Effect of Liquorice-Extract-Containing Antimicrobial Mouthwash on Helicobacter Pylori: An In Vitro Study

Background: The oral route is one of the main portals for Helicobacter pylori transmission. The elimination of this bacterial species from the oral cavity might be useful in oral health and decreasing infections due to H. pylori. This study aimed to evaluate the effect of a liquorice-extract-containing mouthwash at different concentrations on the proliferation of H. pylori in vitro. Methods: H. pylori bacterial species was cultured, and the isolated strains from the specific culture medium were prepared for the welling procedures. The liquorice (Glycyrrhiza glabra) mouthwash at ۱۲.۵% and ۲۵% concentrations was added to the case group wells at ۱,۱/۲,۱/۴,۱/۸, and ۱/۱۶ dilutions. In the control group, regular daily mouthwash containing cetylpyridinium chloride and sodium fluoride components was used. The growth inhibition zones were analyzed in the study groups. The data were analyzed by SPSS and reported using descriptive statistics (means ± standard deviation). Results: In both the mouthwashes containing ۲۵% and ۱۲.۵% concentration, the means of growth inhibition zones at ۱, ۱/۲, ۱/۴, ۱/۸, and ۱/۱۶ dilutions were larger than those in the control group. Further, the largest growth inhibition zone was seen with the undiluted ۲۵% mouthwash. There were no significant differences in the H. pylori growth inhibition zones between ۲۵% and ۱۲.۵% mouthwashes (P = ۰.۱۴). Conclusions: Mouthwashes containing liquorice extracts inhibited the growth of H. pylori more significantly than mouthwash with no liquorice extract. Therefore, it is suggested that liquorice extract-containing mouthwashes be used to prevent H. pylori infections in the oral cavity in clinical studies.