i> L., on experimental animal model. <b>Materials and Methods:</b> The study uses various techniques to characterize nanoparticles, including ultraviolet spectra, dynamic light scattering and Fourier transform infrared. The study used carrageenan-induced rat paw edema as an induction model for inflammation and assessed its antinociceptive effects in mice using the formalin test. As well as evaluation of proinflammatory cytokines IL-6, TNF and IL-1. <b>Results:</b> The produced AgNPs were more compact and stable, according to physical characterization methods compared to chemical prepared nanoparticles. The formulation combining unripe fruit bio-reduced nanoparticles and extract, UF, shows a greater acute anti-inflammatory effect, while leaf extract has a better late anti-inflammatory effect. These bioengineered nanoparticles show efficient <i>in vivo</i> anti-acute inflammation, reducing skin inflammation through decreased cellular infiltrates and cytokine release. <b>Conclusion:</b> <i>Juglans regia</i> L., extract and silver nanoparticles show notable effects in both the early and late stages of the antinociceptive formalin test. While, bioengineered NP/UF and NP/LV can be used as topical analgesics. The potent topical anti-inflammatory and analgesic effects of these medications provide a sufficient basis for the use of this plant material in dermatological products.