Platinum nanoparticles (PtNPs) exhibit promising biomedical properties, but concerns about biocompatibility and synthesis-related toxicity remain. This study aimed to develop eco-friendly PtNPs using aqueous broccoli extract as a natural reducing and stabilizing agent, and to assess their multifunctional biomedical potential. PtNPs were synthesized through sonochemical reduction of K₂PtCl₆ in broccoli extract, followed by purification and comprehensive physicochemical characterization. UV–Vis confirmed nanoparticle formation at 253 nm, while XRD and FTIR analyses verified the crystalline FCC structure and phytochemical capping. TEM revealed mainly spherical PtNPs with an average core size of 14.83 ± 7.67 nm. Conversely, DLS showed a hydrodynamic diameter of 136.9 ± 11.1 nm and a zeta potential of − 8.6 mV, indicating moderate colloidal stability influenced by biomolecular capping. Biological assessments demonstrated broad-spectrum antibacterial activity, potent antioxidant effects in vitro (DPPH scavenging) and in vivo (improved TAC, reduced TOS and OSI), and accelerated wound healing in a BALB/c excision model (percent closure ≈ 90% by day 7). Additionally, PtNPs significantly lowered fasting blood glucose levels in STZ-induced diabetic rats and showed selective cytotoxicity toward HepG2 cells (IC₅₀ = 8.29 ± 0.59 µg/mL) compared to HDF cells (SI = 4.1). These findings position broccoli-mediated PtNPs as a biogenic nanoplatform with potential applications in antimicrobial, antioxidant, wound healing, antidiabetic, and anticancer therapies. However, further mechanistic studies and long-term biosafety assessments are necessary before clinical translation can occur.
