Chemistry:Galactoflavin
Galactoflavin is a synthetic compound and riboflavin (vitamin B2) antagonist and antimetabolite. It is a biochemical tool used primarily in research to induce riboflavin deficiency in animal models and humans. It is structurally similar to riboflavin, where the ribose-derived side chain is replaced by a galactose-derived group.
Chemical properties
Galactoflavin's chemical formula is C18H22N4O7 and has a molecular weight of 406.40 g/mol. Galactoflavin appears as yellow crystals that decompose at 260 °C and exhibit absorption maxima at 223, 267, 370, and 445 nm.[1] It displays yellow-green fluorescence in water.[1]
Biological activity
As a riboflavin analog, galactoflavin competes with riboflavin in metabolic pathways, leading to depletion of riboflavin-containing coenzymes such as flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) in tissues such as liver and kidney.[2] This antagonism results in riboflavin deficiency symptoms that are reversible with excess riboflavin supplementation. In rats, galactoflavin feeding reduces flavin content in mitochondria and affects oxidative phosphorylation.[3]
The antiriboflavin effect of galactoflavin was first demonstrated in 1945 and was found to produce riboflavin deficiency in rats reversible by excess riboflavin.[4]
In humans, galactoflavin rapidly induces riboflavin deficiency, with clinical signs including anemia, glossitis, angular stomatitis, and dermatitis appearing within weeks.[5]
Research uses
Galactoflavin has been employed to study the effects of riboflavin deficiency on growth, enzyme activity, and congenital malformations.[6][7][8] In pregnant rats, it induces multiple congenital abnormalities in embryos, including cardiovascular defects and hydrocephalus, by disrupting terminal electron transport systems. It has also been investigated for potential antitumor effects due to its ability to cause regression of tumors in rodents through riboflavin deficiency.
In mice, dietary galactoflavin affects hepatocyte ultrastructure.[9] It impairs adrenal ascorbic acid response to stress in rats.[10]
References
- ↑ 1.0 1.1 Merck Index (11th ed.), p. 678, 4239. Galactoflavin
- ↑ PROSKY L; BURCH HB; BEJRABLAYA D; LOWRY OH; COMBS AM (1964). "The Effects of Galactoflavin on Riboflavin Enzymes and Coenzymes". The Journal of Biological Chemistry 239 (8): 2691–2695. doi:10.1016/S0021-9258(18)93906-2. PMID 14235554.
- ↑ Beyer, Robert E.; Lamberg, Stanley L.; Neyman, M. Arthur (1961). "The Effect of Riboflavin Deficiency and Galactoflavin Feeding on Oxidative Phosphorylation and Related Reactions in Rat Liver Mitochondria". Canadian Journal of Biochemistry and Physiology 39: 73–88. doi:10.1139/o61-009.
- ↑ Gladys A. Emerson, Elizabeth Wurtz, and Oscar H. Johnson (1945). "The Antiriboflavin Effect of Galactoflavin". Journal of Biological Chemistry 160 (1): 165–167. doi:10.1016/S0021-9258(18)43108-0.
- ↑ Lane, Montague; Alfrey, Clarence P.; Mengel, Charles E.; Doherty, Maureen A.; Doherty, Jean (1964). "The Rapid Induction of Human Riboflavin Deficiency with Galactoflavin". Journal of Clinical Investigation 43 (3): 357–373. doi:10.1172/JCI104921. PMID 14135487.
- ↑ Nelson, Marjorie M.; Baird, Catherine D.C.; Wright, Howard V.; Evans, Herbert M. (1956). "Multiple Congenital Abnormalities in the Rat Resulting from Riboflavin Deficiency Induced by the Antimetabolite Galactoflavin". The Journal of Nutrition 58: 125–134. doi:10.1093/jn/58.1.125. PMID 13286747.
- ↑ Aksu, Oguz; MacKler, Bruce; Shepard, Thomas H.; Lemire, Ronald J. (1968). "Studies of the development of congenital anomalies in embryos of riboflavin-deficient, galactoflavin fed rats. II. Role of the terminal electron transport systems". Teratology 1 (1): 93–102. doi:10.1002/tera.1420010110. PMID 4302703.
- ↑ Lane, M.; Brindley, C. O. (1964). "Laboratory and Clinical Studies with the Riboflavin Antagonist, Galactoflavin". Experimental Biology and Medicine 116: 57–61. doi:10.3181/00379727-116-29158. PMID 14200132.
- ↑ Tandler, Bernard; Hoppel, Charles L. (1974). "Ultrastructural effects of dietary galactoflavin on mouse hepatocytes". Experimental and Molecular Pathology 21 (1): 88–101. doi:10.1016/0014-4800(74)90081-1. PMID 4370691.
- ↑ Slater, Grant G. (1959). "INFLUENCE OF GALACTOFLAVIN AND INANITION ON THE ADRENAL ASCORBIC ACID RESPONSE TO STRESS IN RATS1". Endocrinology 65 (5): 731–738. doi:10.1210/endo-65-5-731. PMID 13831613.
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