• Journal of the Korean Chemical Society
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• v.57 no.3
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• pp.335-340
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• 2013

A chemical reaction of PBDEs was implemented using the polyethylene glycols (PEGs) and KOH, along with different reaction conditions such as temperatures and times. Removal efficiencies of PBDEs before and after chemical reaction were examined by difference of concentration. PBDEs was not removed at lower temperatures of 25 and $50^{\circ}C$. However, under the increased temperature, removal efficiency of PBDEs in ${\sigma}$-xylene was gradually increased, showing completely removal of PBDEs containing 5-6 bromines on biphenyl frame. When increasing the reaction conditions to 4 hours and $150^{\circ}C$, removal efficiency of PBDEs reached almost 100%. In studying the reaction of PEGs with PBDEs, it confirmed that the PBDEs led to less brominated by PEGs through a stepwise process with the successive elimination of bromines.

• Journal of Embryo Transfer
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• v.26 no.4
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• pp.297-304
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• 2011

Polybrominated diphenyl ethers (PBDEs) are a class of "brominated" (bromine containing) man-made chemicals used as flame retardant additives in plastics, foams, and textiles. PBDEs are found in various environmental contaminants in air, soil, sediment, and water, and 209 individual forms (congeners) of PBDE exist. Among these, 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) is the dominant congener found in the environment. Exposure to BDE-47 is now worldwide, and levels of BDE-47 have been detected in the blood of animals, including humans. BDE-47 can adversely affect the developmental system in both humans and animals. BDEs have structural similarities to polychlorinated biphenyls and thyroid hormones. However, recent studies have shown that BDEs may act as hormonal disrupting chemicals with detrimental effects. Therefore, a reliable assessment of BDE-47 toxicological action is required to understand the detrimental impacts of BDE-47 on human health. In this review, we overview recent studies on the distribution and potential toxicological effects of BDE-47 in humans and animals.

• Toxicological Research
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• v.35 no.1
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• pp.93-101
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• 2019

Tetrabromobisphenol A (TBBPA), the most common industrial brominated flame retardant, acts as a cytotoxic, neurotoxic, and immunotoxicant, causing inflammation and tumors. However, the mechanism of TBBPA-induced matrix metalloproteinase-9 (MMP-9) expression in human breast cancer cells is not clear. In human breast cancer MCF-7 cells, treatment with TBBPA significantly induced the expression and promoter activity of MMP-9. Transient transfection with MMP-9 mutation promoter constructs verified that $NF-{\kappa}B$ and AP-1 response elements are responsible for the effects of TBBPA. Furthermore, TBBPA-induced MMP-9 expression was mediated by $NF-{\kappa}B$ and AP-1 transcription activation as a result of the phosphorylation of the Akt and MAPK signaling pathways. Moreover, TBBPA-induced activation of Akt/MAPK pathways and MMP-9 expression were attenuated by a specific NADPH oxidase inhibitor, and the ROS scavenger. These results suggest that TBBPA can induce cancer cell metastasis by releasing MMP-9 via ROS-dependent MAPK, and Akt pathways in MCF-7 cells.

• Environmental Analysis Health and Toxicology
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• v.24 no.4
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• pp.303-309
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• 2009

Hepatic antioxidant defense systems were examined in rats treated with tetrabromobisphenol-A (TBBPA), a brominated flame retardant, at the doses of 0, 250, 500 and 1,000 mg/kg for four weeks. Hepatic ratio of glutathione disulfide to glutathione (GSH) and levels of malondialdehyde, oxidative stress markers were not changed in rats treated with TBBPA. Hepatic expression of antioxidant enzymes including GSH peroxdiase-1 (GPX-1)/GSH reductase (GR), alpha-, mu- and pi-class glutathione-S-transferase (GST) and gamma-glutamylcysteine ligase catalytic subunit was determined using immunoblot analysis. Alpha-class GSTs, GPX-1 and GR levels were significantly decreased in rats treated with TBBPA at the dose of 500 or 1,000 mg/kg. These results show that TBBPA results in down-regulation of hepatic expression of antioxidant enzymes related with GSH, suggesting the liver in TBBPA-treated rats may be more sensitive to oxidants.

• Toxicological Research
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• v.27 no.2
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• pp.61-70
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• 2011

Brominated flame retardants (BFRs) are present in many consumer products ranging from fabrics to plastics and electronics. Wide use of flame retardants can pose an environmental hazard, which makes it important to determine the mechanism of their toxicity. In the present study, dose-dependent toxicity of tetrabromobisphenol A (TBBPA), a flame retardant, was examined in male prepubertal rats (postnatal day 18) treated orally with TBBPA at 0, 125, 250 or 500 mg/kg for 30 days. There were no differences in body weight gain between the control and TBBPA-treated groups. However, absolute and relative liver weights were significantly increased in high dose of TBBPA-treated groups. TBBPA treatment led to significant induction of CYP2B1 and constitutive androstane receptor (CAR) expression in the liver. In addition, serum thyroxin (T4) concentration was significantly reduced in the TBBPA treated group. These results indicate that repeated exposure to TBBPA induces drug-metabolising enzymes in rats through the CAR signaling pathway. In particular, TBBPA efficiently produced reactive oxygen species (ROS) through CYP2B1 induction in rats. We measured 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of DNA oxidative damage, in the kidney, liver and testes of rats following TBBPA treatment. As expected, TBBPA strongly induced the production of 8-OHdG in the testis and kidney. These observations suggest that TBBPA-induced target organ toxicity may be due to ROS produced by metabolism of TBBPA in Sprague-Dawley rats.

• Analytical Science and Technology
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• v.27 no.6
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• pp.321-332
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• 2014

The accumulation levels of hexabromocyclododecanes (HBCDs) were measured in samples of muscle tissue from crucian carp (Carassius auratus) and also in samples of associated sediments. Samples were collected from 15 sites along the courses of four major rivers. Widespread contamination by HBCDs in this area was identified from the results of this investigation. HBCDs were found above the detection limit from all of the sampling sites. The ${\Sigma}HBCDs$ (sum of ${\alpha}$-, ${\beta}$-, and ${\gamma}$-HBCDs) levels ranged from 1.3 to 19 ng/g (lipid wt) in the crucian carp musscle tissue samples, and from 0.17 to 30 ng/g (dry wt) in the associated sediment samples. The predominance of ${\alpha}$-diastereomer in the muscle tissue of the carp and ${\gamma}$-diastereomer in the sediments was identified, accounting for 88% and 60% of the ${\Sigma}HBCDs$, respectively. The ${\Sigma}HBCDs$ levels in the muscle tissue samples of carp collected from the upstream sections of each river were much lower than those in the samples from carp in the downstream sections. In addition, the ${\Sigma}HBCDs$ levels in carp tissue samples from an isolated site were much lower than those in carp collected from the sites along the major rivers. This suggests that HBCD contamination in the rivers is likely to be sourced from the environment adjacent to them.