Biogenic vanadium pentoxide nanoparticles from Parmentiera cereifera for biological activity and green metrics evaluation

Green nanotechnology offers a sustainable alternative to conventional synthesis of metal and metal-oxide nanomaterials by minimizing toxic reagents and reducing chemical consumption. Among these, vanadium pentoxide (V₂O₅) has attracted considerable interest due to its catalytic and biomedical properties; however, environmentally benign synthesis routes remain limited. To the best of our knowledge, this is the first report describing the use of aqueous leaf extract of Parmentiera cereifera for the green synthesis of V₂O₅ nanoparticles, thereby establishing a previously unexplored plant–metal system. The plant extract served as a source of phytochemicals that facilitated coordination with vanadate species, precursor formation, and stabilization, while ammonium metavanadate (NH₄VO₃) was used as the vanadium precursor. A vanadium-containing precursor was generated under relatively mild reaction conditions (70 °C, near-neutral pH), where phytochemicals promoted complexation and controlled precursor assembly rather than reduction of vanadium, and subsequently calcined at 450 °C to obtain crystalline V₂O₅ nanoparticles. The resulting nanoparticles were characterized using UV–visible spectroscopy, FTIR, XRD, SEM, TEM, EDX, dynamic light scattering (DLS), and zeta potential analysis. Their biological activities, including α-amylase inhibition, cytotoxicity, and antimicrobial efficacy, were evaluated alongside sustainability metrics. The synthesized nanoparticles exhibited a characteristic absorption band at ~ 320 nm and distinct V–O/V = O vibrations, confirming V₂O₅ formation. XRD analysis revealed an orthorhombic crystalline phase with an average crystallite size of ~ 45 ± 5 nm, while microscopy showed quasi-spherical particles in the 20–60 nm range. A zeta potential of − 28.4 mV and a hydrodynamic diameter of approximately 46.3 nm indicated good colloidal stability. Functionally, the nanoparticles demonstrated concentration-dependent α-amylase inhibition (IC₅₀ ≈ 38.4 µg mL⁻ 1 ), greater cytotoxic effects toward A549 cells than HEK-293 cells under the tested conditions, and broad-spectrum antimicrobial activity against bacterial and fungal pathogens. Although the synthesis employed a plant-mediated approach, crystallization of V₂O₅ required a calcination step at 450 °C. Overall, this study introduces Parmentiera cereifera as a novel biogenic resource for V₂O₅ nanoparticle synthesis and presents an environmentally compatible approach with potential biomedical relevance. Further studies focusing on phytochemical profiling, surface chemistry analysis, batch-to-batch reproducibility, mechanistic validation, and in vivo evaluation are warranted.