Sustainable Biofabrication of SnO₂ and BaO Nanoparticles via Thymus serpyllum leaves Extract: Structural Elucidation and Biopotential Assessment

The emergence of multidrug-resistant microbes and oxidative stress due to free radicals poses a serious threat to human health, rendering conventional antibacterial therapies ineffective. Hence, developing eco-friendly strategies to counter these issues is essential. In this study, an environmentally benign route was adopted for the phytofabrication of barium oxide (BaO) and stannous oxide (SnO₂) nanoparticles (NPs) using Thymus serpyllum leaf extract. The synthesized NPs were characterized by UV-Vis spectroscopy, scanning electron microscopy (SEM), and energy-dispersive X-ray (EDX) analysis to confirm their purity, morphology, and optical properties. The X-ray diffraction (XRD) analysis was carried out to study the crystalline nature whereas Fourier transform infrared (FTIR) spectroscopy verified the effective capping of NPs by T. serpyllum phytochemicals. The antimicrobial activity of the biosynthesized SnO₂ and BaO NPs was tested against Klebsiella pneumoniae using the disc diffusion method, while their antioxidant potential was evaluated using ABTS and DPPH assays. Both nanomaterials exhibited excellent antibacterial and radical-scavenging activities. The results highlight T. serpyllum as a promising biotemplate and reducing agent for nanoparticle synthesis. To the best of our knowledge, this is the first report on the phytosynthesis of BaO NPs and the dual biofabrication of BaO and SnO₂ NPs using T. serpyllum leaf extract.