Comparative urine metabolomics of mice treated with non-toxic and toxic oral doses of (-)-epigallocatechin-3-gallate.

The green tea polyphenol, (-)-epigallocatechin-3-gallate (EGCG), has been studied for its potential positive health effects, but human and animal model studies have reported potential toxicity at high oral bolus doses. This study used liquid chromatography-mass spectrometry-based metabolomics to compare the urinary EGCG metabolite profile after administration of a single non-toxic (100 mg kg-1) or toxic (750 mg kg-1) oral bolus dose to male C57BL6/J mice to better understand how EGCG metabolism varies with dose. EGCG metabolites, including methyl, glucuronide, sulfate, and glucoside conjugates, were tentatively identified based on their mass to charge (m/z) ratio and fragment ion patterns. Partial least squares discriminant analysis (PLS-DA) results showed clear separation of the urine metabolite profiles between treatment groups. The most differentiating metabolites in the negative and positive ion modes were provisionally identified as di-glucuronidated EGCG quinone and di-glucuronidated EGCG, respectively. The presence of EGCG oxidation products at toxic dose is consistent with studies showing that EGCG toxicity is associated with oxidative stress. Relative amounts of methylated metabolites increased with dose to a lesser extent than glucuronide and sulfate metabolites, indicating that methylation is more prominent at low doses, whereas glucuronidation and sulfation may be more important at higher doses. One limitation of the current work is that the lack of commercially-available EGCG metabolite standards prevented absolute metabolite quantification and identification. Despite this limitation, these findings provide a basis for better understanding the dose-dependent changes in EGCG metabolism and advance studies on how these differences may contribute to the toxicity of high doses of EGCG.

Survey for acrylamide in processed foods from Korean market and individual exposure estimation using a non-parametric probabilistic model.

Acrylamide, a known carcinogen, is formed during preparation of food containing reducing sugar and asparagine. Because acrylamide exposure of the population is primarily through food, the maximum levels of acrylamide in food were set by the European Commission in 2017. Moreover, in the 2016 Korean Total Diet study, acrylamide showed the lowest margin of exposure among 23 food-processing-related chemicals, necessitating risk reduction options. Therefore, the objective of this study was to determine the variation of acrylamide content in different food items and identify the food categories, to provide options for risk management. Acrylamide was analysed using high-performance liquid chromatography coupled with tandem mass spectrometry in more than 1,000 processed food items. To estimate acrylamide exposure, the analytical data obtained herein and the food consumption data of Korean National Health and Nutrition Examination Survey from 2013 to 2017 were used. A non-parametric technique of a probabilistic model was used for exposure estimation. Confectioneries (here this category includes potato and similar savoury snacks) contained a wide range of acrylamide content. Particularly, the highest acrylamide content was detected in a tea made of Jerusalem artichoke. The presence of acrylamide in turmeric along with the Jerusalem artichoke was reported in this study for the first time. The main contributors of dietary acrylamide exposure were confectioneries for youths aged 3-18 years and coffee for adults aged 19-80 years. Therefore, risk management in confectionery and coffee could help reduce acrylamide exposure for Koreans. In addition, the mitigation strategies for food containing high acrylamide content, such as Jerusalem artichoke tea, are needed to reduce acrylamide exposure to loyal consumers.

Carcinogenic risk associated with popular Korean dishes: An approach of combined risk assessments using Oral Slope Factor and BMDL10 values.

Cooking-related carcinogens are formed during the heating or processing of foods. To date, numerous studies analyzing carcinogens present in cooking ingredients or formed through different cooking methods have been conducted. However, combined risk assessment is important for practical reasons. The purpose of this study was to conduct a combined risk assessment of five cooking-related genotoxic carcinogens encompassing 25 chemicals: heterocyclic amines, acrylamide, furan, polycyclic aromatic hydrocarbons, and nitrosamines. Oral Slope Factor (OSF) and benchmark dose lower-bound confidence limit 10% (BMDL10) of the compounds were obtained from public databases, and the values for the compounds that did not have published reference values were approximated using related toxicity values. The high-risk contributing food items and cooking methods for each carcinogen were selected for the study based on the Korean Total Diet Study (TDS) and Korea National Health and Nutrition Examination Survey (KNHANES). Exposure to the carcinogens from selected dishes per serving was estimated based on concentrations determined in TDS and consumption data gathered from 24-h recalls in the 2014 to 2016 KNHANES. The combined cancer risks were obtained by summing the risks of individual compounds in a dish, which were calculated by multiplying the OSF values by the concentrations of carcinogens per serving. The combined risks were used to compare the risk of different dishes, not to calculate the lifetime risk from the individual dishes. The risks of the dishes prepared with potatoes were found to be high, whereas namul (vegetable dish) had the lowest risk. Soup or stew dishes exhibited relatively high risks. Estimated combined risks based on BMDL10 showed similar trends, except for fried potatoes and roasted or fried meat dishes. Combined risks of cooking-related carcinogens may vary based on the major contributors of individual carcinogens. The results of this study could provide an insightful guideline for selecting menus for consumers.