Figure 1.

The inhibition of LF-1 on the growth, acid production, and acid tolerance of planktonic Streptococcus mutans. The relative cell viability of S. mutans under LF-1 treatment within 6 h was evaluated using the MTT method. (A) The acid production capacity of S. mutans under the LF-1 treatment is determined by measuring lactic acid production (B), glycolytic pH drop (C), and LDH activity. (D) The acid tolerance capacity of S. mutans under the LF-1 treatment is evaluated by counting survivors in the lethal acidic environment (E) and measuring the relative F₁F₀-ATPase activity. (F) All data are presented as the mean ± standard deviation from at least three independent experiments, and relative values are obtained by comparison with the untreated control. Columns labelled with different superscript letters denote significant statistical differences in one group (one-way analysis of variance; p < 0.05). MTT: methyl thiazolyl tetrazolium; LDH: lactate dehydrogenase.