ABSTRACT
Glycyrrhetinic acid is a major component of a traditional plant called Licorice. This substance has been found to have some pharmacological properties including anti-inflammatory, anti-viral, anti-bacterial, anti-fungal, anti-allergic, anti-carcinogenic and anti-peptic-ulcer. Glycyrrhetinic acid also affects against some parasites such as Trichomonas vaginalis. In this study, 55 hospital strains of Staphylococcus aureus and 32 Actinobacillus actinomycetemcomitans, were isolated from patient's specimens by culture method. Antibacterial activities of glycyrrhetinic acid against those microorganisms were investigated by determining minimum inhibitory concentration [MIC] and minimum bactericidal concentration [MBC] methods. The MIC for S. aureus and A. actinomycetemcomitans were 64 and 8 micro g/ml respectively. The MBC for S. aureus and A. actinomycetemcomitans were 64 and 16 micro g/ml respectively. It is concluded that Glycyrrhetinic acid is effective against Staphylococcus aureus and Actinobacillus actinomycetemcomitans in appropriate concentrations