| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Coptis spp | Rhizome | -- | -- | * | |
| Hydrastis canadensis | Rhizome | 20000.0 | 30000.0 | * | |
| Hydrastis canadensis | Plant | -- | -- | * | |
| Xanthorhiza simplicissima | Plant | -- | -- | Jeffery B. Harborne and H. Baxter, eds. 1983. Phytochemical Dictionary. A Handbook of Bioactive Compounds from Plants. Taylor & Frost, London. 791 pp. |