ABSTRACT
Vitamin E (α-tocopherol) occurs in nature as a single compound in which carbon atoms 2, 4′ and 8′ are in the R position and the phytyl side chain is straight (RRR, Fig. 10.1). Synthetic vitamin E (all-rac-α-tocopherol) is a mixture of eight stereoisomers including RRR. Half of the material is in the 2R-conformation, half in the 2S. It is believed that biopotency depends largely on the 2R-position; this is evident from the relative potencies in Fig. 10.1 (in brackets) as determined in the rat gestation-resorption test (1).
