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Laetrile
Other common name(s): amygdalin, vitamin B17, Amigdalina B-17

Scientific/medical name(s): mandelonitrile beta-D-gentiobioside (the form found most often in Mexican clinics), mandelonitrile-beta-glucuronide (this is the patented drug Laetrile)

Description
Laetrile is a chemically modified form of amygdalin, a naturally-occurring substance found mainly in the kernels of apricots, peaches, and almonds. However, the terms amygdalin and Laetrile are often used interchangeably. The name Laetrile is also used to describe a closely related and partly man-made substance. Laetrile and amygdalin are promoted as alternative cancer treatments.

Overview
Available scientific evidence does not support claims that Laetrile or amygdalin is effective in treating cancer or any other disease. Both contain a small amount of a substance that can be converted to cyanide in the body, and several cases of cyanide poisoning have been linked to the use of Laetrile. The U.S. Food and Drug Administration (FDA) has not approved Laetrile as a medical treatment in the United States.

Izvor

Apple and crabapple seeds contain amygdalin, a cyanide and sugar compound that degrades into hydrogen cyanide (HCN) when metabolized. Cyanide itself is a poison that kills by denying blood the ability to carry oxygen and thereby causes its victims to die. It's not an urban legend that apple seeds contain cyanide.

The National Institute of Health says:
"The edible portions of dietary plant species commonly used in the United States contain relatively low levels of cyanogen glycosides, although some pits and seeds of common fruits, apple, apricot, peach, contain significantly higher concentrations."

Isto to na drugi nacin

What many people do not know is that peach pits contain a commonly known poison that is deadly when eaten. This poison in the pit is cyanide in the form of amygdalin. There is about eighty-eight milligrams of cyanide in the average peach pit. If the pit is accidentally swallowed, the hard shell covering it will keep the cyanide from being released suddenly. Also, if swallowed, the most the cyanide will cause is a bad stomachache. The usual fatal dose of cyanide for an adult is about as low as one and a half milligrams per every kilogram of body weight (one kilogram equals about 2.2046 pounds). Small doses, such as in the peach pit, consumed over time can eventually lead to a weak immune system, irreversible paralysis, and other symptoms.
Although not entirely lethal for an adult, the cyanide in a peach pit is lethal for children; therefore a child should never eat that has not had the pit cut out of it. Even though peach pits are solid and stone like, if they are bitten into or ground up for any reason, the poison will be released. So for children, peaches should always be served cut up with no pit. Because children have smaller bodies, it does not take as much poison to go through their systems and to harm them.

Fruits from the genus of prunus usually contain this poison prevalent in the peach pit. Other fruits that contain poisonous pits are: cherries, apricots, plums, almond, and, to a smaller degree, elderberries. The purpose of these poisonous pits is to repel herbivores from eating the trees' fruit before they are ready. This poison can also be found in the leaves of many plants from the prunus genus, such as the leaves of a chokecherry, which are known to contain the same poison.

These fruits are perfectly fine to eat, but the pits should be disregarded as food. Although almonds contain cyanide raw, they can be cooked to remove the poison, making them fit enough to eat. If someone has any of the prunus plants in the same area where animals are usually kept, then the poison in these pits and leaves can be deadly. Many animals, such as horses or goats, have a liking for the taste for some of the plants and can end up dying as a result of consuming them. Other than that, fruits and nuts from the prunus genus are a fine treat.

http://www.drgourmet.com/askdrgourmet/peachpits.shtml#.Unu30hywXBw

http://voices.yahoo.com/the-unknown-danger-peach-pits-poison-3799134.html

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Amygdalin (from Ancient Greek: ἀμυγδαλή amygdálē "almond"), C20H27NO11, is a glycoside initially isolated from the seeds of the tree Prunus dulcis, also known as bitter almonds, by Pierre-Jean Robiquet and Antoine Boutron-Charlard, in 1830[1] and subsequently investigated by Liebig and Wöhler in 1830. Several other related species in the genus of Prunus, including apricot (Prunus armeniaca) and black cherry (Prunus serotina),[2] also contain amygdalin.
Since the early 1950s, both amygdalin and a modified form named laetrile or Vitamin B17 have been promoted as cancer cures. However, neither of these compounds nor any other derivatives are vitamins in any sense,[3] and studies have found them to be clinically ineffective in the treatment of cancer, as well as dangerously toxic. They are potentially lethal when taken by mouth, because certain enzymes (in particular, glucosidases that occur in the gut and in various kinds of seeds, edible or inedible) act on them to produce cyanide.[4][5][6][7][8] The promotion of laetrile to treat cancer has been described in the medical literature as a canonical example of quackery,[9][10][11] and as "the slickest, most sophisticated, and certainly the most remunerative cancer quack promotion in medical history."[3]

mygdalin is extracted from almonds or apricot kernels by boiling in ethanol; on evaporation of the solution and the addition of diethyl ether, amygdalin is precipitated as white minute crystals. Liebig and Wöhler were already able to find three decomposition products of the newly discovered amygdalin: sugar, benzaldehyde, and prussic acid (hydrogen cyanide).[12] Later research showed that sulfuric acid decomposes it into D-glucose, benzaldehyde, and prussic acid; while hydrochloric acid gives mandelic acid, D-glucose, and ammonia.[13]
Several glucosidase enzymes are known to act on amygdalin, leading to its decomposition by various pathways. Maltase causes partial degradation, giving D-glucose and mandelic nitrile glucoside, C6H5CH(CN)O·C6H11O5. Emulsin, on the other hand, decomposes it into benzaldehyde, cyanide, and two molecules of glucose; this enzyme occurs in the bitter almond, and consequently the seeds invariably contain free cyanide and benzaldehyde. An "amorphous amygdalin" is said to occur in the cherry laurel (Prunus laurocerasus). Lastly, amygdalin beta-glucosidase and prunasin beta-glucosidase consecutively catalyze loss of the two glucose units to yield mandelonitrile, which can then decompose to form free cyanide and benzaldehyde. One gram of amygdalin would release 68 mg of hydrogen cyanide if fully decomposed along this route.
Natural amygdalin has the R configuration at the chiral benzyl center. Under mild basic conditions, this stereogenic center epimerizes; the S epimer is called neoamygdalin.[14]
Laetrile[edit]

Laetrile (CAS No. 1332-94-1)
Amygdalin is sometimes confused with laevomandelonitrile, also called laetrile for short; however, amygdalin and laetrile are different chemical compounds.[14] Laetrile, which was patented in the United States, is a semi-synthetic molecule sharing part of the amygdalin structure, while the "laetrile" made in Mexico is usually amygdalin, the natural product obtained from crushed apricot pits, or neoamygdalin.[15]
Laetrile has a melting point of 214 to 216 degrees Celsius.[16] Its Chemical Abstracts Service Registry Number is 1332-94-1 and its International Union of Pure and Applied Chemistry nomenclature name is (2S,3S,4S,5R,6R)-6-[(R)-cyano(phenyl)methoxy]-3,4,5-trihydroxyoxane-2-carboxylic acid. Laetrile's chemical formula is C14H15NO7 and its PubChem number is 5484354.[17] Its molecular weight is 309.2714 grams/mole.[17] Laetrile is also classified as a cyanogenic glycoside.[18]
Though it is sometimes sold as "Vitamin B17", it is not a vitamin. Amygdalin/laetrile was claimed to be a vitamin by chemist Ernst T. Krebs in the hope that if classified as a nutritional supplement it would escape the federal legislation regarding the marketing of drugs. He could also capitalise on the public fad for vitamins at that time.[3]
Toxicity[edit]

The metabolism of amygdalin produces hydrogen cyanide, a potent toxin. Beta-glucosidase, one of the enzymes that catalyzes the release of cyanide from amygdalin, is present in the human small intestine and in a variety of common foods. This leads to an unpredictable and potentially lethal toxicity when amygdalin or laetrile is taken orally.[3][19][20] Ingestion of purified amygdalin or apricot kernels can cause severe toxicity and death due to cyanide poisoning.[15] Numerous case reports in medical literature describe serious cyanide poisoning in patients who ingested laetrile as a cancer treatment.[9][21] Blood cyanide concentrations may be measured as a means of confirming the diagnosis in hospitalized patients or to assist in the forensic investigation of a fatal overdose.[22]
Some laetrile promoters have claimed that the cyanide generated by laetrile is immediately harmlessly detoxified by the mitochondrial enzyme rhodanese into thiocyanate. However, these claims are false. First, because thiocyanate is also toxic, although to a lesser degree. Second, the body only can use the small amount of rhodanese that is present in the blood, regardless of the stores present in kidneys and liver. Third, the limited factor in this conversion are the stores of cystine, cysteine, and other sulfur compounds, which are rapidly depleted in laetrile poisoning. Fourth, blood analysis shows undetoxified cyanide in persons poisoned with laetrile or with apricot kernels.[9]