Effect of harvest time on some in vitro functional properties of hop polyphenols

Abstract

Health benefits of hop polyphenols are well studied. In the present investigation, we examined the antioxidant activity, anti-nitric oxide (NO) production, and anti-adipocyte differentiation of polyphenols extracted from hops (HPP), harvested at different times for over 4years. Saaz hop variety from the Czech Republic was used in the in vitro assays. Twenty-three polyphenols were quantitatively analyzed using Orbitrap liquid chromatography-mass spectrometry (LC-MS), and their health promoting effects were assayed individually. Strong effects of low concentrations of HPP were observed in the above three assays. A significant increase in anti-adipocyte differentiation activity per unit weight of HPP was obtained in the early harvested samples. A significant difference in anti-NO production activity per unit weight of HPP was observed among the different harvest years. HPP significantly increased in early harvested samples. Our results suggest that some in vitro functional properties of hops vary with harvest time and year and are dependent on different polyphenols.

Keywords: (+)-Catechin (PubChem CID: 9064); 8-Prenylnaringenin (PubChem CID: 480764); Anti-NO production; Anti-adipocyte differentiation; Antioxidant; Chlorogenic acid (PubChem CID: 1794427); Gentistic acid (PubChem CID: 220285); Harvest time; Harvest year; Hop polyphenols; Isorhamnetine (PubChem CID: 5281654); Isoxanthohumol (PubChem CID: 513197); Kaempferol (PubChem CID: 5280863); Procyanidin B2 (PubChem CID: 122738); Quercetin (PubChem CID: 5280343); Saaz; Xanthohumol (PubChem CID: 639665).