2.2. Determination of GTE constituents
2.2.1. Determination of total polyphenols
The total phenolic content of extract was estimated using the Folin–Ciocalteu colorimetric procedure [18]. Quantification was done on the basis of a standard curve with (+)-catechin (concentration span 1–10 μg/ml) and result was expressed as catechin equivalents (mg CE/g extract) per g of sample (average value of 5 probes ± standard error).