Xiaoying Lyu1, Liang Wang1, Yusen Shui1, Qingsong Jiang1, Lan Chen1, Wen Yang1, Xiaoya He1, Jumei Zeng2, Yuqing Li3. 1. State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China. 2. West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, Sichuan 610041, China. Electronic address: zengjumei@scu.edu.cn. 3. State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China School of Stomatology, Sichuan University, Chengdu, Sichuan 610041, China. Electronic address: liyuqing@scu.edu.cn.
Abstract
OBJECTIVE: The current study aimed to assess the antimicrobial activity of ursolic acid (UA) against multi-species biofilms formed by Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii, as well as to measure its biocompatibility. METHODS: Crystal violet staining, CFU counting, CCK-8 assays and scanning electron microscopy (SEM) were applied to investigate the effect of UA on multi-species biofilms. UA's effect on exopolysaccharides (EPS) production was measured using confocal laser scanning microscopy (CLSM) and the anthrone-sulfuric acid method. Fluorescent in situ hybridization (FISH) was applied to visualize and quantify the microbial composition of multi-species biofilms. Quantitative real-time PCR (qRT-PCR) was used to measure the expression of virulence genes of S. mutans, S. sanguinis, and S. gordonii under UA treatment. Moreover, CCK-8 assays were performed to evaluate its cytotoxicity against human oral keratinocytes (HOKs) and human gingival epithelial cells (HGEs). RESULTS: The results showed that UA had significant antimicrobial activity against common oral streptococci. UA also reduced the EPS synthesis of oral streptococci and suppressed gtf genes' expression. In addition, UA reduced the proportion of S. mutans in multi-species biofilms. Besides, UA had low cytotoxicity against HOKs and HGEs. CONCLUSIONS: UA exhibited antibiofilm activity against oral pathogenic bacteria and had the potential to be used in dental caries treatment.
OBJECTIVE: The current study aimed to assess the antimicrobial activity of ursolic acid (UA) against multi-species biofilms formed by Streptococcus mutans, Streptococcus sanguinis, and Streptococcus gordonii, as well as to measure its biocompatibility. METHODS:Crystal violet staining, CFU counting, CCK-8 assays and scanning electron microscopy (SEM) were applied to investigate the effect of UA on multi-species biofilms. UA's effect on exopolysaccharides (EPS) production was measured using confocal laser scanning microscopy (CLSM) and the anthrone-sulfuric acid method. Fluorescent in situ hybridization (FISH) was applied to visualize and quantify the microbial composition of multi-species biofilms. Quantitative real-time PCR (qRT-PCR) was used to measure the expression of virulence genes of S. mutans, S. sanguinis, and S. gordonii under UA treatment. Moreover, CCK-8 assays were performed to evaluate its cytotoxicity against human oral keratinocytes (HOKs) and human gingival epithelial cells (HGEs). RESULTS: The results showed that UA had significant antimicrobial activity against common oral streptococci. UA also reduced the EPS synthesis of oral streptococci and suppressed gtf genes' expression. In addition, UA reduced the proportion of S. mutans in multi-species biofilms. Besides, UA had low cytotoxicity against HOKs and HGEs. CONCLUSIONS:UA exhibited antibiofilm activity against oral pathogenic bacteria and had the potential to be used in dental caries treatment.