Zinc benzoate, a contaminating environmental compound derived from polystyrene resin inhibits A-type monoamine oxidase

Toru Egashira, Kumiko Sakai, Fusako Takayama, Mami Sakurai, Satoshi Yoshida

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8 Citations (Scopus)


The contaminants in deionized and distilled water (DDI water) boiled with polystyrene resin inhibited A-type monoamine oxidase (MAO, MAO-A preferentially deaminates serotonin and norepinephrine and regulates these amines concentration) activity in monkey brain mitochondria. To identify these contaminants, we attempted measurements by HPLC, FT-IR and NMR. The compound inhibiting MAO-A activity was zinc benzoate. Although it potently inhibited MAO-A activity, zinc benzoate did not effect MAO-B in monkey brain mitochondria. It also reversibly and competitively inhibited MAO-A activity in a dose-dependent manner. Zinc benzoate, however, did not inhibit either MAO-A or -B activities in rat brain mitochondria. These results indicate that zinc benzoate, which inhibits MAO-A activity, is easily incorporated in DDI water by boiling polystyrene and also may be a contaminating environmental chemical compound that alters the levels of serotonin and norepinephrine in the central nervous system.

Original languageEnglish
Pages (from-to)161-165
Number of pages5
JournalToxicology Letters
Issue number2
Publication statusPublished - Nov 30 2003
Externally publishedYes



  • Environmental compound
  • MAO-A
  • MAO-B
  • Monkey brain mitochondria
  • Zinc benzoate

ASJC Scopus subject areas

  • Toxicology

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