Characterization of a Corrinoid Compound from Pacific Bluefin Tuna (Thunnus orientalis) Liver

Abstract

A substantial amount of vitamin B₁₂ (357 ± 42.7 μg/100 g) was detected in pacific bluefin tuna (Thunnus orientalis) liver using a microbiological assay method. To evaluate whether tuna liver contains true vitamin B₁₂ or an inactive corrinoid compound, a corrinoid compound was purified and characterized. The purified compound was identical to that of authentic vitamin B₁₂, judging by TLC and LC/ESI-MS/MS chromatograms, and ¹H NMR spectral data. These results indicate that pacific bluefin tuna liver contains substantial amounts of true vitamin B₁₂ and would be an excellent source of the vitamin.