Table 5. Change in the mean FRAP antioxidant capacity, phenolic and flavonoid concentration of two bottles each of nine herbal supplements*.
| Water Extractions | Methanol Extractions | |||||||
|---|---|---|---|---|---|---|---|---|
| Supplier | Supplement | Bottle | A(TE) | P (GAE) | F (CE) | A (TE) | P (GAE) | F (CE) |
| Spring Valley^ | Echinacea | 1 | - | |||||
| Spring Valley^ | Echinacea | 2 | - | - | - | |||
| Sundown Naturals | Echinacea | 1 | - | - | ||||
| Sundown Naturals | Echinacea | 2 | - | - | - | |||
| Nature’s Way | Echinacea Goldenseal | 1 | - | - | - | - | ||
| Nature’s Way | Echinacea Goldenseal | 2 | - | - | - | |||
| Spring Valley^ | Echinacea Goldenseal | 1 | - | - | - | |||
| Spring Valley^ | Echinacea Goldenseal | 2 | - | - | ||||
| Spring Valley | Turmeric | 1 | - | - | - | |||
| Spring Valley | Turmeric | 2 | - | - | - | - | ||
| Sundown Naturals | Turmeric | 1 | - | - | - | - | - | |
| Sundown Naturals | Turmeric | 2 | - | - | - | - | - | |
| Nature’s Way | Valerian | 1 | - | - | - | |||
| Nature’s Way | Valerian | 2 | - | - | - | |||
| Spring Valley^ | Valerian | 1 | - | - | ||||
| Spring Valley^ | Valerian | 2 | - | - | - | |||
| Sundown Naturals | Valerian | 1 | - | - | - | |||
| Sundown Naturals | Valerian | 2 | - | - | - | |||
* Assays were conducted on two bottles each 5 capsules per bottle two years after the initial supplement testing conducted January to February 2019. Data was analyzed with a one-tailed t-test with an α level of 0.05 and a test value of < -25% change.
^Supplements that had expired at the time of the retest.