Anti-inflammatory activity of anti-hyperlipidemic drug, fenofibrate, and its phase-I metabolite fenofibric acid: in silico, in vitro, and in vivo studies.

Fenofibrate, an anti-hyperlipidemic drug and its phase-I biotransformed metabolite fenofibric acid, was studied for COX-1 (PDB ID: 3N8Y) and COX-2 (PDB ID: 1PXX) inhibition potentials in silico and in vitro for their effects on human recombinant COX-2 enzyme isolated from a Baculovirus expression system in sf21 cells (EC 1.14.99.1) using a conventional spectrophotometric assay. Furthermore, the compounds were also screened for their anti-inflammatory potentials in vivo using carrageenan-induced paw oedema method in Wistar rats. The test compounds fenofibric acid, fenofibrate, and the standard drug diclofenac exhibited binding energies of - 9.0, - 7.2, and - 8.0 kcal mol-1, respectively, against COX-2 and - 7.2, - 7.0, and - 6.5 kcal mol-1, respectively, against COX-1. In in vitro studies, both the test compounds inhibited COX-2 enzyme activity. Fenofibric acid showed an IC50 value of 48 nM followed by fenofibrate (82 nM), while diclofenac showed an IC50 value of 58 nM. Furthermore, under in vivo conditions in carrageenan-induced paw oedema rodent model, fenofibric acid exhibited relatively potent anti-inflammatory activity compared with fenofibrate. Hence, we conclude that fenofibric acid and fenofibrate are not only anti-hyperlipidemic but also shows potent anti-inflammatory activity, which may have an additional impact in the treatment of diabetic complications, viz., hyperlipidemia and inflammation leading to atherosclerosis.