Amygdalin

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Chemical structure of Amygdalin
Chemical structure of Amygdalin

Amygdalin (from Greek: ἀμυγδάλη, almond), C20H27NO11, is a glycoside isolated from bitter almonds by H. E. Robiquet and A. F. Boutron-Charlard in 1830, and subsequently investigated by Liebig and Wöhler, and others. Some sources claim Ernst T. Krebs was the discoverer of the substance, and Krebs is generally credited with popularizing it as a purported cancer cure and as "Vitamin B17."

Contents

[edit] Chemistry

Amygdalin is extracted from almond cake by boiling ethanol; on evaporation of the solution and the addition of diethyl ether, amygdalin is precipitated as white minute crystals. Sulfuric acid decomposes it into d-glucose, benzaldehyde, and prussic acid (hydrogen cyanide); while hydrochloric acid gives mandelic acid, d-glucose, and ammonia.[1]

The decomposition induced by enzymes may occur in two ways. Maltase partially decomposes it, giving d-glucose and mandelic nitrile glucoside, C6H5CH(CN)O·C6H11O5; this compound is isomeric with sambunigrin, a glucoside found by E.E. Bourquelot and Danjou in the berries of the common elder, Sambucus nigra. 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. Closely related to these glucosides is dhurrin, C14H17O7N, isolated by W. Dunstan and T. A. Henry from the common sorghum or "great millet," Sorghum vulgare; this substance is decomposed by emulsin or hydrochloric acid into d-glucose, cyanide, and p-hydroxybenzaldehyde.[citation needed]

[edit] Nomenclature

Amygdalin is also called laevomandelonitrile, or laetrile for short. This is a typical pharmaceutical abbreviation from laevomandelonitrile. Some claim that laetrile is derived from a Latin word meaning "joyfulness" as laetari is the Latin verb meaning "to rejoice or exult".[citation needed]

The National Cancer Institute explains that "the names Laetrile, laetrile, and amygdalin are often used in place of one another, but they are not the same product. The chemical make-up of Laetrile patented in the United States is different from the laetrile/amygdalin produced in Mexico. The patented laetrile is a partly synthetic (man-made) form of amygdalin, while the laetrile/amygdalin made in Mexico comes from crushed apricot pits."[2]

Though it is sometimes sold as "Vitamin B17", it is not a vitamin, as no disease is associated with a dietary deficiency of laetrile.

[edit] Cancer cure

Amygdalin has been advocated by some as a "cure" or a "preventative" for cancer, but due to a lack of scientifically accepted evidence of its efficacy, it has not been approved for this use by the United States' Food and Drug Administration.[2]

The US government's National Institutes of Health reports that two clinical trials with laetrile have been published. One Phase I study found that amygdalin caused minimal side effects; the side effects that were seen were similar to the symptoms of cyanide poisoning. One Phase II study with 175 patients had some patients reporting improvements in symptoms, but all patients showed cancer progression 7 months after completing treatment, and it was determined no further tests were necessary.

While no double-blind clinical trials may have been conducted, a clinical trial was carried out in 1982 by the Mayo Clinic[3] and three other U.S. cancer centers under NCI sponsorship. Laetrile and "metabolic therapy" were administered as recommended by their promoters to 178 patients with advanced cancer for which there was no proven treatment. None were cured or stabilized or had any improvement of cancer-related symptoms. The median survival rate was about five months. In survivors after seven months, tumor size had increased. Several patients suffered from cyanide poisoning.

In 1974, the American Cancer Society officially labelled laetrile as "quackery," but advocates for laetrile claim a conspiracy with regard to this label.[4] Pro-laetrile groups assert that financial motivations have tainted the published research. These advocates reason that a cure as cheap and plentiful as apricot kernels would not be welcomed by the pharmaceutical industry. So, even today, many American and Canadian cancer patients travel to Mexico for treatment with the substance, under the auspices of Dr. Ernesto Contreras. One of these patients was actor Steve McQueen, who died while undergoing treatment in Mexico after developing mesothelioma. Steve McQueen did not develop mesothelioma from his actual treatment. Laetrile's foremost advocates within the United States can be found in all spectra of the political and science field from alternative newspapers like The Village Voice to individuals like the one-time chief chemist of the National Cancer Institute's cytochemistry laboratory,[5] Dean Burk Ph.D.[6], and G. Edward Griffin, author of "The Discovery of Noah’s Ark".

While some people believe that cancer is related to such a lack of "B17," and thus that it can be used as cancer treatment, it has not been firmly established as medical fact. The lack of information and the self-medication of patients with amygdalin causes severe problems in cancer treatment.[7]

A review of the clinical evidence was published in 2006 with the conclusion "Therefore, the claim that laetrile has beneficial effects for cancer patients is not supported by sound clinical data."[8]

[edit] Famous case in history

Jason Vale was the nation's leading spokesman for the legalization of laetrile. He was a national arm wrestling champion after he was cured of kidney, pancreatic and spleen cancer, purportedly by eating apricot seeds. However, in 2004 he was convicted[9] of fraud and sentenced to 63 months in prison for his methods of marketing laetrile, for defrauding the U.S. government by claiming that he qualified for Legal Aid, and for criminal contempt. Representatives of the Memorial Sloan-Kettering Cancer Center testified on the side of the prosecution during Vale's criminal trial.

[edit] Famous supporters of amygdalin

Dr Dean Burk, biochemist with a Ph.D. from Cornell Medical College,[6] became Head of National Cancer Institute (NCI) Cytochemistry Section in 1937 and headed this department for over three decades. Andrew McNaughton of the McNaughton Foundation requested a scientific experiment by Dr. Burk of the (NCI), the results were a famous comment which was used in a G. Edward Griffin documentary "A World Without Cancer"[10] that “When we add "laetrile" (amygdaline) to a cancer culture under the microscope,” “providing the enzyme glucosidase also is present, we can see the cancer cells dying off like flies.”[11] He also claimed in Congressional testimony that laetrile was less toxic than sugar.[12] Dr Dean Burk then went on to become a life long supporter of laetrile / amygdaline as a Cancer prevention and cure.

[edit] Amygdalin research

On 6 September, 2000 the British Association Festival of Science released a news story about how cyanide can be used to target cancer cells. Dr Mahendra Deonarain explained how Imperial College scientists "engineered the enzyme", which the cassava plant, almond tree, and hydrangea, have. This enzyme produces "cyanide when it comes into contact with a particular sugar molecule." Dr Deonarain went on to explain that this system would be "Tumour Specific."[13]

BBC News published another article on April 12, 1999 explaining the work of Professor Monica Hughes. She focused on the Cassava plant and Tapioca which is derived from it. "It is one of many plants which manufactures cyanide to deter animals who might want to eat it." and that "It does this by producing a chemical called linamarin which releases hydrogen cyanide when it is broken down by the linamarase enzyme."[14] Professor Hughes' research has been funded by the European Union, but her funding has now run out and she is looking for other sources. This is despite the fact that Spanish researchers claim/found that a brain tumour in a rat was totally eradicated after one week of the genetic treatment that Dr Monica is working on. They found that the system allowed the localised release of small doses of cyanide through the breakdown of linamarin by linamarase. " In 1977, Dr. Vern L. van Breeman of Salisbury State College, Maryland, reported that the addition of apricot kernels [rich in Laetrile] to standard food in pilot experiments with special strains of mice bred to develop breast cancer and leukemia showed impressive differences both in terms of developing the disease and increased survival times between the animals that [ate] the kernels and those that did not. When he reported his early findings... seven of the animals in the leukemia control group and five in the breast cancer [control] group had died, while none of the mice on the kernels had. Ultimately only one of the mammary cancer mice developed a slow-growing tumor, and, while the leukemia results were less impressive in terms of total symptoms, leukemia-prone mice that ate apricot kernels enjoyed life extensions up to 50% over what would normally be expected."[citation needed]

Veteran cancer researcher Kanematsu Sugiura (who had a 4-volume set of his collected scientific papers published in 1965) performed three sets of experiments between September 1972 and June 1973 "to determine the effects of amygdalin...upon mice with spontaneous mammary tumors."[citation needed] In an internal report to his colleagues at Sloan-Kettering Institute, he said that "The results clearly show that amygdalin significantly inhibits the appearance of lung metastases in mice bearing spontaneous mammary tumors and increases significantly the inhibition of the growth of the primary tumor over the appearance of inhibition in the untreated animals."[citation needed]

[edit] Government regulations

Laetrile is a compound that has been used as an anticancer treatment in humans worldwide. It is not approved by the US Food and Drug Administration (FDA) as a treatment for cancer or any other medical condition. The drug is made and used as a cancer treatment in Mexico.[15]

Since laetrile has not been approved as a treatment for cancer in the United States by the FDA,[15] doctors may not prescribe it specifically to cure cancer. However in certain US states the use of laetrile is authorized.[16] In Montana this "does not prevent a physician from prescribing laetrile as a dietary supplement to a patient not suffering from any known malignancy, disease, illness, or physical condition."[17], while in Indiana "a physician can prescribe or administer amygdalin (laetrile) instead of or in addition to customary or accepted modes of therapy in the treatment of a malignancy, a disease, an illness, or a physical condition of a patient" who has signed a written informed request.[18]

In the United States, the Food and Drug Administration continues to seek jail sentences for vendors selling laetrile for cancer treatment, calling it a "highly toxic product that has not shown any effect on treating cancer."[19]

Amygdalin is commonly manufactured in Mexico. But due to the controversial status of amygdalin, it may be banned or difficult to locate in some locations.

At the University of Nebraska and Auburn University in Alabama, eligible employees can be reimbursed for the cost of laetrile, if prescribed.[20][21]

[edit] References

This article incorporates text from the Encyclopædia Britannica Eleventh Edition, a publication now in the public domain.

  1. ^ J. W. Walker, V. K. Krieble (1909). "The hydrolysis of amygdalin by acids. Part I". Journal of the Chemical Society 95 (11): 1369 - 1377. DOI:10.1039/CT9099501369. 
  2. ^ a b What is laetrile?, National Cancer Institute, Retrieved on 14 January 2007
  3. ^ Moertel, C.G., (1982). "A clinical trial of amygdalin (laetrile) in the treatment of human cancer.". N. Engl. J. Med. (306): 201-206. 
  4. ^ A Cancer Drug Shows Promise, at a Price That Many Can't Pay, New York Times, 15 February 2006, Retrieved on 14 January 2007
  5. ^ Dean Burk, 84, Noted Chemist At National Cancer Institute, Dies, Washington Post, 9 October 1988
  6. ^ a b Dr Dean Burk, The Moss Reports
  7. ^ Schraub S. (2000). "Unproven methods in cancer: a worldwide problem". Supportive Care in Cancer 8: 10-15. DOI:10.1007/s005209900057. 
  8. ^ Milazzo, Stefania; Stephane Lejeune, Edzard Ernst (2006-11-15). "Laetrile for cancer: a systematic review of the clinical evidence". Supportive Care in Cancer. DOI:10.1007/s00520-006-0168-9. 
  9. ^ New York Man Sentenced to 63 Months for Selling Fake Cancer Cure, Medical News Today, 22 June 2004, Retrieved on 14 January 2007
  10. ^ Griffin, G. Edward. A World Without Cancer - The Story Of Vitamin B17 (Video).
  11. ^ Vitamin B17 “..cancer cells were dying like flies.”, Cancer Tutor - Alternative Cancer Treatments Information Center
  12. ^ Wilson, Benjamin, MD. The Rise and Fall of Laetrile. Quackwatch. Retrieved on February 12, 2007.
  13. ^ Cyanide targets cancer, BBC News, 6 September 2000, Retrieved 14 January 2007
  14. ^ Tapioca treatment for cancer, BBC News, 12 April 1999, Retrieved 14 January 2006
  15. ^ a b Is laetrile approved by the FDA for use as a cancer treatment in the United States?, National Cancer Institute, Retrieved on 14 January 2007
  16. ^ Mennenga, Jerry (1978-04-02). Laetrile: Legal but undefined and unavailable. Illinois Issues. Retrieved on January 14, 2007.
  17. ^ Montana Code: Laetrile not endorsed -- permitted as a dietary supplement, Montana State Government, Montata Code Annotated 2005, Retrieved on 14 January 2007
  18. ^ Prescription or administration permitted with written informed request, Indiana State Government, Information Maintained by the Office of Code Revision Indiana Legislative Services Agency, Chapter 23. Drugs: Use of Amygdalin (Laetrile), Retrieved on 14 January 2007
  19. ^ US FDA (June 22, 2004). Lengthy Jail Sentence for Vendor of Laetrile—A Quack Medication to Treat Cancer Patients. FDA News
  20. ^ Health Care Reimbursement Account (PDF). University of Nebraska. Retrieved on January 14, 2007.
  21. ^ Payroll and Employee Benefits, Auburn University, Retrieved on 14 January 2007

[edit] External links

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