Nonylphenol Polyethoxylates Degraded by Three Different Wavelengths of UV and Their Genotoxic Change—Detected by Generation of γ‐H2AX. (30th October 2012)

• Record Type: Journal Article
• Authors: Kubota, Toru; Toyooka, Tatsushi; Ibuki, Yuko
• Is Part Of: Photochemistry and photobiology. Volume 89:Number 2(2013:Mar./Apr.)
• Page Start: 461
• Page End: 467
• Publication Date: 2012-10-30
• Subjects: Photochemistry -- Periodicals; Light -- Physiological effect -- Periodicals; 541.35
• DOI: 10.1111/php.12002
• Languages: English
• ISSNs: 0031-8655

Abstract

Abstract: UV rays in sunlight are an important factor in the degradation of chemicals. In this study, we investigated the degradation of nonionic surfactants, nonylphenol polyethoxylates (NPEOs) with 10 or 70 ethylene oxide (EO) units using UVA, B and C, and their genotoxic change based on phosphorylation of histone H2AX (γ‐H2AX), a marker of DNA damage. NPEOs were degraded dependent on the energy of UV, that is, UVC having the highest energy was most effective, whereas UVA having the lowest energy caused little change. The EO side chain of NPEO(70) was broken near the benzene ring by UV, producing NPEOs with a shortened EO chain (around 10 units). The generation of γ‐H2AX reflected the pattern of degradation; shortening of the EO chain changed NPEO(70) into an inducer for γ‐H2AX, and degradation of NPEO(10) attenuated the genotoxicity. The γ‐H2AX generated by NPEO(10) and UV‐degraded NPEO(70) was independent of the cell cycle. The formation of DNA double strand breaks detected by gel electrophoresis was consistent with the results for γ‐H2AX. These results suggested that UV rays can make NPEOs harmless or genotoxic according to the degradation of the EO side chain, the effects being dependent on wavelength. Abstract : The long ethylene oxide (EO) chain of a nonylphenolpolyethoxylate(NPEO[70]) was broken near the benzene ring by UV, producing NPEOs with a short EO chain (around 10 units). NPEO(10) was further degraded and disappeared. The effect was dependent on the energy of UV. A genotoxic marker, phosphorylation of histone H2AX (γ‐H2AX), was generated according to the degradation patterns; shortening of the EO chain changed NPEO(70) into an inducer for γ‐H2AX, and degradation of NPEO(10) attenuated the genotoxicity. UV rays can make NPEOs harmless orgenotoxic according to the degradation of EO side‐chains.