Chizuko Yukizaki

Miyazaki Prefectural Wood Utilization Research Center, Миядзаки, Miyazaki, Japan

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Publications (18)20.98 Total impact

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    ABSTRACT: Blueberry (Vaccinium virgatunz Aiton) leaf extract (BLEx) has attracted attention as a beneficial food component. Here, we examined the effect of dietary BLEx on glucose and lipid metabolism in mice fed a high-fat, high-sucrose diet (HFHSD). Growth parameter data showed that 3% BLEx slightly reduced body weight and adipose tissue weight accompanied by inhibition of HFHSD-induced enlargement of adipocytes. Liver weight was significantly reduced in the 3% BLEx group secondary to reduction of lipid accumulation in the hepatocytes. HFHSD-induced augmentation of fasting serum glucose levels was ameliorated by 3% BLEx. HFHSD-induced increase of fasting serum insulin level, Homeostasis Model Assessment for Insulin Resistance (HOMA-IR) and Quantitative Insulin Sensitivity Check Index (QUICKI) also tended to be ameliorated. Oral glucose tolerance tests (OGTTs) revealed that 3% BLEx normalized HFHSD-induced elevation of the area under the curve for serum glucose, whereas dietary BLEx, even for the 3% dose, did not have a suppressive effect on the serum glucose change after OGTT. Taken together, these observations suggest that BLEx is a promising agent for the prevention of HFHSD-induced insulin resistance.
    No preview · Article · Nov 2015 · Food Science and Technology Research
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    ABSTRACT: Adult T-cell leukemia/lymphoma (ATL) is a fatal malignancy caused by infection with human T-lymphotropic virus type-1 and there is no accepted curative therapy for ATL. We searched for biological active substances for the prevention and treatment of ATL from several species of herbs. The ATL cell growth-inhibitory activity and apoptosis assay showed that carnosol, which is an ingredient contained in rosemary (Rosmarinus officinalis), induced apoptosis in ATL cells. Next, to investigate the apoptosis-inducing mechanism of carnosol, we applied proteomic analysis using fluorescent two-dimensional differential gel electrophoresis and mass spectrometry. The proteomic analysis showed that the expression of reductases, enzymes in glycolytic pathway, and enzymes in pentose phosphate pathway was increased in carnosol-treated cells, compared with untreated cells. These results suggested that carnosol affected the redox status in the cells. Further, the quantitative analysis of glutathione, which plays the central role for the maintenance of intracellular redox status, indicated that carnosol caused the decrease of glutathione in the cells. Further, N-acetyl-L-cystein, which is precursor of glutathione, canceled the efficiency of carnosol. From these results, it was suggested that the apoptosis-inducing activity of carnosol in ATL cells was caused by the depletion of glutathione.
    No preview · Article · Dec 2013 · Human Cell

  • No preview · Article · Mar 2013
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    Full-text · Article · Mar 2013
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    ABSTRACT: The serum and liver lipid-lowering effects of dietary freeze-dried blueberry leaf powder (BL) and its hydrothermal extract (BLHE) were examined in rats fed diets with or without cholesterol supplementation. Administration of 1% and 3% BL had no adverse effects on food intake or growth; however, relative liver weights were reduced in rats fed diets with and without dietary cholesterol. In the absence of dietary cholesterol, a dose-dependent reduction was evident. The effects of dietary BL on the concentration of serum lipids were marginal; however, the effects on liver triacylglycerol (TG) and cholesterol levels were apparently dose-dependent when the animals were fed diets free of cholesterol. Further, BL significantly attenuated dietary cholesterol-dependent accumulation of hepatic cholesterol, but not of TG. Hydrothermal treatment studies suggested that the active component of BL in terms of its liver lipid-lowering activity is relatively stable at high temperatures. Histopathological analysis of hepatic tissues revealed that BL administration suppresses fatty infiltrations induced by an AIN 76-based high-sucrose diet. The results of this study suggest that some of the active components of BL extracts, which are incorporated into the liver, prevent fatty liver in rats. These results provide further support for the investigation of dietary BL and derivatives thereof as functional human foods.
    Full-text · Article · Feb 2013 · Journal of oleo science
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    ABSTRACT: We evaluated the effects of dried blueberry leaves (BL) and its hot-water extract (BLEx) on blood pressure of spontaneously hypertensive rats (SHR). A continuous 3-week administration of BL (3 %) and BLEx (1.5 %) reduced systolic blood pressure compared to the control group from the 2-week feeding point. Additionally, we fractionated BLEx and investigated the compound responsible for the enhanced blood pressure-lowering effect. BLEx were fractionated into 5-fractions using Sephadex LH-20 and Diaion HP20SS chromatography, and assayed for angiotensin-I-converting enzyme (ACE) inhibitory activity in vitro. The fraction composed of proanthocyanidins showed the most potent inhibitory activity (IC50, 0.004 mg/mL) and reduced systolic blood pressure of SHR. These results suggest that BL and BLEx have anti-hypertensive effects and one of the active components has been identified as a proanthocyanidin.
    No preview · Article · Jan 2013 · Nippon Shokuhin Kagaku Kogaku Kaishi
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    ABSTRACT: Adult T-cell leukaemia (ATL) is caused by human T-cell leukaemia virus type I (HTLV-I) infection and is resistant to conventional chemotherapy. We evaluated the inhibitory effects of agricultural plants on the proliferation of seven ATL-related human leukaemia cells, using three ATL cell lines (ED, Su9T01 and S1T), two human T-cell lines transformed by HTLV-I infection (HUT-102 and MT-2) and two HTLV-I-negative human T-cell acute lymphoblastic leukaemia cell lines (Jurkat and MOLT-4). A total of 52 samples of 80% ethanol extracts obtained from 30 types of agricultural plants were examined. On the basis of IC(50) values, we selected samples with greater activity than genistein, which was used as a positive control. The highest inhibitory effect was observed with extracts from leaves of Vaccinium virgatum Aiton (blueberry) on four cell lines (ED, Su9T01, HUT-102 and Jurkat); seeds of Momordica charantia L. (bitter gourd) exhibited the second highest activity. The bitter gourd seeds suppressed the proliferation of three cell lines (Su9T01, HUT-102 and Jurkat). The extracts from edible parts of Ipomea batatas LAM. (sweet potato), edible parts of Colocasia esculenta (L.) Schott (taro), skin of taro and seeds of Prunus mume Sieb. et Zucc. (mume) showed markedly greater inhibitory effects on Su9T01 than genistein. These findings suggest that ATL-preventative bioactive compounds may exist in these agricultural plants, which are considered to be functional foods.
    No preview · Article · Feb 2011 · Journal of Natural Medicines
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    ABSTRACT: Hepatocyte growth factor (HGF) is useful as a potential therapeutic agent for hepatic and renal fibrosis and cardiovascular diseases through inducing proliferation of epithelial and endothelial cells. HGF inducers may also be useful as therapeutic agents for these diseases. However, there have been no reports on induction of HGF production by plant extracts or juices. An extract of bitter melon (Momordica charantia L.) pulp markedly induced HGF production. There was a time lag of 72 h before induction of HGF production after the extract addition. Its stimulatory effect was accompanied by upregulation of HGF gene expression. Increases in mitogen-activated protein kinases (MAPKs) were observed from 72 h after the extract addition. Inhibitors of MAPKs suppressed the extract-induced HGF production. The extract also stimulated cell proliferation. Both activities for induction of HGF production and cell proliferation were eluted together in a single peak with 14,000 Da on gel filtration. The results indicate that bitter melon pulp extract induced HGF production and cell proliferation of human dermal fibroblasts and suggest that activation of MAPKs is involved in the HGF induction. Our findings suggest potential usefulness of the extract for tissue regeneration and provide an insight into the molecular mechanism underlying the wound-healing property of bitter melon.
    No preview · Article · Mar 2009 · Cytokine
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    ABSTRACT: Bitter gourd ( Momordica charantia L.) pericarp, placenta, and seed extracts were previously shown to induce apoptosis in HL60 human leukemia cells. To determine the active component that induces apoptosis in cancer cells, bitter gourd ethanol extract was fractionated by liquid-liquid partition and silica gel column chromatography. Several fractions obtained by silica gel column chromatography inhibited growth and induced apoptosis in HL60 cells. Among them, fraction 7 had the strongest activity in inhibiting growth and inducing apoptosis in HL60 cells. A component that induced apoptosis in HL60 cells was then isolated from fraction 7 by another silica gel column chromatography and high-performance liquid chromatography (HPLC) using a C18 column and was identified as (9Z,11E,13E)-15,16-dihydroxy-9,11,13-octadecatrienoic acid (15,16-dihydroxy alpha-eleostearic acid). 15,16-Dihydroxy alpha-eleostearic acid induced apoptosis in HL60 cells within 5 h at a concentration of 160 microM (50 microg/mL). (9Z,11E,13E)-9,11,13-Octadecatrienoic acid (alpha-eleostearic acid) is known to be the major conjugated linolenic acid in bitter gourd seeds. Therefore, the effect of alpha-eleostearic acid on the growth of some cancer and normal cell lines was examined. alpha-Eleostearic acid strongly inhibited the growth of some cancer and fibroblast cell lines, including those of HL60 leukemia and HT29 colon carcinoma. alpha-Eleostearic acid induced apoptosis in HL60 cells after a 24 h incubation at a concentration of 5 microM. Thus, alpha-eleostearic acid and the dihydroxy derivative from bitter gourd were suggested to be the major inducers of apoptosis in HL60 cells.
    No preview · Article · Nov 2008 · Journal of Agricultural and Food Chemistry
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    ABSTRACT: Bitter gourd ( Momordica charantia L.) is a popular tropical vegetable in Asian countries. Previously it was shown that bitter gourd placenta extract suppressed lipopolysaccharide (LPS)-induced TNFalpha production in RAW 264.7 macrophage-like cells. Here it is shown that the butanol-soluble fraction of bitter gourd placenta extract strongly suppresses LPS-induced TNFalpha production in RAW 264.7 cells. Gene expression analysis using a fibrous DNA microarray showed that the bitter gourd butanol fraction suppressed expression of various LPS-induced inflammatory genes, such as those for TNF, IL1alpha, IL1beta, G1p2, and Ccl5. The butanol fraction significantly suppressed NFkappaB DNA binding activity and phosphorylation of p38, JNK, and ERK MAPKs. Components in the active fraction from bitter gourd were identified as 1-alpha-linolenoyl-lysophosphatidylcholine (LPC), 2-alpha-linolenoyl-LPC, 1-lynoleoyl-LPC, and 2-linoleoyl-LPC. Purified 1-alpha-linolenoyl-LPC and 1-linoleoyl-LPC suppressed the LPS-induced TNFalpha production of RAW 264.7 cells at a concentration of 10 microg/mL.
    Full-text · Article · Jul 2008 · Journal of Agricultural and Food Chemistry
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    ABSTRACT: The effect of drying temperature on the antioxidant activity of lemon balm (Melissa officinalis) leaves was investigated. Lemon balm leaves were dried with a ventilation dryer at 45°C, 55°C and 65°C, followed by milling. Among the three different temperature treatments, drying at 45°C resulted in the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, which is an index of antioxidant activity. The concentrations of polyphenols and rosmarinic acid were also highest in the sample treated at 45°C, suggesting that these antioxidants play an important role in the DPPH radical scavenging activity of the dry powders. On the other hand, when considering the use of dry lemon balm leaves as herbal tea, the 45°C-, 55°C-and 65°C-dry powder was extracted with hot water and DPPH radical scavenging activity was measured for each. All of the hot water extracts showed some extent of DPPH radical scavenging activity ; however, the highest activity was noted in the extract from the 45°C-dry powder. The concentrations of polyphenols and rosmarinic acid in hot water extracts were also highest in the 45°C-treated sample. These observations suggest that 45°C is the best drying temperature for retaining high antioxidant activity of lemon balm leaves in herbal tea production.
    No preview · Article · Jan 2008 · Nippon Shokuhin Kagaku Kogaku Kaishi
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    ABSTRACT: In our previous study, we showed the presence of liver lipid-lowering activity in the rat by Miyazaki-koimidori (KM), a traditional variety of bitter melon (Momordica charantia). Here, we studied the effect of novel varieties of M. charantia and ethanol/water extracts on rat liver lipid levels. First, we found that the liver lipid-lowering activity of Sadowara-sangou (S3), a main variety of bitter melon in Miyazaki was comparable to that of KM. Next, the effect of ethanol/water (100:0, 80:20, 60:40) extracts of S3 on liver lipid reduction was examined, and we found that the 60% ethanol extract was the most effective in lowering hepatic triglyceride levels. Finally, in addition to S3, 4 novel bitter melon cultivars (Miyazaki-N-ichigou, N 1; Miyazaki-N-nigou, N2; Miyazaki-N-sangou, N3; Miyazaki-N-yongou, N4) were fed to rats and the serum and liver triglycerides were analyzed. Among the 5 varieties, N3 and N4 tended to exert the most potent hepatic triglyceride-lowering activity, suggesting a variety-dependent difference. In these experiments, diets containing either bitter melon or ethanol/water extract caused no adverse effects on food intake or growth of rats, and the effects on serum lipids were marginal. The results of the present and previous studies clearly show that bitter melon exhibits a potent hepatic triglyceride-lowering activity.
    No preview · Article · Jan 2008 · Nippon Shokuhin Kagaku Kogaku Kaishi
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    Full-text · Article · Jul 2006 · HortScience: a publication of the American Society for Horticultural Science
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    ABSTRACT: We previously demonstrated that bitter gourd (Momordica charantia L.) ethanol extract induced apoptosis in HL60 human leukemia cells. To examine the effect of different bitter gourd cultivars on cancer cell growth, we determined the effect of nine bitter gourd cultivars grown in Miyazaki prefecture on the growth of HL60 cells. Although growth inhibitory effect of seed extracts was stronger than that of pericarp or placenta extracts, all the extracts inhibited the growth of HL60 cells at concentrations of 25-200 μg/ml. The extracts of pericarp, placenta and seeds of bitter gourds cultivars induced apoptosis in HL60 cells after 24 h incubation. Suppression of inflammatory responses is expected to reduce inflammatory disease and development of cancer. Therefore, we determined the effect of the major bitter gourd cultivar 'Sadowara 3' on the bacterial lipopolysaccharide (LPS)-induced TNFa production from RAW264.7 mouse macrophage-like cells. Placenta extract inhibited the TNFα production induced by LPS; however, it did not have any effect on the growth of RAW264.7 cells. The bitter gourd placenta is suggested to possess the suppressive effect on inflammatory responses.
    No preview · Article · Jan 2006 · Nippon Shokuhin Kagaku Kogaku Kaishi
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    ABSTRACT: The hypolipidemic effect of dietary methanol fraction (BMMF) extracted from bitter melon (Koimidori variety), at the levels of 0.5% and 1.0%, was examined in male golden Syrian hamsters fed diets supplemented with and without cholesterol. The feeding of BMMF at 0.5% and 1.0% levels in the diets for 4 wk tended to reduce food intake and growth, although there was no difference in food efficiency (weight gain/food intake). An effect of dietary BMMF on serum triglyceride was not seen in hamsters fed diets free of cholesterol, while hypertriglyceridemia induced by dietary cholesterol was significantly lowered in a dose-dependent manner in those fed diets containing the BMMF Serum total cholesterol concentration also tended to decrease in a dose-dependent manner following feeding of increasing amounts of BMMF in the presence and absence of cholesterol in the diet. The effects of dietary BMMF on liver triglyceride and total cholesterol levels were marginal, although dietary cholesterol caused a marked accumulation of these lipid molecules in the liver. These results suggest that the BMMF contains some components that could ameliorate lipid disorders such as hyperlipidemia.
    Full-text · Article · Sep 2004 · Journal of Nutritional Science and Vitaminology
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    ABSTRACT: Effects of three different varieties (Koimidori, Powerful-Reishi, and Hyakunari) of bitter melon (Momordica charantia) and those of methanol fraction extract of Koimidori variety on serum and liver triglycerides were studied in rats. Feeding of diets containing either bitter melon or various fractions isolated by organic solvents caused no adverse effects on food intake or growth of rats. When the effect of three different varieties of bitter melon was compared, the Koimidori variety was found to be the most effective in lowering hepatic triglyceride levels as compared to the other two varieties, suggesting a variety-dependent difference in their activity. Furthermore, the active component(s) responsible for the liver triglyceride lowering activity of Koimidori variety was assumed to be concentrated in the methanol fraction, but not in other fractions such as the n-hexane, the acetone, or the residual fraction. The triglyceride lowering activity was furthermore confirmed by the dose-dependent reduction of hepatic triglyceride, resulting the lowest level in rats fed 3.0% supplementation. In these experiments, the effects on serum lipids were marginal. The results of the present and previous studies clearly show that bitter melon, especially Koimidori variety, exhibits a potent liver triglyceride-lowering activity.
    Full-text · Article · May 2004 · Journal of Ethnopharmacology
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    ABSTRACT: The effects of dietary bitter melon (Momordica charantia) freeze-dried powder on serum glucose level and lipid parameters of the serum and liver were studied in rats fed diets supplemented with and without cholesterol. Rats were fed the diets for 14 days containing bitter melon freeze-dried powder at the level of 0.5, 1 and 3% without an added dietary cholesterol (experiment I) and those containing bitter melon at the level of 1% with or without 0.5% cholesterol and 0.15% bile acid (experiment II). No adverse effect of dietary bitter melon powder on growth parameters and relative liver weight were noted. Dietary bitter melon resulted in a consistent decrease in serum glucose levels in rats fed cholesterol-free diets, but not in those fed cholesterol-enriched diets, although no dose-response was noted. Addition of cholesterol to the diets as compared to those without added cholesterol caused hypercholesterolemia and fatty liver. Bitter melon had little effect on serum lipid parameters, except for high density lipoprotein (HDL)-cholesterol; HDL-cholesterol levels tended to decrease by dietary cholesterol, while they were consistently elevated by dietary bitter melon both in the presence and absence of dietary cholesterol, indicating an antiatherogenic activity of bitter melon. In addition, bitter melon exhibited a marked reduction in the hepatic total cholesterol and triglyceride levels both in the presence and absence of dietary cholesterol; the reduction of triglyceride levels in the absence of dietary cholesterol was in a dose-dependent manner. These results suggest that bitter melon can be used as a health food.
    Full-text · Article · Oct 2000 · Journal of Ethnopharmacology
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    ABSTRACT: 宮崎県産の穀類、野菜類、果物類、ハーブ類などの農産物44種98品目のエタノール抽出物について、Ames法を利用した抗変異原試験、第II相反応の硫酸抱合に注目した抗変異原試験の2つの試験を行った。高い抗変異原作用を示したものは、カンショの茎、ダイズ、ゴボウ、マンゴー果皮、シソ科ハーブ類であり、中でもダイズ、ゴボウ、マンゴー果皮は、Ames法を利用した抗変異原試験よりも第II相反応の硫酸抱合を重視した抗変異原試験において顕著な抗変異原作用を示した。今回2つの抗変異原試験を用いて抗変異原作用をもつ農産物の検索を行うことにより、食品のもつ抗変異原活性を幅広く検出することができた。 Forty four different farm products which are grown in Miyazaki prefecture were studied for antimutagenic activities. The selected samples are ethanol extracts from grains, vegetables, fruits and herbs. The Ames test and novel antimutagenic test using phase II conjugation enzyme (sulfotransferase) were used to determine the antimutagenic activities. Stalk of sweet potato, soybean, burdock, pericarp of mango and labiate herb had strong antimutagenic activities. While, when sulfate conjugation method is Ames test. The antimutagenic activity of the food was able to be widely detected by using two methods.
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