Silver nanoparticle disinfectant synthesized with aqueous extract of Minthostachys verticillata (Griseb.) Epling...

Urgent need for faster and greener disinfectant led to the development of this formulation based on a plant extract and silver nanoparticles. The plants were selected based on their ability to reduce silver salt, antioxidant capacity, antibacterial property and ethnomedical use. Antioxidant, antimicrobial, and physicochemical properties of Minthostachys verticillata "peperina" for silver nanoparticles synthesis were investigated. This species exhibits the highest antioxidant activity. Glycosylated flavonoids and tannins were identified, with rutin confirmed by UPLC-MS at 6.05 ± 0.3 mg/g of dry extract. Mv@AgNP synthesis was achieved at 85 °C and 10 min. UV-Vis spectroscopy confirmed a plasmon resonance peak at 440 nm, and DLS analysis indicated stable nanoparticles over 120 days. SEM revealed predominantly spherical nanoparticles (∼20 ± 10 nm), while EDS confirmed the presence of the elemental silver. FT-IR analysis suggested that flavonoids and phenolic compounds acted as key reducing and stabilizing agents. Mv@AgNP demonstrated antibacterial activity against Staphylococcus aureus and Escherichia coli, achieving total inhibition within 5-10 min. TEM imaging revealed bacterial membrane disruption, including a blebbing effect and disintegration of the coccal membrane in S. aureus, as well as membrane lysis, the formation of holes inside the bacteria, and a bubbling phenomenon in E.coli. Biofilm assays showed significant structural damage and reduced matrix density. Additionally, Mv@AgNP exhibited antifungal activity against Candida albicans, with inhibition observed within 2 min. These findings highlight M.verticillata-derived AgNPs as a promising natural antimicrobial agent with potential applications in biomedical and pharmaceutical fields.