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Volume 68, Issue 1
Displaying 1-4 of 4 articles from this issue
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Reviews
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(JSNFS Award for Excellence in Research (2014) )Junji Terao2015 Volume 68 Issue 1 Pages 3-11
Published: 2015
Released on J-STAGE: February 20, 2015
JOURNAL FREE ACCESSDietary antioxidants are expected to exert their physiological functions in vivo by regulating oxidative stress responsible for aging and aging-related degenerative diseases. However, evaluation of their effectiveness in humans is difficult because their bioavailability is still largely unknown. To resolve this problem, integrated studies from experiments using cultured cells to human clinical trials should be carried out with regard to the absorption, distribution, metabolism, excretion and behavior of dietary antioxidants at the target site. We attempted to evaluate the effectiveness of carotenoids and flavonoids for prevention of a variety of oxidative stress-related diseases from the viewpoint of their action as direct antioxidants and/or tuning factors for the cellular redox signaling pathway. It is likely that β-carotene accumulates in the skin in its original form and acts as a direct singlet oxygen quencher. Quercetin seems to require a deconjugation reaction from its conjugated metabolites to active aglycone in order to exert its physiological function in vivo, because this flavonoid is obligatorily converted to its conjugated metabolites during intestinal absorption. We proposed some plausible mechanisms for the prevention of atherosclerosis, depression and disuse muscle atrophy. These would be helpful for assessing the effectiveness of dietary antioxidants in human clinical trials.View full abstractDownload PDF (1454K) -
(Young Investigator Award of JSFNS (2014) )Hiroaki Kanouchi2015 Volume 68 Issue 1 Pages 13-17
Published: 2015
Released on J-STAGE: February 20, 2015
JOURNAL FREE ACCESSVitamin B6 is reported to have anti-tumorigenic effects, but the mechanism responsible is not well understood. We found that vitamin B6 activates p53, resulting in growth suppression and apoptosis in human breast cancer MCF-7 cells. Among the vitamin B6 analogs, pyridoxal has the strongest effect. Differences in the effects of these analogs may be related to differences in cell surface interactions. Pyridoxal was observed to show the strongest binding to the cell surface among the vitamin B6 analogs. Although epidemiological studies have shown that homocysteinemia is related to dementia, precisely how homocysteine induces dementia has not been clarified. Homocysteine is an amino acid and its metabolism requires vitamin B6, folate, and vitamin B12. We conclude that U-251MG glioma cells may secrete molecules that are cytotoxic to SH-SY5Y neuroblastoma cells upon stimulation with homocysteine. Epidemiological studies on the relationship between human plasma homocysteine concentrations and dietary habits in the Amami Islands, Kagoshima Prefecture, found that a high consumption of beans or eggs was related to lower homocysteine concentrations in men and postmenopausal women respectively.View full abstractDownload PDF (796K)
Research Notes
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Fumiko Sakata, Katsunori Sasaki, Takayuki Uchida, Kazuo Chiku, Yutaka ...2015 Volume 68 Issue 1 Pages 19-23
Published: 2015
Released on J-STAGE: February 20, 2015
JOURNAL FREE ACCESSPreviously, we have reported that rats with protein-energy malnutrition suffer from impaired iron metabolism due to induction of hepcidin-25. Supply of iron under conditions of high levels of hepcidin-25 would carry a risk of iron overload. In this study, hepcidin-25 kinetics and iron metabolism were investigated after protein re-feeding in rats with protein-energy malnutrition. Iron metabolism under conditions of iron supply was also investigated. Supply of protein in the protein re-feeding period allowed an increase of hepcidin-25 in serum, followed by a temporary reduction, and enhancement of iron deposition in the spleen. On the other hand, when no iron was supplied, iron deficiency anemia occurred, but slight iron deposition in the spleen was still observed. These results suggest that in protein-energy malnutrition, impairment of iron utilization may persist even after protein re-feeding once the protein has accumulated.View full abstractDownload PDF (723K) -
Noriko Bando, Miki Kataoka, Toshiyuki Nakamura, Rie Mukai, Takashi Yam ...2015 Volume 68 Issue 1 Pages 25-29
Published: 2015
Released on J-STAGE: February 20, 2015
JOURNAL FREE ACCESSWe investigated the bioavailability of soy isoflavones from processed soybean products. Five healthy male volunteers ingested soy milk, soy curd (tofu) , boiled soybeans (nimame) , or fermented soybeans (natto) in a single dose, and blood was collected 90 min later for measurement of the plasma isoflavone concentration. Each subject ingested test meals containing an isoflavone equivalent of 50 mg aglycone. The total amount of each isoflavone was determined by HPLC analysis after deconjugation of conjugated metabolites using sulfatase H-1. The concentration of glycitein was below the detection limit before and after intake of the soybean products. The concentrations of daidzein and genistein were elevated in all subjects after ingestion of all the test meals, and the concentration of genistein was higher than that of daidzein except after ingestion of fermented soybeans. Ingestion of boiled soybeans appeared to result in a higher concentration of total isoflavones (daizein and genistein) than ingestion of soy curd. These results suggest that the bioavailability of isoflavones from soybeans varies according to the type of processing.View full abstractDownload PDF (731K)
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