Ag-Conjugated Nanoparticle Biosynthesis Mediated by Rosemary Leaf Extracts Correlates with Plant Antioxidant Activity and Protein Content

Abstract

<em> In recent years, the world has witnessed an explosion of interest in biogenic synthesis of metallic nanoparticles (NPs), using plant extracts; however, the plant constituents involved in this reaction are poorly characterized. Here, major components of Rosemary </em><em>(Rosmarinus officinalis L.) </em><em>leaf extracts were isolated monthly during 2012-2013 and their competences for Ag–conjugated nanoparticle biosynthesis were studied</em><em>.</em><em> Formation of Ag/AgCl–NPs was examined using UV-visible spectroscopy and characterized by </em><em>Fourier transform infrared spectroscopy (</em><em>FTIR), </em><em>X-ray powder diffraction (</em><em>XRD), and </em><em>Transmission electron microscopy (</em><em>TEM). Correlation analysis showed that extracts with more protein contents and higher total reducing capacity were more efficient in biosynthesis of Ag/AgCl–NPs. There existed no correlation between total phenolic, ascorbic acid and anthocyanin contents with Ag/AgCl–NPs</em><em> biosynthesis </em><em>activity</em><em>. These results partly explain the mechanisms controlling plant mediated biosynthesis of nanoparticles, with possible applications in standardization of plant materials harvested throughout a year.</em>