Linamarin is a

cyanogenic Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms. In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of a ...

glucoside A glucoside is a glycoside that is 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. The name was o ...

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. Although a perennial plant, cassava is extensively ...

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

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. Textiles made from flax are known in ...

. 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 Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

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 gut mi ...

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 GI tract contains all the major organs of the digestive system, in humans ...

, 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 . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many ...

ated relative

lotaustralin Lotaustralin is a cyanogenic glucoside found in small amounts in Fabaceae austral trefoil (''Lotus australis''), cassava (''Manihot esculenta''), lima bean (''Phaseolus lunatus''), roseroot (''Rhodiola rosea'') and white clover (''Trifolium repen ...

can decompose to the toxic chemical

hydrogen cyanide Hydrogen cyanide, sometimes called prussic acid, is a chemical compound with the formula HCN and structure . It is a colorless, extremely poisonous, and flammable liquid that boils slightly above room temperature, at . HCN is produced on an ...

; 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 t ...

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 African or Africans may refer to: * Anything from or pertaining to the continent of Africa: ** People who are native to Africa, descendants of natives of Africa, or individuals who trace their ancestry to indigenous inhabitants of Africa *** Ethn ...

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

Hans Rosling Hans Rosling (; 27 July 1948 – 7 February 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 deve ...

. 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 the 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 obesi ...

and

diabetes Diabetes, also known as diabetes mellitus, is a group of metabolic disorders characterized by a high blood sugar level ( hyperglycemia) over a prolonged period of time. Symptoms often include frequent urination, increased thirst and increased ap ...

, although studies in

experimental animal Animal testing, also known as animal experimentation, animal research, and ''in vivo'' testing, is the use of non-human animals in experiments that seek to control the variables that affect the behavior or biological system under study. This ...

s 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 Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...

and occurs when linamarin is exposed to

linamarase Linamarase, or beta-D-glucosidase (), is an enzyme found in many plants including cassava and the Phaseolus lunatus, butter bean. In cassava it is found in the cell walls. When the plant is chewed or ground, it exposes the enzyme to compounds like ...

, an enzyme normally expressed in the

cell wall A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mech ...

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 Blanch or blanching may refer to: People * Andrea Blanch (born 1935), portrait, commercial, and fine art photographer * Arnold Blanch (1896–1968), born and raised in Mantorville, Minnesota * Stuart Blanch, Baron Blanch (1918–1994), Anglican bi ...

boiling Boiling is the rapid vaporization of a liquid, which occurs when a liquid is heated to its boiling point, the temperature at which the vapour pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmosphere. Th ...

, or

fermentation Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...

.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 millet. For ...

(toasted cassava

tuber Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growing ...

s), porridge-like

fufu Fufu (or fufuo, foofoo, foufou ) is a dough-like food found in West African cuisine. In addition to Ghana, it is also found in Sierra Leone, Guinea, Liberia, Cote D'Ivoire, Benin, Togo, Nigeria, Cameroon, the Democratic Republic of Congo, the ...

, the dough agbelima, and cassava

flour Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many culture ...

. 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 o ...

.Siritunga D, Sayre R (2003). "Generation of cyanogen-free transgenic cassava". Planta 217 (3): 367-73.

References

{{Glycosides Plant toxins Cyanogenic glycosides