Antibacterial activity of 18β-glycyrrhetinic acid against in vitro.

Gonorrhea is the second most common sexually transmitted diseases worldwide. Chronic infection of () can lead to severe complications. Presently, has developed resistance to almost all antibiotics used for the treatment of gonorrhea. Thus, it's urgent to explore new approaches to treat gonorrhea. Presently, nontraditional treatment method as an alternative to antibiotic use is getting more and more attention. Here we demonstrated that 18β-glycyrrhetinic acid (GRA) exhibited robust antimicrobial activity against in vitro. GRA led to a significant decline in viable in a dose dependent manner compared with DMSO treatment (P < 0.001). Addition of GRA resulted in a significant reduction in viable bacteria within 2 h post-inoculation (P < 0.001). Minimum inhibitory concentrations (MICs) to GRA ranged from 3.9 to 62.5 μg/ml overall, with MIC50 and MIC90 values of 31.25 μg/ml and 62.5 μg/ml, respectively. There was no significant difference of MIC 50 and MIC90 between multi-drug resistant (MDR) strains and non-MDR strains. Minimum bactericidal concentration (MBC) ranges were 3.9-125 μg/ml, basically consistent with MIC values. GRA inhibited biofilm formation and diminished pre-formed biofilm. These data suggested that GRA could be a candidate for gonorrhea treatment.