Characterization of a vitamin B12 compound from unicellular coccolithophorid alga (Pleurochrysis carterae)

A unicellular coccolithophorid alga, Pleurochrysis carterae, contained 125.4 +/- 1.2 mug of vitamin B-12 per 100 g dry cell weight of the lyophilized algal cells. A vitamin B-12 compound was purified from the lyophilized algal cells and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified pink-colored compound were identical to those of authentic vitamin B-12, but not those of vitamin B-12 analogues inactive for humans. When 22-week-old B-12-deficient rats which excreted substantial amounts of methylmalonic acid (75.5 +/- 12.3 mg/day) in urine were fed the P. carterae (10 g per kg diet)-supplemented diet for 12 d, urinary methylmalonic acid excretion (as an index of vitamin B-12 deficiency) of the rats became undetectable and hepatic vitamin B-12 level of the rats was significantly increased.