Distilled water, rectified ethyl alcohol 96% V/V, sodium carbonate (Carl Roth GmbH & Co, Karlsruhe, Germany), Folin-Ciocalteu reagent (Sigma Aldrich, St. Louis, USA), gallic acid monohydrate (Sigma Aldrich, St. Louis, USA), hydrochloric acid (Sigma Aldrich, Germany), DMAC (4-dimethylaminocinnamaldehyde) (Sigma Aldrich, Germany), epicatechin (Sigma Aldrich, Germany), ABTS (2,2'-Azino-di(3-ethyl-benzthiazoline sulphonic acid ( 6