RESUMEN
Toxins of Escherichia coli (STEC) causing Uremic Hemolytic Syndrome (UHS) generate oxidative stress in human blood with more production of nitric oxide (NO) than reactive oxygen species (ROS). Shiga toxin (Stx) together with the hemolysin (Hly) increased lipid oxidation, as evaluated by malondialdehyde MDA and oxidation of proteins. The addition of Ziziphus mistol Griseb extracts decreased NO, ROS, MDA and simultaneously caused an increase in the degradation of oxidized proteins to advanced oxidation protein products (AOPPs) in controls and samples with toxins. Furthermore, the nitrosylated proteins/AOPP ratio was reduced, due to the increase of AOPP. Z. mistol Griseb extracts exhibited a high proportion of polyphenols and flavonoids, with evident correlation with ferrous reduction antioxidant potential (FRAP). The plasma of eight children with UHS showed oxidative stress and NO stimulus, comparable to the effect of toxins during the assays in vitro. UHS children presented high levels of nitrosylated proteins respect to control children of similar age. Although the degradation of oxidized proteins to AOPP rose in UHS children, the nitrosylated proteins/AOPP rate increased as a consequence of the elevated nitrosative stress observed in these patients.