Evaluation of antibacterial, antibofilm and antioxidant activities of synthesized silver nanoparticles (AgNPs) and casein peptide fragments against Streptococcus mutans

Abstract

IntroductionInappropriate antibiotic advising and consumption have been identified as the major factors in the development of antibiotic resistance in Streptococcus mutans. According to recent evidence, the microbial flora responsible for causing dental caries has developed resistance to the commercially available drugs. MethodsIn the current study, the silver nanoparticles (AgNPs) were synthesized in the presence of E. coli supernatant. Casein peptide fragments were produced by the partial proteolysis of cow milk caseins in the presence of pepsin and trypsin. Then, the antibacterial, antibiofilm and antioxidant activity of AgNPs and casein peptide fragments were assessed. The cariogenic bacterium Streptococcus mutans which is the major cause of dental caries worldwide was used as the target cells. Different spectroscopic practices and microscopic analyses were applied. ResultsThe AgNPs, with almost spherical morphology demonstrated significant antibacterial, antibiofilm and antioxidant activities. The casein hydrolysates which were obtained with the partial/precise enzymatic hydrolysis indicated a size-dependent antibacterial activity. Additionally, a significant improvement in the antibacterial activity was observed when a combined mixture of casein hydrolysates and AgNPs were applied. ConclusionA combination of casein peptide fragments and AgNPs may offer a novel practical strategy against the cariogenic bacterium S. mutans.