Antimicrobial Activity of Medium Molecular Weight Chitosan against Streptococcus mutans

Abstract

The purpose of this study was to evaluate the antimicrobial activity of medium molecular weight chitosans (MMWCs; 3,500~7,800 Da) and high molecular weight chitosan (HMWC, 200 kDa) with a deacetylation degree of 95% against representative oral pathogen, Streptococcus mutans, which is a principal etiological agent of dental caries in humans. Among bioactive substances, HMWC shows significant inhibitory effect on S. mutans and chitosans exerted molecular weight dependent growth inhibition of 80% on growth rate of S. mutans. Furthermore, synthesis of exopolysaccharide (EPS) and acidogenic properties of S. mutans were also inhibited by MMWCs, showing that MMWC1 having 7,800 Da among the MMWCs exhibited the strongest antibacterial efficacy against S. mutans. Consequently, it was found that MMWC1 is of a potent natural material available in antibacterial component useful for oral health.