Tocobest^TM

Vitamin E Homologues

Natural & synthetic VE

Bioactivity

Tocobest^TM VE series

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Bioactivity

The first dietary role discovered for tocopherol was as an essential nutrient for normal development of an animal foetus -- hence the name tos (Greek: childbirth), phero (Greek: to bring forth) and ol (alcohol). Tocopherol fertility restoration assays provided a basis for quantification, so-called "International Units" (IUs). (Different biological assays and IUs were established for all the fat-soluble vitamins.) The acetate of dl-alpha-tocopherol was arbitrarily assigned the value of one IU per milligram (mg). (Acetate and succinate derivatives are more stable, and hence more suited for storage and for use in supplements.) Natural alpha tocopherol (RRR-alpha-tocopherol) had an activity of 1.49 IU per mg, whereas synthetic alpha-tocopherol had an activity of 1.10 IU per mg. Beta, gamma and delta tocopherols had activities of 0.60 IU, 0.30 IU and 0.015 IU per mg, respectively. For alpha-tocopherol, the asymmetric carbon at the 2-position of the chromanol ring is the major (perhaps the only) determinant of the difference in biological activity.

Biological activity:

However, there are many biological functions of tocopherol, and the different forms do not have the same relative activities for each function. For example, a review of cancer prevention by Vitamin E stated that gamma-tocopherol is the most potent form for preventing breast cancer Moreover, chemical assays became precise enough in the 1950s to make biological assays unnecessary. The United States Pharmacopeia (USP) no longer uses IU units. Therefore, the United States Food and Nutrition Board now quotes Recommended Daily Allowances (RDAs) in milligrams rather than in IUs.