Bitter acids from hydroethanolic extracts of Humulus lupulus L., Cannabaceae, used as anxiolytic

Abstract

Humulus lupulus L., Cannabaceae, is commonly used as light sedative and anxiolytics in folk medicine. HPLC-DAD-ESI-MSn represents a powerful tool for the analysis of natural products, since it can simultaneously provide a UV chromatogram and significant structural information about compounds in complex mixture. The aim of this work was characterize the constituents present in hydroethanolic extract. Compounds 1-9 were tentatively characterized on the basis of UV, MS/MS, after reversed phase separation, retention time and literature data. The main phenolic compounds (based on peak area) were characterized as hulupinic acid (9), cohulupone (8), two oxidized hop alfa-bitter acids (principal constituents), one being a oxidized cohumulinone (5) and the other an oxidized humulinone (7) derivatives, together with a procyanidin dimer B (3), flavonoids rutin (4) and kaempferol-7-O-rutinoside (6). This plant known, due to anxiolytic property and beer flavoring, showed oxidized hop bitter acids, as principal constituents, in its hydroethanolic extract.