US EPA

746833 

Journal Article 

Parabens and phthalates: Their metabolism, AhR ligand activity, estrogenic activity, and P450-inhibitory activity 

Ozaki, H; Shinohara, S; Tange, S; Sugihara, K; Kitamura, S; Ohta, S 

2007 

0 

Organohalogen Compounds
ISSN: 1026-4892 

69 

2991-2994 

http://www.dioxin20xx.org/pdfs/2007/07-323.pdf
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P-Hydroxyalkylbenzoates (parabens) have antimicrobial activity, and have been widely used as preservatives in food, cosmetic and pharmaceutical products. Phthalate diesters are commonly used as plasticizers for polyvinyl chloride-based products. In this study, we examd. the arylhydrocarbon receptor (AhR) ligand activity, estrogen receptor (ER) ligand activity, and chytochrome P 450-inhibitory (P 450) activity of parabens and phthalates. We also studied the metab. of parabens and phthalates in vitro in rat. Parabens with a medium-length side chain (C4?C6) showed AhR ligand activity and ER ligand activity, but the phthalates examd. here lacked these activities. Parabens and phthalates with a side chain of medium length (C6?C9) showed higher inhibitory effects on P 450 activity than did those with a short (C1?C4) side chain. Benzyl-n-butylphthalate showed the greatest inhibitory effect on P 450 activities among the phthalates tested in this study. It was found that carboxylesterase (CES) involved in the hydrolysis of parabens in liver, intestine and lung. The hydrolytic activity of liver microsomes toward parabens decreased with decreasing side chain length of the parabens. CES in the solubilized fraction of liver microsomes is involved in the hydrolysis of phthalates with the short side chain (C2?C4), while an enzyme in the insol. fraction is involved in the hydrolysis of phthalates with a long side chain (C6).