Vitro-derived hop plantlets, var. Magnum, are a rich source of bioactive compounds

In recent years, the increasing demand for bioactive compounds extracted from plant matrices for use in the pharmaceutical, cosmetic or agri-food industries has stimulated research into the search for green sources from which these molecules can be extracted. Hops (Humulus lupulus L.) are the subject of numerous studies due to their richness in bioactive metabolites, such as terpenoids, phenolic compounds (e.g. xanthohumol), alkaloids and bitter acids (humulone and lupulone), with antioxidant, antimicrobial and antiviral properties, in all parts of the plant. In addition to the biomass of hop plants grown in open field, stakeholders can also make use of micropropagated plants, whose production is independent of the season. In this study, vitro-derived hop plantlets, var. Magnum, were evaluated as a potential source of bioactive compounds, testing two matrices (whole plant or leaves only), two extraction techniques (shaker or sonicator) and two solvents (ethanol/water or water only). Total phenolic content (TPC) and antioxidant activity (AO) (DPPH, ABTS and FRAP) were measured for each extract. All tests showed a higher concentration of biomolecules in the leaves, both in terms of TPC and AO, when shaker and alcoholic solvent were used. However, even though the TPC of the green extracts was lower, leaf extracts with water showed comparable values to those extracted with ethanol/water (respectively, 10.02 ± 0.63 mg GAE/g vs. 13.39 ± 0.47 mg GAE/g). Results obtained, although preliminary, have confirmed the richness in terms of polyphenols of vitro-derived hop plantlets, var. Magnum, and the potential of green extraction techniques. Further studies are needed to increase the extraction yield, finding alternative solvents suitable for green extraction.