Table 1. Human [2-14C](−)-epicatechin metabolites present in urine.
| [2-14C](−)-Epicatechin metabolites | Urine collection periods |
|||||
|---|---|---|---|---|---|---|
| 0–4 h | 4–8 h | 8–12 h | 12–24 h | 24–48 h | 0–48 h | |
| (−)-Epicatechin-3′-O-glucuronide | 8.0 ± 1.4 | 5.7 ± 1.3 | 2.9 ± 0.8 | 2.0 ± 0.8 | – | 18.6 ± 2.5 |
| (−)-Epicatechin-3′-sulfate | 6.0 ± 0.7 | 1.2 ± 0.4 | 0.3 ± 0.1 | 0.2 ± 0.2 | – | 7.7 ± 0.9 |
| (−)-Epicatechin-5-sulfate | 1.3 ± 0.2 | – | – | – | – | 1.3 ± 0.2 |
| 3′-O-Methyl(−)-epicatechin-4′-sulfate | 0.7 ± 0.2 | – | – | – | – | 0.7 ± 0.2 |
| 3′-O-Methyl(−)-epicatechin-5-sulfate | 7.1 ± 0.9 | 1.8 ± 0.3 | 0.4 ± 0.1 | 0.3 ± 0.2 | – | 9.6 ± 1.2 |
| 3′-O-Methyl(−)-epicatechin-7-sulfate | 0.9 ± 0.2 | 0.3 ± 0.1 | – | – | – | 1.2 ± 0.3 |
| 4′-O-Methyl(−)-epicatechin-5-sulfate | 1.0 ± 0.2 | 0.1 ± 0.1 | – | – | – | 1.1 ± 0.3 |
| 4′-O-Methyl(−)-epicatechin-7-sulfate | 0.3 ± 0.1 | 0.1 ± 0.1 | – | – | – | 0.4 ± 0.2 |
| Sum of SREMs | 25.3 ± 3.1 | 9.2 ± 0.9 | 3.6 ± 0.8 | 2.5 ± 0.8 | – | 40.6 ± 4.5 (20 ± 2%) |
| 5-(Phenyl)-γ-valerolactone-sulfate-O-glucuronide-I | 0.1 ± 0.1 | 0.9 ± 0.8 | 0.2 ± 0.2 | 0.4 ± 0.3 | – | 1.6 ± 0.7 |
| 5-(4′-Hydroxyphenyl)-γ-valerolactone-3′-sulfate | 3.6 ± 1.1 | 16.0 ± 3.0 | 9.8 ± 2.0 | 8.1 ± 2.9 | 0.5 ± 0.5 | 38.0 ± 4.7 |
| 5-(Phenyl)-γ-valerolactone-3′-sulfate | 0.1 ± 0.1 | 2.4 ± 1.1 | 1.2 ± 0.9 | 1.0 ± 0.8 | – | 4.7 ± 2.7 |
| 5-(3′-Hydroxyphenyl)-γ-hydroxyvaleric acid-4′-sulfate; 5-(3′-Hydroxyphenyl)-γ-valerolactone-4′-O-glucuronide | 0.2 ± 0.2 | 7.7 ± 1.5 | 3.7 ± 1.2 | 2.3 ± 1.2 | – | 13.9 ± 2.2 |
| 5-(4′-Hydroxyphenyl)-γ-hydroxyvaleric acid-3′-sulfate; 5-(4′-Hydroxyphenyl)-γ-valerolactone-3′-O-glucuronide; 5-(Phenyl)-γ-valerolactone-sulfate-O-glucuronide-II | 0.9 ± 0.6 | 13.1 ± 4.5 | 6.6 ± 1.3 | 3.4 ± 1.3 | – | 24.0 ± 5.2 |
| 5-(3′-Hydroxyphenyl)-γ-hydroxyvaleric acid-4′-O-glucuronide | – | 1.3 ± 0.5 | 0.5 ± 0.3 | 0.5 ± 0.1 | – | 2.3 ± 0.7 |
| 5-(Phenyl)-4-hydroxyvaleric acid-3′-sulfate | – | 1.9 ± 1.0 | 0.3 ± 0.2 | 0.7 ± 0.7 | – | 2.9 ± 1.6 |
| Sum of 5C-RFMs | 4.9 ± 1.6 | 43.3 ± 8.3 | 22.3 ± 4.1 | 16.4 ± 5.4 | 0.5 ± 0.5 | 87.4 ± 9.6 (42 ± 5%) |
| Hydroxyphenylacetic acid-sulfate | – | 0.9 ± 0.5 | 0.8 ± 0.6 | 1.2 ± 0.4 | – | 2.9 ± 1.1 |
| 3-(3′-Hydroxyphenyl)hydracrylic acid | – | 0.7 ± 0.4 | 2.2 ± 0.5 | 5.3 ± 2.3 | 3.3 ± 1.7 | 11.5 ± 4.4 |
| Hippuric acid | 0.6 ± 0.4 | 7.2 ± 3.9 | 5.6 ± 2.6 | 7.1 ± 2.1 | 5.9 ± 4.1 | 26.4 ± 7.1 |
| 3′-Hydroxyhippuric acid | – | 1.6 ± 0.5 | 2.8 ± 0.7 | 7.0 ± 2.9 | 5.5 ± 2.3 | 16.9 ± 5.8 |
| Sum of 3/1C-RFMs | 0.6 ± 0.4 | 10.4 ± 4.1 | 11.4 ± 2.5 | 20.6 ± 4.1 | 14.7 ± 5.5 | 57.7 ± 6.9 (28 ± 3%) |
Data are expressed as mean ± SEM in μ mol (n = 8); bold, italicized figures in parentheses represent urinary recoveries of metabolites as a percentage of (—)-epicatechin intake; SREMs-structurally related (—)-epicatechin metabolites; 5C-RFMs-5 carbon side chain ring fission metabolites; 3/1C-RFMs-3 to 1 carbon side chain ring fission metabolites;-not detected.