Tropane alkaloids
The tropane alkaloids are naturally occurring organic compounds from the group of alkaloids , which are chemically derived from tropane . Most of them are esters of different carboxylic acids with the tropanols .
Occurrence
About 140 different tropane alkaloids are known. They are mainly found in the nightshade family (Solanaceae), bindweed family (Convolvulaceae), redwood family (Erythroxylaceae), silver tree family (Proteaceae) and rhizophore family . Occasionally, they have also been found in milkweed plants (Euphorbiaceae) and cruciferous vegetables (Brassicaceae).
structure
The tropane alkaloids are often esters of 3α-tropanol (synonym: tropine) or, more rarely, 3β-tropanol (pseudotropin).
3α-tropanol, tropine
3β-tropanol, pseudotropin
The Solanaceae alkaloids atropine (also (±) -hyoscyamine, a mixture of stereoisomers ), L - (-) - hyoscyamine and scopolamine are derived from 3α-tropanol .
Atropine
Hyoscyamine
Scopolamine
The coca alkaloids cocaine and ecgonine found in the redwood plants , on the other hand, are C-2 functionalized and partly esterified derivatives of 3β-tropanol.
Cocaine
Ecgonine
Polyhydroxylated 3β-tropanol derivatives ( calystegins ) are also known; these show a pronounced inhibitory effect on glycosidase .
The non-esterified pyrrolidine alkaloids , such as hygrin and cuscohygrin, are often found as companions of the tropane alkaloids .
biosynthesis
The tropane alkaloids are biosynthetically formed from ornithine and arginine . About N -Methylputrescin arises N -Methylpyrrolin , which in turn either two acetate linked units over methylecgonine to cocaine leads or after decarboxylation on tropinone to the 3- Tropanolen .
Esterification of 3α-tropanol with tropic acid (which is derived from the amino acid phenylalanine ) leads to hyoscyamine.
The place of origin of the tropane alkaloids is the root of the plant; in the genera Atropa , Hyoscyamus and Datura , the compounds are transported and stored in the aboveground parts of the plant via the sap.
Extraction
The tropane alkaloids can be obtained from the plants by extraction with ethanol . The extract is evaporated , the residue is extracted with water and hydrochloric acid and the alkaloids present as salts are fractionally crystallized .
Ecgonine is extracted from coca leaves and can be converted into cocaine by esterification with methanol and subsequent acylation .
Tropane alkaloids can also be obtained from cell cultures using biotechnology . The hyoscyamine, accessible with the help of the cell culture of Hyoscyamus niger , can be converted into scopolamine. With the help of transgenic Atropa belladonna plants, the yield of scopolamine could be increased compared to natural plants.
use
Some tropane alkaloids are of pharmaceutical importance and are used as mydriatics and spasmolytics for the respiratory and gastrointestinal tract, as well as against asthma and as sedatives.
Tropane alkaloids in baby formula and other foods
Since tropane alkaloids occur in plants such as henbane , thorn apple , angel's trumpet or deadly nightshade, which can also grow in grain fields, the harvest can be correspondingly contaminated. For this reason, the organic supplier Alnatura has repeatedly had to recall baby foods. According to the Federal Institute for Risk Assessment (BfR), however, no cases of health damage from the consumption of contaminated products are known to date.
At the beginning of June 2018, popcorn of the Netto and Edeka own brands "America Style" (Netto), "Gut & Cheap" (Edeka, Marktkauf) and in mid-June 2018 "Mike Mitchell" (Penny) from the manufacturer XOX pastry GmbH had to pay due to an increased amount of tropane alkaloids are being recalled nationwide. In September 2018, the drugstore chain dm “Paleo Muesli” had to recall its own brand “dmBio” because tropane alkaloids were detected during its own controls.
literature
- Entry to tropane alkaloids. In: Römpp Online . Georg Thieme Verlag, accessed on August 4, 2014.
Individual evidence
- ↑ Recall Alnatura millet balls: traces of questionable plant substances found , test.de from April 1, 2015, accessed on September 24, 2015.
- ↑ Recall from Edeka and Netto: Do not eat it, otherwise you will no longer see properly , chip.de from June 1, 2018, accessed on June 1, 2018.
- ↑ Recall of "Mike Mitchell Sweet Popcorn 200 g". June 22, 2018, accessed July 5, 2018 .
- ↑ Recall: Tropane alkaloids - dm calls back "dmBio Paleo Muesli, 500 g" from September 20, 2018, accessed on September 24, 2018.