Table 1. Antiviral effects of the crude extracts of 11 teas on Chicken/Yamaguchi/7/04 (pre-treatment test).
| Tea extracts | Infectivity (Log10 TCID50/ml)a) | ||||||
|---|---|---|---|---|---|---|---|
| Treatment time after mixing the virus with the extract | |||||||
| 10 min | Immediately b) | ||||||
| Treated | Untreated | (Log10 reduction)c) | Treated | Untreated | (Log10 reduction) | ||
| Hibiscus | ≤1.5 | 6.1 | (≥4.6)d) | <1.5 | 6.2 | (≥4.7) | |
| Black | 3.0 | 5.5 | (2.5) | 3.2 | 5.5 | (2.3) | |
| Tencha | 4.7 | 6.0 | (1.3) | 5.0 | 6.0 | (1.0) | |
| Rosehip | 4.0 | 6.5 | (2.0) | 5.7 | 6.0 | (0.3) | |
| Burdock | NTe) | NT | 5.5 | 6.2 | (0.7) | ||
| Green | 4.0 | 6.0 | (2.0) | 6.0 | 6.3 | (0.3) | |
| Jasmine | 6.0 | 6.0 | (0.0) | 6.0 | 6.3 | (0.3) | |
| Ginger | 5.5 | 6.2 | (0.7) | NT | NT | ||
| Rose | 3.0 | 6.0 | (3.0) | 5.5 | 6.3 | (0.8) | |
| Lavender | 6.0 | 6.0 | (0.0) | 5.8 | 6.3 | (0.5) | |
| Oak | NT | NT | 5.7 | 6.2 | (0.5) | ||
a) The virus was mixed with the extract (treated) or medium (untreated) and inoculated into the MDCK cells. The virus titers were measured at 5 dpi. b) In effect, a period of 10 sec was required to start the first dilution of the mixture immediately after mixing. c) Log10 reduction in titers was calculated as follows: (extract-untreated virus titers)−(extract-treated virus titers). d) Bold figures of log reduction >2.0 indicate effective reduction; underlined, bold figures >3.0 indicate highly effective reduction. e) NT: not tested.