The Rapid Induction of Human Riboflavin Deficiency with Galactoflavin *

Abstract

Signs of riboflavin deficiency require many months to develop in patients placed on riboflavinrestricted diets (1-6). The demonstrations that riboflavin deficiency induced by dietary restriction or riboflavin antagonists resulted in regression of rodent tumors (7-13) prompted several efforts in this laboratory to produce riboflavin deficiency in patients with neoplastic disease (14, 15). Riboflavin antagonists were used in these studies with the objective of producing the deficiency state rapidly, since a regimen requiring many months of dietary restriction would not lend itself to therapeutic evaluation in patients with metastatic cancer. These earlier investigations did not result in the production of clinical evidences of riboflavin deficiency or in objective demonstrations of tumor regression. The administered riboflavin antagonists, selected on the basis of their effectiveness in rats, were shown to be metabolized differently in man. The most active of these agents against rat tumors, 6,7-dimethyl-9-(2'-acetoxyethyl) -isoalloxazine, was rapidly and almost completely hydrolyzed in man, although a significant amount of the absorbed drug was excreted unchanged by rats. With the objective of producing human riboflavin deficiency, an analog was sought that would be an effective riboflavin antagonist in rodents and would be metabolized similarly in rodents and in man.The present paper describes studies with 1O-Ddulcityl -7,8-dimethyl-isoalloxazine, galactoflavin,

Iron-Induced Hepatocarcinogenesis—Preventive Effects of Nutrients

“…Consequently, hepatic iron contents were significantly reduced by riboflavin deficiency. Thus, riboflavin antagonists, such as galactoflavin (124), would be expected as a novel therapeutic agent for HIO, unlike other nutrients whose agonistic actions are desired therapeutically. However, there are contradictory studies on the effect of riboflavin on anemia (125)(126)(127).…”

“…Riboflavin deficiency was shown to reduce intestinal iron absorption and utilization, leading to anemia in humans and rats ( 123 , 124 ). Consequently, hepatic iron contents were significantly reduced by riboflavin deficiency.…”

Interactions between Micronutrients: Synergies and Antagonisms

“…Riboflavin deficiency in human adults is known to result in low hemoglobin levels. When riboflavin deficiency was induced in human volunteers, the subjects got anemia, which was restored when riboflavin status was restored [34]. Studies in the Gambia have also shown that iron given with riboflavin supplements was more efficient in restoring hematologic parameters than iron given alone [35,36].…”

Riboflavin deficiency in cystic fibrosis: three case reports

“…The objective signs of riboflavin deficiency include angular stomatitis, chielosis, seborrhoeic dermatitis, glossitis and visual changes (McLaren, 1982). In experimental deficiency, Lane et al . (1964) found that sore throat and angular stomatitis were usually the first symptoms to appear followed ultimately by hypoplastic anaemia and neuropathy (Alfrey & Lane, 1970).…”