History of carnitine

Carnitine was first isolated from meat extract by Gulewitsch and Krimberg as well as Kutscher in 1905 and was first thought to be involved with muscle function. Its structure was not established until 1927.

Gulewitsch and Krimberg identified the structure of carnitine as 3-hydroxy-4-N-trimethyl-aminobutyric-acid (C7H15NO), which was later confirmed in 1927 by Tomita and Sendju.

Then, another 20 years elapsed before Fraenkel, in 1947, while investigating the role of folic acid in the nutrition of insects found that the meal worm (Tenebrio molitor) required a growth factor present in yeast. Without carnitine, the meal worms could not use fat stores when starved.

In 1955, two observations further substantiated carnitine’s role in fat metabolism. Fritz showed that carnitine stimulated fatty acid oxidation in liver slices and liver homogenates. Fraenkel and Friedman found that carnitine could be reversibly acetylated by acetyl coenzyme A (CoA).

Fraenkel called this factor ‘Vitamin BT’; vitamin B because of its water soluble property, and the T standing for Tenebrio. Because of not being recognized as a vitamin, the name was subsequently changed to carnitine.

The word carnitine is derived from Latin word carno or carnis, which means flesh or meat.
History of carnitine