Phytoestrogens are a group of plant polyphenols, which are structurally and functionally comparable to mammalian hormone estrogen. Due to their ability to bind to estrogen receptors, they have great potential for the treatment of many diseases, such as breast and prostate cancers, osteoporosis, atherosclerosis, and neurodegenerative and vascular diseases. At the same time, they alleviate menopausal symptoms and represent a suitable alternative to estrogen hormone therapy. As a result, the determination of their presence and quantity in various food products is becoming more widespread. This is also the purpose of our research, where we determined the content of phytoestrogens in different types of beer.
The concentrations of xanthohumol, isoxanthohumol and 8-prenylnaringenin, which are the main representatives of plant compounds with estrogenic activity in hops and beer, were determined by HPLC method. Various sample clean-up techniques were included in the analysis to help improve the results. In addition to numerous filtrations, the main technique was solid-phase extraction (SPE), with which the desired analytes were further isolated and concentrated. The latter was performed on a C8 reverse-phase SPE column, where the elution solvent was acetonitrile. The eluents were then analyzed on an HPLC-DAD instrument and the concentrations of the analytes were calculated from the chromatograms obtained using the standard addition method. Concentrations of xanthohumol ranged between 0.14 and 2.0 mg/L, isoxanthohumol between 0.47 and 0.98 mg/L, and 8-prenylnaringenin from 0 (or below the detection limit) up to 0.0411 mg/L.
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