Tocopherols and 6-Hydroxy-chroman-2-Carbonitrile Derivatives Inhibit Vascular Smooth Muscle Cell Proliferation by a Nonantioxidant Mechanism

The effects of two groups of similar compounds, a series of tocopherols and one of 6-hydroxy-chroman-2-carbonitrile, have been studied in vascular smooth muscle cells. A poor correlation has been found between antiproliferative and antioxidant properties of these molecules. D-α-Tocopherol inhibits cell proliferation, while D-α-tocopherylquinone has been found neither to inhibit nor to activate. D-β-Tocopherol, a poor inhibitor of smooth muscle cell proliferation, has been shown to be capable of preventing and reversing the inhibition by D-α-tocopherol. It is concluded that the tocopherols and carbonitrile derivatives tested here appear to inhibit smooth muscle cell proliferation by a nonantioxidant mechanism. The competition between D-α-tocopherol and D-β-tocopherol suggests the existence of a common binding site for the two molecules.