Flavin and the pellagra-preventing factor as separate constituents of a complex vitamin B2

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Abstract
Rats were fed on a vit. Ba-deficient diet similar to that used by Langston and Day for the production of cataract, but with the vit. B1 provided in the form of the International Standard; ca. 30% of these rats developed symptoms of severe and characteristic pellagra after 3-4 mos. Later use of purer preparations of vit. B1led to more regular production of symptoms, indicating that the International Standard is contaminated with the anti-pellagra vitamin and possibly with other "B" factors. The results indicated that: (1) Flavin has no anti-pellagra action, but is a constituent of the vit. B1complex in the sense that it causes some improvement in the weight curve when given as a supplement to vit. Bi. For adequate growth, however, it was necessary to supplement the vit. B1 plus flavin with a third fraction, which possesses anti-pellagra properties, and which was given in the form of "Peters'' eluate" (PE). With vit. B1 and flavin alone all rats developed severe pellagra (8 cases). (2) with vitamin B1plus the pellagra-preventing fraction only (PE) pellagra was always prevented or cured (13 cases). Without the further addition of flavin, however, body weights remained subnormal. (3) The combined effect of vit. B1 plus flavin plus (PE) was approximately equal, in its weight-promoting action and in the cure or prevention of symptoms, to that of the total complex given in the form of marmite. These results confirm the finding of Gyorgy that flavin does not possess anti-pellagra activity. Both flavin and the anti-pellagra factor should be regarded as separate constituents of the "heat-stable, growth-promoting vit. B2 complex.".