Synthesis, Bioproduction and Bioactivity of Perillic Acid-A Review

Perillic acid (PA) is a limonene derivative in which the exocyclic methyl is oxidized to a carboxyl group. Although endowed with potential anticancer activity, PA has been much less explored regarding its biological properties than analogous compounds such as perillyl alcohol, perillaldehyde, or limonene itself. PA is usually described in mixture with alcohols and ketones produced in the oxidation of monoterpenes, with relatively few existing reports focusing on the PA molecule. This study provides a comprehensive review of PA, addressing its origin, the processes of obtaining it through organic synthesis and biotransformation, and the pharmacological tests in which it is either the lead compound or reference for in vitro efficacy in experimental models. Although feasible and generally poorly yielded, the synthesis of PA from limonene requires multiple steps and the use of unusual catalysts. The most economical process involves using (-)-β-pinene epoxide as the starting material, ending up with (-)-PA. On the other hand, some bacteria and yeasts are successful in producing, exclusively or at satisfactory purity level, PA from limonene or a few other monoterpenes, through environmentally friendly approaches. The compiled data revealed that, with few exceptions, most reports on PA bioactivity are related to its ability to interfere with the prenylation process of oncogenic proteins, an essential step for the growth and dissemination of cancer cells. The present survey reveals that there is still a vast field to disclose regarding the obtaining and scaling of PA via the fermentative route, as well as extending prospective studies on its properties and possible pharmacological applications, especially in the preclinical oncology field.