In red blood cells, NADPH is essential for regenerating which antioxidant, whose deficiency contributes to hemolysis in G6PD deficiency?

• A. Glutathione
• B. NADPH
• C. Catalase
• D. Superoxide dismutase

Answer: (A)

Red blood cells rely on reduced glutathione to neutralize peroxides, and the reduced form is kept active by glutathione reductase using NADPH as the reducing power. NADPH mainly comes from the pentose phosphate pathway, so any impairment there limits the ability to regenerate glutathione. In G6PD deficiency, the pathway’s activity drops, NADPH production falls, and glutathione cannot be efficiently regenerated from its oxidized form. Without sufficient reduced glutathione, oxidative damage accumulates to red blood cell membranes and hemoglobin, leading to hemolysis under oxidative stress. While catalase and superoxide dismutase are important antioxidants, their primary actions don’t rely on regenerating a reduced form like glutathione, and NADPH is not itself the antioxidant but the reducing power that maintains glutathione in its active form.