Linamarin is a

cyanogenic In chemistry, cyanide () is an inorganic chemical compound that contains a functional group. This group, known as the cyano group, consists of a carbon atom triple-bonded to a nitrogen atom. Salt (chemistry), Ionic cyanides contain the cyanid ...

glucoside A glucoside is a glycoside that is chemically derived from glucose. Glucosides are common in plants, but rare in animals. Glucose is produced when a glucoside is hydrolysed by purely chemical means, or decomposed by fermentation or enzymes. Th ...

found in the leaves and roots of plants such as

cassava ''Manihot esculenta'', common name, commonly called cassava, manioc, or yuca (among numerous regional names), is a woody shrub of the spurge family, Euphorbiaceae, native to South America, from Brazil, Paraguay and parts of the Andes. Although ...

lima bean A lima bean (''Phaseolus lunatus''), also commonly known as butter bean, sieva bean, double bean or Madagascar bean, is a legume grown for its edible seeds or beans. Origin and uses ''Phaseolus lunatus'' is found in Meso- and South America. Tw ...

s, and

flax Flax, also known as common flax or linseed, is a flowering plant, ''Linum usitatissimum'', in the family Linaceae. It is cultivated as a food and fiber crop in regions of the world with temperate climates. In 2022, France produced 75% of t ...

. It is a

acetone cyanohydrin Acetone cyanohydrin (ACH) is an organic compound used in the production of methyl methacrylate, the monomer of the transparent plastic polymethyl methacrylate (PMMA), also known as acrylic. It liberates hydrogen cyanide easily, so it is used as a ...

. Upon exposure to

enzyme An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...

s and

gut flora Gut microbiota, gut microbiome, or gut flora are the microorganisms, including bacteria, archaea, fungi, and viruses, that live in the digestive tracts of animals. The gastrointestinal metagenome is the aggregate of all the genomes of the g ...

in the human

intestine The gastrointestinal tract (GI tract, digestive tract, alimentary canal) is the tract or passageway of the digestive system that leads from the mouth to the anus. The tract is the largest of the body's systems, after the cardiovascular system. T ...

, linamarin and its

methyl In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula (whereas normal methane has the formula ). In formulas, the group is often abbreviated as ...

ated relative lotaustralin can decompose to the toxic chemical

hydrogen cyanide Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...

; hence food uses of plants that contain significant quantities of linamarin require extensive preparation and detoxification. Ingested and absorbed linamarin is rapidly excreted in the urine and the glucoside itself does not appear to be acutely toxic. Consumption of cassava products with low levels of linamarin is widespread in the low-land tropics. Ingestion of food prepared from insufficiently processed cassava roots with high linamarin levels has been associated with dietary toxicity, particularly with the

upper motor neuron Upper motor neurons (UMNs) is a term introduced by William Gowers in 1886. They are found in the cerebral cortex and brainstem and carry information down to activate interneurons and lower motor neurons, which in turn directly signal muscles ...

disease known as

konzo Konzo is an epidemic paralytic disease occurring among hunger-stricken rural populations in Africa where a diet dominated by insufficiently processed cassava results in simultaneous malnutrition and high dietary cyanide intake. Konzo was first ...

to the African populations in which it was first described by Trolli and later through the research network initiated by

Hans Rosling Hans Rosling (; 27July 19487February 2017) was a Swedish physician, academic and public speaker. He was a professor of international health at Karolinska Institute and was the co-founder and chairman of the Gapminder Foundation, which developed t ...

. However, the toxicity is believed to be induced by ingestion of

, the breakdown product of linamarin.Banea-Mayambu JP, Tylleskar T, Gitebo N, Matadi N, Gebre-Medhin M, Rosling H. (1997). Geographical and seasonal association between linamarin and cyanide exposure from cassava and the upper motor neurone disease konzo in former Zaire. ''Trop Med Int Health'' 2(12):1143-51. Dietary exposure to linamarin has also been reported as a risk factor in developing

glucose intolerance Prediabetes is a component of metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus. It usually does not cause symptoms, but people with prediabetes often have obesity ( ...

and

diabetes Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of th ...

, although studies in experimental animals have been inconsistent in reproducing this effectSoto-Blanco B, Marioka PC, Gorniak SL. (2002). Effects of long-term low-dose cyanide administration to rats. ''Ecotoxicol Environ Saf'' 53(1):37-41. Soto-Blanco B, Sousa AB, Manzano H, Guerra JL, Gorniak SL. 2001. Does prolonged cyanide exposure have a diabetogenic effect?. Vet Hum Toxicol. 43(2):106-8. and may indicate that the primary effect is in aggravating existing conditions rather than inducing diabetes on its own.Yessoufou A, Ategbo JM, Girard A, Prost J, Dramane KL, Moutairou K, Hichami A, Khan NA. (2002). Cassava-enriched diet is not diabetogenic rather it aggravates diabetes in rats. ''Fundam Clin Pharmacol'' 20(6):579-86. The generation of cyanide from linamarin is usually enzymatic and occurs when linamarin is exposed to linamarase, an enzyme normally expressed in the

cell wall A cell wall is a structural layer that surrounds some Cell type, cell types, found immediately outside the cell membrane. It can be tough, flexible, and sometimes rigid. Primarily, it provides the cell with structural support, shape, protection, ...

s of cassava plants. Because the resulting cyanide derivatives are volatile, processing methods that induce such exposure are common traditional means of cassava preparation; foodstuffs are usually made from cassava after extended blanching,

boiling Boiling or ebullition is the rapid phase transition from liquid to gas or vapor, vapour; the reverse of boiling is condensation. Boiling occurs when a liquid is heated to its boiling point, so that the vapour pressure of the liquid is equal to ...

, or

fermentation Fermentation is a type of anaerobic metabolism which harnesses the redox potential of the reactants to make adenosine triphosphate (ATP) and organic end products. Organic molecules, such as glucose or other sugars, are catabolized and reduce ...

.Padmaja G. (1995). Cyanide detoxification in cassava for food and feed uses. ''Crit Rev Food Sci Nutr'' 35(4):299-339. Food products made from cassava plants include

garri In West Africa, ''garri'' (also known as ''gari'', ''galli'', or ''gali'') is the flour of the fresh starchy cassava root. In the Hausa language, ''garri'' can also refer to the flour of guinea corn, maize, rice, yam, plantain and mille ...

(toasted cassava

tuber Tubers are a type of enlarged structure that plants use as storage organs for nutrients, derived from stems or roots. Tubers help plants perennate (survive winter or dry months), provide energy and nutrients, and are a means of asexual reproduc ...

s), porridge-like

fufu Fufu (or fufuo, foofoo, foufou ) is a pounded meal found in West African cuisine. It is a Twi word that originates from the Akans in Ghana. The word has been expanded to include several variations of the pounded meal found in other African c ...

, the dough agbelima, and cassava

flour Flour is a powder made by Mill (grinding), grinding raw grains, List of root vegetables, roots, beans, Nut (fruit), nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredie ...

. Research efforts have developed a transgenic cassava plant that stably downregulates linamarin production via

RNA interference RNA interference (RNAi) is a biological process in which RNA molecules are involved in sequence-specific suppression of gene expression by double-stranded RNA, through translational or transcriptional repression. Historically, RNAi was known by ...

References

{{Glycosides Plant toxins Cyanogenic glycosides