| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Catharanthus roseus | Plant | -- | -- | Jeffery B. Harborne and H. Baxter, eds. 1983. Phytochemical Dictionary. A Handbook of Bioactive Compounds from Plants. Taylor & Frost, London. 791 pp. | |
| Cornus mas | Leaf | -- | -- | Bate-Smith, E. C., Ferguson, I. K., Hutson, K., Jensen, S. R., Nielsen, B. J., Swain, T. 1975. Phytochemical Interrelationships in the Cornaceae. Biochem. Syst. Ecol., 3: 79. | |
| Lonicera japonica | Flower | -- | -- | Leung, A. Y. and Foster, S. 1995. Encyclopedia of Common Natural Ingredients 2nd Ed. John Wiley & Sons, New York. 649 pp. | |
| Menyanthes trifoliata | Plant | -- | -- | Chemical Constituents of Oriental Herbs (3 diff. books) | |
| Strychnos nux-vomica | Fruit | -- | -- | * |