Total phenolic and antioxidant capacity of the Potentilla argentea and Potentilla tommasiniana (Rosaceae) extracts

Potentilla argentea and Potentilla tommasiniana, (Rosaceae) are well known plants in the Balkan Peninsula [1]. Tested herbal material was rhizome with root and herb of P. argentea and P. tommasiniana collected in 2007at different locations around Sarajevo, Bosnia and Herzegovina. Total phenolic content was determined as described by Price & Butler using the Prussian blue assay [2]. Radical scavenging capacity of plant extracts (methanol/water 70%) against stable DPPH was determined spectrophotometrically according to the method described by Yen and Duh [3]. Subsequently, condensed tannins were extracted with ethyl acetate and antioxidant capacity of water/methanol extract was re-estimated in order to determine the antioxidant capacity attributed to compounds other than soluble condensed tannins. The phenolic content (% of gallic acid in dry herbal material) in this study was 13.11% and 6.20% for herbs P. tommasiniana and P. argentea respectively, and 8.38 and 7.00% for rhizome and root of P. tommasiniana and P. argentea respectively. Percentage inhibition of DPPH radical obtained with plant extracts was as follows: for herbal extract of P. tommasiniana, it was 76.77% and for P. argentea, 96.46%; for rhizome with root extracts for P. tommasiniana, it was 74.75% and for P. argentea, 94.44%. After removing of soluble condensed tannins by ethyl acetate, the results in water/methanol extract were for herbs of P. tommasiniana and P. argentea, 42.71% and 39.70% respectively, while in case of rhizome with root, they were 67.86% and 33.17% for P. tommasiniana and P argentea respectively. On the basis of antioxidant capacity found for extracts, it can be presumed that the main antioxidant capacity in herb was from condensed tannins (soluble in ethyl acetate) for P. argentea, while rhizome and root of P. tommasiniana have other antioxidants that significantly keep high antioxidant capacity.

References: 1. Josifović M. Editor (1977) Flora SR Srbije Dodatak IX; Srpska akademija nauka i umetnosti, Beograd.

2. Price M.L., Butler L.G. (1977) J. Agr. Food Chem. 25:1268–1273. 3. Yen, G. C., and Duh, P. D. (1994) J. Agr. Food Chem., 42: 629–632.