This invention refers to the synthesis and purification of a hydroxide derivative of fatty acids, as well as to the separation method of its enantiomers (or optic isomers) [-] and [+], to the enantiomer [-], to pharmaceutical compositions which include it, and to its use as medicines, as well as to an in vitro method of diagnosis/prognosis and evaluation of the potential use of the molecule of the invention in different pathologies, as well as its use for the regulation of certain enzymes and the study of their activity and effects.