| Co-Investigator(Kenkyū-buntansha) |
TAKENAKA Shigeo HAGOROMO-GAKUENN JUNIOR COLLGE, HUMAN LIVING SCIENCE, ASSISTANT PROFESSOR, 人間生活学科, 助教授 (10280067)
NAKAYAMA Rei HAGOROMO-GAKUENN JUNIOR COLLGE, HUMAN LIVING SCIENCE, ASSISTANT PROFESSOR, 人間生活学科, 助教授 (00189086)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1998: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Vitamin B_<12> concentrations of dried green (Enteromorpha sp.) and purple (Porphyra sp.) Iavers (nori) were determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor chemiluminescence methods. The values determined by using the microbiological method (68.58±2.9 and 32.26±1.61 u g/1OOg of dry weight) were identical to (bund by using the chemiluminescence method (60.20±2.21 and 25.07±0.54 <μg/100g dry weight) in both dried green and purple lavers, respectively. The vitamin B_<12> concentration of an algal health food, spirulina (Spirulina sp.) tablets, was determined. The values determined with the microbiological method were 〜6-9-fold greater in the spirulina tablets than the values determined with chemiluminescence method. The contents of vitamin B_<12> in foods were assayed by using a fully automated chemiluminescence analyzer, which was compared with a microbiological method. In shellfishes and spirulina, the values determined by the microbiological
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method were〜6-8 told greater than the values determined by the chemiluminescence method, although there was good similarity between the values by the two methods in other foods. To clarify the bioavailability of vitamin B_<12> in lyophilized purple laver(nori), total vitamin B_<12> and vitamin B_<12> analogue contents were determined, and the effects of feeding the laver to vitamin B_<12>-deficient rats were investigated. The purple laver contained five types of biologically active vitamin B_<12> compounds(cyano-, hydroxo-, sulfito-, adenosyl-, and methylcobalamin), in which vitamin B_<12> coenzymes (adenosyl- and rnethylcobalamin) comprised about 60% of the total vitamin B_<12>. When 9-week-old vitamin Burdeficient rats, which excreted substantial amounts of methylmaIonic acid(71.7(SE 20.2) μ mol/d) in urine, were fed the diet purple laver (10μg/kg diet) for 20 d. urinary methylmalonic acid excretion (as an index of vitamin B_<12> deficiency) become uncletectable 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. Dunaliella tertiolecta neither required vitamin B_<12> for growth nor took up exogenous vitamin B_<12> significantly. The Dunaliella cells grown in a vitamin B_<12>-free medium contained biologically active vitamin B_<12> (20.18±5.53 ng/g wet weight). About 77% of vitamin B_<12> found in the cells was recovered in macromolecular fractions (adenosyl- B_<12>, 39% ; and methyl- B_<12>, 21%). These results suggest that the alga has ability to synthesize vitamin B_<12> coenxymes.
To examine the antioxidative compounds of nonpmtein amino acids in a red alga. Porphyra yezoensis, an ethanol extract of the cultured thalli was fractionated with Dowex column. The basic fraction V showed strong antioxidative capacities with ferric thiocyanate and TBARS measurements. In this basic fraction, histidine, 3-methylhistidine, carnosine, and anserine wewre detected beside ornitine, lysine, and arginine by amino acid analysis. The occurrence ofcarnosine and anserine suggests that the histidine-related compounds also contribute to the antioxidative reactions in P. yezoensis. The antioxidant activities of several extracts from Susabinori were measured by the ferric thiocyanate method and the thiobarbituric acid method. The methanol, acetone, ethyl acetate, and Ivexane extracts, and the chloroform-soluble and water-soluble fractions from the chloroform-metanol extract exhibited higher activities than a -tocopherol. The hot water extract showed little activity. Thin-layer 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 antioxiclant was isolated from the methanol extract, accompanied by several amino acids such as leucine and phenylalanine. This compound was identified as usujilene, a kind ofmycosporine-glycine like amino acid. Less
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