Contents of all forms of vitamin Bsub(6), pyridoxine-beta-glucoside and 4-pyridoxic acid in mature milk of Japanese women according to 4-pyridoxolactone-conversion high performance liquid chromatography
2013
Yagi, T. (Kochi University, Nankoku, Kochi (Japan). Graduate School of Integrated Arts and Sciences, Faculty of Agriculture and Agricultural Science Program) | Iwamoto, S. | Mizuseki, R. | Furuya, M. | Nakayama, K.
The contents of six vitamin Bsub(6) forms, pyridoxine-beta-glucoside, and 4-pyridoxic acid in mature milk of 20 Japanese lactating women consuming ordinary Japanese foods were determined by a 4-pyridoxolactone-conversion HPLC method. These compounds were determined with the average recovery rate of 83.9% or more. The average total content of vitamin Bsub(6) forms was 1.01+-0.32 (micromol/L). Pyridoxal and pyridoxal 5'-phosphate were found in all of the samples, and their average contents were 0.71+-0.28 (micromol/L) and 0.16+-0.07 (micromol/L), respectively. Pyridoxamine, pyridoxine, pyridoxamine 5'-phosphate, pyridoxine 5'-phosphate, and pyridoxine-beta-glucoside were found in 15, 14, 13, 9, and 7 samples, respectively. The presence of pyridoxine 5'-phosphate was for the first time found in human milk. A method for the determination of 4-pyridoxic acid, which is the excretion form of vitamin Bsub(6), was modified to quantitate it by isocratic HPLC. 4-Pyridoxic acid was found in all samples, and its average content was 0.094+-0.040 (micromol/L), which was only 12% of its content in cow (Holstein) milk. The total content of vitamin Bsub(6) forms, and predominant presence of pyridoxal among other vitamin Bsub(6) forms in the Japanese women's milk samples shared similar characteristics with American women's milk samples.
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