Analyses of metals impact on humulus lupulus strobili antioxidant capacity

Abstract

This paper presents results of analyses of metal ions effects on hop strobili antioxidant characteristics. Determination of total phenols (TP), total flavonoids (TF) and fifteen phenolic compounds, as well as the antioxidant activity (DPPH, ABTS and FRAP) of hop extracts from eight samples was conducted using UV/Vis spectrophotometry and HPLC method. Contents of 24 elements in mineralized hop samples were determined by ICP-OES. Very strong negative relationship between TP, TF, antioxidant capacity results and Pb, Co, Cr, Sb and Na was determined applying principal component and cluster analyses. Namely, the higher concentrations of these metals were associated with lower contents of TP and TF and lower values of antioxidant tests. Impact of metal ions on phenolic and flavonoids content and antioxidant activity of hop strobili has not been previously published.