Japan Food Research Laboratories

Shibuya-ku, Japan

Japan Food Research Laboratories

Shibuya-ku, Japan
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Kudo Y.,Tohoku University | Yasumoto T.,Japan Food Research Laboratories | Konoki K.,Tohoku University | Cho Y.,Tohoku University | Yotsu-Yamashita M.,Tohoku University
Marine Drugs | Year: 2012

Identification of new tetrodotoxin (TTX) analogs from TTX-possessing animals might provide insight into its biosynthesis and metabolism. In this study, four new analogs, 8-epi-5,6,11-trideoxyTTX, 4,9-anhydro-8- epi -5,6,11-trideoxyTTX, 1-hydroxy-8-epi-5,6,11-trideoxyTTX, and 1-hydroxy-4,4a-anhydro-8-epi-5,6,11-trideoxyTTX, were isolated from the newt, Cynops ensicauda popei , and their structures were determined using spectroscopic methods. These are the first 8- epi -type analogs of TTX that have been found in a natural source. Furthermore, we examined the composition of the TTX analogs in this newt and in the ovary of the puffer fish, Fugu poecilonotus, using LC/MS. The results indicate that TTX and 11-deoxyTTX were present in both sources. However, 6- epiTTX and 8-epi-type analogs were detected only in the newt, while 5,6,11-trideoxyTTX was a specific and major analog in the puffer fish. Such considerable differences among analog compositions might reflect differences in the biosynthesis or metabolism of TTX between these animals. © 2012 by the authors; licensee MDPI.

Espina B.,University of Santiago de Compostela | Louzao M.,University of Santiago de Compostela | Cagide E.,University of Santiago de Compostela | Alfonso A.,University of Santiago de Compostela | And 3 more authors.
British Journal of Pharmacology | Year: 2010

Background and purpose: Okadaic acid (OA) and microcystins (MCs) are structurally different toxins with the same mechanism of action, inhibition of serine/threonine protein phosphatases (PPs). Methyl okadaate (MeOk), a methyl ester derivative of OA, was considered almost inactive due to its weak inhibition of PP1 and PP2A. Here, we have investigated the activity and potency of MeOk in hepatic cells in comparison with that of OA and MCs. Experimental approach: We tested the effects of MeOK, OA and microcystin-leucine and arginine (MC-LR) on the metabolic rate, the actin cytoskeleton and glucose uptake in a rat hepatocyte cell line (Clone 9) and in primary cultured rat hepatocytes. PP2A was assayed to compare OA and MeOk activity. Key results: MeOk disrupted the actin cytoskeleton and depressed the metabolic rate of both types of rat hepatocytes, being six-fold less potent than OA in Clone 9 cells but nearly six-fold more potent in primary cultured hepatocytes. However, unlike OA, MeOk did not change glucose uptake in these cells, suggesting a weak inhibition of PP2A, as confirmed in direct assays of PP2A activity. Conclusions and implications: Although MeOk was originally described as a weakly bioactive molecule, it clearly depressed the metabolic rate and disrupted the cytoskeleton in primary and immortalized rat hepatocytes. Furthermore, MeOk affected primary hepatocytes at much lower concentrations than those affecting immortalized cells. These effects were unrelated to PP2A inhibition. Our results suggest the risk to public health from MeOk in foodstuffs should be re-evaluated. © 2009 The British Pharmacological Society.

Naito S.,Japan National Agriculture and Food Research Organization | Matsumoto E.,Japan Food Research Laboratories | Shindoh K.,Japan National Agriculture and Food Research Organization | Nishimura T.,Japan Food Research Laboratories
Food Chemistry | Year: 2015

The effects of polishing, cooking, and storing on total arsenic (As) and As species concentrations in rice were studied adopting typical Japanese conditions. Total and inorganic As levels in three white rice samples polished by removing 10% of bran by weight were reduced to 61-66% and 51-70% of those in brown rice. The As levels in the white rice after three washings with deionized water were reduced to 81-84% and 71-83% of those in raw rice. Rinse-free rice, which requires no washing before cooking because bran remaining on the surface of the rice was removed previously, yielded an effect similar to that of reducing As in rice by washing. Low-volume cooking (water:rice 1.4-2.0:1) rice to dryness did not remove As. The As content of brown rice stored in grain form for one year was stable. © 2014 Elsevier Ltd. All rights reserved.

Yogi K.,Okinawa Institute of Science and Technology | Yogi K.,Okinawa Prefectural Institute of Health and Environment | Oshiro N.,Okinawa Prefectural Institute of Health and Environment | Inafuku Y.,Okinawa Prefectural Institute of Health and Environment | And 2 more authors.
Analytical Chemistry | Year: 2011

Toxin profiles of representative ciguatera species caught at different locations of Japan were investigated in fish flesh by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Identification and quantification of 16 toxins were facilitated by the use of 14 reference toxins prepared by either synthesis or isolation from natural sources and the previous LC-MS data thereof. Sodium adduct ions [M + Na] + were used as parent and product ions. Distinct regional differences were unveiled: ciguatoxin-1B type toxins were found in snappers and groupers from Okinawa, ciguatoxin-3C type toxins were found in a spotted knifejaw, Oplegnathus punctatus, from Miyazaki located 730 km north of Okinawa, and both types of toxins were found in a red snapper, Lutjanus bohar, from Minamitorishima (Marcus) Island. Twelve toxins were identified in a dinoflagellate, Gambierdiscus toxicus, collected as the primary toxin source in French Polynesia. Occurrence of M-seco-toxins in fish and oxidized toxins in the dinoflagellate was confirmed for the first time. The present LC-MS/MS method is rapid, specific, and accurate. It not only outperforms the currently employed mouse bioassays but also enables the study of the toxin dynamics during the food chain transmission. © 2011 American Chemical Society.

Shiro H.,Kao Corporation | Kondo N.,Kao Corporation | Kibune N.,Japan Food Research Laboratories | Masukawa Y.,Kao Corporation
European Journal of Lipid Science and Technology | Year: 2011

In response to great concerns about glycidol fatty acid esters (GEs), trace contaminants in edible oils which possibly form during refining processes, we previously developed direct methods to quantify GEs using a combination of double SPE and HPLC-MS. In this study, those quantitative methods were improved to be more rapid without the use of harmful chloroform. To improve the speed, the HPLC-MS measuring time was reduced from 15 to 5min by using a step gradient HPLC system, and the evaporation time after the first SPE was shortened from 4 to 1.5h by changing the solvent used from acetonitrile to methanol. To replace chloroform with other solvents, we adopted tert-butyl methyl ether/ethyl acetate to dissolve the oils and n-hexane/ethyl acetate to separate them during the second SPE. The limit of quantification for GE-in-oil was 0.082-0.11μg/g, which is the most sensitive of all existing methods. The recovery values of spiked GEs at concentrations of 1 or 10μg/g were close to 100%. The levels quantified using an internal standard C17:0-GE were comparable with those using external standards in four different edible oils tested. This rapid method not using chloroform can be useful as a routine method to quantify GEs in oils. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Uchida H.,Agilent Technologies | Taira Y.,Okinawa Institute of Science and Technology | Yasumoto T.,Japan Food Research Laboratories
Rapid Communications in Mass Spectrometry | Year: 2013

RATIONALE The ovatoxins are palytoxin analogs of a dinoflagellate origin implicated in human intoxication. The structures of ovatoxin-A, ovatoxin-d, and ovatoxin-e produced by the IK2 strain of Ostreopsis ovata collected in Japan were elucidated using liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOFMS). The novel structures and a new insight into the spectral data are presented. METHODS The structural elucidations were carried out by complementary use of positive and negative ion LC/QTOFMS. Ostreocin-D (C127H219N3O53), another palytoxin congener previously elucidated by negative fast-Atom bombardment collision-induced tandem mass spectrometry (FAB CID MS/MS), was used as a reference. RESULTS Positive ion spectra allowed deduction of hydroxyl positions based on the conjugated polyene structures produced, while the negative ion spectra allowed assignments of cleavage sites of C-C bonds. The analysis could be performed using a small sample without extensive purification. CONCLUSIONS Ovatoxin-A IK2 (C129H223N3O52), ovatoxin-d IK2 (C129H223N3O53), and ovatoxin-e IK2 (C129H223N3O53) were tentatively assigned to 42-hydroxy-17,44,70-trideoxypalytoxin, 42-hydroxy-17,70-dideoxypalytoxin and 42,82-dihydroxy-17,44,70- trideoxypalytoxin, respectively. The wide applicability of the method was suggested. Copyright © 2013 John Wiley & Sons, Ltd.

Yoshida M.,Japan National Institute of Health Sciences | Katsuda S.-I.,Japan Food Research Laboratories | Maekawa A.,Tokyo Institute of Technology
Journal of Toxicologic Pathology | Year: 2012

Involvements of estrogen receptor (ER)α, proliferating cell nuclear antigen (PCNA) and p53 in the uterine carcinogenesis process in Donryu rats, a high yield strain of the uterine cancer were investigated immunohistochemically. ERα was expressed in atypical endometrial hyperplasia, accepted as a precancerous lesion of the uterine tumors, as well as well- and in moderately-differentiated endometrial adenocarcinomas, and the intensities of expression were similar to those in the luminal epithelial cells of the atrophic uterus at 15 months of age. The expression, however, was negative in the tumor cells of poorly differentiated type. Good growth of implanted grafts of the poorly-differentiated adenocarcinomas in both sexes with or without gonadectomy supported the estrogen independency of tumor progression to malignancy. PCNA labeling indices were increased with tumor development from atypical hyperplasia to adenocarcinoma. The tumor cells in poorly-differentiated adenocarcinomas were positive for p53 positive but negative for p21 expression, suggesting accumulation of mutated p53. These results indicate that the consistent ERα expression is involved in initiation and promotion steps of uterine carcinogenesis, but not progression. In addition, PCNA is related to tumor development and the expression of mutated p53 might be a late event during endometrial carcinogenesis. © 2012 The Japanese Society of Toxicologic Pathology.

Narukawa T.,Japan National Institute of Advanced Industrial Science and Technology | Matsumoto E.,Japan Food Research Laboratories | Nishimura T.,Japan Food Research Laboratories | Hioki A.,Japan National Institute of Advanced Industrial Science and Technology
Analytical Sciences | Year: 2014

The concentrations of 16 elements in 10 rice flour samples and the distribution of the elements in the rice grains from which the flour were made were determined by ICP-MS and ICP-OES after microwave-assisted digestion of the samples. Arsenic speciation analysis was carried out by HPLC-ICP-MS following heat-assisted extraction of the sample. The concentrations of inorganic As (As(III) and As(V)), monomethylarsonic acid (MMAA) and dimethylarsinic acid (DMAA) and their distribution in the rice grains were determined. Portions of the brown rice were polished/milled to different degrees to yield milled off samples and polished rice samples. All samples were powdered and analyzed for 16 elements and for As species. The recoveries and mass balances for all elements in all samples showed good agreements with the starting materials. As(III), As(V), MMAA and DMAA were detected, and the sums of the concentrations of all species in the extract were 86 - 105% of the total As concentration in each case. © 2014 The Japan Society For Analytical Chemistry.

Yamazaki K.,Japan Food Research Laboratories | Ogiso M.,Japan Food Research Laboratories | Isagawa S.,Japan Food Research Laboratories | Urushiyama T.,Chiyoda Corporation | And 2 more authors.
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2013

A new, direct analytical method for the determination of 3-chloro-1,2-propanediol fatty acid esters (3-MCPD esters) was developed. The targeted 3-MCPD esters included five types of monoester and 20 types of diester. Samples (oils and fats) were dissolved in a mixture of tert-butyl methyl ether and ethyl acetate (4:1), purified using two solid-phase extraction (SPE) cartridges (C18 and silica), then analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Five monoesters and five diesters with the same fatty acid group could be separated and quantified. Pairs of 3-MCPD diesters carrying the same two different fatty acid groups, but at reversed positions (sn-1 and sn-2), could not be separated and so were expressed as a sum of both compounds. The limits of quantification (LOQs) were estimated to be between 0.02 to 0.08 mg kg-1, depending on the types of 3-MCPD ester. Repeatability expressed as relative standard deviation (RSDr%) varied from 5.5% to 25.5%. The new method was shown to be applicable to various commercial edible oils and showed levels of 3-MCPD esters varying from 0.58 to 25.35 mg kg-1. The levels of mono- and diesters ranged from 0.10 to 0.69 mg kg-1 and from 0.06 to 16 mg kg-1, respectively. © 2013 Copyright Taylor and Francis Group, LLC.

Yamazaki K.,Japan Food Research Laboratories | Isagawa S.,Japan Food Research Laboratories | Kibune N.,Japan Food Research Laboratories | Urushiyama T.,Chiyoda Corporation
Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment | Year: 2012

A novel GC-MS method was developed for the determination of acrylamide, which is applicable to a variety of processed foods, including potato snacks, corn snacks, biscuits, instant noodles, coffee, soy sauces and miso (fermented soy bean paste). The method involves the derivatization of acrylamide with xanthydrol instead of a bromine compound. Isotopically labelled acrylamide (d3-acrylamide) was used as the internal standard. The aqueous extract from samples was purified using Sep-Pak™ C18 and Sep-Pak™ AC-2 columns. For amino acid-rich samples, such as miso or soy sauce, an Extrelut™ column was used for purification or extraction. After reaction with xanthydrol, the resultant N-xanthyl acrylamide was determined by GC-MS. The method was validated for various food matrices and showed good linearity, precision and trueness. The limit of detection and limit of quantification ranged 0.5-5 and 5-20 μg kg-1, respectively. The developed method was applied as an exploratory survey of acrylamide in Japanese foods and the method was shown to be applicable for all samples tested. © 2012 Copyright Taylor and Francis Group, LLC.

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