Hop Flower Supercritical Carbon Dioxide Extracts Coupled with Carriers with Solubilizing Properties—Antioxidant Activity and Neuroprotective Potential

Lupuli flos shows many biological activities like antioxidant potential, extended by a targeted effect on selected enzymes, the expression of which is characteristic for neurodegenerative changes within the nervous system. Lupuli flos extracts (LFE) were prepared by supercritical carbon dioxide (scCO(2)) extraction with various pressure and temperature parameters. The antioxidant, chelating activity, and inhibition of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase by extracts were studied. The extracts containing ethanol were used as references. The most beneficial neuroprotective effects were shown by the extract obtained under 5000 PSI and 50 °C. The neuroprotective effect of active compounds is limited by poor solubility; therefore, carriers with solubilizing properties were used for scCO(2) extracts, combined with post-scCO(2) ethanol extract. Hydroxypropyl-β-cyclodextrin (HP-β-CD) in combination with magnesium aluminometasilicate (Neusilin US2) in the ratio 1:0.5 improved dissolution profiles to the greatest extent, while the apparent permeability coefficients of these compounds determined using the parallel artificial membrane permeability assay in the gastrointestinal (PAMPA GIT) model were increased the most by only HP-β-CD.