Table 2.
α-Amylase Inhibition by Tea and Grape Seed Extracts and Individual Catechins
| Extracts | IC50 (μg/mL) | IC90 (μg/mL) | Catechins | IC50 (μg/mL) | IC90 (μg/mL) | ||
|---|---|---|---|---|---|---|---|
| Acarbose (positive control) | (n=7) | 6.9 ± 0.8a | 42.8 ± 4.7e | C | (n=3) | 160 ± 67b,c,d | > 290* |
| Grape seed extract | (n=3) | 8.7 ± 0.8a,b | 28.1 ± 2.0e | EC | (n=3) | N.D. | N.D. |
| Green tea extract | (n=4) | 34.9 ± 0.9c | 192 ± 15f | EGC | (n=3) | N.D. | N.D. |
| Teavigo® | (n=4) | 44.2 ± 6.1c | 144 ± 19f | ECG | (n=2) | ~27 | ~50 |
| White tea extract | (n=4) | 378 ± 134d | > 500* | EGCG GCG |
(n=2) (n=2) |
~24 ~17 |
~36 ~144 |
Different letter superscripts denote significant differences in IC50 or IC90 values as determined by unpaired t-test (p < 0.05)
*
Exceeds maximum concentration tested
N.D. = value not determined
Values presented are mean ± standard error or approximate values if weak inhibition was observed