| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Hyssopus officinalis | Essential Oil | -- | -- | * | |
| Citrus aurantium | Pericarp | -- | -- | * | |
| Citrus aurantium | Plant | -- | -- | * | |
| Aframomum melegueta | Seed | -- | -- | Wealth of India. | |
| Elettaria cardamomum | Fruit Essent. Oil | -- | 377000.0 | * | |
| Citrus aurantium | Hull Husk | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. |