Bajer M., Kosakowska O., Pelc M., Bączek K.

The aim of the present study was to determine the content of phenolic acids and the antioxidant activity in leaves and roots of two species of willow herb (Epilobium sp.) and evening primrose (Oenothera sp.). The content of phenolic acids was determined by HPLC method, the antioxidant activity was measured by FRAP and DPPH method. The results show that extracts from the investigated plants differed in respect of the content of phenolic acids and the value of antioxidant activity. Extracts from willow herb were characterized by a higher antioxidant activity in comparison to evening primrose. The highest antioxidant activity was observed in leaves of Epilobium hirsutum, collected in the vegetative phase of the plants development. This extract also contained the highest amount of phenolic acids (ellagic and caffeic) which indicate strong antioxidant activity.

Key words: willow herb, evening primrose, flavonoids, phenolic acids, antioxidant activity