Table 2.
Acute toxicity of usnic acid or Usnea lichen in Fischer 344 rats and B6C3F1 mice.
| Rdt - Usnic dcid | Rat - Usnea Lichen | Mouse - Usnic Acid | Mouse - Usnea Lichen | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| Target Dose as mg/kg usnic acid in feed |
Dead/Moribund | Liver pdthology | Dead/Moribund | Liver pathology | Dead/Moribund | Liver pathology | Dead/Moribund | Liver pathology | ||||||||
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| M | F | M | F | M | F | M | F | M | F | M | F | M | F | M | F | |
| 200 | 100% | 100% | 100% | 80% | — | — | — | — | 40% | 20% | 80% | 60% | 100% | 100% | — | — |
| 100 | 20% | 60% | 100% | 100% | 100% | 100% | 100% | 100% | 0% | 0% | 80% | 0% | 60% | 100% | 100% | 40% |
| 30 | 0% | 0% | 20% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 40% | 0% |
| 5 | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% |
| Control (0) | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% | 0% |
The animals were exposed to either pure (+)-usnic acid or equivalent concentrations of usnic acid (predominantly the (+) enantiomer) in Usnea lichen (U.scabrata and U. cavernosa) mixed in feed for 14 days. Liver lesions consisted of cell swelling or contraction, cytoplasmic vacuolization, clearing or clumping of organelles, increased cytoplasmic eosinophilia and are associated with factors leading to irreversible cellular degeneration and necrosis. Data taken from Ali et al. (66) and unpublished work.