MECHANISM OF ACTION VIA INHIBITION OF PHOSPHODIESTERASES AND MOLECULAR DOCKING OF ANTIINFLAMMATORY SECONDARY METABOLITES AND NSAIDs

Abstract

The objective of this study was the evaluation of anti-inflammatory secondary metabolites, 19-deoxyicetexone (DEOX), 7,20-dihydroanastomosine (DAM), kramecyne, and piquerol, as phosphodiesterase inhibitors in an in vitro model and their molecular docking study. In the in vitro model of phosphodiesterase inhibition, DAM exhibits inhibitory activity on phosphodiesterases that hydrolyze cAMP and cGMP. It is well known that these substrates are hydrolyzed by PDE-4 and PDE-5 respectively. In the case of DEOX and kramecyne, they showed inhibitory activity on phosphodiesterases when cGMP substrate was used, but not when cAMP was used as substrate; this fact shows selectivity. Piquerol did not show statistically significant activity. Likewise, DEOX was more efficient with cGMP substrate than the other metabolites to inhibit the activity of phosphodiesterase. Rolipram and sildenafil were used as reference PDE inhibitor drugs and showed phosphodiesterase inhibitory activity in our test model. Non-steroidal anti-inflammatory drugs (NSAIDs) were evaluated as PDE inhibitors: indomethacin, diclofenac, and naproxen. Indomethacin showed inhibitory activity on PDE isolated from bovine brain using cAMP and cGMP as substrates, indicating that indomethacin is capable of inhibiting phosphodiesterases whose catalytic site forms a substrate-enzyme complex with cAMP (39 %) and cGMP (27 %). Molecular coupling analysis was carried out using the Hermes-Gold program. This program allowed obtaining the couplings between the anti-inflammatory secondary metabolites with phosphodiesterases 4 and 5. The method was validated by obtaining the RMSD values for the coupling between the reference drugs and the cocrystallized ligands. Molecular interactions were analyzed in 3D and 2D where the participation of enzyme amino acids was evidenced, as well as the metals Zn2+ and Mn2+, which showed interaction with rolipram and indomethacin in PDE4. Interaction with metals was not observed with PDE5. The secondary metabolite DAM coupled to the PDE4 and PDE5 catalytic sites in a similar way to rolipram and sildenafil respectively. Likewise, it is the first time that the interaction between indomethacin with PDE4 and PDE5 has been shown in an in silico molecular coupling, where indomethacin showed a stronger coupling with PDE-4 even than rolipram, a known PDE-4 inhibitor. © 2023 Laboratorios Mixim S.A. de C.V.. All rights reserved.