Aim: The aim of this study was to investigate the in-vitro efficacy of Glycyrrhetinic acid against Helicobacter pylori (H. pylori) strains, as compared with conventional antibacterial agents.
Methods: A total of 41 H. pylori isolates were used, 6 of which were of standard strains (NCTC 1637), 8 of which were drug-sensitive, and 27 were resistant to drugs isolates. Clarithromycin and metronidazole resistance in all strains of H. pylori were determined by the Epsilometer test (E-test) method. MIC study was performed by using microdilution broth method.
Results: Glycyrrhetinic acid was found to be effective against H. pylori NCTC 1637 in doses of 12.0±4.38 µg/mL, while the MIC value of clinical H. pylori isolates susceptible to antimicrobials was 20.8±10.11 µg/ml. It was found that the MIC values for antimicrobial-sensitive clinical H. pylori isolates was higher when compared with H. pylori NCTC 1637 strains. The MIC values of the standard antimicrobial agents against drug-resistant H. pylori strains were higher than H. pylori NCTC 1637 strains and drug-sensitive H. pylori strains. The MIC value was found to be 14.22±7.77 µg/ml for metronidazole, 3.89±1.90 µg/ml for clarithromycin, 2.33±1.0 µg/ml for amoxicillin, 2.44±0.88 µg/ml for levofloxacin and 4.89±2.47 µg/ml for tetracycline, whereas the MIC value of Glycyrrhetinic acid was 26.67±8.0 µg/ml in metronidazole-resistant H. pylori isolates. Besides, MIC values of the antimicrobials and 18ß-Glycyrrhetinic acid among the strains resistant to clarithromycin were as follows: 3.25±2.12 µg/ml for metronidazole, 9.71±4.54 µg/ml for clarithromycin, 2.06±1.32 µg/ml for amoxicillin, 3.88±4.22 µg/ml for levofloaxacin and 3.25±1.04 µg/mL for tetracycline and 22.0±11.11 µg/ml for Glycyrrhetinic acid.
Conclusion: Glycyrrhetinic acid had significant antimicrobial activity against H. pylori strains. Although further in-vivo studies are needed on antimicrobial activity of Glycyrrhetinic acid, increased resistance to drugs currently used in treatment suggests that Glycyrrhetinic acid may be a potential agent for the treatment of H. pylori.
