COMPARATIVE STUDY ON THE POLYPHENOL CONTENT AND ANTIOXIDANT ACTIVITY OF SOME MEDICINAL PLANTS

11 species of medicinal plants including 9 of Apiacea family, 2 of Umbelliferea family and 1 - of Liliacea family were examined for their total contents of polyphenols (TP) and phenol fractions FP, NFP and F-3-ols. The antioxidant activity was estimated by 3 assay methods applying 2 stable free radicals - DPPH center dot and ABTS(center dot+), and the ferric reducing reagent FRAP. It was established that the leaves of the Lemon thyme L. and Rosmarinus officinalis L. species have the highest levels of TP, 16.85 and 16.84 mg GAE/g dw, respectively. The species under study were characterised by high content of FP and NFP and lower content of F-3-ols, 146 and 111 mu g CE/g, respectively. The antioxidant potential corresponds with the TP content and depends on the herb type and the assay method. The values of IC50 of thyme and rozemary, determined with DPPH and ABTS, are the lowest thus indicating the presence of polyphenols with highest activity (1/IC50). The correlation coefficients (R-2) between TP and IC50 measured with DPPH and ABTS amount to 0.9101 and 0.9133, respectively. The results on polyphenols content and antioxidant activity of the separate herbs were discussed and compared with the data reported by other authors.