Q. What do you understand by Cyanogenic glycosides?
Cyanogenic glycosides are present in a number of food plants and seeds. Cassava is a staple dietary item in tropical Africa, South America and South East Asia. The plant is a rich source of cyanogenic glycosides, which may be hydrolysed chemically or enzymatically to yield the poisonous hydrogen cyanide. Signs and symptoms of acute cassava poisoning are headache, breathlessness, gasping, paralysis, muscle weakness, coma and death. Linamarin, a cyanogenic glycoside, can be removed fiom cassava by leaching out with water. Jn fact, cassava is consumed only after treatments like soaking, fermentation and drying which will minimise the amount of toxin in the root. It contain a high concentration of cyanide precursors. These inhibit the oxidative processes of cells causing them to die very quickly. Because the body rapidly detoxifies cyanide, an adult human can withstand 50-60 ppm for an hour without serious consequences. However, exposure to concentrations of 200-500 ppm for 30 minutes is usually fatal. Other foods rich in cyanide are apple seeds, bitter almonds and laetrile, the bogus cancer remedy produced fiom peach kernels. Consumption of these foods has resulted in cases of severe illness and even death.