Masatoshi Nishi

Comparison of polybrominated diphenyl ethers in fish, vegetables, and meats and levels in human milk of nursing women in Japan

At present, little is known about the occurrence of polybrominated diphenyl ethers (PBDEs) in fish and food products sold in Japan. To investigate whether human exposure to PBDEs through the diet is significant, the concentrations of PBDEs were determined in fish and in meat and vegetables sold in two food markets in the city of Hirakata, Osaka prefecture. The concentrations of PBDEs in the breast milk of 12 primiparae nursing women at one month after delivery also were determined to ascertain the relationship between the levels found in the diet and levels in humans. sigma PBDE concentrations ranged between 21 and 1650 pg/g fresh weight in the edible tissues of five species of fish and one shellfish species. The highest concentrations were measured in yellow-fin tuna, followed by short-necked clam, salmon, yellowtail, mackerel and young yellowtail. Interestingly, sigma PBDE concentrations were not statistically significantly different in two cultured mackerel samples from Japan and mackerel collected from northern European waters. sigma PBDE concentrations in beef, pork and chicken meat (ranging between 6.25 and 63.6 pg/g fresh weight) and in three different vegetables (ranging between 38.4 and 134 pg/g fresh weight) were significantly lower than the concentrations in fish. In human milk, sigma PBDE concentrations ranged between 668 and 2840 pg/g lipid basis, which is comparable to the levels in populations of nursing women reported in Sweden and elsewhere. There was a strong positive relationship between PBDE concentrations in human milk and dietary intake of fish and shellfish, which was established in the women from responses to a questionaire on food consumption habits. The results of this study of food products commonly consumed in Japan and the levels found in nursing women raise a concern about low level PBDE contamination of fish and other foods intended for human consumption.

Cautionary note for DMPO spin trapping in the presence of iron ion

2-Hydroxy-5,5-dimethyl-1-pyrrolidinyloxy (DMPO-OH), which is known to be produced by spin trapping of hydroxyl radicals (.OH) with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) and has been a good monitor for detecting .OH in biological systems, has been examined by EPR for its production scheme in the presence of iron ion. In an aqueous DMPO solution containing ferric ion (Fe3+), DMPO-OH was produced and addition of methanol, a good scavenger for .OH, to this solution led to an aminoxyl radical, DMPO-OCH3, instead of DMPO-CH2OH which is produced by DMPO spin trapping of .CH2OH arising from H-abstraction by .OH. Also EPR measurements at 77K indicated the formation of a chelate between DMPO and Fe3+. Based on these, it has been elucidated that DMPO-OH as well as DMPO-OCH3 is formed by the nucleophilic attack of water and methanol to the chelating DMPO, respectively.

Antimicrobial alkaloids from Zanthoxylum tetraspermum and caudatum.

Two benzophenanthrene alkaloids, 8-acetonyldihydronitidine and 8-acetonyldihydroavicine were isolated from Zanthoxylum tetraspermum stem bark along with liriodenine, sesamin, lichexanthone and (+)-piperitol-gamma,gamma-dimethylallylether. The species endemic to Sri Lanka, Z. caudatum, contained sesamin, savinin, liriodenine, decarine and 8-O-desmethyl-N-nornitidine. 8-Acetonyldihydronitidine and 8-acetonyldihydroavicine showed significant antibacterial activity while the former along with liriodenine was strongly antifungal. Savinin exhibited potent spermicidal activity. Both savinin and sesamin exhibited significant insecticidal activity.

Anti-Herpes Simplex Virus substances produced by the marine green alga, Dunaliella primolecta

Among 106 microalgae tested, the cytopathic effect (CPE) upon Vero cells of herpes simplex virus, Type 1 (HSV-1) was inhibited by four methanol extracts of Dunaliella bioculata C-523, D. primolecta C-525, Lyngbya sp. M-9 and Lyngbya aerugineo-coerulea M-12. The green alga, D. primolecta, had the highest anti HSV-1 activity, since 10 μg mL-1 of extract from this alga completely inhibited the CPE. This activity was similar to that of acyclovir at the same concentration. We compared anti-viral activities against adeno virus, herpes simplex virus-2 (HSV-2), Japanese Encephalitis and Polio viruses. Only the CPE of HSV-2 was inhibited. Thus, the factor was specific against HSV. The antiviral activity was apparently excited during HSV adsorption and invasion of the cells. We optimized the conditions for anti HSV-1 activity by prolonging the exposure of HSV-1 to the extract. After 2 h, the CPE of even a high titer of HSV-1 (106 TCID50/0.1 mL) was completely inactivated. By use of various chromatographic techniques, three green substances having anti-HSV activity were purified from the algal mass of D. primolecta, and 5 μg mL-1 of this purified substances completely inhibited the CPE. From the analysis of NMR and MS, the chemical structures of the active substances were identified as pheophorbide-like compounds.

An Artifact in the ESR Spectrum Obtained by Spin Trapping with Dmpo

In order to overcome a common problem in spin trapping with high concentrations of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) where ESR spectra are obtained which include an unidentified set of lines composed of a triplet of doublets, commercial DMPO was analyzed for its impurities by high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy. It has been determined that this undesirable ESR spectrum is due to an impurity included in the spin trap. This compound has been assigned to the hydroxylamine which is a DMPO-derivative having an epoxy ring located at the 2 and 3 positions.

Dmpo Spin Trapping in the Presence of Fe Ion

Aminoxyl radical formation from DMPO in the presence of Fe ion was studied to clarify the ambiguous ESR signals obtained by spin trapping with DMPO. It was found that when DMPO was used in a Fenton system, a Fe-DMPO complex was formed immediately. This complex was subsequently attacked by oxidative species originating from H2O2 and thus oxidative degradation of DMPO was induced in the Fenton system. On the other hand, in the case of M4PO, the degradation was found to be very slow, indicating that the 3 position of DMPO was favorably attacked by the oxidative species. Some of the degradation products are probably aminoxyl radicals. This series of the degradation products are probably aminoxyl radicals. This series of reactions may compete with spin trapping and make it difficult to analyze ESR spectra obtained in the presence of Fe ion.

A flavonol glycoside from Epimedium diphyllum

Abstract A novel flavonol glycoside named diphylloside C was isolated from the underground parts of Epimedium diphyllum and its structure was determined on the basis of spectral analyses (negative ion FAB-MS, 1 H- 1 H COSY, NOESY, INEPT and 1 H- 13 C COSY, etc) as des- O -methylanhydroicaritin 3- O -β- d -glucosyl-(1 → )2-α- l -rhamnoside 7- O -β- d -glucosyl-(1 → 2)-β- d -glucoside.

An iridoid from randia dumetorum

Abstract 10-Methylixoside, a new iridoid glucoside, has been isolated and characterized from Randia dumetorum leaves by FAB and negative-ion mass spectrometry and 13 CNMR and 1 HNMR (normal mode, COSY and NOE, J relation 2D).

Determination of panaxytriol, a new type of tumour growth inhibitor from Panax ginseng, by capillary gas chromatography

Panax ginseng is known for its unique antitumour therapeutical effect’. During a series of studies aimed at isolation of the tumour growth inhibitory substance from Panax ginseng, we found a substance, a polyacetylenic alcohol, which inhibits tumour cell growth in a dose-dependent fashion in vitro ‘y3 Data from infrared (IR), proton and carbon-l 3 nuclear magnetic resonance and high-resolution mass spectra were identical with those of authentic panaxytriol, heptadec-l-ene-4,6-diyne-3,9,10-triol, previously described by several investigators4g5. In order to examine the mechanism of cell growth inhibition caused by panaxytriol, it is important to develop an assay method for panaxytriol. We describe in this paper a gas chromatographic (GC) method for its quantitation by silylation.

ろ紙クロマトグラフィーにより食用青色1号(ブリリアントブルーFCF)アルミニウムレーキから検出された付随色素の構造

One of eight Food Blue No. 1 aluminum lakes (B-1Als) used in the official inspection of coal-tar colors in fiscal year 1999 had a violet sub-spot during paper chromatography and was rejected. To clarify the orgin of the sub-spot, the violet subsidiary color (Sub-V) was isolated from the sample. On the basis of NMR and MS analyses and ion chromatography, the structure of the subsidiary color was elucidated to be 2-[[4-[N-ethyl-N-(3- sulfophenylmethyl)amino]phenyl][4-hydroxyphenyl]methylio]benzenesulfonic acid. The relative content of Sub-V to that of m,m-B-1 in the rejected sample was determined to be 39.5% by HPLC. The relative contents in other submitted samples of B-1Al were in the range of 1.1-3.6%.