Content of selected secondary metabolites in wild hop

Abstract

We focused on the determination of biologically active secondary metabolites in wild hops over the course of the vegetation period in four selected sites in Piešťany. Hop was collected in four collection periods in 2010. The objects of research were the leaves of male and female plants, and female cones. Analysis of the extracts from wild hop confirmed differences in total content of polyphenols, flavonoids between the localities and in the growing seasons over the vegetation period. The extracts from leaves from the first harvest in localities “gSládkovičova” and the river Vah showed higher levels of polyphenols (4.91–6.93 mg g−1 of dry mass), flavonoids (2.28–2.99 mg g−1 of dry mass) than the extracts from cones collected at the end of the vegetation period (polyphenols 3.63–5.33 mg g−1 of dry mass, flavonoids 1.86–2.16 mg g−1 of dry mass). The extracts from leaves from the first harvest from the “tennis court” site showed lower values of polyphenols and flavonoids. Our findings were that the leaves from the first harvest at the beginning of the growing season contained higher amounts of the secondary metabolites investigated than the cones at the end of the growing season. The content of α-bitter acids in wild hop cones ranged from 1.64 % to 2.91 %, in leaves from 0.11 % to 0.99%. Concentration of β-bitter acids in cones varied from 1.63 % to 1.93 % and in leaves from 0.02 % to 0.61 %.