| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Mentha pulegium | Essential Oil | -- | 6500.0 | * | |
| Agathosma betulina | Leaf | 450.0 | 900.0 | Williamson, E. M. and Evans, F. J., Potter's New Cyclopaedia of Botanical Drugs and Preparations, Revised Ed., Saffron Walden, the C. W. Daniel Co., Ltd., Essex UK, 362 pp, 1988, reprint 1989. | |
| Barosma betulina | Leaf | 450.0 | 900.0 | * | |
| Mentha pulegium | Plant | 65.0 | 154.0 | Duke, J. A. Writeups or information summaries on approximately 2,000 economic plants, USDA, ARS, Beltsville, MD 20705. | |
| Agathosma betulina | Leaf Essent. Oil | -- | -- | * |