Table 3.
EC50 values for pure individual polyphenolic compounds and metabolites assessed by AOP1 and NRF2 bioassays in different cell lines. EC50 values are expressed in micrograms of product per milliliter. Asymmetrical 95% CIs are indicated. R2 is the coefficient of determination obtained by non-linear regression model fit. ND stands for no dose–response effect and in this situation EC50 value could not be determined (no fit). There are no statistical differences among EC50 values marked with the same symbol. All other EC50 values are statistically different (p < 0.05). AOP1 in HepG2 was only assessed for quercetin (EC50: 6.47 µg/mL, 95% CI [6.13, 6.83] and epicatechin (EC50: 222.0 µg/mL, 95% CI [201.5, 244.6]. The catalase-like assay in HepG2 was only performed for quercetin (EC50: 57.88 µg/mL, 95% CI [ND, 80.06] and 3,4-DHPVL (EC50: 320.7 µg/mL, 95% CI [223.9, 430.7].
| Cell-Based Assay | AOP1 | NRF2/ARE | |||||||
|---|---|---|---|---|---|---|---|---|---|
| Cell Model | Caco-2 Cells | SH-SY5Y Cells | HepG2 Cells | ||||||
| EC50 | EC50 (µg/mL) | R2 | 95% CI | EC50 (µg/mL) | R2 | 95% CI | EC50 (µg/mL) | R2 | 95% CI |
| Epicatechin | 17.71 | 0.993 | (ND, 22.82) | ND | ND | ND | ND | ND | ND |
| Quercetin | 1.52 | 0.999 | (1.48, 1.56) | 1.38 | 0.998 | (1.21, 1.68) | 5.26 | 0.972 | (4.37, 6.33) |
| Chlorogenic acid | 257.5 | 0.970 | (143.5, 926.6) | ND | ND | ND | ND | ND | ND |
| Caffeic acid | 142.0 | 0.991 | (114.2, 189.8) | 173.3 | 0.991 | (142.4, 222.9) | 46.01 | 0.976 | (39.72, 52.74) |
| Transferulic acid | 189.1 | 0.993 | (146.6, 269.3) | 322.9 | 0.989 | (261.0, 422.2) | ND | ND | ND |
| Hippuric acid | ND | ND | ND | ND | ND | ND | ND | ND | ND |
| Vanillic acid | ND | ND | ND | ND | ND | ND | ND | ND | ND |
| Cyanidin-3-galactoside | 70.38 | 0.989 | (49.07, 155.9) | 190.0 | 0.980 | (138.7, 261.9) | ND | ND | ND |
| Cyanidin | 4.51 | 0.998 | (4.05, 5.02) | 33.02 | 0.997 | (29.86, 36.52) | ND | ND | ND |
| 3,4-DHPVL | 259.8 | 0.992 | (212, 340.9) | ND | ND | ND | 74.55 | 0.937 | (47.12, 177.4) |