Abstract
We report the development of a new colorimetric probe (L-ol) for investigations of the redox process regulated by hypochlorous acid (HOCl) and glutathione (GSH). The HOCl/GSH redox-switching cycle process was investigated in detail by UV-vis absorption spectroscopy, colorimetric analysis assay and high-resolution mass spectrometry (HRMS). The switchable absorbance responses were attributed to the HOCl-induced oxidation of the p-methoxyphenol unit to the benzoquinone derivative (L-one) and sequential reduction of L-one to hydroquinone (L-ol’) by GSH. In phosphate-buffered saline (PBS) buffer, the absorbance of L-ol at 619 nm underwent a remarkable bathochromic-shift, accompanied by a color change from pale yellow to blue in the presence of HOCl. With further addition of GSH, the absorbance of L-one exclusively recovered to the original level. Meanwhile, the blue-colored solution returned to the naive pale yellow color in the presence of GSH. The detection limits for HOCl and GSH were calculated to be 6.3 and 96 nM according to the IUPAC criteria. Furthermore, L-ol-loaded chromatography plates have been prepared and successfully applied to visualize and quantitatively analyze HOCl in several natural waters.
Highlights
The redox balance between reducing and oxidizing species is important in the regulation of a signal pathway in biosystems
The hypochlorous acid (HOCl)/GSH regulated redox-switching process was first monitored by the high-resolution mass spectrometry (HRMS)
The results indicate that L-ol could be used to monitor the HOCl/GSH regulated redox-switching regulated redox-switching process in real-time
Summary
The redox balance between reducing and oxidizing species is important in the regulation of a signal pathway in biosystems. The reduction–oxidation state of the cell is primarily a consequence of the precise balance between the levels of reactive oxygen species (ROS) and antioxidant [5,6,7,8] Among these ROS, hypochlorous acid (HOCl) is an endogenous microbicidal agent and a highly potent oxidant that is mainly generated by the catalysis of myeloperoxidase (MPO) in the presence of chloride and hydrogen peroxide under physiological conditions [9,10,11]. Variations in GSH concentration have been linked to many oxidative stress and regulating thecancer, redox aging, environment of the internal compartments [18,19,20,21,22,23]. Variations in GSH concentration have been linked to many pathological processes including cancer, GSH was found to protect cells from the damage caused by HOCl [28].
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