The phenolic compounds, secondary metabolites of hops represent a large family of compounds that could be subsequently divided into smaller groups based on the similarities between their chemical structures. The antibacterial, antifungal and antiviral properties of hops are well known, but there is a lack of information about antimicrobial activities of individual hop compounds. This study was carried out with an objective to identify compounds present in hops that have potential antibacterial activity. In the first stage of experiment, the active compounds with potential anti-microbial activity had to be extracted from hop cones. Therefore, minced hop cones were applied on solid growth medium inoculated with Staphylococcus aureus. The active substances that migrated into the medium created an inhibition zone. In the second stage of experiment, the inhibition zones were cut out from Petri dishes, active compounds were extracted from these zones and consequently analyzed using LC-HRMS. These complex assays were developed and optimized. The data were acquired by using a quadrupole-orbitrap hybrid mass spectrometer by targeted-MS2 experiment in both ionization modes. The MS method has been developed as a screening method with a subsequent fragmentation of compound of interest on the base of inclusion mass list. The unknown compounds extracted from inhibition zones have been identified either by searching against a database or their structure has been elucidated on the basis of their fragmentation spectra. On the basis of this experiment the list of active compounds with potential anti-microbial activities was enhanced.

Faculty of Science Charles University Prague Albertov 6 CZ 128 43 Prague 2 Czech Republic

Research Institute for Brewing and Malting Prague PLC Lípová 15 CZ 120 44 Prague 2 Czech Republic

Thomayer's Hospital Vídeňská 800 CZ 140 59 Prague 4 Czech Republic

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