Antimicrobial activity and stability of Prunus mume fruit extract against Streptococcus mutans KCCM 40105 strain

In this study, natural materials with antibacterial activity against the Streptococcus mutans KCCM 40105 strain were selected, and the most efficient extraction conditions were observed. The active substance was stable under various treatment conditions. Of the 10 food materials groups, only Prunus mume fruit showed antibacterial activity against S. mutans strains. The antimicrobial activity by the various extraction solvents was 18.66 mm (clear zone diameter) in the ethanol extract and 20.18 mm in the water extract. Measurements of the antibacterial activity according to the mixing ratio of the two solvents revealed the 30% ethanol extract to have the highest activity (20.49 mm). Measurements of the minimum inhibitory concentration (MIC) showed activity at a concentration of 3.0 mg/mL. The stability to heat was observed, but the extract was not active at pH 6.0 or higher. The antimicrobial activity of the 30% ethanol extract of P. mume treated with enzymes was the same with both 10 ppm and 100 ppm of the nine enzymes. On the other hand, the activity tended to decrease slightly at 1,000 ppm. The activity of the catazyme enzyme and hydrogen peroxide treatment decreased at the treatment concentration of 100 ppm.