Biosynthesis of Silver Nanoparticles Mediated by Lippia graveolens Aqueous Extract

The synthesis of silver nanoparticles (AgNPs) with plant extracts has acquired a lot of interest in recent years, due to its different applications in areas such as medicine, optics, food, pharmaceutic, among others. The aim of this work was to evaluate aqueous extracts of Mexican oregano (Lippia graveolens), rich in antioxidant compounds, to synthesize AgNPs. L. graveolens extract was characterized by HPLC and the antioxidant capacity was evaluated by ABTS, DPPH and CUPRAC. The effect of factors such as pH, concentration of precursor and temperature on the synthesis of AgNPs was studied. The particles were characterized by SEM, TEM, FTIR and their stability was evaluated with respect to time. The AgNps showed a spherical shape with an average diameter of 2.4 nm, and antimicrobial activity against S. aureus, L. monocytogenes and E. coli. After 30 days of storage, the AgNps agglomerated to form dendritic structures.