Anticholinesterase Activity and Bioactive Compound Profiling of Six Hop (Humulus lupulus L.) Varieties

Hops (Humulus lupulus L.) are widely recognized for their use in brewing, but they also possess significant pharmacological properties due to their rich bioactive compounds, with many varieties exhibiting diverse characteristics. This study investigates the chemical composition and biological activities of extracts from six hop varieties, focusing on quantifying xanthohumol and lupulone using High-Performance Liquid Chromatography (HPLC) and Total Phenolic Content (TPC) analysis. The hop varieties demonstrated significant variability in bioactive compound concentrations, with Aurora showing the highest xanthohumol (0.665 mg/g) and Zwiegniowski the highest lupulone (9.228 mg/g). TPC analysis revealed Aurora also had the highest phenolic content (22.47 mg GAE/g). Antioxidant activities were evaluated using DPPH, ABTS, CUPRAC, and FRAP assays, with Aurora and Oregon Fuggle displaying the most potent capacities. Aurora, in particular, showed the highest activity across multiple assays, including significant acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and tyrosinase inhibition, with IC50 values of 24.39 mg/mL, 20.38 mg/mL, and 9.37 mg/mL, respectively. The chelating activity was also assessed, with Apolon demonstrating the strongest metal ion binding capacity (IC50 = 1.04 mg/mL). Additionally, Aurora exhibited the most effective hyaluronidase inhibition (IC50 = 10.27 mg/mL), highlighting its potential for anti-inflammatory applications. The results underscore the influence of genetic and environmental factors on the bioactive compound profiles of hop varieties and their biological activity offering promising avenues for pharmaceutical and nutraceutical applications. However, further studies are needed to fully understand the potential interactions between hop cones components.