5
0 -MeSO 2 -CB132. Enantiomer-selective MeSO 2 -PCB analysis of the lung samples
showed an excess and dominance of the second eluting atropisomer of 4-MeSO 2 -
CB149. In both lung and adipose tissues, small amounts of the first eluting
atropisomer of 5-MeSO 2 -CB149 were present. However, this atropisomer was not
detected in the liver.
An in-depth study on the metabolic profile for PCB 132 (Norstrom et al. 2006)
revealed the preferential transformation in the R-configuration of the corresponding
methyl sulfone PCBs in laboratory experiments on rats (Rattus novegicus L.). The
examination of the liver, lung and adipose tissue from the exposed rats confirmed a
strong retention of one of the CB-132 atropisomers and a similar, but even more
pronounced, accumulation of one of the atropisomers of the meta- and para-methyl
sulfone-substituted CB-132 transformation products in these tissues. The herereported results point towards the enantioselective formation of the
methylsulfonyl-CB132 metabolites in rodents.
As a part of the conventional cytochrome-induced phase II detoxification process
in organisms, glutathione-S-transferase-mediated conjugation into more polar
sulphone-containing metabolites is a common feature for many lipophilic organic
pollutants (Aydemir and Kavrayan 2009; Simpson et al. 2009; Nahrgang et al.
2013). Therefore, the enantiomeric profile for other chiral organic pollutants are
currently under investigation. Relevant methyl sulphone pollution has been also
found for DDT even in remote Arctic environments (Letcher et al. 1995).
In addition to methylsulphone PCBs (already reported), Larsson et al. also
developed a method for the atropisomer separation of chiral methyl-sulfone DDT
derivatives and bis(4-chlorophenyl) sulfone (BCPS) in environmental samples
(Larsson et al. 2004a, b). Environmentally relevant meta-/para pairs are chiral and
exist, thus, as atropisomeric pairs. Methylsulphonyl-DDE (MeSO 2 -DDE) is a major
DDE metabolite, while bis(4-chlorophenyl) sulphone (BCPS) is a commercial
monomer used for thermoplastic production. All these sulphones are well-known
Fig. 8.26 Enantioselective separation of MeSO 2 -hexa PCBs in a rat liver sample, 2 weeks after a
single dose of the commercial PCB-mixture Clophen A50
8.2 Transformation/Accumulation of Chiral Xenobiotics in Higher Organisms
185
0 -MeSO 2 -CB132. Enantiomer-selective MeSO 2 -PCB analysis of the lung samples
showed an excess and dominance of the second eluting atropisomer of 4-MeSO 2 -
CB149. In both lung and adipose tissues, small amounts of the first eluting
atropisomer of 5-MeSO 2 -CB149 were present. However, this atropisomer was not
detected in the liver.
An in-depth study on the metabolic profile for PCB 132 (Norstrom et al. 2006)
revealed the preferential transformation in the R-configuration of the corresponding
methyl sulfone PCBs in laboratory experiments on rats (Rattus novegicus L.). The
examination of the liver, lung and adipose tissue from the exposed rats confirmed a
strong retention of one of the CB-132 atropisomers and a similar, but even more
pronounced, accumulation of one of the atropisomers of the meta- and para-methyl
sulfone-substituted CB-132 transformation products in these tissues. The herereported results point towards the enantioselective formation of the
methylsulfonyl-CB132 metabolites in rodents.
As a part of the conventional cytochrome-induced phase II detoxification process
in organisms, glutathione-S-transferase-mediated conjugation into more polar
sulphone-containing metabolites is a common feature for many lipophilic organic
pollutants (Aydemir and Kavrayan 2009; Simpson et al. 2009; Nahrgang et al.
2013). Therefore, the enantiomeric profile for other chiral organic pollutants are
currently under investigation. Relevant methyl sulphone pollution has been also
found for DDT even in remote Arctic environments (Letcher et al. 1995).
In addition to methylsulphone PCBs (already reported), Larsson et al. also
developed a method for the atropisomer separation of chiral methyl-sulfone DDT
derivatives and bis(4-chlorophenyl) sulfone (BCPS) in environmental samples
(Larsson et al. 2004a, b). Environmentally relevant meta-/para pairs are chiral and
exist, thus, as atropisomeric pairs. Methylsulphonyl-DDE (MeSO 2 -DDE) is a major
DDE metabolite, while bis(4-chlorophenyl) sulphone (BCPS) is a commercial
monomer used for thermoplastic production. All these sulphones are well-known
Fig. 8.26 Enantioselective separation of MeSO 2 -hexa PCBs in a rat liver sample, 2 weeks after a
single dose of the commercial PCB-mixture Clophen A50
8.2 Transformation/Accumulation of Chiral Xenobiotics in Higher Organisms
185