The vitamin B(12) 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 approximately 6-9-fold greater in the spirulina tablets than the values determined with the chemiluminescence method. Although most of the vitamin B(12) determined with the microbiological method was derived from various vitamin B(12) substitutive compounds and/or inactive vitamin B(12) analogues, the spirulina contained a small amount of vitamin B(12) active in the binding of the intrinsic factor. Two intrinsic factor active vitamin B(12) analogues (major and minor) were purified from the spirulina tablets and partially characterized. The major (83%) and minor (17%) analogues were identified as pseudovitamin B(12) and vitamin B(12), respectively, as judged from data of TLC, reversed-phase HPLC, (1)H NMR spectroscopy, ultraviolet-visible spectroscopy, and biological activity using L. leichmannii as a test organism and the binding of vitamin B(12) to the intrinsic factor.

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To clarify the bioavailability of vitamin B 12 in lyophylized purple laver (nori; Porphyra yezoensis), total vitamin B 12 and vitamin B 12 analogue contents in the laver were determined, and the effects of feeding the laver to vitamin B 12 -deficient rats were investigated. The amount of total vitamin B 12 in the dried purple laver was estimated to be 54´5 and 58´6 (SE 5´3 and 7´5 respectively) mg/100 g dry weight by Lactobacillus bioassay and chemiluminescent assay with hog intrinsic factor respectively. The purple laver contained five types of biologically active vitamin B 12 compounds (cyano-, hydroxo-, sulfito-, adenosyl-and methylcobalamin), in which the vitamin B 12 coezymes (adenosyl-and methylcobalamin) comprised about 60 % of the total vitamin B 12 . When 9-week-old vitamin B 12 -deficient rats, which excreted substantial amounts of methylmalonic acid (71´7(SE 20´2) mmol/d) in urine, were fed the diet supplemented with dried purple laver (10 mg/kg diet) for 20 d, urinary methylmalonic acid excretion (as an index of vitamin B 12 deficiency) became undetectable and hepatic vitamin B 12 (especially adenosylcobalamin) levels were significantly increased. These results indicate that vitamin B 12 in dried purple laver is bioavailable to rats.Vitamin B 12 deficiency: Purple laver: Urinary methylmalonate excretion: Hepatic vitamin B 12 content

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The antioxidant activities of several extracts from Susabinori (Porphyra yezoensis) were measured by the ferric thiocyanate method and the thiobarbituric acid method. The methanol, acetone, ethyl acetate, and hexane extracts, and the chloroform-soluble and water-soluble fractions from the chloroform-methanol extract exhibited higher activities than α-tocopherol. The hot water extract showed little activity. Thinlayer chromatography analysis of the active extracts suggested the existence of several antioxidants. The activity of the chloroform soluble fraction was due to chlorophyll analogs. A strong antioxidant was isolated from the methanol extract, accompanied by several amino acids such as leucine and phenylalanine. This compound was identified as usujilene, a kind of mycosporine-glycine like amino acid.Paper no. J8916 in JAOCS 76, 649-653 (May 1999).Seaweeds, such as laver and kelp, are commonly eaten in Japan and their high dietary fiber and vitamin content have stimulated their evaluation as health foods. In addition, seaweeds contain high levels of polyunsaturated fatty acids (1). Although polyunsaturated fatty acids are very easily oxidized, seaweeds are known to resist oxidation during storage. Fujimoto et al.(2) reported the antioxidant effect of 21 species of marine algae and found that the phospholipid fraction in arame (Eisenia bucyclis) showed efficient activities. Tutour (3) described that brown algae had strong antioxidant activity and that they synergistically enhanced the effect of vitamin E. Furthermore, Nishibori et al. (4) identified pheophytin a, one of the chlorophyll analogs, as a major antioxidant in Aonori (Enteromorpha sp.). In this paper, we describe the antioxidant effect of several extracts from Susabinori (Porphyra yezoensis), one of laver, and the isolation of antioxidants from the methanol extract. EXPERIMENTAL PROCEDURESMaterials and extraction. Cultured P. yezoensis was purchased from Akashiura Fisherman's Union (Hyogo, Japan) in February 1995. A part (10 g each) of the ground freeze-dried material was extracted independently with 200 mL of n-hexane, ethyl acetate, acetone, chloroform/methanol (2:1), methanol, and hot water (90°C) under stirring. Each extract was filtered and concentrated in vacuo. Water was added to the chloroform/methanol extract and then partitioned with chloroform to afford a chloroform-soluble fraction and an aqueous fraction. Antioxidative assay. (i) Ferric thiocyanate method (FTC). The method of Kikuzaki et al. (5) was slightly modified. To a mixture of 2 mg of the fractions of the Susabinori extract, α-tocopherol or isolated compounds in 2 mL of 99.5% ethanol in a vial (φ = 35, h = 80 mm), 2.05 mL of 2.51% linoleic acid in 99.5% ethanol, 4 ml of a 0.05 M phosphate buffer (pH 7.0), and 1.95 mL of water were added. The solution including linoleic acid without any antioxidant or extract was used as control. The vial was placed in an oven at 40°C in the dark. At each test time, to 0.1 mL of this sample solution were added 9.7 mL of 75% ethanol and 0.1 mL of 3...