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Hiroko Tani

    Hiroko Tani

    Three chlamydocin analogues that show activity for reducing the height of rice seedlings without blotch and wilting were isolated from the culture filtrate of the soil fungus Peniophora sp. and were characterized by spectral data and... more
    Three chlamydocin analogues that show activity for reducing the height of rice seedlings without blotch and wilting were isolated from the culture filtrate of the soil fungus Peniophora sp. and were characterized by spectral data and chemical conversion. For two of these, it is their first isolation as natural products. The proposed role of the functional groups of the 2-amino-8-oxodecanoic acid moiety of these analogues is discussed in terms of growth retardant activity.
    ABSTRACT
    ABSTRACT
    Cinnamic acid derivatives, which are dietary phenolic compounds, are attracting attention for their health benefits. Artepillin C, drupanin, baccharin, and p-coumaric acid are major cinnamic acid derivatives in Brazilian green propolis... more
    Cinnamic acid derivatives, which are dietary phenolic compounds, are attracting attention for their health benefits. Artepillin C, drupanin, baccharin, and p-coumaric acid are major cinnamic acid derivatives in Brazilian green propolis (BGP) used as functional food materials. To investigate the metabolism of these cinnamic acid derivatives, each compound was administered to rats, and their metabolic profiles were compared with those administered BGP. Artepillin C metabolized to hydroxylated metabolites (capillartemisin A), as well as glucuronide. Drupanin sulfate, glucuronide, and hydroxylated form were detected in plasma both after ingestion of drupanin and its 3-phenylpropionic acid ester (baccharin). p-Coumaric acid underwent sulfation, but not glucuronidation. These results reveal that the metabolic pathways of cinnamic acid derivatives in rats comprise ester hydrolysis and hydroxylation, as well as phase-II conjugation. Our findings may provide significant information for estim...
    Dry eye is a multifactorial disease characterized by ocular discomfort and visual impairment. Our previous studies have shown that royal jelly (RJ) has restored the capacity for tear secretion by modulating muscarinic calcium signaling.... more
    Dry eye is a multifactorial disease characterized by ocular discomfort and visual impairment. Our previous studies have shown that royal jelly (RJ) has restored the capacity for tear secretion by modulating muscarinic calcium signaling. RJ contains acetylcholine, which is a major cholinergic neurotransmitter, and a unique set of fatty acids with C 8 to 12 chains, which are expected to be associated with health benefits. The purpose of the present study was to investigate the active components involved in tear secretion capacity, focusing on acetylcholine and fatty acids in RJ. Using the stress-induced dry-eye model mice, it was confirmed that acetylcholine with three fatty acids (10-hydroxydecanoic acid, 8-hydroxyoctanoic acid, and (R)-3,10-dihydroxydecanoic acid) was essential for tear secretion. In ex vivo Ca2+ imaging, these three fatty acids suppressed the decrease in intracellular modulation of Ca2+ in the lacrimal gland by acetylcholine when treated with acetylcholinesterase, ...
    Phenolic glucuronides of artepillin C and drupanin were identified as the major metabolites in plasma after ingestion of Brazilian green propolis.
    Both ‘Atago’ and ‘Shinkou’ are late-season japanese pear (Pyrus pyrifolia Nakai) cultivars with russet-brown fruit, and the progenies of crosses made between ‘Nijisseiki’ and unknown cultivars, but they display different growth habit,... more
    Both ‘Atago’ and ‘Shinkou’ are late-season japanese pear (Pyrus pyrifolia Nakai) cultivars with russet-brown fruit, and the progenies of crosses made between ‘Nijisseiki’ and unknown cultivars, but they display different growth habit, fruit size, and fruit quality. To clarify the difference in fruit development between the two cultivars, the levels of endogenous gibberellins (GA1, GA3, and GA4) and abscisic acid (ABA) in fruit were identified and quantified by gas chromatography/mass spectrometry, and a histological study of fruit was carried out. The results showed that cell number rather than cell size of mesocarp is responsible for the difference in fruit size between the two cultivars. Furthermore, analysis of endogenous bioactive gibberellins revealed that ‘Atago’ fruit has much higher levels of GA1, GA3, and GA4 than ‘Shinkou’ fruit during fruit development, particularly during the early period of fruit growth. However, ‘Shinkou’ has a much higher ABA level than ‘Atago’ during...
    Three chlamydocin analogues that show activity for reducing the height of rice seedlings without blotch and wilting were isolated from the culture filtrate of the soil fungus Peniophora sp. and were characterized by spectral data and... more
    Three chlamydocin analogues that show activity for reducing the height of rice seedlings without blotch and wilting were isolated from the culture filtrate of the soil fungus Peniophora sp. and were characterized by spectral data and chemical conversion. For two of these, it is their first isolation as natural products. The proposed role of the functional groups of the 2-amino-8-oxodecanoic acid moiety of these analogues is discussed in terms of growth retardant activity.
    To identify lactic acid bacterial isolates, which promote immunoglobulin A (IgA) production in honeybee products and honeybees (Apis mellifera). Pyrosequencing analysis of the microbiota of honeybee products and honeybees revealed the... more
    To identify lactic acid bacterial isolates, which promote immunoglobulin A (IgA) production in honeybee products and honeybees (Apis mellifera). Pyrosequencing analysis of the microbiota of honeybee products and honeybees revealed the predominance of Lactobacillus kunkeei in honey, bee pollen, bee bread and royal jelly. Lactobacillus kunkeei was isolated from bee pollen, bee bread and honey stomach, and its effect on IgA production was evaluated in vitro. Heat-killed YB38 and YB83 isolates from bee pollen promoted IgA production in mouse Peyer's Patch cells and had little mitogenic activity or effect on IL-2 production in mouse spleen cells in comparison with Listeria monocytogenes, which does exhibit mitogen activity. A pilot study in 11 healthy adults showed that 4-week intake of 1000 mg day(-1) heat-killed YB38 increased secretory IgA (SIgA) concentrations and secretion in saliva with no adverse effects. Heat-killed Lact. kunkeei YB38 from bee pollen increases IgA production and may safely improve immune responsiveness. This is the first report of microbiota analysis of royal jelly and the immune efficacy of Lact. kunkeei from honeybee products in humans.
    ABSTRACT (E)-9,10-Dihydroxy-2-decenoic acid 1 was isolated as a new compound from royal jelly. The planar structure was deduced by spectroscopic analyses, whereas the absolute configuration was established by chemical synthesis of both... more
    ABSTRACT (E)-9,10-Dihydroxy-2-decenoic acid 1 was isolated as a new compound from royal jelly. The planar structure was deduced by spectroscopic analyses, whereas the absolute configuration was established by chemical synthesis of both enantiomers of 1. The natural product was revealed to be ca. 3.5:1 mixture of (R)- and (S)-acids by comparison of 1 with authentic samples.
    Fruits and seeds of melinjo (Gnetum gnemon L.) are resveratrol derivative-rich materials. Pharmacokinetics of resveratrol derivatives in healthy volunteers after oral administration of 1000 mg of melinjo seed extract (MSE) powder were... more
    Fruits and seeds of melinjo (Gnetum gnemon L.) are resveratrol derivative-rich materials. Pharmacokinetics of resveratrol derivatives in healthy volunteers after oral administration of 1000 mg of melinjo seed extract (MSE) powder were assessed and compared with those after oral dosing of trans-resveratrol (tRV) powder containing 4.8 mg of tRV only, equivalent to the content in 1000 mg MSE powder. Plasma tRV concentrations with enzymatic hydrolysis were maintained over 24 h, with a tmax of 12 h and a mean residence time (MRT) of 14 h, 5 and 2 times higher than those for tRV powder intake, respectively. Gnetin C, a resveratrol dimer, with hydrolysis was maintained in plasma for >96 h with a 36 h MRT. With repeated doses once daily for 28 days, plasma tRV and gnetin C concentrations with hydrolysis were in good agreement with the theoretical curves. MSE powder was well tolerated up to the oral dosing of 5000 mg with no serious adverse events.
    Melinjo (Gnetum gnemonL.) seed extract (MSE) containingtrans-resveratrol (3,5,4′-trihydroxy-trans-stilbene) and other derivatives exerts various beneficial effects. However, its mechanism of action in humans remains unknown. In this... more
    Melinjo (Gnetum gnemonL.) seed extract (MSE) containingtrans-resveratrol (3,5,4′-trihydroxy-trans-stilbene) and other derivatives exerts various beneficial effects. However, its mechanism of action in humans remains unknown. In this study, we aimed to investigate beneficial effects of MSE in healthy adult males. In this double-blind, randomized controlled study, 30 males aged 35–70 years with ≤10% flow-mediated dilatation received placebo or 750 mg MSE powder for 8 weeks, and twenty-nine males (45.1±8.8years old) completed the trial. There was a significant difference in the melinjo and placebo groups. Compared with the placebo control, MSE significantly reduced serum uric acid at 4 weeks and 8 weeks (n=14and 15, resp.). HDL cholesterol was significantly increased in the melinjo group. To clarify the mechanism of MSE for reducing uric acid, we investigated xanthine oxidase inhibitory activity, angiotensin II type 1 (AT1) receptor binding inhibition rate, and agonistic activities for...
    Genomic destabilisation is associated with the induction of mutations, including those in cancer-driver genes, and subsequent clonal evolution of cells with abrogated defence systems. Such mutations are not induced when genome stability... more
    Genomic destabilisation is associated with the induction of mutations, including those in cancer-driver genes, and subsequent clonal evolution of cells with abrogated defence systems. Such mutations are not induced when genome stability is maintained; however, the mechanisms involved in genome stability maintenance remain elusive. Here, resveratrol (and related polyphenols) is shown to enhance genome stability in mouse embryonic fibroblasts, ultimately protecting the cells against the induction of mutations in the ARF/p53 pathway. Replication stress-associated DNA double-strand breaks (DSBs) that accumulated with genomic destabilisation were effectively reduced by resveratrol treatment. In addition, resveratrol transiently stabilised the expression of histone H2AX, which is involved in DSB repair. Similar effects on the maintenance of genome stability were observed for related polyphenols. Accordingly, we propose that polyphenol consumption can contribute to the suppression of cancers that develop with genomic instability, as well as lifespan extension.
    A new cinnamic acid derivative, (E)-3-[4-hydroxy-3-((E)-3-formyl-2-butenyl)phenyl]-2- propenoic acid (20) has been isolated from the ethanol extract of Brazilian green propolis along with three known cinnamic acid derivatives,... more
    A new cinnamic acid derivative, (E)-3-[4-hydroxy-3-((E)-3-formyl-2-butenyl)phenyl]-2- propenoic acid (20) has been isolated from the ethanol extract of Brazilian green propolis along with three known cinnamic acid derivatives, 3,4-dihydroxy-5-prenyl-(E)-cinnamic acid (4), capillartemisin A (6) and 2,2-dimethylchromene-6-(E)-propenoic acid (8), and a flavonoid, dihydrokaempferide (16) by liquid-liquid participation, a series of column chromatography and preparative HPLC. Their structures have been determined by spectroscopic analyses and chemical synthesis of compound 20. The simultaneous quantification of 20 constituents, including 10 cinnamic acid derivatives, 7 flavonoids and 3 caffeoylquinic acid derivatives, has also been developed and validated using LC-MS/MS. The new compound 20 was shown to activate PPAR α but not PPAR β or γ.
    The royal jelly fatty acids were metabolized to dicarboxylic acids, absorbed into the circulation and then excreted in the urine.
    Melinjo (Gnetum gnemon L.) seed extracts (MSEs) are rich in resveratrol dimers (gnemonoside A, C, D, gnetin C), trans-Resveratrol, and other resveratrol derivatives. trans-Resveratrol is a widely studied caloric restriction mimetic. In... more
    Melinjo (Gnetum gnemon L.) seed extracts (MSEs) are rich in resveratrol dimers (gnemonoside A, C, D, gnetin C), trans-Resveratrol, and other resveratrol derivatives. trans-Resveratrol is a widely studied caloric restriction mimetic. In mice fed a high-fat diet (HFD), trans-Resveratrol protects against obesity, type 2 diabetes, and premature death. Here, treatment of HFD-fed mice with 2.0% MSE significantly reduced body weight gain (p < 0.001), blood insulin (p < 0.01), and HOMA-IR (p < 0.05) after 8 weeks compared with untreated HFD-fed mice. Additionally, 0.2% MSE treatment of HFD-fed mice significantly improved physiological activity (p < 0.05) at 18 months of age and reduced risk of death due to HFD by 25% (hazard ratio = 0.75, p = 0.036). These data show that MSE can improve several aspects of metabolic syndrome and survival in mice and may have health benefits as a dietary supplement.
    Four new metabolites, botcinins A-D, were isolated from the culture filtrate of a strain of Botrytis cinerea. Their structures were determined by spectroscopic methods, mainly NMR techniques, molecular modeling, and the modified... more
    Four new metabolites, botcinins A-D, were isolated from the culture filtrate of a strain of Botrytis cinerea. Their structures were determined by spectroscopic methods, mainly NMR techniques, molecular modeling, and the modified Mosher's method. They exhibited antifungal activities against Magnaporthegrisea, a pathogen of rice blast disease. Botcinins B and C have a MIC of 12.5 microM, and botcinins A and D are not active below 100 microM.
    A comparison of the plant growth retardant activity of the chlamydocin analogues, compound 1, six derivatives from 1 and 2, and two synthetic analogues revealed that there are two types of retardant in chlamydocin analogues. One, for... more
    A comparison of the plant growth retardant activity of the chlamydocin analogues, compound 1, six derivatives from 1 and 2, and two synthetic analogues revealed that there are two types of retardant in chlamydocin analogues. One, for example in compound 1, requires an oxygen atom at C-8 of the 2-aminodecanoic acid moiety to show retardant activity. The other, for example in compound 8, requires no oxygen atom at C-8 but requires a specific alkyl group chain length for activity. To determine the differences in mode of action of both types of retardant, rice seedlings were separately treated with compounds 1 and 8, and after appearance of dwarfism, their endogenous ABA and GA(1) levels were determined and compared to those of the control. Treatment with 1 (10 nmol/plant) increased ABA levels 4 times higher than that of the control and decreased GA(1) levels to 20% of that of the control. Treatment with 8 (30 nmol/plant) did not affect the ABA level but decreased GA(1) content to 5% of...