Linamarin

Linamarin is a cyanogenic glucoside found in the leaves and roots of plants such as cassava, lima beans, and flax. Upon exposure to enzymes 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 are inhibited by extensive preparation and detoxification requirements. Linamarin itself is not acutely toxic, although neurotoxic effects of long-term exposure have been suggested. Consumption of linamarin-containing cassava products is widespread in the developing world and has been associated with dietary toxicity, particularly with the upper motor neuron disease known as konzo to the African populations in which it was first described, through the work of Hans Rosling. Dietary exposure to linamarin has also been reported as a risk factor in developing glucose intolerance and diabetes, although studies in experimental animals have been inconsistent in reproducing this effect and may indicate that the primary effect is in aggravating existing conditions rather than inducing diabetes on its own.

The generation of cyanide from linamarin is usually enzymatic and occurs when linamarin is exposed to linamarase, 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, boiling, or fermentation. Food products made from cassava plants include garri (toasted cassava tubers), porridge-like fufu, the dough agbelima, and cassava flour.

Recent research efforts have developed a transgenic cassava plant that stably downregulates linamarin production via RNA interference.