Characterization and Antibacterial Activity of Green Copper Nanoparticles Synthesized by Saponaria officinalis L., a plant with high saponin content

Abstract

Metallic nanoparticles are generally more stable and active than the metal ions from which they were synthesized where both nanoparticles and metal ions usually have antimicrobial properties. Their antimicrobial effect generally covers gram-positive, gram-negative bacteria along with fungi. And unlike antibiotics that target specific essential synthetic pathways in the cell antimicrobial actions of metallic nanoparticles are nonspecific. Due to this fact NPs with antibacterial properties are foresen as potential agents against stubborn bacterial infections that show multidrug resistance. In this work we report copper nanoparticle (CuNP) synthesis through green route, structural characterization and evaluation of its’ antibacterial properties. Source of reducing agent selected was soapwort (Saponaria officinalis L.) root extracts that are known to be high in saponin content. Main aim of generating green nanoparticles from copper and S. officinalis root extracts was to combine antibacterial effects of both CuNPs and bioactive phytochemicals from soapwort. Structural characterisation of the Green-CuNPs were performed through scanning electron microscopy (SEM), UV-Visible spectroscopy (UV-Vis), fourier conversion infrared spectrophotometer (FTIR) and X-ray diffraction (XRD) analysis. Green-CuNPs coated (perhaps) with saponins and other active phytochemicals were tested for their antimicrobial activities against two common bacteria (Eschericia coli and Staphylococus aeurous). The bulk of the genrated NP were shown to be pure nanocrystalline structures (XRD analysis) with average diameter of 17 nm. FTIR analysis data confirmed both CuNP formation and functionalization with aromatic hydrocarbon structures (possibly saponins). In the evaluation of antimicrobial properties, it was observed that NPs had weak to moderate but statistically significant antimicrobial effects against E. coli and S. aeurous when used at high doses. Further diagnostics and experimentations may be done to reveal the true mechanistics of antimicrobial activity of Green-CuNPs synthessised with S. officinalis.