Evaluation of the In Vitro Anti-Inflammatory Potential of Biogenically Synthesized Silver/Silver Oxide Nanoparticles Utilizing Pumpkin Agricultural Byproducts ^†

The abundant bioactive compounds and anti-inflammatory metabolites in pumpkins have prompted increasing research interest in utilizing cucurbit residues to derive in vitro anti-inflammatory agents. The present study investigates and compares the anti-inflammatory potential of Ag/Ag₂O nanoparticles (NPs) synthesized using pumpkin peels (PPs), seeds (PSs), and leaves (PLs). Ag/Ag₂O NPs were synthesized using the aqueous extracts of pumpkin byproducts under varying conditions, including different concentrations of AgNO₃, varying extract-to-ion solution ratios, differing irradiation methods (solar, microwave, UV, etc.), and varied incubation times. Biosynthesized Ag/Ag₂O NPs were characterized via UV–visible spectrophotometry, Fourier Transform Infrared spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray diffraction (XRD) analyses. Anti-inflammatory activity was assessed through egg albumin denaturation and human red blood cell membrane stabilization assays. The activity was compared to that of standard anti-inflammatory drugs ibuprofen and aspirin (100–1000 ppm). The biogenic Ag/Ag₂O NPs synthesized under optimum conditions exhibited characteristic surface plasmon resonance peaks ranging from 436 to 450 nm in UV–vis spectrophotometry, confirming NP formation. FTIR spectroscopy revealed the functional groups in the plant extracts involved in NP synthesis. SEM imaging showed the agglomerated spherical morphologies of the NPs. TEM analysis indicated particle sizes ranging from 7 to 10 nm. XRD patterns confirmed the face-centered cubic crystalline structure of Ag/Ag₂O NPs. The PP-mediated Ag/Ag₂O NPs exhibited significantly higher (p < 0.05) anti-inflammatory activity compared to ibuprofen in the egg albumin denaturation assay, with IC₅₀ values of 478 ppm and 598 ppm, respectively, while the PL-mediated Ag/Ag₂O NPs demonstrated significantly higher membrane stabilization activity compared to aspirin, with IC₅₀ values of 419 ppm and 452 μg/mL, respectively. In both assays, the anti-inflammatory activity of the plant extracts alone was very low compared to Ag/Ag₂O NPs. The biomimetic approach showed that biosynthesized Ag/Ag₂O NPs exhibited enhanced anti-inflammatory effects, demonstrating promise as novel anti-inflammatory agents with potential in the sustainable production of nanotherapeutics.