This study aimed to select natural materials with antibacterial activity against
Streptococcus mutans (S. mutans) KCCM
40105 and determine their most efficient extraction conditions. The
antibacterial activity was stable under various treatment conditions. Of the 17
material groups, extracts of Sophora flavescens (SF) and
Schisandra chinensis (SC) showed antibacterial activity
against the S. mutans strain. Measuring the antibacterial
activity based on ethanol concentration revealed that the 30% ethanol extracts
of SF and SC showed the highest antibacterial activity as observed by the
inhibition zones of 10.69 and 14.49 mm, respectively. The minimum inhibitory
concentrations of the 30% ethanol extracts of SF and SC against the S.
mutans strain were 2.0 and 5.0 mg/mL, respectively. Heat stability
was confirmed; however, the 30% ethanol extract of SC was inactive at pH values
≥6.0. The antibacterial activity of the 30% ethanol extract of SF and SC
treated with nine enzymes was the same at 10 ppm and 100 ppm. However, the
activity tended to decrease marginally in the 1,000 ppm concentration treatment
group.