The paper aimed to determine and compare the antioxidant activity of two tinctures and selected flavonoids present in the tinctures. The tinctures were prepared from hawthorn fruits and motherwort herb. The group of selected flavonoids included rutin, quercetin, hyperosid, epicatechine, and procyanidin B2. Two methods were employed to determine antioxidant activities: the inhibition of peroxynitrite-induced nitration of tyrosine was measured, and the ability to quench radicals was examined by of the stable radical 2,2-diphenyl-1-picrylhydrazyl (DPPH). Both tinctures under study were able to quench radicals and reactive forms of oxygen and nitrogen. The motherwort herb tincture was more effective, but no direct effect of phenolic compounds on the extent of antioxidant activity was demonstrated. The total content of polyphenols in the motherwort herb tincture was higher by 163 %, nevertheless antiperoxynitrite activity was higher just by 19 % (p < 0.05), and the ability to reduce DPPH differed in both tinctures in a minimal manner. Of the individual flavonoids, the substances present in the tinctures in higher concentrations contributedmost to antioxidant activity. In the hawthorn fruit tincture it was epicatechine and hyperosid, whereas in the motherwort herb tincture it was rutin.

        Key words: Crataegi fructus – Leonuri herba – tinctures – flavonoids – antioxidant activity