Abstract

The oxidative stress results from a change in the physiological balancebetween oxidant and antioxidant species. This condition induces an chemical change in the redox state of cells.. The function of t-PMET is to cooperate with intracellular redox pairs, like piruvate and lactate, to maintain thecytoplasmatic NAD+/NADH balance. The t-PMET is correlated with the modulation of internal pH and redox homeostasis, as it is able to activate proton release. Thus, t-PMET causes external and internal pHmodification, as well as development of an inside negative membranepotential. The aim of this work was evaluate the erythrocytes redoxstatus in a group of health volunteers and then to study whether someof flavonoids, enclosed in sub-class of flavonols (Quercetin andKaempferol), are able to modify the erythrocytes redox homeostasis.Our attention has been focused on red blood cells (RBC) because a close link between t-PMET and metabolic status of erythrocytes has been reported. The RBCs act as antioxidants to themselves and, inaddition, their mobility carries their antioxidant capabilities to all the plasma accessible parts of the body.The subjects that participating at this work attested no supplement intake or some other substance that could interfere with our tests. Human venous blood from twenty healthy volunteers of both sexes between the ages of 25-50 years were obtained by venipuncture in heparin after an over-night fast and centrifuged.The antioxidant capacity of plasma was analyzed by crocin bleaching assay and FRAP. On the other hand, the reducing activityin erythrocytes that represents the body redox state of the last 120 dayswas evaluated by FRAP method. After centrifugation at 3000 rpm for10 minutes at 4°C, plasma was separate from red blood cells. Theresultant plasma was transferred to microcentrifuge tubes and used atleast in part for ferric-reducing activity power (FRAP) and for CrocinBleaching Assay (CBA) and the others aliquots was stored -80°Cbefore to use for further analysis. Red blood cells, after removal ofbuffy coat and upper 15% of the packed red blood cells, were washedtwo times with cold PBS. A stock solution (20mM) of each flavonoid was prepared in dimethyl sulfoxide and then diluted 1:2 with PBS. Packed RBC (10%v/v) were incubatedin PBS containing 5mM glucose at 37°C for 10. minutes with a50 μM concentration of each flavonoids. After this time the suspensionswas centrifuged, the RBC were washed and then analyzed. The percentage of hemolysis was evaluated in the same sample by measuring the haemoglobin contents.The extent of lysis was not different than the controls and never higher than 0.5%.All the values confirm the data of literatureabout the antioxidant status of human being in physiological condition.All compounds were taken up by the erythrocytes and displayingsignificant FIC-reducing activity. Both the analysed compounds(Quercetin and Kaempferol) are able to increase the reducingactivity of the erythrocytes of 15% and 13% respectively respect to thevalue recorded for the control. On the other hand, only the quercetinwas able to increment the activity of the tPMET system; not any significantdifference has been recorded between the Kaempferol and thecontrol group .This study shows that the flavonoids are able to form stable complexeswith the erythrocytes and to influence the intracellular redox homeostasis.Therefore, it could affirm that the polyphenols are able toincrease the defence of erythrocytes against ROS. This work underlinesthat the RBC plays a pivotal role in the distribution and bioavailabilityof circu
Lingua originaleEnglish
Pagine59-60
Numero di pagine2
Stato di pubblicazionePublished - 2015

All Science Journal Classification (ASJC) codes

  • ???subjectarea.asjc.1300.1300???
  • Plant Science
  • Biochemistry, medical

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