Publications by authors named "Yoshihito Okada"

Although Aiton leaves and stems inhibit adult T-cell leukemia (ATL) cells, leaves and stems can differ between individual plants and by time and location. In this study, leaf and stem components were profiled in the same individual plant using direct-injection electron ionization-mass spectrometry (DI-EI-MS) metabolomics, with the aims of analyzing the anti-ATL activity, and quantifying proanthocyanidins (PACs). Leaves, stems, and leaf/stem mixtures showed distinct and characteristic spectra.

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The C-NMR spectral data for the 15-carbon flavonoid skeleton in eleven methoxyflavones isolated from Kaempferia parviflora (Zingiberaceae) were processed by principal component analysis (PCA). Based on the PCA score plots, the methoxyflavones were categorized into three groups according to their structural features. The cytotoxicities of the methoxyflavones toward 3T3-L1 murine preadipocyte cells were evaluated by 3-(4,5-dimethylthiazole-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTT) assay and found to differ according to structure.

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Metabolic profiling is often used to identify possible correlations between a compound's metabolic profile and biological activity. Direct-injection electron ionization-mass spectrometry "fingerprinting" is useful for characterizing biological materials. We demonstrate the utility of direct-injection electron ionization-mass spectrometry for metabolic profiling using 100 different extracts of leaves from 20 blueberry cultivars collected at 5 time points from April to December 2008.

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Direct-injection electron ionization-mass spectrometry (DI-EI-MS) is a multivariate analysis method useful for characterizing biological materials. We demonstrated the use of DI-EI-MS for metabolic profiling using several closely related lichen species: Cladonia krempelhuberi, C. gracilis, C.

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The roots and stolons of some Glycyrrhiza species are used worldwide for traditional folk medicines and commercial pharmaceuticals. Phenolic constituents such as flavonoids and coumarins are medicinal and vary according to species. Therefore, species identification is important for quality analysis.

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An electron ionization mass spectrometry (EI-MS)-based metabolomic approach was applied to Sophora flavescens to identify the geographical origin of each sample. The score plot from principal component analysis using the EI-MS data showed that Japanese S. flavescens samples tended to cluster away from Chinese S.

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In order to identify the country of growth of Sophora flavescens by chemical fingerprinting, extracts of plants grown in China and Japan were analyzed using direct analysis in real time mass spectrometry (DART)-MS. The peaks characteristic of each country of growth were statistically analyzed using a volcano plot to summarize the relationship between the p-values of a statistical test and the magnitude of the difference in the peak intensities of the samples in the groups. Peaks with ap value < 0.

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Background: Castanea mollissima Blume (Chinese chestnut), as a food product is known for its various nutrients and functional values to the human health. The present study was carried out to analyze the anti-diabetic complications and anti-cancer activities of the bioactive compounds present in C. mollissima.

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Article Synopsis
  • The 5-year survival rate for oral cancer patients has stagnated at around 50% for 30 years, mainly due to ineffective tumor-targeting of existing drugs, prompting a search for more effective plant extracts.
  • Two human oral cancer cell lines and normal oral cells were tested for cell viability after exposure to various plant extracts using the MTT method, determining cytotoxicity and tumor specificity.
  • Camptotheca acuminate leaf showed the highest tumor specificity, indicating significant potential for anti-cancer treatment, with other promising extracts also identified but with lower specificity scores.
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In order to identify Glycyrrhiza species by chemical fingerprinting, the bark of the roots and stolons of Glycyrrhiza uralensis Fischer and G. glabra Linné were analyzed using DART (Direct Analysis in Real Time)-MS. The characteristic peaks of each species were determined statistically by volcano plot.

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We demonstrate that NMR-based metabolomics studies can be used to identify xanthine oxidase-inhibitory compounds in the diethyl ether soluble fraction prepared from a methanolic extract of Sophora flavescens. Loading plot analysis, accompanied by direct comparison of 1H NMR spectraexhibiting characteristic signals, identified compounds exhibiting inhibitory activity. NMR analysis indicated that these characteristic signals were attributed to flavanones such as sophoraflavanone G and kurarinone.

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Three new triterpene glucosides, named congmuyenosides C-E (1-3, resp.), along with four known ones, were isolated from an EtOH extract of Aralia elata (Miq.) Seem.

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We demonstrate that NMR-based metabolomics can be used to identify the country of growth (Japan or China) of Sophora flavescens plants. Principle Component Analysis (PCA) conducted on extracts of S. flavescens grown in China provided data distinct from that of extracts of plants grown in Japan.

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This study presents the application of the NMR-based analyses, DOSY and ROSY, to the chalcones, xanthoangelol (1) and 4-hydroxyderricin (2) from Angelica keiskei. We investigated whether virtual separation and structural information from each compound can be obtained. DOSY displays spectra of (1) and (2) in one dimension and diffusion spectra in the other.

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Recently, NMR-based metabolomic analysis has been used to acquire information based on differentiation among biological samples. In the present study, we examined whether multivariate analysis was able to be applied to natural products and/or material field. Each extraction of 24 leaf samples, divided into six locations from the tip of the stem in each of four strains, was analyzed by pattern recognition methods, known as Principal Component Analysis (PCA) and Soft Independent Modeling of Class Analogy (SIMCA).

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Context: Prevalence of diabetes mellitus type 2 (DM-II) is increasing in Japan. Brown alga Ecklonia kurome Okamura (Laminariaceae) (kurome in Japanese) is rich in phlorotannins, a kind of polyphenol. Phlorotannins have been reported to possess various bioactivities; however, few studies have reported its effect on DM-II.

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DART (Direct Analysis in Real Time)-MS is a novel mass spectrometric ion source, and allows the analysis of most compounds at ambient pressure and ground potential by producing [M+H]+ molecular ion species. Using this method, we examined the compounds characteristic of several kinds of licorices. For the analysis of Glycyrrhiza inflata Batalin, the peak at m/z 339 originates mainly from [M+H]+ of licochalcone A (LA), a species-specific compound.

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Linear-type furocoumarins, 5-[(2"E,6"R)-6"-hydroxy-3",7"-dimethylocta-2",7"-dienyloxy]psoralen and 5-[(2"E,6"S)-6"-hydroxy-3",7"-dimethylocta-2",7"-dienyloxy]psoralen (1) were first isolated from whole plants of Seseli hartvigii together with one new natural product 6-(3'-methyl-2'-oxo-3'-butenyl)-7-methoxycoumarin (2), and four known compounds (tamarin, bergaptol, notoptol, and a mixture of beta-sitosterol and stigmasterol). The structure of 1 was elucidated by extensive spectroscopic analysis and chemical conversion. The modified Mosher's method and HPLC were applied to determine its stereochemistry.

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Article Synopsis
  • This study investigated the impact of xanthoceraside on learning and memory deficits in mice caused by beta-amyloid injection.
  • Mice tested showed improved performance in learning tasks, with fewer errors and longer times before making mistakes after being treated with xanthoceraside.
  • Additionally, biochemical analyses indicated that xanthoceraside improved oxidative stress markers and enzyme activities, suggesting it could be a promising treatment for Alzheimer's disease.
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A new simple coumarin glycoside, named praeroside VI (1), along with six known coumarins, were isolated from an aqueous extract of Bai-Hua Qianhu, the root of Peucedanum praeruptorum DUNN. (Umbelliferae). Spectroscopic analysis and chemical studies were carried out to investigate the structure of the new coumarin, which was concluded to be 1.

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Two new coumarin glycosides, praerosides VI (1) and VII (2), were isolated from the roots of Peucedanum praeruptorum Dunn. Their structures were elucidated by chemical reaction and NMR spectroscopic methods.

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Two novel angular-type furanocoumarin glycosides, peucedanoside A (1) and peucedanoside B (2), along with a known compound apterin (3), were isolated from the roots of Peucedanum praeruptorum Dunn. Their chemical structures were determined by MS, NMR spectroscopy and chemical analysis. Complete assignments of the 1H and 13C NMR spectroscopic data were achieved by 1D and 2D NMR experiments including DEPT, HSQC, HMBC and ROESY.

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A new sesquiterpene along with 15 known compounds were isolated from the style of Zea mays L. These structures were elucidated on the basis of spectroscopic analysis. The ability of these compounds to inhibit glycation in vitro was analyzed.

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The effectivity of water extract from the style of Zea mays on diabetic nephropathy was investigated in the development of new natural medicinal resources. Streptozotocin (STZ) induced diabetic rats were used to evaluate the therapeutic effect of the style. Urinary albumin excretion and creatinine clearance were examined for diagnosis of diabetic nephropathy.

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