Biogenic synthesis of noble metal nanoparticles using Melissa officinalis L. and Salvia officinalis L. extracts and evaluation of their biosafety potential

Abstract

In this study we targeted the noble metal nanoparticles (MNPs) biogenic synthesis capacity of of two medicinal species with therapeutic potential, namely Melissa officinalis L. and Salvia officinalis L., cultivated in Romania. Plant material was extracted by maceration, microwave assisted extraction (MAE) and ultrasound assisted extraction (UAE). The total polyphenol content for both simple extracts and nanostructured mixtures was determined using the Folin-Ciocalteu method and antioxidant activity using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Identification and quantification of secondary metabolites of lemon balm and sage were performed by ultra-high performance liquid chromatography (UHPLC). MAE was found to be the optimal method for obtaining the maximum concentration of rosmarinic acid for M. officinalis L., while for S. officinalis L., was UAE. Bright field scanning transmission electron microscopy and energy dispersive X-ray spectroscopy (BFSTEM-EDS) techniques were used in order to investigate particles shape, dispersion and chemical elemental analysis. The Allium assay was used to evaluate the potential cytogenotoxic activity, in the case of S. officinalis L. species being performed for the first time. High total polyphenol content and low frequency of chromosomal aberrations corresponding to crude extracts and extracts supplemented with MNPs, suggest the cytoprotective, antigenotoxic, and safe use of these plant species as potential therapeutic forms in various diseases.