Chiral discrimination in the exchange of α-tocopherol stereoisomers between plasma and red blood cells

The transport of 2R,4′R, 8′R-α-tocopherol and 2S,4′R,8′R-α-tocopherol from plasma into rat red blood cell membranes occurs with essentially no chiral discrimination. The previously demonstrated (10) preference of red blood cell membranes favoring 2R,4′R,8′R-α-tocopherol over the 2S,4′R, 8′R stereoisomer is shown to be due to better retention of the former compound, i.e., to preferential retention of natural vitamin E.