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|Section2= |Section3= |Section8= }} Amygdalin (from Ancient Greek: ' "almond"), is a poisonous cyanogenic glycoside found in many plants, but most notably in the seeds (kernels) of apricot, peach, bitter almond, and plum. Since the early 1950s, both amygdalin and a modified form named laetrile have been promoted as alternative cancer treatments, often using the misnomer Vitamin B17 .〔 But studies have found them to be clinically ineffective in the treatment of cancer, as well as potentially toxic or lethal when taken by mouth, due to cyanide poisoning. Neither amygdalin nor laetrile are vitamins. The promotion of laetrile to treat cancer has been described in the medical literature as a canonical example of quackery, and as "the slickest, most sophisticated, and certainly the most remunerative cancer quack promotion in medical history."〔 == Chemistry == Amygdalin is a cyanogenic glycoside derived from the aromatic amino acid phenylalanine. Amygdalin and prunasin are very common among plants of the Rosaceae, particularly the Prunus genus, Poaceae (grasses), Fabaceae (legumes), and in other food plants, including linseed and manioc. Sambunigrin, obtained from leaves of the elder tree (Sambucus nigra), is isomeric to prunasin. Amygdalin is contained in fruit kernels, such as apricot (8%), peach (6%), bitter almond (5%), and plum (2.5%). The stones are taken out of the fruit and cracked to obtain the kernels, which are dried in the sun or in ovens. The kernels are boiled in ethanol; on evaporation of the solution and the addition of diethyl ether, amygdalin is precipitated as white minute crystals. Natural amygdalin has the R configuration at the chiral phenyl center. Under mild basic conditions, this stereogenic center isomerizes; the S enantiomer is called neoamygdalin. Amygdalin is hydrolyzed by intestinal β-glucosidase, emulsin, and amygdalase to gentiobiose and L-mandelonitrile. Gentiobiose is further hydrolyzed to glucose, whereas mandelonitrile is hydrolyzed to benzaldehyde and hydrogen cyanide. Hydrogen cyanide in sufficient quantities (allowable daily intake: ~0.6 mg) causes cyanide poisoning (fatal oral dose: 0.6-1.5 mg/kg). Apricot pits contain 89-2,170 mg/kg hydrogen cyanide (wet weight). In small quantities these glycosides do exhibit expectorant, sedative and digestive properties. Wild cherry bark (Prunus serotina) is an excellent cough remedy and tonic, as well as a flavouring agent used in cough syrups. It is of benefit as a tea for bronchitis. The main antitussive principle is prunasin.〔 In Chinese medicine, apricot seeds (杏仁, xìngrén) are used against cough and constipation (4.5-9 g). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「amygdalin」の詳細全文を読む スポンサード リンク
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