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Life Sci. 2016 Feb 15;147:137-42. doi: 10.1016/j.lfs.2016.01.039. Epub 2016 Jan 29.
Amygdalin delays cell cycle progression and blocks growth of prostate cancer cells in vitro.
Despite impressive survival benefits from new agents to treat metastasized prostate cancer (PCa), progressive drug resistance hinders long-term response and restricts the efficacy of subsequent therapy. Due to reported antitumor activity of amygdalin and growing popularity for complementary and alternative medicine the potential of this natural, widely used substance to exert antineoplastic effects on prostate cancer cells has been assessed.
LNCaP (castration-sensitive), DU-145 and PC3 cells (castration-resistant) were exposed to different concentrations of amygdalin for 24h or 2weeks. Cell growth was measured by the MTT test, clonal formation by the clonogenic assay. Flow cytometry served to investigate apoptosis and cell cycle phases. Cell cycle regulating proteins and the mTOR-akt signaling axis were analyzed by western blotting.
Amygdalin dose-dependently diminished tumor cell growth with maximum effects at 10mg/ml. Apoptosis of PC3 and LNCaP but not of DU-145 cells was reduced, whereas colony formation was suppressed in all cell lines. A decrease in the number of G2/M- and S-phase cells along with an elevated number of G0/G1-phase cells was recorded. The cell cycle proteins cdk 1, cdk 2 and cdk 4 as well as cyclin A, cyclin B and cyclin D3 were modulated by amygdalin after both 24h and 2weeks. Distinct effects on p19 and p27 expression and on Akt, Rictor and Raptor activation became evident only after 2weeks.
Amygdalin exhibits significant antitumor activity in both castration-sensitive and castration-resistant PCa cell lines and merits further evaluation for therapeutic purposes.
Copyright © 2016 Elsevier Inc. All rights reserved.
Int J Mol Med. 2016 Feb;37(2):526-32. doi: 10.3892/ijmm.2015.2439. Epub 2015 Dec 21.
Amygdalin inhibits the growth of renal cell carcinoma cells in vitro.
Although amygdalin is used by many cancer patients as an antitumor agent, there is a lack of information on the efficacy and toxicity of this natural compound. In the present study, the inhibitory effect of amygdalin on the growth of renal cell carcinoma (RCC) cells was examined. Amygdalin (10 mg/ml) was applied to the RCC cell lines, Caki-1, KTC-26 and A498, for 24 h or 2 weeks. Untreated cells served as controls. Tumor cell growth and proliferation were determined using MTT and BrdU tests, and cell cycle phases were evaluated. Expression of the cell cycle activating proteins cdk1, cdk2, cdk4, cyclin A, cyclin B, cyclin D1 and D3 as well as of the cell cycle inhibiting proteins p19 and p27 was examined by western blot analysis. Surface expression of the differentiation markers E- and N-cadherin was also investigated. Functional blockade by siRNA was used to determine the impact of several proteins on tumor cell growth. Amygdalin treatment caused a significant reduction in RCC cell growth and proliferation. This effect was correlated with a reduced percentage of G2/M-phase RCC cells and an increased percentage of cells in the G0/1-phase (Caki-1 and A498) or cell cycle arrest in the S-phase (KTC-26). Furthermore, amygdalin induced a marked decrease in cell cycle activating proteins, in particular cdk1 and cyclin B. Functional blocking of cdk1 and cyclin B resulted in significantly diminished tumor cell growth in all three RCC cell lines. Aside from its inhibitory effects on growth, amygdalin also modulated the differentiation markers, E- and N-cadherin. Hence, exposing RCC cells to amygdalin inhibited cell cycle progression and tumor cell growth by impairing cdk1 and cyclin B expression. Moreover, we noted that amygdalin affected differentiation markers. Thus, we suggest that amygdalin exerted RCC antitumor effects in vitro.
PMID: 26709398 DOI: 10.3892/ijmm.2015.2439
[Indexed for MEDLINE]
PLoS One. 2014 Aug 19;9(8):e105590. doi: 10.1371/journal.pone.0105590. eCollection 2014.
Amygdalin blocks bladder cancer cell growth in vitro by diminishing cyclin A and cdk2.
Amygdalin, a natural compound, has been used by many cancer patients as an alternative approach to treat their illness. However, whether or not this substance truly exerts an anti-tumor effect has never been settled. An in vitro study was initiated to investigate the influence of amygdalin (1.25-10 mg/ml) on the growth of a panel of bladder cancer cell lines (UMUC-3, RT112 and TCCSUP). Tumor growth, proliferation, clonal growth and cell cycle progression were investigated. The cell cycle regulating proteins cdk1, cdk2, cdk4, cyclin A, cyclin B, cyclin D1, p19, p27 as well as the mammalian target of rapamycin (mTOR) related signals phosphoAkt, phosphoRaptor and phosphoRictor were examined. Amygdalin dose-dependently reduced growth and proliferation in all three bladder cancer cell lines, reflected in a significant delay in cell cycle progression and G0/G1 arrest. Molecular evaluation revealed diminished phosphoAkt, phosphoRictor and loss of Cdk and cyclin components. Since the most outstanding effects of amygdalin were observed on the cdk2-cyclin A axis, siRNA knock down studies were carried out, revealing a positive correlation between cdk2/cyclin A expression level and tumor growth. Amygdalin, therefore, may block tumor growth by down-modulating cdk2 and cyclin A. In vivo investigation must follow to assess amygdalin’s practical value as an anti-tumor drug.
Emerg Med Australas. 2015 Oct;27(5):491-2. doi: 10.1111/1742-6723.12462. Epub 2015 Aug 20.
Apricot kernels: a rare case of cyanide toxicity.
PMID: 26289124 DOI: 10.1111/1742-6723.
Can J Physiol Pharmacol. 1983 Nov;61(11):1426-30.
High-dose ascorbic acid decreases detoxification of cyanide derived from amygdalin (laetrile): studies in guinea pigs.
Cysteine, a sulphur-containing amino acid, is required to metabolize ascorbic acid (as ascorbate sulphate) and detoxify cyanide (to thiocyanate). In guinea pigs, conjoint use of laetrile (a cyanogenic glycoside) and ascorbic acid (in large doses) decreases the detoxification of cyanide derived from laetrile through diminishing the availability of cysteine, but not impairing hepatic rhodanese activity, which is involved in the detoxification of cyanide to thiocyanate. These results agree with the symptoms of a sublethal dose of KCN toxicity manifested by the animals. The studies, therefore, indicate that individuals taking megadoses of ascorbic acid concurrently with laetrile may be subject to self-poisoning.
Ann Pharmacother. 2005 Sep;39(9):1566-9. Epub 2005 Jul 12.
Life-threatening interaction between complementary medicines: cyanide toxicity following ingestion of amygdalin and vitamin C.
To describe a case of severe accidental cyanide poisoning following a single ingestion of amygdalin with therapeutic intent.
A 68-year-old patient with cancer presented to the emergency department shortly after her first dose (3 g) of amygdalin with a reduced Glasgow Coma Score, seizures, and severe lactic acidosis requiring intubation and ventilation. The patient also ingested 4800 mg of vitamin C per day. She responded rapidly to hydroxocobalamin treatment. The adverse drug reaction was rated probable on the Naranjo probability scale.
Amygdalin and laetrile (a synthetic form of amygdalin) are commonly used as complementary or alternative medicine (CAM) for the treatment of cancer. Vitamin C is known to increase the in vitro conversion of amygdalin to cyanide and reduce body stores of cysteine, which is used to detoxify cyanide. Amygdalin has been used for decades by patients with cancer who are seeking alternative therapies, and severe reactions have not been reported with this dose. An interaction with vitamin C is a plausible explanation for this life-threatening response.
This case highlights the fact that CAMs can produce life-threatening toxicity. This case also adds a further note of caution, namely, the potential for serious interactions between CAMs, particularly where there is no tradition of concomitant use.
PMID: 16014371 DOI: 10.1345/aph.1E634
[Indexed for MEDLINE]
Cochrane Database Syst Rev. 2015 Apr 28;(4):CD005476. doi: 10.1002/14651858.CD005476.pub4.
Laetrile treatment for cancer.
Laetrile is the name for a semi-synthetic compound which is chemically related to amygdalin, a cyanogenic glycoside from the kernels of apricots and various other species of the genus Prunus. Laetrile and amygdalin are promoted under various names for the treatment of cancer although there is no evidence for its efficacy. Due to possible cyanide poisoning, laetrile can be dangerous.
To assess the alleged anti-cancer effect and possible adverse effects of laetrile and amygdalin.
We searched the following databases: CENTRAL (2014, Issue 9); MEDLINE (1951-2014); EMBASE (1980-2014); AMED; Scirus; CINAHL (all from 1982-2015); CAMbase (from 1998-2015); the MetaRegister; the National Research Register; and our own files. We examined reference lists of included studies and review articles and we contacted experts in the field for knowledge of additional studies. We did not impose any restrictions of timer or language.
Randomized controlled trials (RCTs) and quasi-RCTs.
DATA COLLECTION AND ANALYSIS:
We searched eight databases and two registers for studies testing laetrile or amygdalin for the treatment of cancer. Two review authors screened and assessed articles for inclusion criteria.
We located over 200 references, 63 were evaluated in the original review, 6 in the 2011 and none in this update. However, we did not identify any studies that met our inclusion criteria.
The claims that laetrile or amygdalin have beneficial effects for cancer patients are not currently supported by sound clinical data. There is a considerable risk of serious adverse effects from cyanide poisoning after laetrile or amygdalin, especially after oral ingestion. The risk-benefit balance of laetrile or amygdalin as a treatment for cancer is therefore unambiguously negative.
- Laetrile treatment for cancer.[Cochrane Database Syst Rev. 2011]
PMID: 25918920 DOI: 10.1002/14651858.CD005476.pub4
[Indexed for MEDLINE]
Neth J Med. 2013 Nov;71(9):496-8.
Cyanide intoxication by apricot kernel ingestion as complimentary cancer therapy.
[Indexed for MEDLINE] Free
Wien Med Wochenschr. 2015 May;165(9-10):185-8. doi: 10.1007/s10354-014-0340-7. Epub 2015 Jan 22.
Severe cyanide poisoning from an alternative medicine treatment with amygdalin and apricot kernels in a 4-year-old child.
The use of complementary and alternative medicine (CAM) is widespread in children with cancer and is poorly regulated.
PATIENTS AND METHODS:
We describe a case of severe cyanide poisoning arising from CAM use. A severely agitated, encephalopathic, unresponsive 4-year-old boy (initial Glasgow Coma Scale of 3) with a history of metastatic ependymoma was brought to our emergency department by ambulance services. Initial blood gas analysis demonstrated severe metabolic/lactic acidosis. On detailed questioning of the parents, the use of CAM including intravenous and oral “vitamin B 17″ (amygdalin) and oral apricot kernel was reported. After administering sodium thiosulfate, rapid improvement in his medical condition with complete recovery without need for further intensive care treatment was seen. Serum cyanide level was markedly elevated.
Cyanide poisoning can be the cause of severe encephalopathy in children receiving CAM treatment with substances containing cyanogenic glycosides.
PMID: 25605411 DOI: 10.1007/s10354-014-0340-7
- Format: Abstract
N Engl J Med. 1982 Jan 28;306(4):201-6.
A clinical trial of amygdalin (Laetrile) in the treatment of human cancer.
One hundred seventy-eight patients with cancer were treated with amygdalin (Laetrile) plus a “metabolic therapy” program consisting of diet, enzymes, and vitamins. The great majority of these patients were in good general condition before treatment. None was totally disabled or in preterminal condition. One third had not received any previous chemotherapy. The pharmaceutical preparations of amygdalin, the dosage, and the schedule were representative of past and present Laetrile practice. 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. The hazards of amygdalin therapy were evidenced in several patients by symptoms of cyanide toxicity or by blood cyanide levels approaching the lethal range. Patients exposed to this agent should be instructed about the danger of cyanide poisoning, and their blood cyanide levels should be carefully monitored. Amygdalin (Laetrile) is a toxic drug that is not effective as a cancer treatment.
PMID: 7033783 DOI: 10.1056/NEJM198201283060403
[Indexed for MEDLINE]
Does use of alternative medicine in addition to conventional therapies predict prolonged survival from cancer? Even if the alternative therapies themselves were useless, one might predict users would live longer,because they tend to have more hope, a greater will to live; nearly three times as likely to believe their cancer was curable even if it wasn’t. But death rates were actually higherin alternative medicine users. Follow them up years later, and 79 percent of the alternative medicine users had died compared to 65 percent of nonusers. Now if the alternative medicine users started out sicker, that could certainly explain that, and they did tend to be, though the difference didn’t reach statistical significance.Bottom line: the association between the use of alternative medicine and shortened survival is not necessarily cause and effect, but it’s possible some of the alternative modalities may have indeed been harmful.
Thanks to the internet, there has been a resurgence of older complementary and alternative cancer treatments, such as laetrile, which is a compound derived from amygdalin, a natural cyanide-containing substance concentrated in apricot kernels, the seeds inside the pits. It was branded as a “vitamin” to skirt regulations—vitamin B-17—but it’s not a vitamin,and the lack of laetrile’s effectiveness against cancer and the risk of side effects from cyanide poisoning led to it being banned decades ago. However, no surprise, you can still buy it on the internet, along with the apricot kernels themselves. Why not just give them a try, though? Because of cyanide intoxication.
Here’s a typical case report. Woman ate some apricot seeds she got at a health food store. So, they’ve got to be healthy, right? Twenty minutes later, she was having trouble breathing, before she slipped into a coma. They made some calculations, and it appears an eight-ounce bag of apricot kernels is enough to kill six people if consumed in one sitting. “Therefore, the continuing sale of apricot kernels as health food is troubling.”
And you never know what you’re getting. Here, this person was consuming aquarter of a teaspoon of ground apricot kernels daily, and had just switched brands the day before she ended up in the ICU.Thankfully, she survived; others are not so lucky, like this 17-year-old who was dead within a day, as severe cyanide poisoning can result in coma, convulsions and cardiovascular collapse. That’s why calling it a vitamin is so insidious. A 32-year-old woman arrives at the emergency room in a coma. Was she on anything? No, she just took some vitamin supplements. Thankfully, a relative showed up with them. Oh, B-17. They gave her acyanide antidote and she survived. But had that relative not showed up, or been delayed in traffic or something, the case could have proved fatal.
So, “[c]ancer patients should be informed about the high risk of developing serious adverse effects due to cyanide poisoning after laetrile or amygdalin,” the natural compound in apricot seeds. Especially at risk may be thosetaking megadoses of vitamin C, or those not getting enough vitamin B12. See, the body has two major ways to detoxify cyanide. It can attach it to B12 to form the supplement form cyanocobalamin, which can be harmlessly peed out. Or, it can use the amino acid cysteine, which is also used to metabolize vitamin C, and so if you take too much vitamin C, levels can drop, and you can end up more vulnerable to cyanide toxicity.
But hey, conventional cancer treatments such as chemo can be toxic, too. It’s all about benefits versus risks. Yeah, amygdalin can block the growth of certain cancer cells in a petri dish, though doesn’t appear to have any anti-cancer effects against laboratory animal tumors. But you don’t know what happens in people…until you put it to the test and do a clinical trial of amygdalin in the treatment of human cancer, which we’ll cover next.
Please consider volunteering to help out on the site.
- Risberg T, Vickers A, Bremnes RM, Wist EA, Kaasa S, Cassileth BR. Does use of alternative medicine predict survival from cancer?. Eur J Cancer. 2003;39(3):372-7.
- Thomson D. Complementary, alternative, proven, unproven. Intern Med J. 2006;36(10):623-4.
- Beadle GF, Yates PM, Najman JM, et al. Beliefs and practices of patients with advanced cancer: implications for communication. Br J Cancer. 2004;91(2):254-7.
- Smith PJ, Clavarino AM, Long JE, Anstey CM, Steadman KJ. Complementary and alternative medicine use by patients receiving curative-intent chemotherapy. Asia Pac J Clin Oncol. 2016;12(3):265-74.
- Milazzo S, Horneber M. Laetrile treatment for cancer. Cochrane Database Syst Rev. 2015;(4):CD005476.
- Ginter E, Simko V. False claims about so called vitamin B 17. Bratisl Lek Listy. 2013;114(4):241.
- Lerner IJ. Laetrile: a lesson in cancer quackery. CA Cancer J Clin. 1981;31(2):91-5.
- O’brien B, Quigg C, Leong T. Severe cyanide toxicity from ‘vitamin supplements’. Eur J Emerg Med. 2005;12(5):257-8.
- Seghers L, Walenbergh-van veen M, Salome J, Hamberg P. Cyanide intoxication by apricot kernel ingestion as complimentary cancer therapy. Neth J Med. 2013;71(9):496-8.
- Sadoff L, Fuchs K, Hollander J. Rapid death associated with laetrile ingestion. JAMA. 1978;239(15):1532.
- Sauer H, Wollny C, Oster I, et al. Severe cyanide poisoning from an alternative medicine treatment with amygdalin and apricot kernels in a 4-year-old child. Wien Med Wochenschr. 2015;165(9-10):185-8.
- Moertel CG, Fleming TR, Rubin J, et al. A clinical trial of amygdalin (Laetrile) in the treatment of human cancer. N Engl J Med. 1982;306(4):201-6.
- Makarević J, Tsaur I, Juengel E, et al. Amygdalin delays cell cycle progression and blocks growth of prostate cancer cells in vitro. Life Sci. 2016;147:137-42.
- Chan TY. A probable case of amygdalin-induced peripheral neuropathy in a vegetarian with vitamin B12 deficiency. Ther Drug Monit. 2006;28(1):140-1.
- Suchard JR, Wallace KL, Gerkin RD. Acute cyanide toxicity caused by apricot kernel ingestion. Ann Emerg Med. 1998;32(6):742-4.
- Vlad IA, Armstrong J, Bertilone C, Matisons M. Apricot kernels: a rare case of cyanide toxicity. Emerg Med Australas. 2015;27(5):491-2.
- Basu TK. Possible toxicological aspects of megadoses of ascorbic acid. Chem Biol Interact. 1977;16(2):247-50.
- Bromley J, Hughes BG, Leong DC, Buckley NA. Life-threatening interaction between complementary medicines: cyanide toxicity following ingestion of amygdalin and vitamin C. Ann Pharmacother. 2005;39(9):1566-9.
NOT with vitamin C….
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|3D model (JSmol)|
|Melting point||223-226 °C(lit.)|
|Solubility in water||H2O: 0.1 g/mL hot, clear to very faintly turbid, colorless|
|Safety data sheet||A6005|
|GHS signal word||Warning|
|GHS hazard statements||H302|
|GHS precautionary statements||P264, P270, P301+312, P330, P501|
|Related compounds||Vicianin, laetrile, prunasin, sambunigrin|
|Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).|
|verify (what is ?)|
Amygdalin(from Ancient Greek: ἀμυγδαλή amygdálē“almond”) is a naturally occurring chemical compound, famous for falsely being promoted as a cancer cure. It is found in many plants, but most notably in the seeds (kernels) of apricot, bitter almonds, apple, peach, and plum.
Amygdalin is classified as a cyanogenic glycosidebecause each amygdalin molecule includes a nitrilegroup, which can be released as the toxic cyanideanion by the action of a beta-glucosidase: eating amygdalin will cause it to release cyanide in the human body, and may lead to cyanide poisoning.
Since the early 1950s, both amygdalin and a modified form named laetrilehave been promoted as alternative cancer treatments, often using the misnomervitamin 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.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 remunerativecancer quack promotion in medical history”.Neither amygdalin nor laetrile is a vitamin.
|1||Chemistry||2||Laetrile||2.1||History of laetrile||2.1.1||Early usage||2.1.2||Subsequent results||2.2||Advocacy and legality of laetrile||3||See also||4||References||5|
Amygdalin is a cyanogenic glycoside derived from the aromatic amino acid phenylalanine. Amygdalin and prunasinare common among plants of the family Rosaceae, particularly the genus Prunus, Poaceae(grasses), Fabaceae(legumes), and in other food plants, including flaxseedand manioc. Within these plants, amygdalin and the enzymes necessary to hydrolyze them are stored in separate locations so that they will mix in response to tissue damage. This provides a natural defense system.
Amygdalin is contained in stone fruitkernels, such as apricot(1.4%), peach(0.68%), bitter almond(5%),and plum(0.04–1.7%), and also in the seeds of the apple(0.3%).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 minute white crystals.Natural amygdalin has the (R)-configuration at the chiral phenyl center. Under mild basic conditions, this stereogenic center isomerizes; the (S)-epimer is called neoamygdalin. Although the synthesized version of amygdalin is the (R)-epimer, the stereogenic center attached to the nitrile and phenyl groups easily epimerizes if the manufacturer does not store the compound correctly.
Amygdalin is hydrolyzedby intestinal β-glucosidase(emulsin)and amygdalin beta-glucosidase(amygdalase) to give gentiobioseand L-mandelonitrile. Gentiobiose is further hydrolyzed to give glucose, whereas mandelonitrile (the cyanohydrinof benzaldehyde) decomposes to give 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).
|IUPAC name(2S,3S,4S,5R,6R)-6-[(R)-cyano(phenyl)methoxy]-3,4,5-trihydroxyoxane-2-carboxylic acid|
|Other namesL-mandelonitrile-β-D-glucuronide, Vitamin B17|
|3D model (JSmol)||Interactive image|
|Melting point||214 to 216 °C (417 to 421 °F; 487 to 489 K)|
|Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).|
Laetrile (patented 1961) is a simpler semisynthetic version of amygdalin. Laetrile is synthesized from amygdalin by hydrolysis. The usual preferred commercial source is from apricot kernels (Prunus armeniaca). The name is derived from the separate words “laevarotatory” and “mandelonitrile”. Laevarotatory describes the stereochemistry of the molecule, while mandelonitrile refers to the portion of the molecule from which cyanide is released by decomposition.A 500 mg laetrile tablet may contain between 5–51 mg of hydrogen cyanide per gram.
Like amygdalin, laetrile is hydrolyzed in the duodenum (alkaline) and in the intestine (enzymatically) to D-glucuronic acidand L-mandelonitrile; the latter hydrolyzes to benzaldehyde and hydrogen cyanide, that in sufficient quantities causes cyanide poisoning.
Claims for laetrile were based on three different hypotheses:The first hypothesis proposed that cancerous cells contained copious beta-glucosidases, which release HCN from laetrile via hydrolysis. Normal cells were reportedly unaffected, because they contained low concentrations of beta-glucosidases and high concentrations of rhodanese, which converts HCN to the less toxic thiocyanate. Later, however, it was shown that both cancerous and normal cells contain only trace amounts of beta-glucosidases and similar amounts of rhodanese.
The second proposed that, after ingestion, amygdalin was hydrolyzed to mandelonitrile, transported intact to the liver and converted to a beta-glucuronide complex, which was then carried to the cancerous cells, hydrolyzed by beta-glucuronidases to release mandelonitrile and then HCN. Mandelonitrile, however, dissociates to benzaldehyde and hydrogen cyanide, and cannot be stabilized by glycolsylation.:9
Finally, the third asserted that laetrile is the discovered vitamin B-17, and further suggests that cancer is a result of “B-17 deficiency”. It postulated that regular dietary administration of this form of laetrile would, therefore, actually prevent all incidence of cancer. There is no evidence supporting this conjecture in the form of a physiologic process, nutritional requirement, or identification of any deficiency syndrome.The term “vitamin B-17″ is not recognized by Committee on Nomenclature of the American Institute of Nutrition Vitamins.Ernst T. Krebsbranded laetrile as a vitamin in order to have it classified as a nutritional supplementrather than as a pharmaceutical.
History of laetrile
Amygdalin was first isolated in 1830 from bitter almondseeds (Prunus dulcis) by Pierre-Jean Robiquetand Antoine Boutron-Charlard.Liebigand Wöhlerfound three hydrolysisproducts of amygdalin: sugar, benzaldehyde, and prussic acid(hydrogen cyanide, HCN).Later research showed that sulfuric acidhydrolyzes it into D-glucose, benzaldehyde, and prussic acid; while hydrochloric acidgives mandelic acid, D-glucose, and ammonia.
In 1845 amygdalin was used as a cancer treatment in Russia, and in the 1920s in the United States, but it was considered too poisonous.In the 1950s, a purportedly non-toxic, synthetic form was patented for use as a meat preservative,and later marketed as laetrile for cancer treatment.
The U.S. Food and Drug Administrationprohibited the interstate shipment of amygdalin and laetrile in 1977.Thereafter, 27 U.S. states legalized the use of amygdalin within those states.
In a 1977 controlled, blinded trial, laetrile showed no more activity than placebo.
Subsequently, laetrile was tested on 14 tumor systems without evidence of effectiveness. The Memorial Sloan–Kettering Cancer Center(MSKCC) concluded that “laetrile showed no beneficial effects.”Mistakes in an earlier MSKCC press release were highlighted by a group of laetrile proponents led by Ralph Moss, former public affairs official of MSKCC who had been fired following his appearance at a press conference accusing the hospital of covering up the benefits of laetrile.These mistakes were considered scientifically inconsequential, but Nicholas Wade in Sciencestated that “even the appearance of a departure from strict objectivity is unfortunate.”The results from these studies were published all together.
The claims that laetrile or amygdalin have beneficial effects for cancer patients are not currently supported by sound clinical data. There is a considerable risk of serious adverse effects from cyanide poisoning after laetrile or amygdalin, especially after oral ingestion. The risk–benefit balance of laetrile or amygdalin as a treatment for cancer is therefore unambiguously negative.
The authors also recommended, on ethical and scientific grounds, that no further clinical research into laetrile or amygdalin be conducted.
The U.S. National Institutes of Healthevaluated the evidence separately and concluded that clinical trials of amygdalin showed little or no effect against cancer.For example, a 1982 trial by the Mayo Clinic of 175 patients found that tumor size had increased in all but one patient.The authors reported that “the hazards of amygdalin therapy were evidenced in several patients by symptoms of cyanide toxicity or by blood cyanide levels approaching the lethal range.”
The study concluded “Patients exposed to this agent should be instructed about the danger of cyanide poisoning, and their blood cyanide levels should be carefully monitored. Amygdalin (Laetrile) is a toxic drug that is not effective as a cancer treatment”.
Additionally, “No controlled clinical trials (trials that compare groups of patients who receive the new treatment to groups who do not) of laetrile have been reported.”
The side effects of laetrile treatment are the symptoms of cyanide poisoning. These symptoms include: nausea and vomiting, headache, dizziness, cherry red skin color, liver damage, abnormally low blood pressure, droopy upper eyelid, trouble walking due to damaged nerves, fever, mental confusion, coma, and death.
The European Food Safety Agency‘s Panel on Contaminants in the Food Chain has studied the potential toxicity of the amygdalin in apricot kernels. The Panel reported, “If consumers follow the recommendations of websites that promote consumption of apricot kernels, their exposure to cyanide will greatly exceed” the dose expected to be toxic. The Panel also reported that acute cyanide toxicity had occurred in adults who had consumed 20 or more kernels and that in children “five or more kernels appear to be toxic”.
Advocacy and legality of laetrile
Advocates for laetrile assert that there is a conspiracybetween the US Food and Drug Administration, the pharmaceutical industryand the medical community, including the American Medical Associationand the American Cancer Society, to exploit the American people, and especially cancer patients.
Advocates of the use of laetrile have also changed the rationale for its use, first as a treatment of cancer, then as a vitamin, then as part of a “holistic” nutritional regimen, or as treatment for cancer pain, among others, none of which have any significant evidence supporting its use.
Despite the lack of evidence for its use, laetrile developed a significant following due to its wide promotion as a “pain-free” treatment of cancer as an alternative to surgeryand chemotherapythat have significant side effects. The use of laetrile led to a number of deaths.The FDA and AMA crackdown, begun in the 1970s, effectively escalated prices on the black market, played into the conspiracy narrative and enabled unscrupulous profiteers to foster multimillion-dollar smuggling empires.
Some North American cancer patients have traveled to Mexicofor treatment with the substance, for example at the Oasis of Hope Hospitalin Tijuana.The actor Steve McQueendied in Mexico following surgery to remove a stomach tumor having previously undergone extended treatment for pleuralmesothelioma(a cancer associated with asbestos exposure) under the care of William D. Kelley, a de-licensed dentist and orthodontist who claimed to have devised a cancer treatment involving pancreatic enzymes, 50 daily vitamins and minerals, frequent body shampoos, enemas, and a specific diet as well as laetrile.
Laetrile advocates in the United States include Dean Burk, a former chief chemist of the National Cancer Institutecytochemistrylaboratory,and national arm wrestlingchampion Jason Vale, who claimed that his kidneyand pancreaticcancers were cured by eating apricotseeds. Vale was convicted in 2004 for, among other things, fraudulently marketing laetrile as a cancer cure.The court also found that Vale had made at least $500,000 from his fraudulent sales of laetrile.
In the 1970s, court cases in several states challenged the FDA’s authority to restrict access to what they claimed are potentially lifesaving drugs. More than twenty states passed laws making the use of Laetrile legal. After the unanimous Supreme Court ruling in Rutherford v. United Stateswhich established that interstate transport of the compound was illegal, usage fell off dramatically.The US Food and Drug Administration continues to seek jail sentences for vendors marketing laetrile for cancer treatment, calling it a “highly toxic product that has not shown any effect on treating cancer.”
- ^“Apricot kernels pose risk of cyanide poisoning”. European Food Safety Authority. 27 April 2016. “A naturally-occurring compound called amygdalin is present in apricot kernels and converts to hydrogen cyanide after eating. Cyanide poisoning can cause nausea, fever, headaches, insomnia, thirst, lethargy, nervousness, joint and muscle various aches and pains, and falling blood pressure. In extreme cases it is fatal”
- ^ Jump up to:
abcLerner IJ (1981). “Laetrile: a lesson in cancer quackery”. Ca. 31(2): 91–5. doi:10.3322/canjclin.31.2.91. PMID 6781723.
- ^ Jump up to:
abcMilazzo S, Horneber M (April 2015). “Laetrile treatment for cancer”. The Cochrane Database of Systematic Reviews(4): CD005476. doi:10.1002/14651858.CD005476.pub4. PMID 25918920.
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Laetrile for cancer: a systematic review of the clinical evidence
- Stefania Milazzo, Stéphane Lejeune, Edzard ErnstPublished 2006 in Supportive Care in CancerDOI:10.1007/s00520-006-0168-9
Many cancer patients treated with conventional therapies also try ‘alternative’ cancer treatments. Laetrile is one such ‘alternative’ that is claimed to be effective by many alternative therapists. Laetrile is also sometimes referred to as amygdalin, although the two are not the same. The aim of this review is to summarize all types of clinical data related to the effectiveness or safety of laetrile interventions as a treatment of any type of cancer. All types of clinical studies containing original clinical data of laetrile interventions were included. We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (from 1951), EMBASE (from 1980), Allied and Complementary Medicine (AMED), Scirus, CancerLit, Cumulative Index to Nursing and Allied Health (CINAHL; all from 1982), CAMbase (from 1998), the MetaRegister, the National Research Register, and our own files. For reports on the safety of laetrile, we also searched the Uppsala database. No language restrictions were imposed. Thirty six reports met our inclusion criteria. No controlled clinical trials were found. Three articles were nonconsecutive case series, 2 were consecutive case series, 6 were best case series, and 25 were case reports. None of these publications proved the effectiveness of laetrile. Therefore, the claim that laetrile has beneficial effects for cancer patients is not supported by sound clinical data. LESS
Can apricot seeds help treat cancer?
There is currently no research to support the claim that apricot seeds can fight cancer. Furthermore, scientists have warned that a compound in the apricot kernel converts to cyanide in the body at levels that could be harmful.
Is eating apricot kernels a safe alternative way to treat cancer or another dangerous health fad? We sort the facts from the fiction.
What are apricot kernels?
People buy apricots, apricot kernels, and apricot kernel oil for a range of purposes.
Apricot kernels are similar in appearance to a small almond. Fresh apricot kernels are white. The skin becomes light brown when dried out.
In Egypt, people mix coriander seeds and salt with ground apricot kernel to make a traditional snack, known as “dokka.”
Some manufacturers use apricot kernelsin the production of cosmetics, medicine, and oil.
The kernels contain protein, fiber, and a high percentage of oil, which people can extract from the kernel.
People use oil pressed from the sweet kernel can be used for cooking in the same way as they might use sweet almond oil. Processed foods, such as amaretto biscuits, almond finger biscuits, and apricot jams, contain apricot kernels.
Some people who live in the North-West Himalayas think wild apricots and their kernels have both nutritional and medicinaluses. Possible uses include biodiesel production, skin, and hair-care products.
Oil and kernels from the bitter variety of apricot kernel are often ingredients in cosmetics, such as body oil, face cream, lip balm, and essential oil.
In India, people use apricot kernel oil is used to make massage oil, because they believe it relievesaches and pains.
A range of apricot kernel products is available for purchase online.
What nutrients do apricot kernels contain?
One study reports that, depending on the type of apricot, the kernels are composed of:
- Oils: From 27.7 to 66.7 percent
- Proteins: Between 14.1 and 45.3 percent, of which 32 to 34 percent are essential amino acids
- Carbohydrates: From 18.1 to 27.9 percent
Around 5 percentof the kernel is fiber.
Apricot kernel oil is high in essential fatty acids. These are necessary for human health, but the human body cannot produce them, so people must take them in through diet.
Linolenic acid plays a vital role in brain function and healthy growth and development. Fatty acids also stimulate skin and hair growth, regulate metabolism, maintain bone health, and support the reproductive system. Many people think that fatty acids have antioxidantproperties.
In a rodent study published in 2011, rats with liver fibrosis received a dose of 1.5 milligrams (mg) three times a week for 4 weeks of ground apricot kernels. Researchers foundthere was an improvementin symptoms.
They suggested this may be due to antioxidant activity, as the kernels contain oleic acid and other polyphenols.
Vitamins and minerals
Can they help fight cancer?
Apricot kernels may have some health benefits, and some people have suggested that they may help fight cancer.
Scientists have proposed that a compound called amygdalin, present in apricot kernels, may be a way to eradicate tumors and prevent cancer by stopping cells from reproducing.
A laboratory study published in 2005 suggested that amygdalin might inhibitgenes that lead to cell proliferation.
What is amygdalin?
Apricot seeds contain amygdalin, which the body can convert to cyanide.
Amygdalin is a naturally occurring substance found in apricot kernels.
It is also present in the seeds of other fruit, including apples, cherries, plums, and peaches. Clover, sorghum, and lima beans also contain amygdalin.
Amygdalin is a cyanogenic glycoside.
When someone eats amygdalin, it converts to cyanide in their body. Cyanide is a fast-acting, potentially deadly chemical.
Depending on the dose, consuming cyanide can lead to:
- a headache
- nausea, vomiting, and abdominal cramps
- mental confusion
- circulatory problems and cardiac arrest
- inability to breath
Cyanide kills cells in the human body by preventing them from using oxygen. Cyanide is particularly harmful to the heart and the brain because they use a lot of oxygen.
Exposure can lead to long-term effectson the heart, brain, and nervous system.
The Centers for Disease Control and Prevention (CDC) note thatapricot seeds “may have substantial amounts of chemicals which are metabolized to cyanide.”
Estimates state that eating 50 to 60 apricot kernelscould deliver a lethal dose of cyanide. Cyanide poisoning can occur at much lower levels, however.
People who follow these dose recommendations are likely to be exposed to cyanide levels that cause cyanide poisoning.
The European Food Safety Authority (EFSA) have warned thata single serving of three small apricot kernels or one large apricot kernel could put adults over the suggested safe levels of cyanide exposure, while one small kernel could be toxic to an infant.
The EFSA advise that no one should consume more than 20 micrograms (mcg)of cyanide per kilogram of body weight at one time. This limits consumption to one kernel for adults. Even half a kernel would be over the limit for children.
Researchers note that the seeds of bitter apricots have a particularly high levelof amygdalin at 5.5 grams (g) in every 100 g.
What is laetrile? What is vitamin B-17?
Some medications contain apricot seeds, but consuming the seeds and and one of the substances they contain could be dangerous.
Laetrile, also called B-17, is a partly synthetic form of amygdalin. It has been proposed as an alternative treatment for cancer.
Laetrile is produced from amygdalin through a chemical reaction with water.
In 1952, the biochemist, Ernst T. Krebs, Jr. developedlaetrile in an injectable form. His father had tried apricot seeds as a cancer treatment in 1920, but this proved to be toxic.
Some people with cancer might take laetrile in the hope thatit will:
- boost their energy levels
- improve their health and sense of wellbeing
- “detox” and cleanse the body
- prolong life
It is available as:
- a skin lotion
- oral tablets
- a liquid inserted into the rectum.
The United States Food and Drug Administration (FDA) do not approveB-17, or laetrile, for use in the U.S. It is deemed unsafe for food and drug use. It has not been shown to have any use in the treatment of any disease.
Side effects of laetrile are similar to those of cyanide poisoning.
- nausea, vomiting, and headache
- very low blood pressureand blue skin due to low oxygen levels
- liver damage
- droopy upper eyelid
- difficulty walking due to nerve damage
Some sources have promotedthe use of laetrile as an anti-cancer agent, and it is available as a treatment in Mexico and some clinics in the U.S.
Some sources suggest that people take laetrile to:
- improve energy levels and well-being
- detox the body
- help them live longer
There is currently no scientific evidence to support the use of laetrile for these purposes or to treat cancer.
In 2018, the National Cancer Institute (NCI) pointed out that laetrile leads to cyanide production in the body and that the American Institute of Nutrition Vitamins have not approved it as a vitamin.
The NCI note:
“Anecdotal reports and case reports have not shown laetrile to be an effective treatment for cancer.”
They add that there are no reports of any controlled clinical trials that have taken place in people.
Also, they point out that because laetrile comes from Mexico, it may not carry the same safety standards governing purity and contents when manufactured.
There is also concern that people might take laetrile instead of following proven therapy regimes for cancer, such as targeted drugs or radiation therapy. Using unproven methods in place of conventional medicine can cause serious harm.
The NCI add that the FDA “has not approved laetrile as a treatment for cancer or any other medical condition.”
What about vitamin B-15?
Also present in apricot kernels is another so-called vitamin, B-15, or calciumpangamate. This, too, has been proposed for treating cancer.
However, as long ago as 1980, scientists concluded thatcalcium pangamate can cause genetic mutations and has a “90-percent probability” of causing rather than curing cancer.
The FDA considers vitamin B-15 “unsafefor food and drug use.”
No reliable evidence confirms laetrile as an effective treatment for cancer, and there is evidence that it is toxic and potentially fatal.
Most websites that support laetrile as a cancer treatment base their claims on anecdotal evidence and unsupported opinions.
One such article was publishedin 2008 by Stephen Krashen, a professor of linguistics at the University of Southern California (emeritas). Krashen argued that “Death by apricot kernels appears to be rare.”
Krashen suggested that people may “accommodate”apricot kernels, “having negative reactions at first but gradually building up to higher doses.”
However, in 2010, researchers published results of a review of 13 children who had experienced cyanide poisoning after eating apricot kernels. All the children attended the same pediatric intensive care unit in Turkey between 2005 and 2009.
The scientists concluded:
“Cyanide poisoning associated with ingestion of apricot seeds is an important poison in children, many of whom require intensive care.”
In 2015, a review of studies published by the Cochrane Library concluded thatthere was no reliable evidence to show any benefit from using laetrile or amygdalin in the treatment of cancer.
A rodent study published in 1975 records no antitumor activity after the use of amygdalin, but notes a risk of toxicity.
In 1982, some people who received laetrile as a cancer treatment showed evidence of cyanide toxicity.Also, there were no recorded examples of any improvement in cancer symptoms.
Consumption of apricot kernels and laetrile is not recommended during pregnancy or while breastfeeding. There is a lack of data on the possible risk of congenital disabilities.
In 2006, Cancer Treatment Watch posted an article, originally published in 1977, describing the use of laetrileas “quackery”and criticizing promoters of the supplement for preying on the fears of people with cancer to maintain a lucrative international business.
In conclusion, the ingestion of laetrile and apricot kernels carries a risk of serious illness and death, but manufacturers and producers continue to promote both products widely today.
Processing foods that contain amygdalin reduces the risk but does not eliminateit. Options include crushing, grinding, grating, soaking, fermenting, or drying.
If the manufacturers can remove the harmful elements can be removed, certain chemicals inside apricot kernels may one day prove usefulfor cancer treatment. For now, however, doctors and other healthcare professionals cannot recomend the use of apricot kernels.