Frontiers in Natural Product Chemistry

Volume: 2

Indexed in: EBSCO.

Frontiers in Natural Product Chemistry is an Ebook series devoted to publishing monographs that highlight important advances in natural product chemistry. The Ebook series covers all aspects of ...
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Corrinoids in Food and Biological Samples

Pp. 229-244 (16)

Fumio Watanabe and Tomohiro Bito

Abstract

Vitamin B12 is synthesized by only certain bacteria but not by plants. Thus, foods derived from animals, namely meat, milk, fish, and shellfish, are major dietary sources of vitamin B12. Intestinal bacteria have the ability to synthesize various corrinoid compounds carrying different base moieties in the lower ligand. Thus, animal manures and human feces contain substantial amounts of various cobamides with different bases. When food corrinoids were purified and characterized, certain food items unexpectedly contained pseudovitamin B12, in which adenine replaces 5,6- dimethylbenzimidazole as the base. Cyanobacteria used as human health supplements provide substantial amounts of pseudovitamin B12, which functions as a cofactor for cobalamin-dependent methionine synthase in these organisms. Oral administration of pseudovitamin B12 to mammals suggests that this cobamide does not act as a vitamin B12 antagonist in the gastrointestinal absorption of vitamin B12 and cobalamindependent enzyme systems. Furthermore, vitamin B12 is converted into an inactive analogue vitamin B12[c-lactone] by the treatment with chloramine-T, which is used as a disinfectant. The unnatural vitamin B12 analogue was found in certain dried mushroom fruiting bodies.

Keywords:

Benzimidazoles, Biosynthesis of corrinoids, Cyanocobalamin, Food, Phenolic compounds, Pseudovitamin B12, Purines, Vitamin B12.

Affiliation:

Faculty of Agriculture, School of Agricultural, Biological and Environmental Sciences, Tottori University, Tottori 680-8553, Japan.