| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Rheum palmatum | Plant | -- | -- | Jeffery B. Harborne and H. Baxter, eds. 1983. Phytochemical Dictionary. A Handbook of Bioactive Compounds from Plants. Taylor & Frost, London. 791 pp. | |
| Rubia cordifolia | Root | -- | -- | * | |
| Morinda citrifolia | Plant | -- | -- | * | |
| Morinda citrifolia | Wood | -- | -- | * | |
| Cinchona pubescens | Tissue Culture | -- | -- | * | |
| Morinda citrifolia | Tissue Culture | -- | -- | * | |
| Morinda citrifolia | Bark | -- | -- | * |