A rapid, cost-efficient, and eco-friendly method for synthesis of silver nanoparticles (AgNPs) was developed using an herb extract (Glycyrrhiza glabra root) as a reducing agent and a kitchen microwave as a reaction accelerator. A solution of dark brown appeared and was examined by UV-visible spectroscopy. Scanning and transmission electron microscopes as well as an atomic force microscope were used to confirm their physical nature. The AgNPs revealed feasibility for treatment of oral diseases. Their antimicrobial activities against Streptococcus mutans were indicated with minimal inhibitory and minimal bactericidal concentrations of 6.25 and 25 μg/ml, respectively. They showed toxicity to cancer cell lines (HN-30) but had no effect on human gingival fibroblasts. Anti-oxidative activity was also observed which suggested potential in medical applications.
