Hemolysis of Human Red Blood Cells by Riboflavin-Cu(II) System: Enhancement by Azide

Iyad Ali's picture
Journal Title, Volume, Page: 
Biochemistry (Mosc). 2005 Sep;70(9):1011-4
Year of Publication: 
Iyad A.F. Ali
Faculty of Pharmacy, Applied Science University, Amman, Jordan
Current Affiliation: 
Department of Biomedical Sciences, Faculty of Medicine & Health Sciences, An-Najah National University, Nablus, Palestine
Sakhnini N
Faculty of Pharmacy, Applied Science University, Amman, Jordan
Naseem I
Department of Biochemistry, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, India
Preferred Abstract (Original): 

Photoactivated riboflavin in the presence of Cu(II) generates reactive oxygen species (ROS) which can hemolyze human red blood cells (RBC). In the present work we examined the effect of sodium azide (NaN3) on RBC in the presence of riboflavin and Cu(II). The addition of NaN3 to the riboflavin-Cu(II) system enhanced K+ loss and hemolysis. The extent of K+ loss and hemolysis were time and concentration dependent. Bathocuproine, a Cu(I)-sequestering agent, inhibited the hemolysis completely. Among various free radical scavengers used to identify the major ROS involved in the reaction, thiourea was found to be the most effective scavenger. Thiourea caused almost 85%inhibition of hemolysis suggesting that ·OH is the major ROS involved in the reaction. Using spectral studies and other observations, we propose that when NaN3 is added to the riboflavin-Cu(II) system, it inhibits the photodegradation of riboflavin resulting in increased ·OH generation. Also, the possibility of azide radical formation and its involvement in the reaction could not be ruled out.

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