Antioxidant Activity of Different Hop (Humulus lupulus L.) Genotypes

Zala Kolenc; Tamara Hribernik; Tomaž Langerholc; Maša Pintarič; Maja Prevolnik Povše; Urban Bren

doi:10.3390/plants12193436

Antioxidant Activity of Different Hop (Humulus lupulus L.) Genotypes

Plants (Basel). 2023 Sep 29;12(19):3436. doi: 10.3390/plants12193436.

Authors

Zala Kolenc^{1

2

3}, Tamara Hribernik⁴, Tomaž Langerholc³, Maša Pintarič³, Maja Prevolnik Povše⁵, Urban Bren^{1

2

6}

Affiliations

¹ Laboratory of Physical Chemistry and Chemical Thermodynamics, Faculty of Chemistry and Chemical Engineering, University of Maribor, Smetanova ulica 17, SI-2000 Maribor, Slovenia.
² Department of Applied Natural Sciences, Faculty of Mathematics, Natural Sciences and Information Technologies, University of Primorska, Glagoljaška ulica 8, SI-6000 Koper, Slovenia.
³ Department of Microbiology, Biochemistry, Molecular Biology and Biotechnology, Faculty of Agriculture and Life Sciences, University of Maribor, Pivola 10, SI-2311 Hoče, Slovenia.
⁴ Department of Lifestock Breeding and Nutrition, Faculty of Agriculture and Life Sciences, University of Maribor, Pivola 10, SI-2311 Hoče, Slovenia.
⁵ Department of Animal Science, Faculty of Agriculture and Life Sciences, University of Maribor, Pivola 10, SI-2311 Hoče, Slovenia.
⁶ Institute of Environmental Protection and Sensors, Beloruska ulica 7, SI-2000 Maribor, Slovenia.

Abstract

The antioxidant activity (AA) of hop extracts obtained from different hop genotypes (n = 14) was studied. For comparison, the purified β-acids-rich fraction and α-acids-with-β-acids-rich fraction were also used to test the antioxidative potential. The AA of purified hydroacetonic hop extracts was investigated using the Ferric Reducing Ability of Plasma (FRAP), Oxygen Radical Absorption Capacity (ORAC) and Intracellular Antioxidant (IA) methods. The FRAP values in different hop genotypes ranged between 63.5 and 101.6 μmol Trolox equivalent (TE)/g dry weight (DW), the ORAC values ranged between 1069 and 1910 μmol TE/g DW and IA potential values ranged between 52.7 and 118.0 mmol TE/g DW. Significant differences in AA between hop genotypes were observed with all three methods. AAs were determined using three different methods, which did not highly correlate with each other. We also did not find significant correlations between AA and different chemical components, which applies both to AA determined using individual methods as well as the total AA. Based on this fact, we assume that the synergistic or antagonistic effects between hop compounds have a more pronounced effect on AA than the presence and quantity of individual hop compounds.

Keywords: FRAP; ORAC; antioxidant activity; genotypes; hop; intracellular antioxidative potential.

Grants and funding

This work was supported by the Slovenian Research Agency program and project grants P2-0046, P2-0438, L2-3175, J1-4398, L2-4430, J3-4498, J7-4638, J1-4414, J3-4497, J4-4633, I0-E015 and J1-2471, as well as by the Slovenian Ministry of Science and Education project grants ELIXIR-SI and OP20.04331.