THE PROANTIOXIDANT ACTIVITIES OF POPULAR ANTIOXIDANTS

Based on: Sotler et al. (2019). PROOXIDANT ACTIVITIES OF ANTIOXIDANTS AND THEIR IMPACT ON HEALTH. Acta clinica Croatica, 58(4), 726–736. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7314298/

• Vitamin C
  • A potent antioxidant
  • Vitamin C can function as a prooxidant depending on the dose
  • It has an antioxidant effect in case of low dose (30 - 100 mg/kg body weight) but a prooxidant effect in case of high dose (1 000 mg/kg body weight)
• Alpha-tocopherol
  • A potent antioxidant
  • A harmful prooxidant in high concentrations
  • When reacting with ROS, alpha-tocopherol becomes a radical, and if there is not enough vitamin C for its regeneration, it remains in the reactive state
• Beta-carotene
  • Prooxidant activity of beta-carotene is dependent on its interaction with biological membranes and the presence of co-antioxidants (such as vitamin C)
  • At higher oxygen tension, beta-carotene loses its effectiveness as an antioxidant
  • A systematic review and meta-analysis revealed increased mortality rates after prolonged use of supplements with beta-carotene, vitamin A and vitamin E
• Flavonoids
  • Act as prooxidants in the systems that contain transition metals
  • Flavonoids, such as quercetin and kaempferol, induce DNA damage and lipid peroxidation in the presence of the transition metal
• Phenolics
  • Display prooxidant effects, especially in systems that encompass redox-active metals
  • The presence of iron or copper catalyses their redox cycling and may lead to the formation of phenolic radicals, which damage lipids and DNA