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DRAFT Reorganization of E.T.Krebs page.

Ernst T. Krebs, Jr. (1911 – 1996) was an American biochemist.[1] He was best known for popularizing two naturally occurring chemical compounds: pangamic acid,[2] given the name vitamin B15 by Krebs, and amygdalin, given the name vitamin B17 by Krebs. He was the co-inventor of a patented, semi-synthetic chemical compound named Laetrile.


Krebs was born in Carson City, Nevada on May 17, 1911.[3] During part of his childhood he lived in a house that his father had built in 1914.[4] That house is in Carson City at 500 N. Mountain Street, 5 doors south of the Nevada Governor's Mansion. Parts of John Wayne's last movie, The Shootist, were filmed at the Krebs' house.[5][6]

Krebs "took his student work at Hahnemann Medical College in Philadelphia 1938-41. He received his AB at the University of Illinois in 1942; he did graduate work at the University of California during 1943-45, researching in pharmacology during the periods of 1942-45".[1] He died at his home in San Francisco, California on September 8, 1996 "due to natural causes; a postmortem revealed no evidence of cancer".[7] He was not related to Hans Adolf Krebs, the biochemist known for discovering the Krebs cycle.

Pangamic acid[edit]

Pangamic acid (CAS No. 20858-86-0)

The United States Patent Office issued a patent to Ernst T. Krebs and Ernst T. Krebs, Jr. on March 15, 1949. The patent was titled "Therapeutic Material and Method of Obtaining the Same". The patent reads, in part, "The present invention consists not only in the preparation itself but also in the method of extracting the chemical principle or association of compounds from seeds of the Prunus family and from other seeds and grains, and particularly rice and barley". The patented "therapeutic material" was to be used to treat "persons afflicted with asthma and allied diseases".[8] The inventors named their therapeutic material "pangamic acid".

Pangamic acid was first isolated by Ernst T. Krebs, Jr., from apricot kernels.[2] It has since been found in pulses[9] and "in whole grains such as brown rice, brewer’s yeast, pumpkin and sunflower seeds, and beef blood".[10]

Krebs gave the name vitamin B15 to pangamic acid; however, its status as a vitamin is in doubt.[10] "It has not yet been shown to be essential in the diet (vitamins must be supplied from external sources), and no symptoms or deficiency diseases are clearly revealed when consumption is restricted".[10]

Scientists in the former Soviet Union "had shown that pangamic acid supplementation can reduce the buildup of lactic acid in athletes and thereby lessen muscle fatigue and increase endurance".[10]

The United States Food and Drug Administration has made efforts to restrain the importation and interstate shipment of pangamic acid on the grounds that pangamic acid and pangamic acid products are unsafe for food and drug use.[11]


Amygdalin (CAS No. 29883-15-6)

Amygdalin was discovered in 1830 by the French chemists Pierre-Jean Robiquet and A. F. Boutron-Charlard.[12] In the presence of amygdalin hydrolase and prunasin hydrolase, amygdalin decomposes into glucose, benzaldehyde, and hydrogen cyanide.[13]

Amygdalin is a member of a group of compounds known as cyanogenic glycosides. This group includes amygdalin, linamarin, lotaustralin, dhurrin, prunasin, and others. Krebs used the term "nitriloside" to refer to those cyanogenic glycosides that have "dietary significance".[1] Amygdalin is the most widely available nitriloside. Amygdalin has been found in more than 800 species of plants and it is found in the tissues of animals that eat those plants.[1]

Amygdalin can be extracted from apricot seeds. Apricot seeds were used as a treatment for tumors "as early as A.D. 502".[14] In seventeenth-century England, apricot oil was used to treat tumors.[14] Amygdalin "was used as an anticancer agent in Russia as early as 1845".[15] In the 1920s, an American physician named Ernst T. Krebs[16] (the father of Ernst T. Krebs, Jr.) used amygdalin to treat cancer. He discontinued using amygdalin to treat cancer because he found that the treatment was too toxic.

Krebs Jr. used his skills as a biochemist to make pure amygdalin. His father, Krebs Sr., then used that pure amygdalin as a treatment for cancer. In regard to such treatment, Krebs Jr. wrote, "All of our successful therapeutic studies were conducted using only pure natural amygdalin. With no exceptions, all theory and successful practice in amygdalin therapy is based upon the clinical use of pure natural amygdalin".[17]

Krebs believed that the dietary consumption of nitrilosides, including amygdalin, is essential to human health. He also believed that cancer is caused by the insufficient consumption of nitrilosides. He regarded amygdalin as a vitamin and he named amygdalin "vitamin B-17". He advocated using amygdalin as a treatment for cancer and, in response to his critics, he stated:

"The opponents of vitamin B-17 in cancer therapy have rather myopically, (I believe), argued that there is no proof that selective hydrolysis of the nitriloside occurs in the neoplastic cell. They reject all existing clinical evidence, however impressive, for this effect. Thus it is an extraordinarily important finding that Doctor Dean Burk reports on his observation of the effect of the incubation of C3H mouse mammary cancer with vitamin B-17 in the Warburg manometer. He reports that the malignant mammary tissue selectively hydrolyzes the added nitriloside to free cyanide, benzaldehyde and sugar with a highly effective cytotoxicity; and that this does not occur in benign or somatic control mammary tissue! This experimental observation means, of course, that the neoplastic tissue carries a specific Beta-glucosidase activity that normal or somatic tissue lacks, which lack here is obvious in view of the total non-toxicity of the material toward normal tissue. This very crucial experiment will, of course, be repeated and checked and rechecked in many laboratories".[1]

In 2005 scientists in the Republic of Korea conducted experiments that involved applying amygdalin to cancer cells. They made and used amygdalin that had a purity exceeding 99%. They found that treating human prostate cancer cells with highly purified amygdalin induces programmed cell death. They concluded that "amygdalin may offer a valuable option for the treatment of prostate cancers".[18]

Other groups of scientists have also conducted experiments with pure amygdalin. They have found that pure amygdalin inhibits or kills cancer cells. See:

Linamarin, like amygdalin, can decompose in a way that releases hydrogen cyanide. In 2003 a group of scientists reported that they had used linamarin in an experiment that "demonstrated complete tumour cell killing".[19]


Laetrile (CAS No. 1332-94-1), invented by Ernst T. Krebs and Ernst T. Krebs, Jr.

The United States Patent Office issued patent number 2,985,664 to Ernst T. Krebs and Ernst T. Krebs, Jr., on May 23, 1961. The patent reads, in part, "this invention relates to certain cyanophoric derivatives of hexuronic acids which have a preservative effect on meat and other organic products".[20] That patent details the process of synthesizing such derivatives. The process includes the use of amygdalin, "preferably prepared from a natural source material such as kernels of the apricot, almonds and other members of the Prunus family and from kernels of other plants containing cyanogenetic gluosides".[20]

One of the hexuronic acid derivatives covered by the patent is named "l-mandelo nitrile-beta-glucuronic acid".[20] The Chemical Abstracts Service (CAS) has assigned the number 1332-94-1 to this chemical compound and it is marketed under the trade name Laetrile.[21] The name Laetrile is derived from the longer chemical name laevomandelonitrile (laevomandelonitrile becomes "Laetrile").

Laetrile has been used as a treatment for cancer.[22] In 1977 the U.S. Commissioner of Food and Drugs concluded that the interstate shipment of Laetrile constitutes a violation of the Federal Food, Drug, and Cosmetic Act.[23] In response, the state of Alaska and 20 other U.S. states adopted laws that legalized the use of Laetrile within those states.[24] And in contrast to those legalizations, the state of California adopted California Business and Professions Code Section 2258, which provides that "the use of laetrile or amygdalin with respect to cancer therapy, constitutes unprofessional conduct".

In 1981 the National Cancer Institute sponsored four clinical trials of Laetrile. A report about these clinical trials was published in the New England Journal of Medicine in January 1982. That report reads, in part, "One hundred seventy-eight patients with cancer were treated with amygdalin (Laetrile) plus a 'metabolic therapy' program consisting of diet, enzymes, and vitamins... No substantive benefit was observed in terms of cure, improvement, or stabilization of cancer, improvement of symptoms related to cancer, or extension of life span... Amygdalin (Laetrile) is a toxic drug that is not effective as a cancer treatment."[25] However, the validity of this clinical trial has been challenged. In a letter to the editor of the New England Journal of Medicine, Michael L. Culbert[26] asserted that these clinical trials did not use pure amygdalin but instead used a "degraded or decomposed form of it (the putative 'RS-epimer racemic mixture')".[27] James Cason, who served as a professor of Chemistry at the University of California at Berkeley from 1945 to 1983,[28] reviewed an infrared spectrum of the amygdalin (Laetrile) that was used in these clinical trials. He wrote, "The amygdalin (Laetrile) used for these tests actually could not have contained more than 15% amygdalin, since its infrared spectrum (supplied by the FDA) showed no detectable absorption at about 4.4 mu, the position of absorption by the nitrile group. Ergo, there is no evidence that the 'amygdalin' used for the tests contained any amygdalin. An authentic sample of amygdalin shows absorption at this wavelength, as it must".[29]

After the conclusion of the N.C.I.-sponsored clinical trials of Laetrile, Time Magazine published an article titled "Laetrile flunks", with the subtitle "Test shows cancer quackery".[30] The article quotes Robert Bradford of the Committee for Freedom of Choice in Cancer Therapy: "The whole thing, as far as we are concerned, is a put-up deal to discredit Laetrile." The article also quotes Charles Moertel of the Mayo Clinic: "We like to be optimistic about the good sense of the public ... But we are not going to stop some people from chasing rainbows".

To this day, Laetrile advocates defend the effectiveness of Laetrile as a treatment for cancer, while the proponents of orthodox medical practices assert that Laetrile is ineffective and toxic. Helene G. Brown,[31] a past-president of the California Division of the American Cancer Society, has succinctly stated the position of orthodox medicine: "Laetrile is goddamned quackery!"[32]


Further reading[edit]


  1. ^ a b c d e Krebs, ET, Jr. (1970). "The Nitrilosides (Vitamin B-17) – Their Nature, Occurence and Metabolic Significance (Antineoplastic Vitamin B-17)". Journal of Applied Nutrition. 22 (3 & 4). ISSN 0021-8960. 
  2. ^ a b Krebs ET Sr, Krebs ET Jr, Beard HH, Malin R, Harrid AT, Bartlett CL. (1951). "Pangamic acid sodium: a newly isolated crystalline water-soluble factor; a preliminary report.". International Record of Medicine and General Practice Clinics. 164 (1): 18–23. ISSN 0097-1650. PMID 14840945.  Unknown parameter |month= ignored (help)
  3. ^ Krebs, Ernst Theodore. Birth Date 05/17/1911.
  4. ^ Image of the house that Dr. Ernst T. Krebs had built in 1914.
  5. ^ Thompson, Peter. "History's home & garden show". Nevada Appeal, June 2, 2005.
  6. ^ Movie character J. B. Books, a.k.a. The Shootist, speaks about Dr. Krebs and his house in this MP3 audio file.
  7. ^ International Council for Health Freedom (1997). "Dr. Krebs dies, but his laetrile legacy lives on". I.C.H.F. Newsletter. ISSN 1093-1376.
  8. ^ United States Patent Office (March 15, 1949). "United States Patent No. 2,464,240".
  9. ^ Singh, Jagdev; Handa, Mrs. Geeta; Nandi, L. N.; Manavalan, R.; Atal, C. K. (1983). "D-Gluconodimethylaminoacetic acid from natural sources". Indian Drugs, 20(5), pp. 185–189.
  10. ^ a b c d Hass E and Levin B (2006). Staying Healthy With Nutrition: The Complete Guide to Diet and Nutritional Medicine. Berkeley, CA: Celestial Arts. ISBN 1587611791.
  11. ^ United States Food and Drug Administration (1976). "CPG Sec. 457.100 Pangamic Acid and Pangamic Acid Products Unsafe for Food and Drug Use".
  12. ^ Robiquet, PJ and Boutron-Charlard, AF (1830). "Extraccon de la Amygdalin" [Extraction of the Amygdalin]. Annales de chimie et de physique [Annals of Chemistry and of Physics] 44, p. 325.
  13. ^ Barceloux, Donald G. (2008). Medical Toxicology of Natural Substances: Foods, Fungi, Medicinal Herbs, Plants, and Venomous Animals. Hoboken, New Jersey; John Wiley & Sons. Page 762.
  14. ^ a b Lewis, WH and Elvin-Lewis, MPF (2003). Medical botany: plants affecting human health. Hoboken, New Jersey; John Wiley & Sons. Page 214. ISBN 0471628824.
  15. ^ National Cancer Institute. "Questions and Answers About Laetrile/Amygdalin". Retrieved 2010-08-25.
  16. ^ Dr. Ernst T. Krebs (September 26, 1876 – January 25, 1970).
  17. ^ Krebs, ET, Jr. (1979). "The extraction, identification and packaging of therapeutically effective amygdalin". In Salaman, M (1984). Nutrition: The Cancer Answer. Menlo Park: Statford Publishing. pp. 293-302. ISBN 0913087017.
  18. ^ Chang, Hyun-Kyung, et al. (2006). "Amygdalin induces apoptosis through regulation of Bax and Bcl-2 expressions in human DU145 and LNCaP prostate cancer cells". Biological & Pharmaceutical Bulletin 29(8), pp. 1597–1602. ISSN 0918-6158. doi:10.1248/bpb.29.1597. PMID 16880611.
  19. ^ Kousparou CA, Epenetos AA, Deonarain, MP (2002). "Antibody-guided enzyme therapy of cancer producing cyanide results in necrosis of targeted cells". International Journal of Cancer 99(1), pp. 138–148. ISSN 1097-0215. doi:10.1002/ijc.10266. PMID 11948505.
  20. ^ a b c United States Patent Office (May 23, 1961). "United States Patent No. 2,985,664". 
  21. ^ Suppliers of Laetrile.
  22. ^ Richardson, JA and Griffin, PI (2005). Laetrile Case Histories: The Richardson Cancer Clinic Experience, 5th edition. Westlake Village, California: American Media. ISBN 0912986387.
  23. ^ Kennedy, Donald (1977). "Laetrile: The Commissioner's Decision". Federal Register, Docket No. 77-22310.
  24. ^ Lerner, Irving J. (1981). "Laetrile: a lesson in cancer quackery". CA Cancer J Clin. 31 (2): 91–95. PMID 6781723. doi:10.3322/canjclin.31.2.91. 
  25. ^ Moertel, Charles G; et al. (28 January 1982). "A clinical trial of amygdalin (laetrile) in the treatment of human cancer." (abstract). N. Engl. J. Med. 306 (306): 201–206. PMID 7033783. 
  26. ^ Cohen, Marcus A. "Michael L. Culbert, ScD, fighter for Health Freedom". Townsend Letter for Doctors and Patients, January 2005. ISSN 1525-4283.
  27. ^ Culbert, Michael L. (1992). "Correspondence". New England Journal of Medicine (307)119.
  28. ^ Heathcock CH, Bartlett PA, Burke JD. In Memoriam: James Cason.
  29. ^ Cason, James (2000). Things Remembered. Danbury, Connecticut: Rutledge Books. Page 367. ISBN 1582440700.
  30. ^ Time Magazine. "Laetrile flunks". May 11, 1981.
  31. ^ Helene G. Brown.
  32. ^ Schultz T and Lindeman B (1973). "The Victimizing of Desperate Cancer Patients". Today's Health 51, pp. 28–33 and 59–61.