β-Glycyrrhetinic acid (BGA) is a natural antibacterial agent. Previous studies reported that BGA has antibacterial effects against several bacteria. This study evaluated the effects of BGA on the regulation of supragingival plaque bacteria. First, the minimum inhibitory concentrations (MICs) of BGA against oral bacteria were measured. Next, the minimum concentrations for inhibition of biofilm formation were evaluated against Streptococcus mutans and Streptococcus sobrinus, possessing insoluble glucan synthesis abilities. The MICs of biofilm formation by these bacteria ranged from 1/8 to 2× MIC. Furthermore, the inhibition effects of BGA against the coaggregation of Porphyromonas gingivalis and Streptococcus gordonii were evaluated. BGA at 32 or 64 μg/mL inhibited the coaggregation of these bacteria after a 30 min incubation. Lastly, the inhibition effects of BGA against human supragingival plaque bacteria were evaluated. Human supragingival plaque samples were obtained from 12 healthy donors. The inhibition effects of BGA against biofilm formation by these plaque bacteria were evaluated. Of 12 samples, the biofilm formation by 11 was significantly attenuated by 128–256 μg/mL of BGA. The number of colony forming units in these biofilms was also significantly attenuated. In conclusion, it was revealed that BGA inhibits the growth and biofilm formation of bacteria, furthermore, the same effect was confirmed with supragingival plaque bacteria. BGA is a good candidate for a natural agent that prevents the outbreak and progression of periodontal disease because it suppresses not only the growth and biofilm formation of bacteria, but also the coaggregation of P. gingivalis with plaque bacteria.

中文翻译：

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β-甘草次酸通过龈上菌斑抑制细菌生长和生物膜形成

β-甘草次酸 (BGA) 是一种天然抗菌剂。先前的研究报告称，BGA 对多种细菌具有抗菌作用。本研究评估了 BGA 对龈上菌斑细菌的调节作用。首先，测量了 BGA 对口腔细菌的最小抑制浓度 (MIC)。接下来，针对具有不溶性葡聚糖合成能力的变形链球菌和远缘链球菌评估了抑制生物膜形成的最低浓度。这些细菌形成生物膜的 MIC 范围从 1/8 到 2×MIC。此外，BGA对牙龈卟啉单胞菌和戈登链球菌共聚集的抑制作用被评估。32 或 64 μg/mL 的 BGA 在孵育 30 分钟后抑制了这些细菌的共聚集。最后，评价了 BGA 对人龈上菌斑细菌的抑制作用。人类龈上牙菌斑样本来自 12 名健康供体。评估了 BGA 对这些菌斑细菌形成生物膜的抑制作用。在 12 个样品中，128-256 μg/mL BGA 显着减弱了 11 个样品的生物膜形成。这些生物膜中菌落形成单位的数量也显着减少。总之，表明BGA抑制细菌的生长和生物膜形成，此外，对龈上菌斑细菌也证实了同样的效果。P. gingivalis带有牙菌斑细菌。