Antioxidant potential of medicinal herbs from the northern Black Sea coastal zones

Abstract

Aqueous-alcoholic extracts of 32 plants used in Bulgarian phytotherapy for treatment of respiratory, gastrointestinal and other inflammatory disorders and widely distributed in the Northern Black Sea coastal zones were screened in-vitro for antioxidant activity and phenolic compounds content. The antioxidant potential presented as UAE (Uric acid equivalents) of the plant extracts was determined using the ABTS cation radical decolorization method. The content of total polyphenols was measured spectrophotometrically according to the Folin-Ciocalteu procedure and calculated as quercetin equivalents (QE). Four Bulgarian medicinal plants were established to have very high antioxidant properties: Fragaria vesca, Hypericum perforatum, Agrimonia eupatoria and Rubus sp. diversa) (UAE above 10mI); another 10 plants had intermediate antioxidant capacity - higher than 4mM; and other 5 - higher than 2mM. Interestingly, those plants comprised 58% of all studied plant species and the high antioxidant potential of these medicinal plants could be a major factor contributing to their healing properties. Polyphenol content varied from 39.52±15.17 µM to 2930.70±62.01 µM. A positive correlation (r =0.98) between antioxidant activity and polyphenol content was found, suggesting that the antioxidant capacity of the aqueous-alcoholic plant extracts is mainly due to their polyphenol content. Scripta Scientifica Medica 2009; 41(1): 7-10.