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Enantioselective analysis of thiobencarb sulfoxide produced by metabolism of thiobencarb by hydroxypropyl‐γ‐cyclodextrin modified micellar electrokinetic chromatography
Author(s) -
Kodama Shuji,
Yamamoto Atsushi,
Matsunaga Akinobu,
Okamura Kazumasa,
Kizu Ryoichi,
Hayakawa Kazuichi
Publication year - 2002
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/1615-9314(20021101)25:15/17<1055::aid-jssc1055>3.0.co;2-s
Subject(s) - sulfoxide , chromatography , chemistry , micellar electrokinetic chromatography , cyclodextrin , enantioselective synthesis , sodium dodecyl sulfate , biochemistry , organic chemistry , detection limit , catalysis
Cyclodextrin‐Modified micellar electrokinetic chromatography was applied to the enantioseparation of thiobencarb sulfoxide, which is produced by S ‐oxygenation of thiobencarb, a herbicide, using γ‐cyclodextrin together with sodium dodecyl sulfate. Factors affecting chiral resolution and migration time of thiobencarb sulfoxide were studied. The optimum running conditions were found to be 20 mM phosphate–5 mM borate buffer (pH 8.5) containing 60 mM hydroxypropyl‐γ‐cyclodextrin and 100 mM sodium dodecyl sulfate with an effective voltage of +20 kV at 20°C using direct detection at 220 nm. Under these conditions, the resolution ( Rs ) of racemic thiobencarb sulfoxide was approximately 1.7. Thiobencarb was treated with a rat liver microsomal fraction containing cofactors (known as S9mix). The ratio between (+)‐ and (–)‐thiobencarb sulfoxide was found to be 15:85. It was also found that the ratio between (+)‐ and (–)‐thiobencarb sulfoxide produced in soil spiked with thiobencarb was 3 : 7. These results indicated marked enantioselectivities for these metabolisms. The activities of thiobencarb, (+)‐ and (–)‐thiobencarb sulfoxides on 5α‐dihydrotestosterone‐ and 17β‐estradiol‐induced transcriptions were also investigated. Whereas thiobencarb and (+)‐thiobencarb sulfoxide did not show any activities, (–)‐thiobencarb sulfoxide showed significant anti‐estrogenic and anti‐androgenic activities, suggesting that thiobencarb sulfoxide can act as both an enantioselective anti‐estrogen and an enantioselective anti‐androgen.