| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Mahonia aquifolium | Root | -- | -- | Kostavolva, D., Brazdovicova, B., Tomko, J. 1981. Isolation of Quaternary Alkaloids from Mahonia aquifolium (Pursh) Nutt. I. Chem Zvesti, 35: 279-283. | |
| Nandina domestica | Plant | -- | -- | * | |
| Phellodendron amurense | Bark | -- | -- | * | |
| Phellodendron amurense | Bl | -- | -- | * | |
| Stephania glabra | Root | -- | -- | * | |
| Xanthorhiza simplicissima | Root | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. |