Biomimetic Oxidative Reactions with Acanthoic Acid.
Acanthoic acid, Annona amazônica, Biomimetic oxidation, Jacobsen catalyst, Natural products.
The acanthoic acid, (-)-pimara-9(11),15-dien-19-oic acid, is a type of pimaradiene diterpene mainly isolated from the Korean medicinal plant, Acanthopanax koreanum. Other species as Annona amazonica, Rollinia pittieri, Rollinia exsucca, Aralia racemosa and Croton oblongifolius Roxb also revealed this diterpene in its constitution. Despite its biological diversity for the treatment of several diseases described in the literature (ulcerative colitis, hepatic fibrosis, type 2 diabetes, inflammatory cardiovascular diseases and periodontal), studies related to its pharmacokinetic parameters such as absorption, metabolites characterization, elimination kinetics in addition to the toxicity related to its administration still need to be investigated. In this way, this study aims to investigate the phase I metabolism of acanthoic acid through biomimetic oxidative reactions with the Jacobsen catalyst, using PhIO, m-CPBA and H2O2 as oxygen donors in homogenous medium. The Jacobsen catalyst is known by its easy synthesis and purification, and along with the metalloporphyrins have the ability to simulate the catalytic activity of the cytochrome P450 enzymes, which are the main responsible by phase I metabolism. Through the analysis by GC-MS, it was possible to observe the ratio 1:60:120 (catalyst:substrate:oxidant) as the more efficient for the conversion of acanthoic acid for the formation of the possible products oxidized mainly in the system with PhIO. However, none products were detected when H2O2 was used as oxidant even in this proportion mentioned. At least six possible products of oxidation were detected which 4 of them can be considered isomers. In this way, the present work may serve as a basis for investigating the oxidation of acanthoic acid by other in vitro methodologies and assist in the characterization of products obtained in vivo. Hopefully, that will encourage future pharmacological and toxicological studies to ensure their safety.