Table 3.
IC50 values for the inhibition of viral H1N1-NA and bacterial VCNA by tannin fractions.
| Tested Substance | Constituent Flavanyl Units | IC50 (Viral) µg/mL | IC50 (Bacterial) µg/mL |
|---|---|---|---|
| Positive control | |||
| oseltamivir acid | 2.9 ± 0.2 (1) | 41 ± 1 | |
| zanamivir | 3.7 ± 0.4 (1) | 17 ± 1 | |
| Tannin fractions | |||
| Diospyros kaki | galloylated flavan-3-ols | 20 ± 1 | 0.5 ± 0.04 |
| EPs® 7630 (2) | (epi)gallocatechin/(epi)catechin | 61 ± 2 | 1.7 ± 0.1 |
| Nelia meyeri | epicatechin | 29 ± 1 | 3.2 ± 0.1 |
| Salix ssp. | catechin | 32 ± 3 | 4.4 ± 0.2 |
| Potentilla erecta | epicatechin/catechin | - | 9.2 ± 1 |
| Betula spp. | epicatechin/catechin | - | 13 ± 1 |
| Rhus leptodictya | fisetinidol | - | 25 ± 1 |
IC50 values are expressed as mean ± SD (n = 3–6 independent experiments); (1) data are in ng/mL; (2) proportion of polyphenols ca. 40%. EPs® 7630 (root extract of Pelargonium sidoides).