Table 5.
Green tea catechin metabolites in blister fluid presupplementation and postsupplementation, with or without UVR exposure.
| Compound | Amount/blister fluid collected |
|||
|---|---|---|---|---|
| Pre, No UVR | Pre, UVR | Post, No UVR | Post, UVR | |
| Conjugated form | Peak area ratio/μl | Peak area ratio/μl | Peak area ratio/μl | Peak area ratio/μl |
| EC-O-sulfate | ND | ND | 5±3 (10) | 9±5 (8) |
| EC-O-glucuronide | ND | ND | ND | 3±2 (3) |
| O-Me-EC-O-sulfate | ND | ND | 4±2 (8) | 5±3 (10) |
| EGC-O-glucuronide | ND | ND | 2±2 (2) | 3.3±0.2 (2) |
| O-Me-EGC-O-sulfate | ND | ND | 3±2 (6) | 2±2 (7) |
| O-Me-EGC-O-glucuronide | ND | ND | 1 (1) | 2 (1) |
| Gallic acid-O-glucuronide | 1±1 (2) | 12 (1) | ND | ND |
| O-Me-gallic acid-O-sulfate | 57±37 (11) | 90±73 (11) | 46±28 (11) | 55±38 (11) |
| M4-O-sulfate | ND | ND | 2±1 (4) | 5±3 (4) |
| M4-O-glucuronide | ND | ND | 0.7±0.4 (2) | 4 (1) |
| O-Me-M4-O-sulfate | ND | ND | 9±6 (6) | 14±8⁎ (7) |
| M6/M6′-O-sulfate | 7±4 (3) | 15±16 (2) | 46±47 (10) | 78±88 (9) |
| M6/M6′-O-glucuronide | ND | ND | 3±3 (4) | 6±5 (4) |
| Benzoic acid-O-sulfate | ND | ND | 2 (1) | 4±4 (3) |
| Syringic acid-O-sulfate | ND | 2 (1) | ND | ND |
| Syringic acid-O-glucuronide | ND | 2 (1) | ND | ND |
| 3-Hydroxybenzoic acid-O-sulfate | ND | ND | 8 (1) | 8±6 (3) |
| Free form | pmol/μl | pmol/μl | pmol/μl | pmol/μl |
| EGCG | 20 (1) | 14 (1) | 9 (1) | ND |
| Hippuric acid | 340±380 (11) | 670±800 (11) | 230±150 (11) | 350±330 (11) |
| Benzoic acid | 10,550 (1) | 30,570 (1) | ND | ND |
Data are the average peak area ratio relative to the internal standard (EG; 2 μg/ml) ×10−6 in total blister fluid extracted for the conjugated forms. Samples were analyzed pre and post 12 weeks supplementation and with or without UVR irradiation. Samples were analyzed in biological duplicate and technical duplicate; mean±SE. The data in brackets are the number of subjects in which the metabolite was identified. EC, epicatechin; EGC, epigallocatechin; EG, ethyl gallate; EGCG, epigallocatechin gallate; ND, not detected.
⁎
P<.05 compared to post no UVR (two-tailed Wilcoxon signed-rank test).