Anti-oxidant therapy: does it have a role in the treatment of human disease?

Free radical oxidative stress has been implicated in the pathogenesis of a variety of human diseases. Natural anti-oxidant defences have also been found to be defective in many of the same diseases. Many researchers have concluded that, if the imbalance between the oxidative stresses and anti-oxidant defence can be corrected by supplementing natural anti-oxidant defences, it may be possible to prevent or retard disease progression. Potential anti-oxidant therapies include natural anti-oxidant enzymes and vitamins or synthetic agents with anti-oxidant activity. Diseases where anti-oxidant therapy may be beneficial can be divided into those involving acute intervention, such as reperfusion injury or inflammation, and those involving chronic preventative therapy, such as atherosclerosis, carcinogenesis and diabetic vascular disease. The pharmaceutical considerations are different in each case. The principles guiding the development, use and assessment of anti-oxidant therapies are discussed in this review.