Insights into cyclooxygenase-2 inhibition by isolated bioactive compounds 3-caffeoyl-4-dihydrocaffeoyl quinic acid and isorhamnetin 3-O-beta-D-glucopyranoside from Salicornia herbacea

Abstract

Background: Cyclooxygenase-2 (COX-2) is an important enzyme with numerous biological functions. Overexpression of COX-2 has been associated with various inflammatory-related diseases and therefore, projected as an important pharmacological target. Purpose: We aimed to investigate the inhibitory potential of isolated bioactive compounds, 3-caffeoyl-4-dihydro-caffeoyl quinic acid (CDQ) and isorhamnetin 3-O-beta-D-glucopyranoside (IDG), from Salicornia herbacea against COX-2 using both computational and in vitro approaches. Methods: Computational analysis, including molecular docking, molecular dynamics (MD) simulations, and postsimulations analysis, were employed to estimate the binding affinity and stability of CDQ and IDG in the catalytic pocket of COX-2 against Celecoxib as positive control. These predictions were further evaluated using in vitro enzyme inhibition as well as gene expression mediation in macrophages cells. Results: Molecular docking analysis revealed substantial binding energy of CDQ (-6.1 kcal/mol) and IDG (-5.9 kcal/mol) with COX-2, which are lower than Celecoxib (-8.1 kcal/mol). MD simulations (100 ns) and post simulation analysis exhibited the substantial stability and binding affinity of docked CDQ and IDG compounds with COX-2. In vitro assays indicated significant COX-2 inhibition by CDQ (IC50 = 76.91 +/- 2.33 mu M) and IDG (IC50 = 126.06 +/- 9.44 mu M). This result supported the inhibitory potential of isolated bioactive compounds against COX-2. Also, a cellular level study revealed a downregulation of COX-2 expression in tumor necrosis factor-alpha stimulated RAW 264.7 macrophages treated with CDQ and IDG. Conclusion: Computational and experimental analysis of CDQ and IDG from S. herbacea established their potential in the inhibition and mediation of COX-2. Hence, CDQ and IDG can be considered for therapeutic development against COX-2 linked disorders, such as inflammation and cancer. Furthermore, CDQ and IDG structures can be served as a lead compound for the development of advanced novel anti-inflammatory drugs.