RESUMO
Oxidative stress (OS), defined as a disturbance in the balance between the production of reactive oxygen species (ROS) and antioxidant defenses, can result in the development of many serious diseases like diabetes or cancer. Moreover, the role of oxidative stress in the acceleration of the aging process is also confirmed. ROS are constantly produced in the natural biochemical processes, mainly during cellular respiration. Their enhanced production may be the result of e.g., an inappropriate diet high in saturated fats, low in fiber, fruits and vegetables, insufficient physical activity or smoking. To prevent oxidative stress, besides changes in life style, the additional supplementation of antioxidants is proposed. On the Polish market, the number of food supplements with declared antioxidant activity is still increasing. However, their antioxidant properties are rarely confirmed experimentally. The aim of our study was to determine the antioxidant potential of selected dietary supplements available on the market and recommended in chronic fatigue syndrome. The antioxidant potential was measured using four methods: FRAP, ORAC, HORAC, EPR/DPPH. Moreover, the content of polyphenols in the dietary supplements was also determined.