Rapid Bactericidal Action of Propolis against Porphyromonas gingivalis
Rapid Bactericidal Action of Propolis against Porphyromonas gingivalis
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DOI：
10.1177/0022034518758034
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发表时间：
2018-07-01
影响因子：
7.6
通讯作者：
Nakao, R.
中科院分区：
文献类型：
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作者：
Yoshimasu, Y.;Ikeda, T.;Nakao, R.
蜂胶是一种由蜜蜂产生的分泌物，被用作治疗牙周病的民间药物。然而，其作用方式和负责其活动的化合物仍然不清楚。在本研究中，我们全面研究了乙醇提取的牙龈卟啉单胞菌（EEP）和EEP衍生物对牙龈卟啉单胞菌的抗菌活性，牙龈卟啉单胞菌是牙周病的关键病原菌。肉汤微量稀释和琼脂稀释试验用于确定EEP对一系列口腔细菌物种的最小抑制浓度，其中牙龈卟啉单胞菌显示出比口腔细菌如链球菌更高的敏感性水平。其对牙龈卟啉单胞菌的抗菌活性即使在广泛的热处理后仍保持不变，证明了高水平的热稳定性。EEP还诱导牙龈卟啉单胞菌细胞死亡，增加膜渗透性在30分钟内。时空分析的基础上高速原子力显微镜显示，EEP立即引发发展异常膜泡，其次是水泡融合事件的细菌表面。此外，我们从EEP中分离出了阿替匹林C、baccharin和熊果酸作为抗牙龈卟啉单胞菌的抗菌化合物。其中，阿替匹林C和baccharin表现出抑菌活性与膜起泡，而熊果酸表现出杀菌活性与膜破裂。特别是，熊果酸表现出更大的能力，影响细菌膜电位增加膜渗透性，可能是因为它的高度亲脂性相比，其他化合物。总之，这些研究结果提供了EEP及其精致的膜靶向抗菌化合物的抗菌活性的机理见解，并暗示了EEP用于治疗牙周炎的窄谱疗法的适用性。此外，本研究中用于可视化微生物纳米级动力学的先进技术将有助于扩大我们对抗菌剂活性和细菌耐药性机制的理解。
Propolis, a resinous substance produced by bees, is used as a folk medicine for treatment of periodontal diseases. However, its mode of the action and the compounds responsible for its activities remain obscure. In the present study, we comprehensively investigated the antibacterial activities of ethanol-extracted propolis (EEP) and EEP-derived compounds toward Porphyromonas gingivalis, a keystone pathogen for periodontal diseases. Broth microdilution and agar dilution assays were used to determine the minimum inhibitory concentrations of EEP against a range of oral bacterial species, of which P. gingivalis showed a higher level of sensitivity than oral commensals such as streptococci. Its antibacterial activity toward P. gingivalis was maintained even after extensive heat treatment, demonstrating a high level of thermostability. EEP also induced death of P. gingivalis cells by increasing membrane permeability within 30 min. Spatiotemporal analysis based on high-speed atomic force microscopy revealed that EEP immediately triggered development of aberrant membrane blebs, followed by bleb fusion events on the bacterial surface. Furthermore, we isolated artepillin C, baccharin, and ursolic acid from EEP as antibacterial compounds against P. gingivalis. Of those, artepillin C and baccharin showed bacteriostatic activities with membrane blebbing, while ursolic acid showed bactericidal activity with membrane rupture. In particular, ursolic acid demonstrated a greater ability to affect bacterial membrane potential with increased membrane permeability, probably because of its highly lipophilic nature as compared with other compounds. Taken together, these findings provide mechanistic insight into the antibacterial activities of EEP and its exquisite membrane-targeting antibacterial compounds and imply the applicability of narrow-spectrum therapeutics with EEP for treatment of periodontitis. In addition, the advanced technology utilized in the present study to visualize the nanometer-scale dynamics of microorganisms will contribute to expanding our understanding of the activities of antimicrobials and the mechanism of drug resistance in bacteria.