Discovery of riboflavin

The British chemist Alexander W. Blyth in 1879 isolated from milk whey a water-soluble, yellow fluorescent compound he called lactochrome, appropriately named for its color and origin. ‘Lacto’ from the milk and ‘chrome’ meaning color because of the yellow pigment.

The search to identify these accessory food factors in milk, whole wheat, yeast, and liver began in the early 1900s.

McCollum and assistant Marguerite Davis produced three papers in 1915 which showed a diet containing 2% of wheat embryo or milk powder with polished rice, casein, salts, and butter fat provided enough of an ‘essential accessory’ to support growth of young rats.

The importance of lactochrome was not fully realized until later investigational studies by Elmer McCollum and Kennedy (1916), Emmett and Luros, and Smith and Hendrick that showed the preventive capabilities of water-soluble food extracts against beriberi, pellagra, and pellagra-like dermatitis.

Several years later, the physiological role of the yellow growth factor was shown by Warburg and Christian (1932) to be a component of a yeast “Zwischenferment,” which was designated the “old yellow enzyme.”

Joseph Goldberger in 1927 proposed there was an anti-pellagra factor in eggs, milk, etc., and it was the same substance as ‘water-soluble B’ identified by McCollum. Goldberger called the substance the pellagra-preventative or P-P dietary factor.

In 1935 Richard Kuhn at Heidelberg, and Paul Karrer at the University of Zurich eventually succeeded in synthesizing the vitamin, now termed riboflavin. They were awarded the Nobel Prize for this and other achievements in 1937 and 1938, respectively. Kuhn first proved that riboflavin is an essential growth factor, viz., vitamin B2.

Kuhn also developed a synthetic route to riboflavin which was licensed to the German company I. G. Farben.

Theorell in 1937 identified the isoalloxazine derivative from the old yellow enzyme as riboflavin-5′-phosphate, also called FMN (flavin mononucleotide). The structure of a second coenzymic form was established by Warburg and Christian (1938) as FAD (flavin adenine dinucleotide) and was shown to participate as the coenzyme of d-amino acid oxidase.
Discovery of riboflavin

Ariboflavinosis

Riboflavin is essential in the diet and the human body is unable to synthesize this vitamin. It is a water-soluble, photosensitive, crystalline pigment the present of which can be determined by fluorometric as well as micro-biological and absorptive-photometrical methods.

Riboflavin is not stored in the body, requiring people to replenish supply daily from the diet. Food sources of riboflavin include: beef liver, dairy products, eggs, meat, wheat germ and tuna fish.

Riboflavin deficiency causes ariboflavinosis, a common nutritional deficiency disease.

In man the syndrome is said to consist of cheilosis, perlèche -like erosions, seborrhea of the face, vascularization of corneo and keratitis.

The facial and labial lesions of ariboflavinosis contribute largely to the typical facies of classic pellagra and with glossitis constitute the picture of "pellagra sine pellagra."

Photophobia, burning and itching of the eyes, a sensation of eyestrain or rapid visual fatigue, poor distant vision and blurred vision in poor light or twilight are specific symptoms.

Red blood cell glutathione reductase activity can be measured for evidence of deficiency, but usually clinical findings are sufficient to consider deficiency.
Ariboflavinosis