Effects of Plant Sterols or β-Cryptoxanthin at Physiological Serum Concentrations on Suicidal Erythrocyte Death

The eryptotic and hemolytic effects of a phytosterol (PS) mixture (beta-sitosterol, campesterol, stigmasterol) or beta-cryptoxanthin (beta-Cx) at physiological serum concentration and their effect against oxidative stress induced by tert-butylhydroperoxide (tBOOH) (75 and 300 mu M) were evaluated. beta-Cryptoxanthin produced an increase in eryptotic cells, cell volume, hemolysis, and glutathione depletion (GSH) without ROS overproduction and intracellular Ca2+ influx. Co-incubation of both bioactive compounds protected against beta-Cx-induced eryptosis. Under tBOOH stress, PS prevented eryptosis, reducing Ca2+ influx, ROS overproduction and GSH depletion at 75 mu M, and hemolysis at both tBOOH concentrations. beta-Cryptoxanthin showed no cytoprotective effect. Co-incubation with both bioactive compounds completely prevented hemolysis and partially prevented eryptosis as well as GSH depletion induced by beta-Cx plus tBOOH. Phytosterols at physiological serum concentrations help to prevent pro-eryptotic and hemolytic effects and are promising candidate compounds for ameliorating eryptosis-associated diseases.