COMPARATIVE ANALYSIS OF BIOACTIVE COMPONENT CONTENT IN TWO VARIETIES OF Humulus lupulus L.

Abstract

Humulus lupulus L. has gained strong scientific interest due to its rich phytochemical profile and diverse biological activities. Among its bioactive constituents, bitter acids have been extensively investigated for their antioxidant, anti-inflammatory, and neuroprotective effects, highlighting their potential therapeutic value in the prevention and management of various health conditions. This study aimed to perform a comparative analysis of the bioactive component content in two Humulus lupulus L. varieties, Herkules and Aurora, as their chemical composition represents a key determinant of the potential application not only in the brewery industry but also in herbal pharmaceutical products. The experimental analysis was conducted using an internally standardized spectrophotometric (UV/Vis spectrophotometer Cary 60 UV-Vis, Agilent Technologies, USA) and gravimetric method, routinely used as an analytical approach in the brewing industry. Diethyl ether extracts, consequently diluted in methanol, were assessed by measuring UV absorbance at wavelengths of 355 nm, 325 nm, and 275 nm. Absorbance at 355 nm predominantly reflects the presence of α-acids (humulones). Measurements at 325 nm are used to quantify oxidized bitter acid derivatives and related soft resin fractions, while absorbance at 275 nm enables the assessment of phenolic constituents and other resinous compounds that may interfere with the analysis. The combined use of these three wavelengths enables selective and more accurate spectrophotometric determination of α-acids in hop extracts. The content of total resins, soft resins, hard resins was determined gravimetrically. The results revealed differences among the analyzed samples, reflecting variability in their chemical composition, emphasizing differences in the content of bioactive components in the two examined varieties. One of the varieties exhibited a higher concentration of α-acids, suggesting a potentially greater biological activity. In conclusion, the obtained results highlight the importance of cultivar-dependent variations in Humulus lupulus and their implications for both phytotherapeutic and brewing applications. The present findings highlight the importance of improved characterization of the chemical profiles of hop varieties, which may support their targeted utilization and warrant further detailed research into their therapeutic potential and role in rational phytotherapy.