Antioxidant activity and total phenolic content of Rheum palmatum roots

ANNA SOKÓŁ-ŁĘTOWSKA, ALICJA ZOFIA KUCHARSKA, ANITA BIESIADA

Abstract

The aim of our work was to investigate the antioxidant activity of Rheum palmatum extracts. Antiradical activity against DPPH and ABTS radicals, reducing power FRAP and total phenolic contents, were investigated in one-, two- and three-year-old roots of rhubarb fertilized with nitrogen at the rates of 50, 100 and 200 kg N/ha. It was proved that nitrogen dose as well as the age of plantation did significantly influence antioxidant activity and total phenolic of root extracts. The highest values were determined in one-year-old plants, antioxidant activity ranged the level of 112–203 μM Trolox/g and total phenolic compounds average content was 22 mg GAE/g FW. Two-year-old roots were characterized by 3–11%, and three-year-old ones by 15–23% lower antioxidant activity and phenolic compounds content. When nitrogen dose increased, polyphenols content, DPPH and FRAP values increased as well, although, ABTS showed a different tendency. Key words: Rheum palmatum, age of plant, phenolics, antioxidant activity
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