Phytosynthesis of gold nanoparticles from Boerhavia diffusa L. and their antibacterial, antifungal, antioxidant, and anticancer activities

This study explores the green synthesis of gold nanoparticles (AuNPs) using the aqueous extract of Boerhavia diffusa L., a plant known for its medicinal properties. The synthesis of AuNPs was confirmed through UV–Vis spectroscopy, showing a characteristic surface plasmon resonance peak at 551 nm, indicating successful nanoparticle (NPs) formation. The physicochemical properties of the NPs were further analyzed using FTIR, XRD, SEM, and DLS, revealing a crystalline structure, spherical morphology, and an average size of 53.17 ± 0.58 nm. The biogenic AuNPs were evaluated for their antimicrobial, antifungal, antioxidant, and anticancer activities. AuNPs exhibited significant antibacterial effects against Listeria monocytogenes, Bordetella bronchiseptica, and Escherichia coli, with zone of inhibition ranging from 25 to 27 mm. In antifungal assays, AuNPs displayed potent activity against Candida albicans, Aspergillus niger, Cryptococcus neoformans, and Trichophyton rubrum, with inhibition zones between 78 and 86 mm. The antioxidant potential was also demonstrated through DPPH, FRAP, and TPC assays, with AuNPs showing ~ 80% radical scavenging activity. Furthermore, cytotoxicity analysis revealed that AuNPs reduced the viability of HepG2 cancer cells by approximately 39% at 100 µg/mL. These findings highlight the potential of BD@AuNPs as multifunctional nanomaterials for biomedical applications, offering eco-friendly and sustainable alternatives for drug delivery and therapy.