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

Abstract

In this research, antioxidant activities of various extracts obtained from Humulus lupulus 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 n-hexane extract of H. lupulus 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 (n-hexane, acetone, and methanol) and methanol-3 (n-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 Fe(2+)/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 H. lupulus 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.

Antiproliferative activity ofHumulus lupulusextracts on human hepatoma (Hep3B), colon (HT-29) cancer cells and proteases, tyrosinase,β-lactamase enzyme inhibition studies

“…Methanol-2 extract shows antiproliferative effect at early time points, 24 h, while all doses of methanol-2 extract were increased the cell viability for 48 and 72 h. Methanol-3 extract did not show any statistically significant effect on the human hepatoma cancer, Hep3B cell line (Table 1, Figure 4). Lastly, 25% aqueous ethanol extract, which displayed a major antioxidant effect with the antioxidant capacity methods 21 , was indicated the proliferative effect at 48 h at low doses of this extract for Hep3B cell line.…”

“…Thirdly, plant material (100 g) was extracted with n-hexane, acetone (f) and methanol (g) (methanol-2) (1 L). Finally, plant material (100 g) was extracted with 25% aqueous ethanol (h) (1 L) according to the reported method 21 . Extracts were stored at +4 C in the refrigerator and detailed information were given in the previous study 21 .…”

“…The amount of total phenolic components determined by the Folin-Ciocalteu reagent was found to be highest in 25% aqueous ethanol (9079 ± 187 mg Ferulic acid equivalent/100 g extract) and methanol-1 (directly) (8343 ± 158 mg Ferulic acid equivalent/100 g extract) extracts 21 . Additionally, comparative screening of antioxidant activities of H. lupulus extracts and quantification of some major components by LCÀMS/MS, qualitatively analysis of the reported ones which were optimal under negative ion SIM mode and co-injection, are going to be valuable for food and health applications 21 . Consequently, phenolic compounds are likely to contribute to the radical scavenging activity of these plant extracts.…”

“…Phenolic acids are plant metabolites widely spread throughout the plant kingdom. Recently, interest on phenolic acids increases due to their protective role, through ingestion of fruits and vegetables, against oxidative damage diseases such as coronary heart disease, stroke and cancers 21 . Referring to our previous study, it was clearly shown that kaempherol 3-O-glucoside, quercetin, ascorbic acid, ferulic acid, gallic acid, ellagic acid, p-coumaric acid, epigallol and pyrogallol are the predominant phenolic compounds identified in the extracts.…”

“…From methanol-1 extract of H. lupulus, for example, ferulic acid, humulone, lupulone, cohumulone, colupulone, adhumulone, adlupulone, xanthohumol, 6-prenylnaringenin, 8-prenylnaringenin, isoxanthohumol, etc. were identified by LCÀMS 21 and co-injection methods were performed for several other compounds including kaempferol, epigallol, quercetin, naringenin and naringin. Due to the richness in various phenolic compounds, the hop plant (H. lupulus L.) is used for beermakings and contains a number of potentially bioactive prenylflavonoids.…”