Vitamin E's positive effects often fail to manifest themselves as strongly as expected, but sometimes administering vitamin E actually has detrimental effects. An international team has now found a possible cause for this.

It has shown that the effect of vitamin E, which is taken as a tablet or capsule, is not based on the vitamin itself, but rather on the effect of a metabolite. This so-called alpha-carboxychromanol has e. g. A promising anti-inflammatory effect.

It is reputed to stop the skin from aging, reduce joint degeneration in rheumatism and arthritis, and even protect against cancer and cardiovascular diseases. For nearly 100 years, researchers have been studying the effects of vitamin E – scientific name alpha-tocopherol – and they have to a great extent clarified the chemical basis of its action.

"Vitamin E is an antioxidant; it neutralizes cell-damaging free radicals," explains Dr. Andreas Koeberle of Friedrich Schiller University Jena (Germany). However, although this has been sufficiently corroborated in cell and animal models under laboratory conditions, Vitamin E has so far failed to convince in clinical studies.

"Here, we find very heterogeneous results," says Koeberle, a biochemist at the Chair of Pharmaceutical/Medicinal Chemistry. "Not just that the positive effects often fail to manifest themselves as strongly as expected, but sometimes administering vitamin E has detrimental effects."

Dr. Koeberle and his colleagues have now found a possible cause for this in a broad-based interdisciplinary study with partners from France, Austria, Italy, and Germany. They have shown that the effect of vitamin E, which is taken as a tablet or capsule, is not based on the vitamin itself, but rather on the effect of a metabolite.

This substance, called alpha-carboxychromanol, has a promising anti-inflammatory effect, among other things. The researchers have published their results in the specialist journal "NATURE Communications."

Key enzyme is inhibited in the inflammatory process

In this study, the researchers have examined in detail the anti-inflammatory potential of alpha-carboxychromanol. The bioactive metabolite inhibits a key enzyme in inflammatory processes: 5-Lipoxygenase (5-LO).

This is a very promising finding, according to Koeberle, because 5-LO plays a central role in inflammatory diseases such as asthma or arthritis. "However, to date, there is only one authorized drug that inhibits 5-LO, but due to its strong side effects, its use is very limited."

The researchers in Jena want to use their findings to develop a new drug candidate for the treatment of inflammatory diseases. A first active substance derived from alpha-carboxychromanol has already been patented, according to Koeberle.