2.5. Determination of total concentration of phenolic compounds in extracts
Samples of the dried extracts were dissolved in H2O at 0.4% (w/v). Aliquots (40 ml) of the extracts were placed in screw-capped test tubes, 500 ml of Folin-Ciocalteu phenol reagent (Merck, Darmstadt, Germany) added and thoroughly mixed. Immediately, 5 ml of 20% (w/v) Na2CO3 were added and mixed vigorously. The samples were then centrifuged at 1200 g for 15 min at 20C and absorbance read at 735 nm.