Hydroperoxides cellular indicators

Particular attention is given to the D-Roms test (14), which is very simple and has been used also to evaluate the antioxidant activity of some products in patients and healthy subjects. The test is based on the determination of hydroperoxides that are derivatives of oxidized lipids and consequently indicate the OS at cellular level. The test is used for the epidemiological study on metabolic syndrome, in Italy by the European Society of Biological Nutrition. 

Great attention has been paid to HAS and their safety application in plastics and coatings. The 4-unsubstituted 2,2,6,6-tetramethylpiperidine is considered as relatively toxic, the acute oral toxicity being about 1 g/kg. The substitution in position 4 (i.e. the general mode in the synthesis of HAS for polymer purposes) dramatically improves the situation. Therefore, commercial HAS like 28 (R = H), 34,35a or 35b were approved for stabilization of packaging materials in contact with food [307]. Some data are available on properties of TEMPO (2,2,6,6-tetramethylpiperidinyl-l-oxyl) and its 4-amino or 4-hydroxy derivatives. They were found to act as weak intrinsic direct mutagens in Salmonella typhimurium. TEMPO increases intracellular hydroperoxide concentration. This may indicate its pro-oxidative effect which does not result, however, in cellular toxicity [314]. 

It has been known for a long time that most of the flavonoids and their derivatives are principles capable of capturing free oxygen radicals, peroxides of fatty acids as well as hydroxyl groups. The capture of superoxide free radicals has been evidenced by the formation of trans-trans hydroperoxides of linoleic acid by flavonoids [173, 174]. The capture of hydroxyl radicals responsible of numerous cell degradations is what indicates its relation with factors of cellular protection. 

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