In vitro anti-Helicobacter pylori activity of Extractum liquiritiae, glycyrrhizin and its metabolites

• Published in: Journal of antimicrobial chemotherapy 2004-07, Vol.54 (1), p.243-246
• Main Authors: Krausse, Rea, Bielenberg, Jens, Blaschek, Wolfgang, Ullmann, Uwe
• Format: Article
• Language: English
• Subjects: Anti-Infective Agents - pharmacology; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; Colony Count, Microbial; Dose-Response Relationship, Drug; glycyrrhetinic acid; Glycyrrhiza - chemistry; Glycyrrhizic Acid - pharmacology; Helicobacter; Helicobacter pylori; Helicobacter pylori - drug effects; liquorice; Medical sciences; Microbial Sensitivity Tests; novel derivatives; Pharmacology. Drug treatments; Plant Extracts - pharmacology; Time Factors
• ISSN: 0305-7453; 1460-2091; 1460-2091
• DOI: 10.1093/jac/dkh287

Objectives: To investigate the in vitro activity of Extractum liquiritiae (EL), glycyrrhizic acid (GL), glycyrrhetinic acid (GA) and a novel lipophilic derivative of glycyrrhetinic acid monoglucuronide (GAMG), acetylated GAMG (aGAMG), against 29 Helicobacter pylori strains. Methods: The MIC of each compound was determined by the agar dilution method, and the killing kinetics were monitored in brain heart infusion broth (∼106–107 cfu/mL) at 0, 4, 24, 48, 72 and 96 h. Results: GA was the most potent compound (MIC50 /90, 50/100 mg/L), inhibiting 79.3% of the strains at MIC ≤50 mg/L. Clarithromycin-resistant strains were susceptible at 12.5 and 25 mg/L, and metronidazole-resistant strains at 25–50 and at 200 mg/L. The MIC distribution (mg/L) of aGAMG was ≤6.25 (29.2%), 50 (4.2%), 100–200 (12.5%) and ≥400 (54.1%). EL and GL were less active (MICs >400 mg/L). GA exhibited rapid, concentration and strain-dependent bactericidal activity. Conclusions: The potent in vitro activity of GA against H. pylori provides a further explanation for its beneficial effect on peptic ulcers. Its effectiveness against clarithromycin-resistant strains provides hope that it can form the basis for an alternative therapeutic agent against H. pylori.