Matcha and Sencha green tea extracts with regard to their phenolics pattern and antioxidant and antidiabetic activity during in vitro digestion

The purpose of this study was to compare the polyphenol, antioxidant and antidiabetic potential of powdered Matcha and bagged Sencha tea during in vitro digestion. Total phenols (TP), flavonoids (TF), flavanols (TFLA), antioxidant and antidiabetic (α-glucosidase inhibition) activity were higher in Matcha tea before and in most in vitro digestion phases. Upon gastric digestion, in Matcha tea TP, TF, TFLA were 2.6, 1.4 and 1.2 times significantly higher (p ≤ 0.05), respectively; gallic acid, gallocatechin, epigallocatechin, quercetin and kaempferol 1.5, 1.6, 1.8, 1.7, 1.2 times, respectively; whereas antioxidant activity was significantly (p ≤ 0.05) higher 3.2 and 1.1 times with ABTS and FRAP and α-glucosidase inhibition 1.8 times. After the intestinal phase, TP and TFLA were 3.4 and 1.7 times significantly (p ≤ 0.05) higher, respectively, antioxidant activity was significantly (p ≤ 0.05) higher 2.4 and 2.0 times with ABTS and FRAP, respectively, while inhibition of α-glucosidase was 1.7 time significantly (p ≤ 0.05) higher in Matcha tea, but the differences in TF, TP and identified phenolics (with the exception of gallic acid) between Matcha and Sencha tea were neutralized. Our results are the first to demonstrate that, during digestion of Matcha powder together with its water extract, Matcha polyphenols are more bioavailable and possess higher antioxidant and antidiabetic activity compared to Sencha.