Linamarin is a cyanogenic glucoside found in the leaves and roots of plants such as

cassava ''Manihot esculenta'', 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 cultivated ...

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. It is a glucoside of

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 s ...

. 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 ...

s and gut flora in the human intestine, linamarin and its methylated relative lotaustralin can decompose to the toxic chemical hydrogen cyanide; 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 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 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 ...

, 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. ...

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 walls 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, or fermentation.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 (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 growin ...

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, t ...

, the dough agbelima, and cassava flour. 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 ...

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

References

{{Glycosides Plant toxins Cyanogenic glycosides