The effect of some derivatives and structural analogs of carnitine on the nutrition of Tenebrio molitor

Abstract

Various compounds structurally related to carnitine were tested on carnitine-deficient Tenebrio larvae to determine whether they would replace carnitine or act as inhibitors. The sulfonic acid and triethyl analogs demonstrated weak carnitine activity. The activity of the O-acetyl derivative and the ethyl ester was almost as high as that of the parent compound. γ-Butyrobetaine was found to inhibit carnitine in a competitive manner, with an inhibition index of 100 to 1000. Compounds other than noted above were found to be both inactive and nontoxic to larvae. It appears that the length of the carbon chain between the onium and carboxyl group, the presence of the onium group, and the presence of a free or easily freed β-hydroxyl group are the most influential factors in determining the physiological activity of carnitine.