The present study details the synthesis of silver nanoparticles (Ag NPs) from Dianthus caryoophyllus plants extract and study its effect on the growth of Streptococcus isolated from the oral cavity. The synthesized silver nanoparticles (Ag NPs) were analyzed by UV visible spectroscopy, diffraction of X-rays (XRD) and Infrared Spectroscopy with Fourier Transform (FTIR). The ability to fight bacteria was also studied by diffusion technique using Agar wells against wild and mutant isolates of different species of Streptococcus including S. mutans, S. salivarius and S. sobrinus. The results showed the most potent antibacterial effect of D. caryophyllus extract was 30 mm in diameter at a concentration of 100 mg/ml against non-mutated S. salivarius and mutated isolates of S. salivarius and S. sobrinus, while the lowest value is 9 mm in diameter at a concentration of 25 mg/ml against non- mutated S. mutans. also findings from the study indicated that silver nanoparticles exhibit antimicrobial properties and the greatest number of the inhibitory zone estimated 35 mm in diameter at a 100 mg/ml concentration against non-mutated isolate of S. salivarius and 15 mm in diameter at concentration of 25 mg/ml against mutated isolate of S. mutans was showed the lowest value of antibacterial effects. The origin of nanoparticles can be useful in industry alternatives to antibiotics as an economic and safe source, but more studies are needs to ensure that they do not effect on human cells.

The present study details the synthesis of silver nanoparticles (Ag NPs) from Dianthus caryoophyllus plants extract and study its effect on the growth of Streptococcus isolated from the oral cavity. The synthesized silver nanoparticles (Ag NPs) were analyzed by UV visible spectroscopy, diffraction of X-rays (XRD) and Infrared Spectroscopy with Fourier Transform (FTIR). The ability to fight bacteria was also studied by diffusion technique using Agar wells against wild and mutant isolates of different species of Streptococcus including S. mutans, S. salivarius and S. sobrinus. The results showed the most potent antibacterial effect of D. caryophyllus extract was 30 mm in diameter at a concentration of 100 mg/ml against non-mutated S. salivarius and mutated isolates of S. salivarius and S. sobrinus, while the lowest value is 9 mm in diameter at a concentration of 25 mg/ml against non- mutated S. mutans. also findings from the study indicated that silver nanoparticles exhibit antimicrobial properties and the greatest number of the inhibitory zone estimated 35 mm in diameter at a 100 mg/ml concentration against non-mutated isolate of S. salivarius and 15 mm in diameter at concentration of 25 mg/ml against mutated isolate of S. mutans was showed the lowest value of antibacterial effects. The origin of nanoparticles can be useful in industry alternatives to antibiotics as an economic and safe source, but more studies are needs to ensure that they do not effect on human cells.