Search Results (3)

This study examined the chemical composition and anti-coccal properties of essential oils and methanolic extracts of six different Humulus lupulus L. varieties from Poland: Iunga, Marynka, Sybilla, Magnum, Tradition and Chinook. The activity of an α-acid-enriched fraction of methanolic extracts was also studied. The chemical composition of essential oils and extracts was determined by gas chromatography–mass spectrometry (GC/MS) and liquid chromatography–mass spectrometry (LC/MS) techniques. The compounds characteristic to H. lupulus extracts include xanthohumol, α-acids, β-acids, and prenylated flavonoids. Essential oil compositions showed a high prevalence of monoterpene hydrocarbon, myrcene and sesquiterpene hydrocarbons, α-humulene and β-caryophyllene. The antimicrobial activity was investigated against eight human cocci pathogenic strains: Staphylococcus aureus MRSA (ATCC 43300), S. aureus MRSA (29213), S. aureus MSSA (ATCC 29213), S. epidermidis (ATCC 12228), Enterococcus faecalis (ATCC 29212), E. faecalis VRE (ATCC 51299), E. faecium (ATCC 19434) and Micrococcus luteus (ATCC 10240). The lowest minimum inhibitory concentrations (MIC) were obtained for extracts and essential oils from Iunga hop samples. Extracts were significantly more active than essential oils. The most susceptible strain to both essential oils and extracts was M. luteus, whilst the least susceptible was E. faecium. The antimicrobial activity correlated with a high concentration of xanthohumol of active extracts rather than with the content of α-acids. Xanthohumol showed considerable activity against MRSA with an MIC value of 3.9 µg/mL. The activity of the α-acid-enriched fraction was mediocre compared to the results of all extracts. Full article

Given the health-beneficial properties of compounds from hop, there is still a growing trend towards developing successful extraction methods with the highest yield and also receiving the products with high added value. The aim of this study was to develop efficient extraction method for isolation of bioactive compounds from the Polish “Marynka” hop variety. The modified two-step supercritical fluid extraction allowed to obtain two hop samples, namely crude extract (E1), composed of α-acids, β-acids, and terpene derivatives, as well as pure xanthohumol with higher yield than that of other available methods. The post-extraction residues (R1) were re-extracted in order to obtain extract E2 enriched in xanthohumol. Then, both samples were subjected to investigation of their antibacterial (anti-acne, anti-caries), cytotoxic, and anti-proliferative activities in vitro. It was demonstrated that extract (E1) possessed more beneficial biological properties than xanthohumol. It exhibited not only better antibacterial activity against Gram-positive bacteria strains (MIC, MBC) but also possessed a higher synergistic effect with commercial antibiotics when compared to xanthohumol. Moreover, cell culture experiments revealed that crude extract neither inhibited viability nor divisions of normal skin fibroblasts as strongly as xanthohumol. In turn, calculated selectivity indexes showed that the crude extract had from slightly to significantly better selective anti-proliferative activity towards cancer cells in comparison with xanthohumol. Full article

Two different extraction methods were used for a comparative study of essential oils obtained from the Humulus lupulus scCO₂ (sc-supercritical) extract: microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD). As a result, the best conditions for the maximum essential oil production were determined for the MAHD method at 335 W microwave power for 30 min at water to raw material ratio of 8:3. The obtained essential oils were enriched in β-myrcene in the amount of 74.13%–89.32% (wt%). Moreover, the first application for determination of the above-mentioned volatile compounds by supercritical fluid chromatography (SFC) with photo-diode array detection (PDA) is presented, which in comparison with gas chromatography coupled with mass spectrometry (GC-MS/MS) resulted in similar values for β-myrcene and α-humulene in obtained samples within less than 1 min. Full article