Date: March 2016
Tropane alkaloids (TA) are natural ingredients of certain plants, such as henbane, thorn apple and belladonna. To date, more than 200 different TAs have been identified in plants. Due to contamination of grains (as is known to be the case with buckwheat and millet) by seeds from henbane or thorn apples, tropane alkaloids can also appear in grain-based foodstuffs. Tropane alkaloids are used in medicine, for example in ophthalmology or treatment of cramps.
The most thoroughly researched tropane alkaloids are (-)-hyoscyamine and (-)-scopalamine. Atropine is the racemic compound of (-)-hyoscyamine and (+)-hyoscyamine, where only the (-)-hyoscyamine enantiomer has anticholinergic effects. According to the German Federal Institute for Risk Assessment, even in low doses, tropane alkaloids can affect heart rate and the central nervous system; dizziness, headaches and sickness are typical symptoms.
For its risk assessment, the European Food Safety Agency (EFSA) extrapolated an acute reference dose (ARfD) as a health-related guideline of 0.016 µg/kg body weight, based on the sum of (-)-hyoscyamine and (-)-scopolamine (ARfD group). The CONTAM panel came to the conclusion that, based on the limited available information on the exposure of infants via food, the group ARfD could be considerably exceeded.
For this reason, Directive (EC) 1881/2006 specifies a maximum content level for atropine and scopolamine. This is respectively 1.0 µg/kg for processed cereal-based foods and other solid food containing millet, sorghum, buckwheat or products derived from them.
The tropane alkaloids atropine (racemate of (-)-hyoscyamine and (+)-hyoscyamine) and scopolamine were determined using HPLC-MS/MS using isotype labelled internal standards. The procedure for extracting and purifying the extracts is based on the QuEChERS method that is internationally established in pesticide analytics. Using the analysis method established in the IKB, atropine and scopolamine can be quantified from a content of just 0.3 µg/kg.