This study aimed to improve the antimicrobial activity of natural extracts against oral bacteria by synergistic combination and nanoencapsulation. Among five natural antimicrobials: clove oil, thymol, naringin, naringenin, and licorice, clove oil and thymol were selected by comparing the antimicrobial activities against Streptococcus mutans and Streptococcus sobrinus before and after nanoencapsulation. The combination of clove oil and thymol (CLTY) was nanoencapsulated using chitosan and poly-γ-glutamic acid. While free CLTY showed additive and synergistic antimicrobial activity against S. mutans and S. sobrinus, respectively, CLTY nanoparticles (NPs) exhibited synergistic activity against both strains in a time-kill kinetic assay. CLTY NPs significantly decreased the growth of salivary S. mutans during testing, compared with free CLTY in the mouth rinse test. These results indicate that nanoencapsulation can significantly increase the synergistic antimicrobial activity of CLTY and maintain its antimicrobial activity in oral cavities for a longer time.

本研究旨在通过协同组合和纳米胶囊化提高天然提取物对口腔细菌的抗菌活性。通过比较纳米胶囊化前后对变形链球菌和远缘链球菌的抗菌活性，从丁香油、百里香酚、柚皮苷、柚皮素和甘草这五种天然抗菌剂中选择丁香油和百里香酚。使用壳聚糖和聚-γ-谷氨酸对丁香油和百里酚（CLTY）的组合进行纳米封装。虽然游离 CLTY 分别对变形链球菌和远缘链球菌表现出加和和协同抗菌活性，但 CLTY 纳米颗粒 (NP) 在时间杀灭动力学测定中对两种菌株表现出协同活性。与漱口水测试中的游离 CLTY 相比，CLTY NP 在测试过程中显着降低了唾液变形链球菌的生长。这些结果表明，纳米胶囊化可以显着提高CLTY的协同抗菌活性，并在口腔中更长时间地保持其抗菌活性。