| Plant | Low PPM | High PPM | StdDev | *Reference | |
|---|---|---|---|---|---|
| Nicotiana tabacum | Leaf | -- | -- | ANON. 1948-1976. The Wealth of India raw materials. Publications and Information Directorate, CSIR, New Delhi. 11 volumes. | |
| Capsicum frutescens | Plant | -- | -- | * | |
| Trigonella foenum-graecum | Seed | -- | -- | * | |
| Capsicum annuum | Plant | -- | -- | * | |
| Citrus sinensis | Pericarp | -- | -- | Jim Duke's personal files. | |
| Glycine max | Seed | -- | -- | * | |
| Eriobotrya japonica | Fruit | -- | -- | List, P.H. and Horhammer, L., Hager's Handbuch der Pharmazeutischen Praxis, Vols. 2-6, Springer-Verlag, Berlin, 1969-1979. |