Fig. 1. Effect of various forms of tocopherol (vitamin E) on the growth of mouse melanoma (B-16) cells in culture. Cells (10⁵) were plated in Lux tissue culture dishes (60 mm). Twenty-four hours after plating, D--tocopherol acid succinate (Sigma; soluble in ethanol), DL--tocopherol free alcohol (Hoffmann-La Roche; soluble in specialized solvent) and Aquasol DL--tocopherol acetate (USV Laboratories; soluble in specialized solvent) at various concentrations were added individually to separate dishes. Growth medium and drug were changed at two days after treatment, and the growth inhibition, based on the amount of protein per dish, in the treated culture was determined at three days after treatment. The average value of the untreated controls was considered 100%, and the growth inhibition of treated cultures was expressed as percentage of untreated controls. The amount of protein per dish in the untreated cultures was 850 ± 67 µg. Each point on the curve represents an average of nine samples; bars, S.D.[7].