Bioassay of Vitamin E by the Dialuric Acid Hemolysis Method

Abstract

A biossay procedure that utilizes the protective effect of a single dose of vitamin E in rats against the in vitro hemolytic action of dialuric acid upon vitamin E-deficient erythrocytes has been described, and its precision, specificity, and dependability studied. A number of precautions that must be observed to obtain good precision in the hemolysis test are set forth. A new single-dose bioassay is described that may be completed in two days and is so designed that the test animals may be used for a number of assay periods. The method will allow easy application to a variety of products that contain vitamin E. Biological potencies determined by this method are reported for several tocopherols and their esters. The results differ from earlier reports in the literature in that the values reported here for d-gamma tocopherol and its acetate are higher and that there is no significant difference between the ester and alcohol forms of the various tocopherols. The d-alpha-tocopherol, in accordance with earlier work, is about 33% more potent than the racemic form.