CATECHINS PROFILE, CAFFEINE CONTENT AND ANTIOXIDANT ACTIVITY OF CAMELLIA SINENSIS TEAS COMMERCIALIZED IN ROMANIA.Rev Med Chir Soc Med Nat Iasi. 2016 Apr-Jun; 120(2):457-63.RM
Catechins profile, caffeine content and antioxidant activity of different green tea and white tea samples commercialized on the Romanian market were investigated.
MATERIAL AND METHODS
Five green tea samples and five white tea samples commonly available on the Romanian market were processed by infusion and the lyophilisates of infusions were analyzed. Total phenolic content was determined using the Folin-Ciocalteu method. Catechins and caffeine profile was analyzed by RP-HPLC-DAD (Agilent Eclipse XDB-C18 column, binary mobile phase (A) 3% acetic acid and (B) methanol). In vitro antioxidant activity was assessed by free radical scavenging and ferrous ion chelating assays.
RESULTS AND DISCUSSIONS
Total phenolic content ranged between 44.73 +/- 0.63 and 63.57 +/- 0.45 GAE% in green tea samples and between 9.69 +/- 0.90 and 52.99 +/- 0.45 GAE% in white tea samples. RP-HPLC-DAD analysis allowed the identification of epigallocatechin gallate (45.18-118.58 mg/g lyophilisate) and caffeine (47.79-108.07 mg/g lyophilisate) in all tea samples; epicatechin was detected in all samples (5.04-31.04 mg/g lyophilisate) except for two white teas infusions. Green tea samples scavenged DPPH radical and chelated ferrous ion with EC50=9.68 +/- 0.02-16.11 +/- 0.02 microg/mL and 10.91 +/- 0.04-18.65 +/- 0.03 microg/mL, respectively. For white teas, EC50 values varied between 9.50 +/- 0.02-20.95 +/- 0.02 microg/mL in DPPH assay and 12.49 +/- 0.03-20.32 +/- 0.07 microg/mL in ferrous ion chelating assay.
This study showed a large variability in the content of catechins and caffeine and in the antioxidant capacity of both green and white tea samples.