Antioxidant therapy for treatment of inflammatory bowel disease: Does it work?

• Major biomarkers used for evaluation of antioxidant therapy were MPO, TBARS/MDA and glutathione levels.
• Challenges were identified for the yet poor use of antioxidant therapy in IBD.
• This review stimulates the investigation of alternative and efficacious antioxidant therapies.

Oxidative stress (OS) is considered as one of the etiologic factors involved in several signals and symptoms of inflammatory bowel diseases (IBD) that include diarrhea, toxic megacolon and abdominal pain. This systematic review discusses approaches, challenges and perspectives into the use of nontraditional antioxidant therapy on IBD, including natural and synthetic compounds in both human and animal models. One hundred and thirty four papers were identified, of which only four were evaluated in humans. Some of the challenges identified in this review can shed light on this fact: lack of standardization of OS biomarkers, absence of safety data and clinical trials for the chemicals and biological molecules, as well as the fact that most of the compounds were not repeatedly tested in several situations, including acute and chronic colitis. This review hopes to stimulate researchers to become more involved in this fruitful area, to warrant investigation of novel, alternative and efficacious antioxidant-based therapies.

Legend: 8-oxodG=8-oxo-2′-deoxyguanosine; AGE=advanced glycation end-products; COX2=cyclooxygenase 2; GR=glutathione reductase; GSH=reduced glutathione; iNOS=inducible nitric oxide synthase; GPx=glutathione peroxidase; GST=glutathione S-transferase; H2O2=hydrogen peroxide; LPO=lipoxygenase; MDA=malonaldheyde; NF-kB=nuclear factor Kappa-light-chain enhancer of activated B cells; Nrf2=nuclear erythroid 2 factor; NOX=NADPH oxidase; HO
• =hydroxyl radical; O2
• –=anion radical superoxide; NO
• =nitric oxide; RONS=reactive oxygen and nitrogen species; SOD=superoxide dismutase; TBARS=thiobarbituric acid reactive substances; ˧ decrease; (–) inhibition; (+) stimulus.Figure optionsDownload as PowerPoint slide