Biological synthesis of gold and silver chloride nanoparticles by Glycyrrhiza uralensis and in vitro applications

The current study highlights the rapid biosynthesis of gold nanoparticles (Gu-AuNps) and silver chloride nanoparticles (Gu-AgClNps) by aqueous root extract of Glycyrrhiza uralensis, a medicinal plant. G. uralensis has been reported for anticancer and hepatoprotective effects. The reduction of chloroauric acid and silver nitrate by the Glycyrrhiza root extract prompted the formation of Gu-AuNps and Gu-AgClNps within 4 and 40min at 80 degrees C, respectively. The complete reaction did not require supplemental reducing and stabilizing agents, which demonstrated green synthesis. Field emission transmission electron microscopy (FE-TEM) revealed the spherical shape of Gu-AuNps and Gu-AgClNps. X-ray diffraction (XRD) showed face-centred cubic structure of Gu-AuNps and Gu-AgClNps with average crystallite size 12.25nm and 8.01nm, respectively. The biosynthesized Gu-AgClNps served as competent antimicrobial agent against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enterica. Additionally, Gu-AuNps and Gu-AgClNps were analyzed for their catalytic ability to reduce methylene blue as model test pollutant. Likewise, both nanoparticles possessed free radical scavenging activity against 2,2-diphenyl-1-picrylhydrzyl (DPPH). Moreover, in vitro cytotoxicity in murine macrophage (RAW264.7) and human breast cancer (MCF7) cells were evaluated. Thus, the study proposes a green synthesis of Gu-AuNps and Gu-AgClNps by G. uralensis extract and in vitro biological applications. [GRAPHICS] .