No abstract

In many contamination situations, various heavy metals act simultaneously and may interact; the present study examines the effects of cadmium (Cd) and zinc (Zn), two chemically similar elements, on trace-element accumulation under different environmental conditions. Chamomile (Matricaria recutita L.) was grown in pot experiments with increasing additions of Cd, Zn, or a combination of both metals to the substrate. The plants were tested on a sandy soil and a humus garden soil. The experiment was performed twice, in summer and in autumn. Because the Cd concentrations reached up to 19.3 mg kg −1 when the Cd supply in the soil was 3 mg kg −1 , chamomile can be characterized as a plant accumulating this heavy metal. More Cd was taken up from the sandy soil than from the humus garden soil, whereas the Zn contents were higher in the plants grown in summer on the garden soil. The addition of Zn to the soils led to a suppressed Cd accumulation into the above-ground plant parts. A further increase in the Zn supply, however, did not afford a further decrease in the Cd levels in the plants. On the other hand, the Cd supply did not influence the Zn accumulation. Thus an appropriate Zn supply to the plants can reduce, but cannot prevent totally, Cd accumulation in chamomile to meet the limits imposed for a pharmaceutical use of this plant. The copper (Cu) and manganese (Mn) contents were little influenced by the Cd and Zn additions to the soils.

The essential oil compounds of 274 individual plants belonging to 13 populations of Origanum vulgare L. (Lamiaceae) from Corsica were studied by GC/FID and GC/MS. On the basis of their monoterpene chemistry three different chemotypes were obvious in the Origanum populations: The first and most common type was a ‘cymyl’ type, with either carvacrol (0.6–65.5%) or thymol (0.0–49.5%) as the main compound. The second, which was very rare, was a ‘sabinyl’ type with sabinene (7.8–20.2%) and cis-sabinene hydrate (0.7–24.8%) as main compounds. The third type was a ‘mixed’ type combining compounds of the ‘cymyl’ and the ‘sabinyl’ pathway. The ‘mixed’ type was rich in cis-sabinene hydrate (0.0–52.4%) and γ-terpinene (0.6–35.4%).

Chamomile flower heads were extracted with boiling water and the elements calcium, potassium, magnesium, zinc and cadmium were recorded in the drug and the resulting infusions. The extractabilities for calcium, magnesium and potassium in the infusions were 19-23%, 47-48% and 65-73%, respectively. Cadmium could be recovered to 15-21% in the infusions and zinc to 23-34%. A longer extraction time gave slightly higher recovery rates for potassium and zinc. The extraction of less plant material gave a slight reduction in the extractability only in the case of cadmium. A single cup of chamomile infusion can only afford a small proportion of the daily requirement of the mineral elements.