Table 1.
Antioxidant therapeutics, therapeutic action and delivery methods.
| Antioxidant type | Therapeutic action | Delivery vehicle |
|---|---|---|
| Antioxidant enzymes | ||
| Superoxide dismutase | Converts superoxide (O2•−) to H2O2 | Conjugates [3,14–16,57], liposomes [33,46,48,135], enzymosomes [49,50], magnetic nanocarriers [30] |
| Catalase | Converts H2O2 to H2O | Conjugates [11,17,18,136], polymeric nanocarriers [71,75,99,100,105] and microspheres [72], macrophage-nanozymes [31,51] |
| Glutathione peroxidase (GPx) | Reduces lipid hydroperoxides and converts H2O2 to H2O | GSH-PEGDA oligomer nanoparticle [44] |
| Nonenzymatic antioxidants | ||
| Vitamins Ascorbic acid (vitamin C) Tocopherol (vitamin E) (α-tocopherol, β-tocopherol) Retinoids (vitamin A) |
Scavenges ROS and upregulates antioxidant enzyme activities. Ascorbic acid scavenges O2•− Tocopherol scavenges lipid peroxyl radicals [137] Retiniods regulate epithelial cell growth. Essential vitamin for vision. Regulates NADPH-dependent lipid peroxidation |
Liposomes, emulsions, micelles, solid lipid nanoparticles, microspheres [35] Liposomes [138,139], niosomes, microemulsions, solid lipid nanoparticles [139] |
| Caroteniods Lycopene β-carotene |
Quenches singlet oxygen, free radicals Pro-vitamin A carotenoid | Solid nanoparticles [140] Liposomes, niosomes [35,141] |
| Polyphenols Flavonoids-catechins, Quercetin, fisetin Phenolic acids- curcumin Resveratrol | Scavenge free radicals, inhibit proinflammatory kinases, antitumor activity Affect inflammatory enzyme activity, protects LDL from oxidation Antitumor interferes with carcinogenesis during initiation, promotion and progression, topoisomerases inhibitor, upregulates MnSOD [142] |
Liposomes [143,144], quercetin nanosuspension [145] Iron-containing solid nanoparticles [146], liposomes, nanoparticles, nanoemulsions [40] Liposomes [147], solid lipid nanoparticles [148], lipid core nanocapsules [149] |
| Thiols N-acetylcysteine | Thiol-disulfide redox, metal chelators, radical quenchers, substrate for GSH redox, reductants of disulfate bonds [137] | Liposomes [36,37] |
| Antioxidant cofactors- coenzyme Q10 (ubiquinone) | Functions in the electron transport chain. Electron carrier from complex I and II to III. Circulating coenzyme Q10 in LDL prevents oxidation of LDL; cardioprotective | Liposomes [150,151], microspheres, nanoparticles, nanoemulsions [151] |
PEG: Polyethylene glycol; ROS: Reactive oxygen species; SOD: Superoxide dismutase. Adapted with permission from [1]