Vitamin B17, Amygdalin or Laetrile:

Truth and Facts

Apricot tree

Vitamin B17, Amygdalin and Laetrile

There are 3 names which are used interchangeable being Vitamin B17, Laetrile and Amygdalin, however they are not the same. Cyanogenic glycosides are a large group of secondary metabolites that are widely distributed in the plant kingdom, including many plants that are commonly consumed by humans.

Amygdalin is a natural compound often found on seeds (kernels) of apricots, bitter almonds, apples, peaches, and plums. There is a nitrile group in each amygdalin molecule, thus, its official classification is of a cyanogenic glycoside.

Laetrile is a patented compound registered in 1961 as a semisynthetic derivative of amygdalin synthesized by hydrolysis from its natural counterpart. The patented version of this chemical compound is different from amygdalin extracted from apricots seeds.

Amygdalin chemical structure

What is Amygdalin?

Amygdalin is a natural occurring cyanogenic glycoside found in over 1,200 plant species involving at least 13% of all plant families, notably in seeds of fruits in the Rosaceae family such as bitter almonds, apricots, and plums. Each molecule of Amygdalin contains one unit of hydrogen cyanide, one unit of benzaldehyde and TWO of glucose (sugar) tightly locked together. Despite its ubiquitousness it is erroneously confused with Laetrile, adding to that, they both are called Vitamin B17.

CAS Reg. No. 29883-15-6
Empirical formula C20H27NO11
Molar mass 457.43 g/mol
Appearance White to beige powder
Melting point 223–226 ºC
Water solubility 50 g/L
Laetrile chemical structure

What is Laetrile?

Laetrile, which was patented in the United States, is a semisynthetic molecule sharing part of the amygdalin structure, it’s a derivative of amygdalin formed by the hydrolytic removal of one glycoside group from the parent compound, that means each molecule of Laetrile contains one unit of hydrogen cyanide, one unit of benzaldehyde and ONE of glucose (sugar) tightly locked together.

Dr. Krebs was able to extract certain glycosides from plants which contained nitrolosides, and eventually applied for a patent for the process of producing a metabolite form of these glycosides for clinical use. He named it “Laetrile.” (Laevo-mandelonitrile-beta-glucuronoside).

CAS Reg. No. 1332-94-1
Empirical formula C14H15NO7
Molar mass 309.27 g/mol
Appearance White powder
Melting point 214–216 ºC
Water solubility 83 g/L

Amygdalin is extracted from the seed inside the apricot endocarp

Multiple seeds and fruit kernels have amygdalin inside of them, the main one is the seed inside the apricot endopcarp "inner woody stone", other seeds with significant amounts of vitamin b17 are:

Fruit Amygdalin Content (mg/g) Weight of seeds (g)
Apricot Seed 14.37 ±0.28
Black cherry 2.68 ± 0.02
Red cherry 3.89 ± 0.31
Nectarine 0.12 ±0.01
Peach 6.81 ± 0.02
Green plum 17.49 ± 0.26
Black plum 10.0 ±0.14
Purple plum 2.16 ±0.02
Yellow plum 1.54 ±0.02
Red plum 0.44 ±0.04
Apple 2.96 ±0.02
Pear 1.29 ±0.04
Drupe fruit diagram-en
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