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Absorption, distribution, metabolism and excretion of 3MCPD 1-monopalmitate after oral administration in rats Boyan Gao, Man Liu, Guoren Huang, Zhongfei Zhang, Yue Zhao, Thomas T. Y. Wang, Yaqiong Zhang, Jie Liu, and Liangli (Lucy) Yu J. Agric. Food Chem., Just Accepted Manuscript • DOI: 10.1021/acs.jafc.7b00639 • Publication Date (Web): 09 Mar 2017 Downloaded from http://pubs.acs.org on March 12, 2017

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Journal of Agricultural and Food Chemistry

Absorption, distribution, metabolism and excretion of 3-MCPD 1-monopalmitate after oral administration in rats Boyan Gao1,2, Man Liu3, Guoren Huang3, Zhongfei Zhang3, Yue Zhao3, Thomas T.Y. Wang4, Yaqiong Zhang3, Jie Liu1*, Liangli (Lucy) Yu2*

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Beijing Advanced Innovation Center for Food Nutrition and Human Health, Beijing

Technology & Business University (BTBU), Beijing 100048, China; 2Department of Nutrition and Food Science, University of Maryland, College Park, MD 20742; 3Institute of Food and Nutraceutical Science, School of Agriculture and Biology, Shanghai Jiao Tong University; 4Diet, Genomics, and Immunology Laboratory, Agricultural Research Service (ARS), USDA, Beltsville, MD 20705

*Corresponding author: Jie Liu and Liangli (Lucy) Yu Contact information of the corresponding author: Liangli (Lucy) Yu, Tel: (01) 301-314-3313, Email: [email protected]; Jie Liu, Tel: (086) 010-6898-4547, E-mail: [email protected]

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ACS Paragon Plus Environment


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Abstract

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Fatty acid esters of monochloropropane 1,2-diol (3-MCPD) are processing-induced

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toxicants and have been detected in several food categories. This study investigated

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the absorption, distribution, metabolism and excretion of 3-MCPD esters in Sprague

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Dawley (SD) rats using 3-MCPD 1-monopalmitate as the probe compound. The

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kinetics of 3-MCPD 1-monopalmitate in plasma was investigated using (SD) rats, and

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the results indicated that 3-MCPD 1-monopalmitate was absorbed directly in vivo and

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metabolized. Its primary metabolites in the liver, kidney, testis, brain, plasma and

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urine were tentatively identified and measured at 6, 12, 24 and 48 hours after oral

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administration. Structures were proposed for 8 metabolites. 3-MCPD

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1-monopalmitate was converted to free 3-MCPD, which formed the phase II

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metabolites. All the metabolites were chlorine-related chemical components; most of

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them existed in urine, reflecting the excretion pattern of 3-MCPD esters.

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Understanding the metabolism of 3-MCPD esters in vivo is critical for assessing their

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toxicities.

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Key words: 3-MCPD ester; toxic kinetics; UPLC-MS; absorption, distribution,

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metabolism and excretion (ADME)

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Introduction

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Fatty acid esters of 3-monochloropropane 1,2-diol (3-MCPD esters), a group of

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chemical toxicants for kidney and testis, could be formed during oil refining process

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and have been detected in many food categories including infant and baby foods.1-7 In

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2004, 3-MCPD ester was first reported together with free 3-MCPD in the processed

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foods, with the esters form in a much higher concentration, especially in oils and fats

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as well as the fried foods.8 In 2013, the European Food Safety Authority estimated a

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tolerable daily value (TDI) of 2 µg/kg body weight for the total amount of free

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3-MCPD.9

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Recent research has investigated the detection methods, the possible formation

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mechanisms, and the toxicology of 3-MCPD esters in vivo and in vitro.10-13 In 2015,

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Sawada and colleagues reported an overview of proteomic changes caused by

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3-MCPD di-esters and free 3-MCPD in rat testis in an early phase of organ

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impairment.14 Onami and colleagues reported the potential subchronic toxicity of two

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3-MCPD di-esters and one 3-MCPD mono-ester to the rat kidneys and epididymis

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after a repeated dose study for 13 weeks.15 Our group also reported the acute toxicity

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of several 3-MCPD mono- and di-esters in mice and their cytotoxicity in rat kidney

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cells.10 The results indicated that 3-MCPD mono-ester might have stronger toxicity

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compared with di-esters. To our best knowledge, there is little information about the

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absorption, distribution, metabolism and excretion (ADME) of 3-MCPD esters,

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although these data are important to access the risk of 3-MCPD esters intake.

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Absorption, distribution, metabolism and excretion (ADME) may alter the

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pharmacokinetics of food components, and consequently influence their beneficial or

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toxicological activities at a selected organ or tissue. Only few studies reported the

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metabolism and metabonomic of 3-MCPD and its fatty acid esters in vivo and their

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metabonomic results in the rat urine and the cultured cells.16-19 In 2013, Li and

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colleagues reported that indoxyl sulfate, xanthurenic acid, phenylacetylglycine,

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nonanedioic acid and taurine can be used as biomarkers and represent the

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consumption of 3-MCPD esters in a long-term toxicity study.16 In 2015, Andreoli and

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colleagues reported that 2,3-dihydroxypropyl mercapturic acid (DHPMA) was

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detected and identified as the metabolite of free 3-MCPD in human urine.18 In 2016,

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the metabolomic study of free 3-MCPD in Wistar rats was evaluated, the results

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indicated that the metabolism of glycine, serine and threonine, as well as the

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metabolism of taurine and hypotaurine, were two key pathways related with the

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3-MCPD.19 Till now, no systemic research about the ADME situation of 3-MCPD

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esters in vivo was reported. Due to this fact, a systematic study about the absorption,

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distribution, metabolism and excretion of 3-MCPD esters in vivo was performed.

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In this study, the absorption of 3-MCPD 1-monopalmitate in rat plasma was

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quantified at different time points after oral administration of 3-MCPD

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1-monopalmitate to rats. The relative concentrations of 3-MCPD 1-monopalmitate in

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different organs and tissues as well as plasma and urine samples were also determined.

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In addition, major metabolites of 3-MCPD 1-monopalmitate in rat liver, kidney, testis,

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brain, plasma and urine were tentatively identified and relatively quantified. The

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results of this study suggested how 3-MCPD 1-monopalmitate might be excreted from

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rats for the first time. These results could significantly advance our understanding

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about the physiological and toxicological properties of 3-MCPD esters.

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Materials and Methods Chemicals and reagents. 3-MCPD 1-monopalmitate was synthesized according

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to a previously reported protocol13 and its purity was above 98% tested by

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UPLC-Q-TOF MS analysis. LC-MS grade isopropanol and methanol were purchased

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from Sigma-Aldrich (St. Louis, MO, USA). LC-MS grade water was obtained from a

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Milli-Q 10 ultra-pure water system (Billerica, MA, USA). All the other chemical

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reagents were analytical grade and purchased from Sigma-Aldrich (St. Louis, MO,

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USA). The chemical reagents and solvents were used without further purification.

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Animals, treatment and sample collection. The animal study protocols were

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approved by the Animal Ethics Committee of the Shanghai Jiao Tong University.

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Male Sprague-Dawley rats, weighing 160-180 g, were bought from SLAC

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experimental animal Co. Ltd (Shanghai, China). The rats were maintained in a

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temperature controlled room with a 12 h light/dark cycle, and were allowed free

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access to drinking water and diet. The animals were acclimatized to the facilities for a

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week, and then fasted with free access to water for 12 h prior to experiment.

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Animals were divided into ten groups randomly, and each group had six rats.

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Two groups were kept in regular cages and treated with 400 mg/kg body weight of

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3-MCPD 1-monopalmitate or pure olive oil vehicle, and 300 µL of blood sample was

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collected in heparinized eppendorf tube via the oculi chorioideae vein before dosing

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and subsequently at 0, 0.167, 0.33, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, 4, 6, 8, 12, and 24 h

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after the treatment for the kinetic study. Another four groups were kept in metabolic

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cages, treated with 400 mg/kg body weight of 3-MCPD 1-monopalmitate, and

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sacrificed to collect the liver, kidney, testis, brain, plasma and urine samples at 6, 12,

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24 and 48 hours after treatment. The four control groups were sacrificed at 6, 12, 24

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and 48 hours after oral administration of same volume pure olive oil. Water and food

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were fed ad libitum 4 hours after treatment during the experiment.

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Animal samples. The blood samples were centrifuged at 4000 rpm for 10

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minutes at 4 °C, and 100 µL of supernatant plasma was accurately collected and

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immediately frozen at -80 °C until further analysis. 300 µL of acetonitrile was added

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to each 100 µL of the plasma sample. The mixture was vortexed for 30 s, and

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followed by centrifugation at 10000 rpm for 10 minutes at 4 °C. The supernatant was

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transferred into a UPLC vial for UPLC-QQQ-MS analysis.

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The liver, kidney, testis and brain samples were removed, weighed, flushed in

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ice-cold saline (0.9% NaCl), and homogenized at 4 °C in 9 times weight ice-cold

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saline to make 10% tissue homogenate. The homogenate was stored at -80 °C, and

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centrifuged at 10000 rpm at 4 °C for 10 min to obtain the supernatant for

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UPLC-Q-TOF-MS analysis.

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The urine samples were collected in metabolic cages at different time points. For

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example, urine samples at 12 hour indicated the urine collected between 6 hour and

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12 hour. 0.2 mL of each urine sample was extracted with 1 mL of water-saturated

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ethyl acetate by vortexing for 30 s and followed by centrifugation at 10000 rpm for 10

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min at ambient temperature. The supernatant was transferred into a clean tube and the

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solvent was removed using a nitrogen evaporator. The residue was re-dissolved in 0.2

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mL of methanol and subjected to UPLC-Q-TOF-MS analysis.

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UPLC-MS conditions. A Waters Acuity UPLC-TQS triple quadrupole MS

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system (Waters, Milford, MA, USA) was selected for quantitatively analysis of

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3-MCPD 1-monopalmitate in rat plasma samples with a Waters Phenyl column (2.1

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mm i.d. × 100 mm, 1.7 µm). The mobile phase consisted of A) water/methanol (9:1,

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v/v) and B) methanol/ isopropanol (4:1, v/v) using the elution gradient started with 0%

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phase B, changed linearly to 35% in 4 min, increased linearly to 95% B at 8 min and

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maintained for 2 min, and returned to its initial condition for 2 min to re-equilibrate

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the column for the next injection. The flow rate was 0.4 mL/min with an injection

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volume of 2 µL. The MS detector conditions were: capillary voltage 3.50 kV;

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sampling cone voltage 60 V; extraction cone voltage 4.0 V; source temperature

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120 °C; and desolvation temperature 450 °C. The flow rates were 150 L/h for cone

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gas and were 800 L/h for the desolvation gas. An ion pair with a parent ion at m/z

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371.2329 ([M+Na]+) and a daughter ion at m/z 110.0135 was selected to create a

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multiple reaction monitoring (MRM) system with the collision energy of 35 eV and a

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mass range from 50 to 1000 m/z in an ESI positive mode. A Waters Acuity UPLC-Xevo G2 Q-TOF MS system (Waters, Milford, MA,

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USA) was selected for metabolite identification and relatively quantification in this

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study. UPLC condition was almost similar as UPLC QQQ MS. Briefly, a Waters

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Phenyl column (2.1 mm i.d. × 100 mm, 1.7 µm) was utilized with a Waters Acuity

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UPLC-Xevo G2 quadrupole-time of flight mass spectrometry (Q-TOF MS). The

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mobile phase consisted of A) water/methanol (9:1, v/v) and B) methanol/ isopropanol

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(4:1, v/v) using the elution gradient started with 0% phase B, changed linearly to 35%

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in 4 min, increased linearly to 95% B at 8 min and maintained for 2 min, and returned

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to its initial condition for 2 min to re-equilibrate the column for the next injection.

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The flow rate was 0.4 mL/min with an injection volume of 2 µL. The MS detector

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conditions were: capillary voltage 3.00 kV; sampling cone voltage 60 V; extraction

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cone voltage 4.0 V; source temperature 120 °C; and desolvation temperature 450 °C.

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The cone gas flow rate was 150 L/h and the desolvation gas flow was 800 L/h. A MSE

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method was used with mass range from 50 to 1200 m/z in both ESI positive and

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negative modes, with a scan time of 0.3 s and the ramp collision energy at 20-35 eV.

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Method evaluation. Different mobile phases, including different ratios of

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methanol/water, acetonitrile/water and methanol/acetonitrile/isopropanol/water, were

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tested in the preliminary study to select an appropriate mobile phase. Finally, mobile

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phase with A) water/methanol (9:1, v/v) and B) methanol/isopropanol (4:1, v/v) with

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gradient elution was utilized in this study. The limit of detection (LOD) and limit of

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quantification (LOQ) were tested by adding different concentrations of 3-MCPD

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1-monopalmitate into blank rat plasma samples. The LOD was determined in the

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relative standard deviation (RSD) less than 20% and accuracy (average concentration

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deviated from the formulated concentration) to less than ± 20% of the measured

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results. Every sample was tested in triplicate. The LOQ was determined in the

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signal/noise (S/N) = 10, and the LOQ in this study was 2 ng/mL of 3-MCPD

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1-monopalmitate. The standard curve showed linear range between 10 to 1000 ng/mL

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determined by 7 different concentrations of 3-MCPD 1-palmitate with a r2 value of

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0.998.

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Recovery was determined by adding low (30 ng/mL), medium (300 ng/mL) and

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high (1000 ng/mL) concentrations of 3-MCPD 1-monopalmitate into blank rats’

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plasma samples, and prepared them following the same protocol for quantification.

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Each concentration was examined in triplicate. The results indicated that the recovery

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of 3-MCPD 1-monopalmitate in plasma samples was 82.55 to 104.63%.

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Kinetic data analysis and statistical evaluation. Pharmacokinetic analysis was

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performed using 3P97® software (Practical Pharmacokinetic Program, Beijing, China).

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Several kinetic parameters such as the maximum concentration (Cmax), time to

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maximum concentration (tmax), mean residence time (MRT), and area under the

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concentration–time curve (AUC) was determined. Cmax and tmax were obtained

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directly from the plasma concentration–time data and AUC was calculated by the

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trapezoidal rule.

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Results were expressed as mean ± standard deviation (S.D.). Statistics were

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analyzed using the SPSS for Windows (version rel. 10.0.5, 1999, SPSS Inc., Chicago,

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IL).

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Results and Discussion

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Kinetics of 3-MCPD 1-monopalmitate in the plasma. The kinetics of

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3-MCPD 1-monopalmitate in rat plasma after oral administration was evaluated for

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the first time. The greatest concentration of 3-MCPD 1-monopalmitate in the plasma

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was 873.72 ng/mL (Cmax) at about 1.67 hours (Tmax) after oral administration (Table

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1), and no free 3-MCPD was detected in the plasma samples at any tested time points

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under the experimental conditions. A previous study reported the existence of high

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level of free 3-MCPD in the blood of Wistar rats using indirect GC-MS determination

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of its heptafluorobutyric acid derivatives.20 Different results between this study and

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the present study might because of different types and age of rats utilized in these two

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studies, the amount of blood samples used to prepare the analytical samples, and the

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limitation of detecting free 3-MCPD using LC-MS. Plasma 3-MCPD

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1-monopalmitate concentration reduced to half after 3.42 hours (t1/2). No 3-MCPD

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1-monopalmitate could be detected after 4 hours, which was its mean resident time

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(MRT). The area under curve (AUC) for 3-MCPD 1-monopalmitate in rat plasma was

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1676.15 h.ng/mL, which represented the maximum amount of 3-MCPD

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1-monopalmitate absorbed into plasma under the testing conditions. These results

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indicated that 3-MCPD 1-monopalmitate could be absorbed and involved in body

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circulation in vivo in its ester form, and could be eliminated from the circulation

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system in 4 hours possibly through metabolism and/or elimination or tissue

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distribution mechanisms. To the best of our knowledge, this is the first report on

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3-MCPD 1-monopalmitate kinetics in an animal model.

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3-MCPD 1-monopalmitate concentrations in rats’ organs and tissues. The

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relative concentrations of 3-MCPD 1-monopalmitate in the liver, kidney, testis and

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brain of rats were also evaluated at 6, 12, 24 and 48 hours after administration in this

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study. Unfortunately the matrix effects of different organs and tissues made it difficult

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to measure the concentration of 3-MCPD 1-monopalmitate in each organs and tissues

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by UPLC QQQ-MS, and UPLC QTOF-MS was used. 3-MCPD 1-monopalmitate

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could be detected only in the liver sample collected 6 h after administration, and the

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average absolute peak area was 90.88. This observation could also be partially due to

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the limitation in the quantitative resolution of UPLC QTOF-MS. All these data that

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3-MCPD 1-monopalmitate was existed in vivo with its original form raised a question

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whether and how 3-MCPD monoester might be delivered into and be metabolized

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locally in each rat organ or tissue.

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Identification of 3-MCPD 1-monopalmitate metabolites in rats’ tissues,

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plasma and urine. Liver, kidney, testis and brain, as well as plasma and urine of rats

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were collected at 6, 12, 24 and 48 hours after oral administration of 3-MCPD

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1-monopalmitate. Liver is the most important metabolic organ, whereas kidney and

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testis have been reported as the targets for the toxic effects of 3-MCPD esters.10, 21, 22

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Brain was selected because the possible nerve toxicity of 3-MCPD esters observed in

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our previous studies,10 and it is important to investigate whether original form or

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metabolites of 3-MCPD 1-monopalmitate could pass through the blood-brain barrier.

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Blood plasma is the most important body fluid and could reflect in vivo environment,

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while urine is one of the most widely used biological samples in studying the

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excretion of metabolites. Liver, kidney, testis, brain and blood were collected from the

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sacrificed rats at the selected time points, while urine samples were collected using

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the metabolic cage.

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The metabolites were identified using UPLC Q-TOF MS and Waters Masslynx

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4.1 and Waters MetaboLynx XS softwares. A total of 8 metabolites were tentatively

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identified based on their accurate formula masses and fragment ion patterns. Major

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metabolites including 3-MCPD, sulfonated 3-MCPD, acetylated 3-MCPD,

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glucuronide 3-MCPD, and 3-MCPD bonded with different amino acids (Figure 1).

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Besides, some metabolites were also detected and speculate as multi-hydroxylated

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3-MCPD and methylated-hydroxylated 3-MCPD, and their structures were not

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reported in the Figure 1.

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The acetylated metabolite was selected as the example to demonstrate how those

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metabolites were characterized. The total ion chromatography of a typical LC-MS

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chromatography of a liver sample and the extracted ion chromatography of acetylated

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metabolites were showed in Figure 2A and 2B, respectively. The MS1 (parent ion)

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and MS2 (fragment ion) mass spectra of the acetylated metabolite with a retention

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time of 1.13 min (Figure 2B) were obtained (Figure 3A and 3B). In the MS1

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spectrum, the molecular ion peak of the metabolite was 151.0258 [M-H]-, so the

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molecular formula could be calculated as C5H9ClO3. In the MS2 spectrum, the major

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fragment ion peak was 135.0306 [M-OH], combined with the information supplied

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from MetaboLynx XS, the structure could be identified as the acetylated 3-MCPD, the

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major peak at m/z 135.0306 in the MS2 could be the structure obtained by eliminating

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a sn-2 hydroxyl group from 3-MCPD. It is understandable that the acetylation could

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also be at the sn-2 position. The site for acetylation of 3-MCPD was finally proposed

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as the sn-1 position due to the relatively lower steric hindrance of this structure.

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A previous study reported that free 3-MCPD could be detected in the serum 30

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min after oral administration of 3-MCPD esters to F344 rats.22 Glycidol was also

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detected in rats serum after oral administration of either glycidol or 3-MCPD di-esters.

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These two metabolites were not detected in plasma samples in this study at all tested

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time points. Only trace amount of free 3-MCPD was detected in urine samples at 24

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hours after oral administration of 3-MPCD 1-monopalmitate to SD rats. No glycidol

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was detected in any tissue or urine samples in this study. In brief, this study

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characterized 8 metabolites in rats’ tissues and/or plasma and urine samples after oral

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administration of 3-MCPD 1-monopalmitate for the first time.

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Tissue distribution of 3-MCPD 1-monopalmitate metabolites. After

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tentatively identified the eight metabolites, the distribution of these metabolites in

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different tissues and body fluids were examined. Acetylated 3-MCPD was detected in

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liver, kidney, testis, urine and brain samples, but not in the plasma samples.

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Glucuronide conjugated 3-MCPD was detected in urine and plasma samples. Free

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3-MCPD, sulfate conjugated 3-MCPD and glycine conjugated 3-MCPD was only

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detected in urine samples. Hydroxylated and glucuronide conjugated 3-MCPD,

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cysteine conjugated 3-MCPD and taurine conjugated 3-MCPD was only detected in

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plasma samples. Acetylated 3-MCPD is the most widely distributed metabolite in the

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rats after oral administration 3-MCPD 1-monopalmitate. It presented in all the four

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tested tissues, including liver, kidney, testis and brain, suggesting its potential to pass

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through the blood-brain barrier. It was also detected in the urine samples, indicating

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that this metabolite might be one excreting form of 3-MCPD 1-monopalmitate and

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possibly other 3-MCPD esters. Glucuronide conjugated, sulfate conjugated, glycine

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conjugated and free 3-MCPD was also detected in urine samples, and might be other

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possible excreting forms for 3-MCPD 1-monopalmitate and other esters. Glucuronide

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conjugated, hydroxylated and glucuronide conjugated, cysteine conjugated and

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taurine conjugated 3-MCPD was detected in plasma, suggesting that glucuronide and

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amino acid addition might be two important ways to distribute 3-MCPD

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1-monopalmitate into blood (Figure 4).

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In addition, the existences of these metabolites in the selected tissue and fluid

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samples were also evaluated at different time points. Acetylated 3-MCPD was

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detected at all the four time points (4, 12, 24 and 48 h) in liver and kidney samples,

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at 12 and 24 hours in the testis and urine samples after oral administration of 3-MCPD

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1-monopalmitate, respectively. Free 3-MCPD, glycine conjugated and sulfate

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conjugated 3-MCPD was only detected at 12-hour urine samples. Glucuronide

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conjugated, hydroxylated and glucuronide conjugated and taurine conjugated

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3-MCPD was detected in 6-hour plasma samples, whereas cysteine conjugated

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3-MCPD presented in the plasma samples at all the four tested time points.

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Possible metabolic pathway of 3-MCPD 1-monopalmitate in vivo. Based on

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the information above, the possible metabolic pathway of 3-MCPD 1-monopalmitate

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in vivo was proposed using MetaboLynx (Figure 4). Briefly, 3-MCPD

281

1-monopalmitate hydrolyzed and loss its fatty acid fragments to form the free

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3-MCPD (phase I metabolite). After that, the free 3-MCPD combined with the

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endogenous substances in vivo, increased polarity for easy urine excretion (phase II

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metabolites). Sulfonated 3-MCPD, acetylated 3-MCPD, glucuronide 3-MCPD and all

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the amino acid conjugated 3-MCPD are the typical phase II metabolites in vivo. This

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pathway clearly represent the possible metabolic process of 3-MCPD

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1-monopalmitate in vivo, especially the chlorine-contained fragment of 3-MCPD

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ester distributed and excreted. 3-MCPD 1-monopalmit was same as common

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glycerides and could be metabolized through acetylation, glucuronide and sulfonation,

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but was unique to be able to form the three amino acid conjugated 3-MCPD. The

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existence of these metabolites might because of the potential toxicity of 3-MCPD

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1-monopalmitate induced more endogenous metabolic reactions to promote its

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excretion. In summary, this study represents the absorption, distribution, metabolism and

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excretion of 3-MCPD 1-monopalmitate in rats. The toxicokinetic factors were

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clarified, 8 chlorine-related metabolites were tentatively identified and relatively

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quantified based on their peak areas in the major tissues, plasma and urine in four

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different time points, and the major excretion form of 3-MCPD 1-monopalmitate was

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also detected as its phase II metabolites. Besides, there are still large amount of

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metabolites remain in tissues 48 hours after oral administration of 3-MCPD

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1-monopalmitate to rats, such as the acetylated 3-MCPD in liver and kidney, and the

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cysteine conjugated 3-MCPD in testis. Suppose that people consume foods contained

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3-MCPD esters everyday, these metabolites might be accumulated in the

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organs/tissues. Therefore, the toxicity effects of these metabolites should also be

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investigated. The present study might advance our understanding of the metabolism

306

process of 3-MCPD esters and provide a base for further studies to have a better

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understanding about the toxicity effects and mechanisms of 3-MCPD esters in vivo.

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Funding

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We gratefully acknowledge the financial support from a Special Fund for

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Agro-scientific Research in the Public Interest (Grant No. 201203069), the National

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High Technology Research and Development Program of China (Grant Nos.

313

2013AA102202; 2013AA102207), a Grant from the Wilmar (Shanghai)

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Biotechnology Research & Development Center Co. Ltd, and Shanghai Jiao Tong

315

University 985-III disciplines platform and talent funds (Grant Nos. TS0414115001;

316

TS0320215001).

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Table 1. Absorption of 3-MCPD 1-monopalmitate in Rats Animal ID 1

2

3

4

5

6

mean

sd

Cmax a

ng/mL

814.74

887.47

680.83

752.69

988.05

1118.55

873.72

160.33

Tmax b

h

2.50

1.50

1.50

1.50

1.50

1.50

1.67

0.41

h

3.50

3.50

4.00

3.00

3.50

3.00

3.42

0.38

h

4.00

4.00

4.00

4.00

4.00

4.00

4.00

0.00

h.ng/mL

2119.80

2000.66

1201.04

1433.48

1472.26

1829.66

1676.15

361.08

t1/2

c

MRT

d

AUC 0-∞ a

e

Cmax is the maximum concentration of 3-MCPD 1-monopalmitate in rats’ plasma; b Tmax is the time of reach the Cmax after oral administration to rats; c t1/2 is the time that the

concentration of 3-MCPD 1-monopalmitate reduced to half of Cmax; d MRT is the abbreviation of mean residence time, indicate the average time of 3-MCPD 1-monopalmitate stays in the body; e AUC is the abbreviation of area under the curve, represent the total amount of 3-MCPD 1-monopalmitate stay in the body.

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Figure Captions Figure 1. Chemical structures of metabolites. Figure 2. Typical UPLC-QTOF-MS A) total ion chromatogram (TIC) of rat liver sample extracts and B) extract ion chromatogram for the acetylated metabolite after oral administration of 3-MCPD 1-monopalmitate to rats. Figure 3. MS spectra of the acetylated metabolite. A) MS1 spectrum and B) MS2 spectrum. Figure 4. Possible metabolic pathway of 3-MCPD 1-monopalmitate in rats.

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Figure 1.

24


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A)

B)

Figure 2.

25



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A)

B)

Figure 3.

26


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Figure 4.

27



Page 28 of 28

TOC Graphic

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Absorption, Distribution, Metabolism and Excretion ... - ACS Publications

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