SUMMARY
Numerous studies that demonstrate the direct relation between oxidative stress and diseases development have been accumulated in the last years. Experimentally, in the oxidative stress state, the raising of the concentration of products resulted from oxidative degradation of lipids, proteins and nucleic acids have been notice, along with the decreasing of the enzymatic and nonenzymatic antioxidants activity. The literature shows a special interest on antioxidants characteristics of various vitamins and provitamines, especially carotenoids.The present paper consist in a comparative study regarding the antioxidant activity of oxygenized carotenoids, with both normal and retro type structure (canthaxanthin and rhodoxanthin) and also in making evident the possible differences that could appear in this activity according to the structure. The oxidative stress state was evaluated in liver and skin using specific markers. Canthaxanthin and rhodoxanthin administration positively influence the oxidative stress markers at cellular level. The carotenoids administration influences differently the activity of antioxidant enzymes in analysed tissues: canthaxanthin activates these enzymes at skin level while rhodoxanthin activates them at hepatic level. The antioxidant effect it's more obvious in the case of canthaxanthin, this pigment demonstrates a higher protecting effect on lipids compared with rhodoxanthin.