Aqueous extract of strawberry (Fragaria x ananassa Duch.) leaves as a stabilizing agent in the synthesis of bio-active silver nanoparticles

The aim of the presented work was to investigate the potential of aqueous extract of cultivated strawberry (Fragaria x ananassa Duch.) leaves for stabilization of silver nanoparticles (AgNPs-E) synthesized at room (RT) and boiling temperature (BT). The synthesis and stability of AgNPs-E were monitored by UV-Vis spectroscopy confirming high stability of the AgNPs-E in the dark at room temperature. The Fourier-transform infrared spectra suggest that molecules containing oxygen and nitrogen functional groups (NH, (NH)C=O, CNO, C-O-C and OH) participate in the reduction and stabilization of formed nanoparticles. As determined by the DPPH test, AgNPs-E synthesized at RT exerted higher antioxidant activity as compared to AgNPs-E synthesized at BT (EC50 values of 0.025 and 0.039 mg cm-3, respectively). Also, the AgNPs-E synthesized at RT exerted higher antibacterial activity against Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Bacillus subtilis and Bacillus luteus. Examination of the AgNPs-E on HeLa and MDCK cell lines showed concentration-dependent and cell line specific effects on the cell viability as evaluated by the MTT test. The obtained results indicate that synthesized AgNPs-E can be used as a base material in production of pharmaceutical preparations for potential skin applications.