Historical overview of Vitamin B1

At one time, the disease beriberi was believed to
be caused by a microorganism or toxin. The fi rst
indication of a nutritional aetiology was the virtual
elimination of beriberi in the Japanese Navy in 1885,
brought about by increasing the proportion of meat
and vegetables in the staple rice diet. In 1890, Eijkman,
a Dutch medical offi cer stationed in Java, discovered
that feeding chickens on polished rice induced a
polyneuritis closely resembling human beriberi,
which could be prevented by the addition of rice bran
to the avian diet. A few years later, Grijns extracted
a water-soluble ‘polyneuritis preventive factor’ from
rice bran and correctly concluded that beriberi is the
result of a dietary lack of an essential nutrient. By
1926, two Dutch chemists, Jansen and Donath, had
succeeded in isolating the factor (by now called vitamin
B1) in crystalline form from rice bran extracts. By
1936, Robert R. Williams had elucidated the structure
of vitamin B1, which he named ‘thiamine’, and accomplished
its synthesis. The failure of thiamin-defi cient
pigeons to metabolize pyruvate led Sir Rudolph Peters
and his colleagues in the early 1930s to establish the
essential role of thiamin in pyruvate metabolism. Lohmann
and Schuster then discovered that the active
coenzyme form of the vitamin was the diphosphate
ester.
(In this text, ‘thiamin’, rather than ‘thiamine’, is used
in accordance with the nomenclature policy of the International
Union of Nutritional Sciences Committee
on Nomenclature.)
11.2 Chemistry and biological activity
The thiamin molecule comprises substituted pyrimidine
and thiazole moieties linked by a methylene
bridge (Fig. 11.1). It is a quaternary amine, which exists
as a monovalent or divalent cation depending on
the pH of the solution. Three phosphorylated forms
of thiamin occur in nature. In living tissues the predominant
form is the diphosphate, usually referred
to as thiamin pyrophosphate (TPP) (Fig. 11.1), which
serves as a coenzyme in several metabolic pathways.
Small amounts of the monophosphate and triphosphate
esters also occur in animal tissues. Thiamin
triphosphate has no coenzyme function, but it has a
role (not yet completely understood) in nerve transmission.
Thiamin monophosphate appears to be
biologically inactive.
The name thiamin and the individual phosphates
of thiamin will be used as specifi c terms; total thiamin
means the sum of thiamin and its phosphates, and
vitamin B1 is a non-specifi c generic term.