A Scoping Review of the Role of Antioxidants in Managing Oxidative Stress in Patients with β-thalassemia

Abstract

Background: β-thalassemia is one of the most common types of anaemia, and oxidative stress contributes to its severity. Research shows conflicting evidence of the therapeutic impact of antioxidants in β-thalassemia patients. Objective: The key aims of the current scoping reviewer are to assess the available research focused on the use of antioxidants in managing oxidative stress, antioxidant status, haematological and liver markers of disease severity in β-thalassemia patients, and antioxidant safety. Methods: A scoping review assessed research from 2005–2023 on antioxidants' role in managing oxidative stress in β-thalassemia patients. Three databases were used: PubMed, Cochrane, and NUsearch. Keywords used included 'antioxidants', 'oxidative stress' and ‘beta-thalassemia.' The antioxidants identified in the current work included vitamins C, E, and A, zinc, N-acetylcysteine, silymarin, curcumin, quercetin, and alpha-lipoic acid. The primary outcomes were changes to the levels of oxidative stress markers and antioxidant levels. Secondary outcomes considered haematological and liver markers linked to safety. Result: In total of 21 studies (4 observational, 17 RCTs) with 1468 participants aged 7.54 ± 3.38 to 57.5 ± 9.96 years were included. Key findings reveal those antioxidants like vitamin C:100 mg, E: 400-600 mg, A: 25,000 IU, silymarin:420 mg, curcumin: 500 mg, and alpha-lipoic acid: 600 mg, significantly reduced malondialdehyde levels (13.9 to 8.7 µmol/L, p<0.05). Silymarin also reduced protein carbonyl (0.31 ± 0.28 to 0.11 ± 0.09 mM/l, p<0.05) in one study. Plasma concentrations of vitamins C, E, A, and zinc increased, also these vitamins, silymarin, curcumin, and N-acetylcysteine significantly increased glutathione levels, total antioxidant capacity and decreased glutathione peroxidases (p<0.05). Curcumin was found to lower superoxide dismutase levels (p<0.001) only in one study. Silymarin, quercetin, alpha-lipoic acid and vitamins significantly reduced serum ferritin, iron, and liver enzyme levels (p<0.05). Haemoglobin levels were consistent except in three studies. Antioxidants were safe with only gastrointestinal adverse effects. Conclusion: Antioxidants have the potential to manage oxidative stress and improve antioxidant status, and haematological and liver markers in β-thalassemia patients. They were generally safe. However, their effect on protein carbonyl, superoxide dismutases and haemoglobin requires further study.