Validation of putative biomarkers of furan exposure through quantitative analysis of furan metabolites in urine of F344 rats exposed to stable isotope labeled furan.

Humans are chronically exposed to furan, a potent liver toxicant and carcinogen that occurs in a variety of heat-processed foods. Assessment of human exposure based on the furan content in foods is, however, subject to some uncertainty due to the high volatility of furan. Biomarker monitoring is thus considered an alternative or complementary approach to furan exposure assessment. Previous work suggested that urinary furan metabolites derived from the reaction of cis-2-butene-1,4-dial (BDA), the reactive intermediate of furan, with glutathione (GSH) or amino acids may serve as potential biomarkers of furan exposure. However, some metabolites were also reported to occur in urine of untreated animals, indicating either background contamination via animal feed or endogenous sources, which may limit their suitability as biomarkers of exposure. The overall aim of the present study was to accurately establish the correlation between external dose and concentration of furan metabolites in urine over time and to discriminate against endogenous formation and furan intake via feed. To this end, the furan metabolites GSH-BDA (N-[4-carboxy-4-(3-mercapto-1H-pyrrol-1-yl)-1-oxobutyl]-L-cysteinylglycine), NAcLys-BDA (R-2-(acetylamino)-6-(2,5-dihydro-2-oxo-1H-pyrrol-1-yl)-1-hexanoic acid), NAcCys-BDA-NAcLys (N-acetyl-S-[1-[5-(acetylamino)-5-carboxypentyl]-1H-pyrrol-3-yl]-L-cysteine) and NAcCys-BDA-NAcLys sulfoxide (N-acetyl-S-[1-[5-(acetylamino)-5-carboxypentyl]-1H-pyrrol-3-yl]-L-cysteine sulfoxide) were simultaneously analyzed by stable isotope dilution ESI-LC-MS/MS as unlabeled and [13C4]-furan dependent metabolites following oral administration of a single oral dose of isotopically labelled [13C4]-furan (0.1, 1, 10, 100 and 1000 µg/kg bw) to male and female F344/DuCrl rats. Although a linear correlation between urinary excretion of [13C4]-furan-dependent metabolites was observed, analysis of unlabeled NAcLys-BDA, NAcCys-BDA-NAcLys and NAcCys-BDA-NAcLys sulfoxide revealed substantial, fairly constant urinary background levels throughout the course of the study. Analysis of furan in animal feed excluded feed as a source for these background levels. GSH-BDA was identified as the only furan metabolite without background occurrence, suggesting that it may present a specific biomarker to monitor external furan exposure. Studies in humans are now needed to establish if analysis of urinary GSH-BDA may provide reliable exposure estimates.

Effects of isoflavones on breast tissue and the thyroid hormone system in humans: a comprehensive safety evaluation.

Isoflavones are secondary plant constituents of certain foods and feeds such as soy, linseeds, and red clover. Furthermore, isoflavone-containing preparations are marketed as food supplements and so-called dietary food for special medical purposes to alleviate health complaints of peri- and postmenopausal women. Based on the bioactivity of isoflavones, especially their hormonal properties, there is an ongoing discussion regarding their potential adverse effects on human health. This review evaluates and summarises the evidence from interventional and observational studies addressing potential unintended effects of isoflavones on the female breast in healthy women as well as in breast cancer patients and on the thyroid hormone system. In addition, evidence from animal and in vitro studies considered relevant in this context was taken into account along with their strengths and limitations. Key factors influencing the biological effects of isoflavones, e.g., bioavailability, plasma and tissue concentrations, metabolism, temporality (pre- vs. postmenopausal women), and duration of isoflavone exposure, were also addressed. Final conclusions on the safety of isoflavones are guided by the aim of precautionary consumer protection.

[Alimentary intake of opioid alkaloids by horses. Hazards due to poppy-containing feeds]. / Alimentäre Aufnahme von Opioid-Alkaloiden durch Pferde. Gefahren durch mohnhaltige Futtermittel.

Opioid alkaloids were identified in the urine of horses during an anti-doping control and in a case of intoxication. In both cases, it was suspected that the horses had ingested poppy-contaminated feed. To verify this suspicion, possible opioid alkaloid sources in Germany were identified through a literature research. Additionally, the contaminated feed was botanically and chemically analysed. The results indicated that both cases were most probably caused by the poppy in the feed. This highlights the previously underestimated risk of an intake of poppy-contaminated feed in horses. Recommendations are formulated for the prevention of positive doping-test results and intoxications by poppy-contaminated feeds in horses. Furthermore, a threshold for morphine in urine samples in competing horses is proposed.

Chemical analysis and risk assessment of prohibited colouring agents in face paint with special regard to CI 15585 (D&C Red No. 9, Pigment Red 53:1).

OBJECTIVES: Face painting in the colours of the national flags has become a mass phenomenon during international mega sporting events. Face paints, belonging to the group of lipophilic decorative cosmetics, pose an analytical challenge, especially in the sample preparation steps to obtain sample extracts of the colouring agents of low solubility. METHODS: In the context of official cosmetics control, a sample of German flag-coloured face paints (n = 42) offered during the soccer world cup 2014 was analysed. Sample-clean-up of hydroalcoholic and dichloromethane sample extracts was conducted using preparative thin-layer chromatography (TLC). For identification, analytical TLC, spectrophotometry considering bathochromic effects, and high-performance liquid chromatography (LC) with diode array detector were applied. Nuclear magnetic resonance (NMR) spectroscopy and LC-tandem mass spectrometry (LC-MS/MS) were used in positive cases for confirmatory analysis. NMR spectroscopy was also applied to determine the identity and purity of reference substances. Risk assessment was provided using the margin of exposure (MOE) methodology. RESULTS: The prohibited red colouring agent CI 15585 (D&C Red No. 9, Pigment Red 53:1), which is carcinogenic in animals, was positively identified in 40% of the analysed samples. Per face painting event, about 0.04 mg kg(-1) bw (adult) or 0.11 mg kg(-1) bw (child) of CI 15585 is systemically absorbed. Assuming an annual use of five times (adult) or 20 times (child), the exposure would be 5.8E-04 mg kg(-1) bw per day (adult) or 5.8E-03 mg kg(-1) bw per day (child). The MOE in these worst-case scenarios would be 6871 (adult) and 695 (child). Because the mechanism of CI 15585 is non-genotoxic and the MOE is higher than a safety factor of 100, CI 15585 does not pose a serious health risk to the consumer, but should be avoided for reasons of precautionary public health protection. CONCLUSION: An analytical strategy to determine colouring agents in face paints was developed and non-compliance with the European Union (EU) cosmetic products regulation in a considerable number of products was detected. An increased control frequency especially at the points of entry into the EU is recommended.

Analysis and risk assessment of furan in coffee products targeted to adolescents.

The aim of this work was to analyse the furan concentrations in coffee products targeted to adolescents and to estimate the health risk for those consumers by using the consumption data of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study (DONALD). Three different kinds of coffee beverages were analysed: 'coffee ready to drink' (i.e. industrially manufactured and packaged products available in cans or plastic cups), 'coffee instant' (i.e. soluble coffee in powder form) and 'coffee from coffee chains' (i.e. freshly prepared coffee sampled on-site). Furan was analysed according to the US Food and Drug Administration (USFDA) method using headspace-GC-MS and quantification with standard addition. The lowest furan concentrations were found within the category 'coffee instant', with an average of 4.6 µg kg(-1), followed by the category 'coffee ready to drink', with an average of 41.3 µg kg(-1), while the products from the coffee chains showed the highest concentrations, on average 100.5 µg kg(-1). According to the obtained furan contents, it seems that the highest furan exposure for adolescents is generally given in the consumption of products within the category 'coffee from coffee chains', while the lowest is given in the category 'coffee instant'. Risk assessment based on the margin of exposure (MOE) approach showed that in different consumption scenarios except for consumers of instant coffee, the MOE lay below 10,000, a range that is judged to be of public health relevance. The lowest MOE was found for consumers in the age group 10-12 years (especially females) and for both sexes in the age group 16-18 years.

[Absinthe - history of dependence to thujone or to alcohol?]. / Absinth - Geschichte einer Thujon- oder Alkoholabhängigkeit?

The etiopathology of absinthe dependence was previously attributed to the effects of the wormwood constituent thujone. Current research proves otherwise. Foremost, it must be considered that the wormwood plant shows a very large variance in quantity of thujone (0 - 70 % in essential oil) dependent on chemo type and cultivation area. Thus, absinthe does not contain thujone in general. Experimental production of absinthes and analyses of vintage absinthes (1900 - 1930) consistently showed that they contained only relatively low concentrations of thujone below today's maximum limits. Scientific literature contains no proof that historic absinthes may have contained thujone in concentrations able to produce toxic effects. The current state of research considers absinthism to be a type of alcoholism with thujone playing none or only a secondary role.

Rapid analysis of taurine in energy drinks using amino acid analyzer and Fourier transform infrared (FTIR) spectroscopy as basis for toxicological evaluation.

So-called energy drinks with very high amounts of taurine (up to 4000 mg/l are usually granted by certificates of exemption) are increasingly offered on the market. To control the currently valid maximum limits of taurine in energy drinks, a simple and rapid analytical method is required to use it routinely in food monitoring. In this article, we describe a fast and efficient analytical method (FTIR-spectroscopy) that is able to reliably characterize and quantify taurine in energy drinks. The determination of taurine in energy drinks by FTIR was compared with amino acid analyzer (ion chromatography with ninhydrin-postcolumn derivatization). During analysis of 80 energy drinks, a median concentration of 3180 mg/l was found in alcohol-free products, 314 mg/l in energy drinks with spirits, 151 mg/l in beer-containing drinks and 305 mg/l in beverages with wine. Risk analysis of these products is difficult due to the lack of valid toxicological information about taurine and its interferences with other ingredients of energy drinks (for example caffeine and alcohol). So far, the high taurine concentrations of energy drinks in comparison to the rest of the diet are scientifically doubtful, as the advertised physiological effects and the value of supplemented taurine are unproven.

Results of hair analyses for drugs of abuse and comparison with self-reports and urine tests.

Urine as well as head and pubic hair samples from drug abusers were analysed for opiates, cocaine and its metabolites, amphetamines, methadone and cannabinoids. Urine immunoassay results and the results of hair tests by means of gas chromatography-mass spectrometry were compared to the self-reported data of the patients in an interview protocol. With regard to the study group, opiate abuse was claimed from the majority in self-reports (89%), followed by cannabinoids (55%), cocaine (38%), and methadone (32%). Except for opiates the comparison between self-reported drug use and urinalysis at admission showed a low correlation. In contrast to urinalysis, hair tests revealed consumption in more cases. There was also a good agreement between self-reports of patients taking part in an official methadone maintenance program and urine test results concerning methadone. However, hair test results demonstrated that methadone abuse in general was under-reported by people who did not participate in a substitution program. Comparing self-reports and the results of hair analyses drug use was dramatically under-reported, especially cocaine. Cocaine hair tests appeared to be highly sensitive and specific in identifying past cocaine use even in settings of negative urine tests. In contrast to cocaine, hair lacks sensitivity as a detection agent for cannabinoids and a proof of cannabis use by means of hair analysis should include the sensitive detection of the metabolite THC carboxylic acid in the lower picogram range.

Simultaneous gas chromatographic-mass spectrometric determination of dopamine, norsalsolinol and salsolinol enantiomers in brain samples of a large human collective.

Using a solid-phase extraction procedure, an enantioselective derivatization and a gas chromatographic-mass spectrometric method, the levels of dopamine (DA) and of the dopamine-derived tetrahydroisoquinoline alkaloids (R)/(S)-salsolinol (SAL) and norsalsolinol (NorSAL) were determined in human brain samples. A complex pre-analytical synthesis of reference substances as well as deuterated internal standards allowed the standardized and reproducible analysis. In this study, to our best knowledge for the first time, the regional distribution of (R)-SAL and (S)-SAL, as well as NorSAL is examined systematically in a large collective of human brain samples obtained by autopsy. The material comprises 91 brains and 8 standardized specimens in each case. Anatomical concentration differences and no ubiquitous occurence were encountered. Significant amounts of (R)-SAL, (S)-SAL and NorSAL were only found in dopamine-rich areas of the basal ganglia, whereas in other regions of the brain no tetrahydroisoquinolines were detected. These findings suggest that the concentration of the substrate dopamine may determine the alkaloid level during in vivo formation. In our opinion, non-enzymatic formation of SAL via the Pictet-Spengler reaction reveals both the SAL enantiomers. An additional enzymatic synthesis of only (R)-SAL could explain the predominant occurrence of this enantiomer. Especially in the nucleus caudatus, the concentrations of DA, SAL and NorSAL decreased significantly with rising age, which may be consistent with apoptotic effects of ageing. Our data can serve as reference for other studies in humans concerning the etiology of alcoholism or other neurodegenerative diseases with the involvement of tetrahydroisoquinolines.