Green-Synthesized Silver Nanoparticles Using <i>Lavandula stricta</i> Delile Exhibit Potent Anti-Inflammatory and Antioxidant Activities in Vivo

Abstract

Background: The unique anti-inflammatory and antioxidant properties of silver nanoparticles (Ag-NPs) have made them a subject of growing scientific interest. Objectives: This study aimed to synthesize Ag-NPs using an aqueous extract of Lavandula stricta and comprehensively evaluate their anti-inflammatory and antioxidant activities in vivo. Methods: Ag-NPs were fabricated via a green synthesis route using L. stricta aqueous extract and 1 mM silver nitrate (AgNO3) as the precursor. The biosynthesized Ag-NPs were characterized by ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential analysis. In vitro antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging and ferric reducing antioxidant power (FRAP) assays, whereas in vivo anti-inflammatory efficacy was assessed using a carrageenan-induced murine paw edema model. Paw tissue homogenates were analyzed for tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), malondialdehyde (MDA), and total antioxidant capacity (TAC). Results: XRD confirmed the crystalline nature of the biosynthesized Ag-NPs, with crystallite sizes ranging from 13.8 to 18.7 nm, whereas TEM showed a mean particle diameter of 24 nm. UV-Vis spectroscopy revealed a characteristic surface plasmon resonance band centered at 400 nm. The biosynthesized nanoparticles exhibited substantial radical-scavenging activity (DPPH IC50 = 235 μg/mL); however, the crude extract showed superior in vitro antioxidant activity (IC50 = 120 μg/mL). In the carrageenan-induced paw edema model, Ag-NPs at 0.6 mg/kg produced 32.3% inhibition of paw swelling, accompanied by reductions in TNF-α (84.6%) and IL-6 (53%). Treatment with Ag-NPs also lowered MDA levels and increased TAC, with both oxidative stress markers reaching values comparable to those in the healthy control group (P > 0.05). Conclusions: These findings support the potential of L. stricta-mediated Ag-NPs as a candidate for managing acute inflammatory conditions and warrant further preclinical investigation.