Abstract Summary/Description
Sodium Chloride Enhances the Photo-Toxic Properties of a 1,4-Naphthoquinone Found in Marine Environments Bianca Vazquez, Owen Waters, Karen Amike, Sneha Kannan, Kathryn B. Grant Naphthoquinones are released into the environment through the incomplete combustion of wood, coal, petroleum, and other organic fuels, especially diesel. A number of naphthoquinones are not only highly toxic to humans but also to organisms that inhabit soil and aquatic environments. Through rainfall, these compounds find their way into bodies of water where they can cause great harm. By sensitizing the production of DNA damaging reactive oxygen species (ROS), irradiation of the PAHs by sunlight often dramatically enhances their toxicity to a variety of life forms. In investigating this problem, our laboratory discovered that high sodium chloride (NaCl) concentrations similar to those that exist in marine environments dramatically increase the levels of dangerous ROS generated by PAHs with anthraquinone frameworks consisting of three fused aromatic rings. The goal of the present study is to determine if naphthoquinone PAHs can also become more phototoxic when high NaCl concentrations are present. Because naphthoquinones have only two aromatic rings, they are more water soluble and therefore are observed at higher concentrations in marine environments. UV-visible spectroscopy was used to determine the stability of the compounds in dimethyl sulfoxide (DMSO) and in sodium phosphate buffer. Additionally, the MDID-5 Plate Reader was utilized to assess the fluorescence of each compound upon irradiation with and without NaCl. These results offer insight into potential levels of hydroxyl radicals generated by each compound via detection by hydroxyphenyl fluorescein (HPF). In addition to affording important mechanistic insights, it is hoped that our work will uncover the structural features that enable PAHs to display a salt-induced ROS enhancement.
