Pseudovitamin B12 Is the Predominant Cobamide of an Algal Health Food, Spirulina Tablets

The vitamin B12 concentration of an algal health food, spirulina (Spirulina sp.) tablets, was determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor chemiluminescence methods. The values determined with the microbiological method were ∼6−9-fold greater in the spirulina tablets than the values determined with the chemiluminescence method. Although most of the vitamin B12 determined with the microbiological method was derived from various vitamin B12 substitutive compounds and/or inactive vitamin B12 analogues, the spirulina contained a small amount of vitamin B12 active in the binding of the intrinsic factor. Two intrinsic factor active vitamin B12 analogues (major and minor) were purified from the spirulina tablets and partially characterized. The major (83%) and minor (17%) analogues were identified as pseudovitamin B12 and vitamin B12, respectively, as judged from data of TLC, reversed-phase HPLC, 1H NMR spectroscopy, ultraviolet−visible spectroscopy, and biological activity using L. leichmannii as a test organism and the binding of vitamin B12 to the intrinsic factor. Keywords: Vitamin B12; pseudovitamin B12; algal health food; spirulina tablet; intrinsic factor; Lactobacillus leichmannii