Laboratory of Research in Applied Microbiology (LaPeMA), University of Franca, Franca, SP 14404-600, Brazil.
Laboratory of Antimicrobial Testing (LEA), Institute of Biomedical Sciences, Federal University of Uberlândia, Uberlândia, MG 38405-320, Brazil.
Biomed Pharmacother. 2020 Sep;129:110467. doi: 10.1016/j.biopha.2020.110467. Epub 2020 Jun 27.
The microorganisms that constitute the oral microbiome can cause oral diseases, including dental caries and endodontic infections. The use of natural products could help to overcome bacterial resistance to the antimicrobials that are currently employed in clinical therapy. This study assessed the antimicrobial activity of the Copaifera pubiflora oleoresin and of the compounds isolated from this resin against oral bacteria. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays provided values ranging from 6.25 to > 400 μg/mL for the C. pubiflora oleoresin and its isolated compounds. The fractional inhibitory concentration index (FICI) assay showed that the oleoresin and chlorhexidine did not act synergistically. All the tested bacterial strains formed biofilms. MICB determination revealed inhibitory action: values varied from 3.12-25 μg/mL for the oleoresin, and from 0.78 to 25 μg/mL for the ent-hardwickiic acid. Concerning biofilm eradication, the C. pubiflora oleoresin and hardwickiic acid eradicated 99.9 % of some bacterial biofilms. Acid resistance determination showed that S. mutans was resistant to acid in the presence of the oleoresin and ent-hardwickiic acid at pH 4.0, 4.5, and 5.0 at all the tested concentrations. Analysis of DNA/RNA and protein release by the cell membrane demonstrated that the oleoresin and hardwiickic acid damaged the bacterial membrane irreversibly, which affected membrane integrity. Therefore, the C. pubiflora oleoresin and ent-hardwickiic acid have potential antibacterial effect and can be used as new therapeutic alternatives to treat oral diseases such as dental caries and endodontic infections.
构成口腔微生物组的微生物会引起口腔疾病，包括龋齿和牙髓感染。天然产物的使用有助于克服目前临床治疗中使用的抗菌药物的细菌耐药性。本研究评估了古巴油胶及其分离化合物对口腔细菌的抗菌活性。最低抑菌浓度（MIC）和最低杀菌浓度（MBC）测定值为 6.25 至 > 400 μg/mL，古巴油胶及其分离化合物的测定值为 6.25 至 > 400 μg/mL。部分抑菌浓度指数（FICI）测定表明油胶和洗必泰没有协同作用。所有测试的细菌菌株都形成了生物膜。MICB 测定显示出抑制作用：油胶的浓度范围为 3.12-25 μg/mL，硬脂酸的浓度范围为 0.78-25 μg/mL。关于生物膜清除，古巴油胶和硬脂酸酸清除了一些细菌生物膜的 99.9%。耐酸测定表明，在 pH 值为 4.0、4.5 和 5.0 的所有测试浓度下，S. mutans 在油胶和 ent-hardwickiic 酸存在下均能抵抗酸性。细胞膜上 DNA/RNA 和蛋白质释放的分析表明，油胶和硬脂酸酸不可逆地破坏了细菌膜，影响了膜的完整性。因此，古巴油胶和硬脂酸酸具有潜在的抗菌作用，可作为治疗龋齿和牙髓感染等口腔疾病的新治疗方法。
