Synergistic Activities of Hypericum perforatum L. and Glabridin against Drug Resistant H. pylori Isolates

Glabridin and Hypericum perforatum L. have many pharmacological activities such as antimicrobial activity, antiproliferative, cytotoxic, anticancerogenic, antiproliferative and antioxidant effect. The aim of this study was to determine the components and to investigate the antimicrobial activity of Hypericum perforatum L. and glabridin against drug resistant H. pylori isolates. The main essential oil components of Hypericum perforatum L. determined by GC-MS were caryophyllene (19,13 %), germacrene-D (13,22 %), α-Pinene (12,59 %) and β-helmiscapene (8,99 %). We also aim to determine the synergistic activity of these two natural products against the drug-resistant H. pylori strains. MIC values of Hypericum perforatum L. essential oils and glabridin against drug resistant H. pylori isolates were carried out by modifying the method described previously. In the experiments in which 1:1 ratio of Hypericum perforatum L. essential oils and glabridin was used, the MIC values (µg/mL) were as follows: 8 For standard strain; 4 for drug sensitive strain; 8 for metronidazole resistant strain; and 16 for clarithromycin resistant strains. In conclusion, it was found that Hypericum perforatum L. essential oils and glabridin had significant antimicrobial activity against HP strains in our study.