The aim of this research was the synthesis of silver nanoparticles (SPA- and SPR-AgNPs) using the aqueous extracts of the aerial (SPA) and the root (SPR) parts of the plant Salvia pratensis L., their characterization, reaction condition optimization, and evaluation of their biological and catalytic activity. UV–Vis spectroscopy, X-ray powder diffraction (XRPD), scanning electron microscopy with EDS analysis (SEM/EDS), and dynamic light scattering (DLS) analysis were utilized to characterize the nanoparticles, while Fourier transform infrared (FTIR) spectroscopy was used to detect some functional groups of compounds present in the plant extracts and nanoparticles. The phenolic and flavonoid contents, as well as the antioxidant activity of the extracts, were determined spectrophotometrically. The synthesized nanoparticles showed twice-higher activity in neutralizing 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS⁺) compared with the respective extracts. SPR-AgNPs exhibited strong antimicrobial activity against almost all of the tested bacteria (<0.0039 mg/mL) and fungal strains, especially against the genus Penicillium (<0.0391 mg/mL). Moreover, they were fully biocompatible on all the tested eukaryotic cells, while the hemolysis of erythrocytes was not observed at the highest tested concentration of 150 µg/mL. The catalytic activity of nanoparticles toward Congo Red and 4-nitrophenol was also demonstrated. The obtained results confirm the possibility of the safe application of the synthesized nanoparticles in medicine and as a catalyst in various processes.

Achillea ageratifolia subsp. serbica is a poorly investigated endemic of the Balkan area and there are almost no data about the potential application of this plant. The purpose of this study was the investigation of the phytochemical composition, antioxidant, antimicrobial, and antibiofilm activity of its water, acetone, and ethyl acetate extracts. The phenolic composition and flavonoids were established using high-performance liquid chromatography with photodiode array detection (HPLC-PDA) analysis, while the chemical composition of the ethyl acetate extracts of the aerial parts of the plant was investigated by gas chromatography-mass spectrometry (GC and GC-MS). Antioxidant and antimicrobial activity, as well as the inhibition ability of biofilm formation on Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 biofilms, were also investigated. The total phenolic content ranged from 18.61 mgGAE/g to 43.78 mgGAE/g of extract. The total flavonoid content ranged from 10.79 mgRUE/g to 34.02 mgRUE/g. The acetone and ethyl acetate extracts of the aerial parts contained chlorogenic acid, myricetin, apigenin, and luteolin. Analysis of the volatile specialized metabolites in the ethyl acetate extract of the aerial parts allowed for the identification of thirty-two constituents. The highest antioxidant activity was detected in the water extract of the aerial parts of the plant (IC50 = 641.06 ?g/ml) and in the ethyl acetate extract of the root (IC50 = 675.33 ?g/ml). Bacillus subtilis and S. aureus showed higher sensitivity to the tested extracts, while the antifungal activity of the marked extracts was significant. All extracts showed a moderate inhibitory effect on the ability of biofilm formation of P. aeruginosa ATCC 27853, while only the ethyl acetate inflorescence extract showed an effect on the biofilm formation of P. aeruginosa ATCC 27853. The tested extracts showed the potential for further investigation and possible application as biofungicides.