Ultrasonic-assisted green synthesis of silver nanoparticles through cinnamon extract: biochemical, structural, and antimicrobial properties

Ultrasonic-assisted green synthesis of silver nanoparticles is gaining more attention owing to its benefits over conventional synthesis process. The main objective of this study was to synthesize silver nanoparticles with aqueous cinnamon extract using ultrasound-assisted extraction and their physico-chemical characterization. Total phenolic content, DPPH, FRAP of cinnamon aqueous extract were 315 mg GAE/g, 89% scavenging activity and 9.5 mmol Trolox eq/100 g reducing power respectively. The synthesized silver nanoparticles were characterized by UV-visible spectroscopy, X-rays Diffraction (XRD), Scanning Electron Microscopy (SEM) with Energy Dispersive X-rays (EDX), Fourier transform infrared (FTIR) and Nuclear Magnetic Resonance (NMR). XRD spectra depicted that the nanoparticles were crystallite in structure and 50 nm in size. SEM micrographs showed that nanoparticles were spherical in shape. EDX, FTIR and NMR spectra indicated that the phenolic compounds present in cinnamon aqueous extract played their role in capping and reducing the silver ions. Cinnamon-based silver nanoparticles showed potential antimicrobial activity against Gram negative and Gram-positive bacteria. Thus, cinnamon extract obtained through ultrasonic-assisted extraction could be a valuable source of polyphenols, which actively participated in the reduction and stabilization of silver nanoparticles.