Influences of <em>Dryopteris crassirhizoma</em> Extract on<em> </em>the Viability, Growth and Virulence Properties of <em>Streptococcus </em><em>m</em><em>utans</em><em></em>

Abstract

<em>Dryopteris crassirhizoma </em>is traditionally used as an herbal remedy for various diseases, and has been identified in a previous study as a potential anti-caries agent. In this study, the effect of a methanol extract of <em>D. crassirhizoma</em> on the viability, growth and virulence properties of <em>Str</em><em>eptococcus mutans</em>, a cariogenic dental pathogen, was investigated. In addition, the phytochemical composition of the extract was analyzed. The extract showed bactericidal and bacteriostatic activity against oral bacteria (MIC and MBC of <em>S. mutans</em>: 62.5 and 250 μg/mL, respectively). At two times the MBC, the extract significantly eliminated <em>S. mutans</em> up to 99.9% after 1 h incubation. The extract also dose-dependently reduced growth rates of <em>S. mutans</em> at sub-MIC levels. Furthermore, at sub-MIC levels, virulence properties (acid production, acid tolerance, glucosyltransferase activity and sucrose-dependent adherence) of <em>S. mutans</em> were also inhibited in a dose-dependent manner. GC-MS analysis revealed the presence of mono and disaccharides (44.9%), fatty acids (12.3%) and sugar alcohols (6.8%) in the extract. These data indicate that the extract might be useful for the control of dental caries.

Keywords

• &lt;em&gt;Streptococcus mutans&lt;/em&gt;
• &lt;em&gt;Dryopteris crassirhizoma&lt;/em&gt;
• virulence properties