Cyanogenic Glycosides
Dongyou Liu in Handbook of Foodborne Diseases, 2018
Derived from the aromatic amino acid phenylalanine, amygdalin is a cyanogenic glycoside that can be hydrolyzed by intestinal β-glucosidase (emulsin) and amygdalase to yield gentiobiose and L-mandelonitrile (bencaldehyde-cyanohydrin). While gentiobiose is further hydrolyzed into glucose, the cyanohydrin of mandelonitrile decomposes to produce benzaldehyde (consisting of a benzene ring with an aldehyde substituent, and responsible for the bitter taste of these foods) and HCN (also known as prussic acid). It is estimated that 1 g of amygdalin could theoretically release 59 mg of HCN after complete hydrolysis. Amygdalin is found in stone fruit kernels of apricot (8%, containing 89–2170 mg total HCN per kg), peach (6%), bitter almond (5%, containing 2500 mg of HCN per kg), plum (2.5%), and apple [4].
Plant Source Foods
Chuong Pham-Huy, Bruno Pham Huy in Food and Lifestyle in Health and Disease, 2022
Seeds are small embryonic plants enclosed in a coat, the product of the ripened ovule of flowering plants after pollination and the completion of the reproduction process (153). Seeds are made of complex matrices in the outer layer and germ, and rich in minerals, oils, proteins, carbohydrates, vitamins, mono and polyunsaturated fatty acids, and antioxidants that protect the plant’s DNA from oxidative stress, thus facilitating the perpetuation of the species. Some edible seeds are: flaxseed (linseed), sesame seed, chia seed, quinoa seed, pumpkin seed, sunflower seed, and hemp seed. Sunflower seed, rapeseed, and cottonseed are used commercially in the production of oils. However, some seeds, such as castor seed of the plant Ricinus communis, seed of the strychnine tree, and seeds of bitter almond, peach, and apricot, are toxic. Ricin, a water-soluble lectin present in castor seed, is highly toxic and can cause death if consumed (154). In contrast, castor oil extracted from castor seed is not toxic and can be used in food additives or in pharmacy as a laxative because ricin is not soluble in castor oil. Seed of the strychnine (Strychnos nux-vomica) tree can cause deadly convulsion. Seeds of bitter almond, apricot, and peach, containing amygdalin, may cause cyanide poisoning with high intake. Except for some particular cases cited above, most seeds frequently consumed such as flaxseed, sesame seed, chia seed, and quinoa seed, are good for health.
Gases
Frank A. Barile in Barile’s Clinical Toxicology, 2019
Cyanic acid (hydrogen cyanate, HCNO) is the starting chemical principle for the various salt forms of cyanide, including the sodium (cyanogran, NaCN), potassium (KCN), and calcium (CaCN) salts. Hydrogen cyanide (HCN, hydrocyanic acid, prussic acid) is a gas and a catalyst and is prepared from the cyanate salts. In addition, the compounds occur naturally as cyanogenic glycosides. The compounds are found from 0.01% to 14% in the seeds of various nuts, including almonds (highest concentration, 2%–14%), cherries, plums, apples, peaches, apricots, pears, plums, and rosaceous plants, as well as in bamboo sprouts and cassava. Figure 25.2 illustrates the hydrolysis of amygdalin, the most widely distributed cyanogenic glycoside. Most hydrolyzing agents, in the presence of the enzyme β-glucuronidase, are capable of producing the hydrolysis products of amygdalin—that is, mandelonitrile glucoside (an intermediate) plus glucose, benzaldehyde, and hydrocyanic acid. Cyanogenic glycosides and hydrolysis of amygdalin.
Molecular mechanism of amygdalin action in vitro: review of the latest research
Published in Immunopharmacology and Immunotoxicology, 2018
Przemysław Liczbiński, Bożena Bukowska
Amygdalin is a representative of chemical organic compounds of cyanogenic glycosides with a molecular formula of C20H27O11 (Figure 1) and a molecular mass of 457.42 g/mol. Amygdalin is composed of benzaldehyde, hydrocyanic acid and two glucose molecules (D-mandelonitrile-β-D-glucoside-6-β-glucoside). It is a widespread compound in the environment, occurring in seeds of many plants, including black cherries, peaches, plums, apples, apricots, etc1. Amygdalin is not a toxic compound but hydrogen cyanide (HCN), which is formed during the enzymatic hydrolysis, has toxic properties. Years of research on the effects of amygdalin have shown its wide range of properties, including its supportive function in treatment of asthma, bronchitis, leprosy or colorectal cancer. Due to the presence of benzaldehyde in the amygdalin molecule it has analgesic properties2. Anticancer activity of amygdalin is still controversial and has been subject to a lot of research. This ability may be associated with enzymatic hydrolysis, which results in hydrocyanic acid release3.
Amygdalin Modulates Prostate Cancer Cell Adhesion and Migration In Vitro
Published in Nutrition and Cancer, 2020
Jens Mani, Jens Neuschäfer, Christian Resch, Jochen Rutz, Sebastian Maxeiner, Frederik Roos, Felix K.-H. Chun, Eva Juengel, Roman A. Blaheta
During the late 1970s amygdalin became one of the most popular natural compounds employed by tumor patients. Despite warnings of the potential risk of cyanide toxicity, amygdalin has experienced a strong renaissance as an “alternative” option in treating cancer. Still, controlled clinical studies have not been carried out and questions about amygdalin’s efficacy have not yet been satisfactorily answered. The present data, evaluated with in vitro models, point to significant amygdalin induced modulation of adhesion and chemotaxis of androgen resistant prostate cancer cell lines, DU-145 and PC3. However, the two cell lines responded quite differently to amygdalin exposure. In the DU-145 cell line, tumor-endothelial cell interaction, adhesion to collagen, chemotaxis, and migration were all reduced by amygdalin, whereas adhesion of PC3 increased following 2-week long-term exposure to amygdalin. No significant differences were seen in the motile behavior of PC3 after amygdalin exposure, so that elevated PC3 binding may not be accompanied by a parallel elevation of chemotactic activity. Rather, adherent cells may remain attached and not transmigrate.
Rebound metabolic acidosis following intentional amygdalin supplement overdose
Published in Clinical Toxicology, 2020
Rachel M. Shively, Stephen A. Harding, Robert S. Hoffman, Adam D. Hill, Alfredo J. Astua, Alex F. Manini
Amygdalin is a cyanogenic glycoside found in seeds of the genus Prunus. As a supplement, it has been marketed as “Amygdalin,” “Vitamin B-17,” and “Laetrile.” Amygdalin is hydrolyzed by the enzyme beta-glucosidase into hydrogen cyanide (HCN), benzaldehyde, and glucose. Cyanide then exerts toxicity via inhibition of oxidative phosphorylation [1]. Mammalian cells contain trace amounts of beta-glucosidase, mostly in the liver [2]. However, gastrointestinal (GI) bacteria have large amounts, allowing for substantial cyanide production with amygdalin ingestion [3]. As toxicity does not occur until amygdalin is metabolized to cyanide, toxic amygdalin ingestions present in a delayed fashion.
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