Comparative Study of Antioxidant Properties and Total Phenolic Content of the Extracts of <i>Humulus lupulus</i> L. and Quantification of Bioactive Components by LC–MS/MS and GC–MS

In this research, antioxidant activities of various extracts obtained from <i>Humulus lupulus</i> L. were compared by DPPH, ABTS, FRAP, and CUPRAC assays. The amount of total phenolic components determined by the Folin-Ciocalteu reagent was found to be highest for 25% aqueous ethanol (9079 ± 187.83 mg Ferulic acid equivalent/100 g extract) and methanol-1 (directly) (8343 ± 158.39 mg Ferulic acid equivalent/100 g extract) extracts. The <i>n</i>-hexane extract of <i>H. lupulus</i> exhibited the greatest with DPPH (14.95 ± 0.03 μg Trolox equivalent/g sample). The highest phenolic content in the ethanolic extract could be the major contributor to its highest CUPRAC activity (3.15 ± 0.44 mmol Trolox equivalent/g sample). Methanol-2 (<i>n</i>-hexane, acetone, and methanol) and methanol-3 (<i>n-</i>hexane, dichloromethane, ethylacetate, and methanol) extracts, respectively, exhibited the most potent ABTS (7.35 ± 0.03 mM Trolox equivalent) and FRAP (1.56 ± 0.35 mmol Fe²⁺/g sample) activities. Some of the components from the crude extracts were determined by LC–MS/MS and GC–MS analyses. Comparative screening of antioxidant activities of <i>H. lupulus</i> extracts and quantification of some major components by LC–MS/MS, qualitatively analysis of the reported ones which were optimal under negative ion SIM mode and coinjection, are going to be valuable for food and health applications.