How Is Quinine Made in Plants?
Quinine is a drug compound originally isolated from the bark of the cinchona tree and used for several centuries to treat malaria. While its origin is well known, the process by which it is synthesized in the plant is still poorly understood. Does this Spark an idea?
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Features
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Quinine belongs to a class of compounds collectively called plant alkaloids. When purified and used as a drug compound, it acts to kill the malaria parasite, plasmodium falciparum, by interfering with the process whereby the parasite rids itself of byproducts formed when it breaks down hemoglobin, a protein found in red blood cells.
Function
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According to the University of Southern Maine's page on plant alkaloids, the full pathway for quinine synthesis is complex and is not yet fully understood, although it's believed that quinine is synthesized from the amino acid tryptophan. Experiments involving radiolabeled geraniol and tryptophan (molecules "tagged" using radioactive isotopes so that their fate can be determined) showed that both tryptophan and geraniol are involved in quinine synthesis.
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Theories/Speculation
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According to a 2006 review in the journal of the Royal Society of Chemistry, it's currently believed that quinine is derived from strictosidine. Strictosidine is a compound formed from secologanin and tryptamine, a compound related to tryptophan. In this proposed scheme, the conversion from strictosidine to quinine takes place via a pathway that involves several intermediate compounds. Further research is necessary to confirm that this model is in fact the correct one.
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References
- Photo Credit mosquito image by Daniel Wiedemann from Fotolia.com
