Dual effect of Caffeine and Curcumin as Antioxidants on Human Hemoglobin in the Presence of Methyl Tert-butyl Ether (MTBE)

Document Type: Article

Authors

1 Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran

2 Department of Chemical Engineering, University of Bonab, Bonab, Iran

3 Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran. Center of Excellence in Biothermodynamics, University of Tehran, Tehran, Iran

4 Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran

5 Departments of Ophthalmology and Visual Sciences, Cell and Regenerative Biology, and Biomedical Engineering, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA

Abstract

Extensive use of methyl tert‐butyl ether (MTBE) has raised significant threats to the environment through pollution of environmental resources including ground waters. This compound could accumulate in the blood stream through inhalation of contaminated air since MTBE has a high affinity for blood proteins. The interaction of blood proteins such as human hemoglobin (Hb) with MTBE results in conformational and likely functional changes. The main mechanism for harmful effects of MTBE on Hb is through production of reactive oxygen species (ROS). In this regard, the present work was proposed to study the possible antioxidant potential of two dietary antioxidant agents, curcumin and caffeine, on the reduction of MTBE damage on Hb. Different spectroscopic methods including fluorescence, UV‐visible, circular dichroism, chemiluminescence, and molecular docking were used to study the interactions of curcumin and caffeine with Hb in the presence of MTBE. Our results showed caffeine could decrease the aggregation and ROS effects of MTBE on Hb. However, in the presence of curcumin the MTBE mediated aggregation of Hb was enhanced. These opposing effects of curcumin and caffeine as antioxidants were mainly contributed to the high iron chelating activity of curcumin. Thus, the complex formation between curcumin and heme further enhanced ROS production capability of MTBE.

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