Comparative Study on Phenolic Compounds and Antioxidant Activities of Hop (Humulus lupulus L.) Strobile Extracts

Abstract

In this study, we investigated the phenolic compounds in hop strobile extracts and evaluated their antioxidant property using DPPH and ABTS assay. The total phenolic compound (TPC) and total flavonoid compound (TFC) estimated in two different solvent extracts considerably varied depending on the extraction solvent. The most abundant phenolic compound in hop strobile was humulones (α-acid) with levels ranging from 50.44 to 193.25 µg/g. El Dorado accession revealed higher antioxidant activity in ethanol extracts (DPPH: IC50 124.3 µg/mL; ABTS: IC50 95.4 µg/mL) when compared with that of the other accessions. Correlations between DPPH (IC50) scavenging TFC in ethanol extract (TFC_E, −0.941), and TPC_E (−0.901), and between ABTS (IC50) scavenging TFC_E (−0.853), and TPC_E (−0.826), were statistically significant at p < 0.01 level, whereas no significant correlation was observed between antioxidant activities, TPC and TFC in water extract. This study is the first to report that variations in the level of phenolic contents and antioxidant activity of various hop cultivars depended on the type of extraction solvent used and the cultivation regions. These results could provide valuable information on developing hop products.

Comparative Assessment of the Antioxidant and Anticancer Activities of Plicosepalus acacia and Plicosepalus curviflorus: Metabolomic Profiling and In Silico Studies

“…Additionally, they formed promising interactions with the key amino acids Leu 83 and Lys 89 inside the CDK-2 protein, and Met 769 inside the EGFR active sites. It deserves mention that the docking results in the current study are in line with the reported antitumor activities of these phytoconstituents, especially for prostate cancer, and their cycle arrest and apoptotic effects are mediated through the deactivation of cyclins/CDKs and the activation of apoptotic proteins such as caspases, p53 and p21, the CDK inhibitor [ 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 , 91 , 92 ].…”

“…These findings could be linked to the differences in TPC between P. curviflorus and P. acacia extracts, as several studies have evidenced the strong association between the antioxidant activity estimated by DPPH assay and TPC and TFC levels, principally owing to the phenolic compounds’ redox properties [ 56 ]. Thus, they can donate an electron or hydrogen radical to a DPPH free radical, transforming it into a neutralized stable diamagnetic molecule [ 57 ].…”

Modelling and optimization of polyphenol and antioxidant extraction from Rumex hastatus by green glycerol-water solvent according to response surface methodology

“…Hence, they play a major role in the electron transfer ability, making an influential contribution to the activity ( Rahman et al., 2015 ; Amarowicz and Pegg, 2019 ). The oxygen-sensitive antioxidants and aqua-soluble antioxidants may deteriorate upon heating at high temperatures as determined in the relative investigation of antioxidant and polyphenolic potential of Hop Strobile extracts ( Lyu et al., 2022 ). Slight fluctuations could be observed since the ARA is solvent and species dependent, and TPC and TFC activities contribute to the total anti-radical activity determined ( Sukairi et al., 2021 ).…”

Relationship between Total Antioxidant Capacity, Cannabinoids and Terpenoids in Hops and Cannabis

“…Antioxidants are bioactive compounds that, even in small amounts, slow or stop oxidation processes influenced by reactive oxygen species (ROS) or ambient oxygen enzymes [ 6 , 7 ]. Various studies have reported that diverse naturally occurring antioxidants are found in medicinal plants at different concentrations and with varied physical and chemical properties [ 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. Although antioxidants are classified as either lipid-soluble (hydrophobic) and water-soluble (hydrophilic), plant-based antioxidants such as phenolic compounds and vitamin C are mostly hydrophilic [ 17 , 18 ].…”

“…Hops may be considered a natural antioxidant since the α-acids, β-acids, and xanthohumol present in this plant have significant hydroxyl radical scavenging and antioxidant activities [ 26 , 29 , 30 ]. A comparative study using three hop accessions (Calypso, Cascade, and Cluster) demonstrated the presence of high antioxidant activity with the DPPH assay, measuring 342.3, 211.8, and 196.8 µg mL −1 , respectively [ 16 ].…”