| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Achillea millefolium | Plant | -- | -- | Pedersen, M. 1987. Nutritional Herbology. Pederson Publishing. Bountiful, Utah. 377 pp. | |
| Catha edulis | Plant | -- | -- | * | |
| Euonymus atropurpureus | Root | -- | 20900.0 | * | |
| Jatropha curcas | Seed | -- | -- | * | |
| Withania somnifera | Root | -- | -- | ANON. 1948-1976. The Wealth of India raw materials. Publications and Information Directorate, CSIR, New Delhi. 11 volumes. |