二甲基生育酚 ，rac-5,7-Dimethyltocol

Application Notes:

This synthetic product is very similar in structure to tocopherol (vitamin E) and tocotrienol but is not found naturally and is therefore an ideal MS, HPLC, and GC internal standard for tocopherols and tocotrienols.1 In experimental procedures it has been found that the functionality of rac-5,7-dimethyltocol is different from tocopherols and tocotrienols. For example, rac- 5,7-dimethyltocol has less antioxidant activity than natural tocopherols2 and contributes less to cellular microviscostiy than other tocopherols.3 However, it has been shown that rac-5,7-dimethyltocol (like most other tocopherols but not tocol) can be converted in vitro into alpha-tocopherol.

References: 
1. J. Kramer “A rapid method for the determination of vitamin E forms in tissues and diet by high-performance liquid chromatography using a normal-phase diol column” Lipids, Vol.32:3 pp. 323-330 1997 
2. H. Olcott and J. Van der Veen “Comparison of antioxidant activities of tocol and its methyl derivatives” Lipids, Vol. 3:4 pp. 331-334, 1968 
3. S. Urano et al. “Vitamin E: Inhibition of Retinol-induced Hemolysis and Membrane-stabilizing Behavior” Journal of Biological Chemistry, Vol. 267:26 pp. 18365-18370, 1992