Viscum album subsp. austriacum-mediated biosynthesis of magnesium nanoparticles: In vitro anticancer, antibiofilm, and antioxidant activities with computational validation.

Viscum album L. (European mistletoe) is a medicinally significant hemiparasitic plant with a rich bioactive phytochemical profile. Despite growing interest in its pharmacological properties, studies integrating nanoparticle biosynthesis, comprehensive biological evaluation, and computational analysis remain scarce for its austriacum subspecies. In this study, magnesium nanoparticles (VA-MgNPs) were green-synthesized using the ethanol extract of Viscum album subsp. austriacum as a bioreducing and capping agent, and their biological activities were comparatively assessed alongside the crude extract and Mg(NO3)2·6H2O precursor control. LC-HR/MS analysis identified quinic acid (10,027.49 μg/g) and chlorogenic acid (5294.12 μg/g) as the dominant phenolic constituents. The synthesized VA-MgNPs were characterized by FT-IR, UV-Vis, FE-SEM, TEM, and XRD analyses, confirming nanocrystalline formation with a mean crystallite size of approximately 66.47 nm. Antioxidant evaluation using DPPH, ABTS, and FRAP assays revealed that the crude extract retained superior radical scavenging capacity, which is attributed to the consumption of free phenolic hydroxyl groups during nanoparticle formation. In contrast, VA-MgNPs demonstrated markedly enhanced anticancer activity against breast (MCF-7: IC50 = 124 μg/mL; MDA-MB-231: IC50 = 96 μg/mL) and colorectal (HCT116: IC50 = 105 μg/mL; HT-29: IC50 = 135 μg/mL) cancer cell lines, with lower cytotoxicity toward non-tumorigenic cells, indicating selective antiproliferative action. Although antibacterial activity was limited across tested strains, VA-MgNPs exhibited significant antibiofilm activity, achieving up to 75% inhibition against Pseudomonas aeruginosa. Molecular docking simulations revealed that chlorogenic acid and its magnesium complex displayed strong binding affinities toward antioxidant- and antimicrobial-related protein targets, with binding energies reaching -8.5 kcal/mol, mechanistically supporting the observed biological activities. These findings demonstrate that VA-MgNPs are a promising nanotherapy platform, particularly for antibiofilm and anticancer applications.