Novel Epigallocatechin Gallate and Catechin-Specific Induction Pathway for the Formation of Small Silver Nanoparticles With Antibacterial Activity

Abstract

Polyphenols are frequently used in the environmentally friendly synthesis of silver nanoparticles. However, not all compounds can produce nanoparticles that are both exceptionally small and highly uniform. This study explored the potential of two compounds, epigallocatechin gallate (EGCG) and catechin (CC), for the synthesis of small spherical silver nanoparticles (AgNPs) using a straightforward, rapid, and eco-friendly method. These organic compounds serve as reducing agents to reduce silver ions and also function as capping and stabilizing agents, helping prevent nanoparticles from aggregating. The average particle size measured is 17.71 ± 1.60 nm for catechin AgNPs and 17.48 ± 1.54 nm for EGCG–AgNPs at 64 ppm in solution. Additionally, the silver concentration was accurately quantified by atomic absorption spectrometry, with the solution concentration measured at 57 ppm and the solid concentration after centrifugation at 64 ppm. Once investigating the antibacterial properties, the ZOI (zone of inhibition) was 35.5 ± 0.3 for Pseudomonas aeruginosa ATCC 27853, with the MIC (minimum inhibitory concentration) being 0.2 μL/mL. For Staphylococcus aureus ATCC 6538, the ZOI was 23 ± 0.2 with the MIC of 0.5 µL/mL.