Molecular Docking Analysis of Curcuminoids from Curcuma longa Extract on iNOS as an Immunomodulator Candidate in Broilers

Enteritis is an inflammatory reaction as a form of the body’s response to the invasion of pathogenic microorganisms in the intestine. However, excessive formation of Nitric Oxide (NO) by inducible Nitrite Oxide Synthase (iNOS) during inflammation processes can trigger cellular toxicity and widespread intestinal tissue damage. Curcuma longa extract contains active compounds, such as curcumin, tannin, alkaloids, flavonoids, and has the potential as an antioxidant, anti-inflammatory, antimicrobial, anti-toxicity, hepatoprotective, nephroprotective, and anticoagulant. This study aimed to investigate the interactions of curcuminoid active compounds in Curcuma rhizome extract on iNOS compared to diclofenac sodium (a non-steroidal anti-inflammatory drug) through computational analysis to explore the potential of Curcuma as a herbal therapy candidate for poultry enteritis. Preparing the three-dimensional structure of iNOS, sodium diclofenac, and curcuminoid active compounds contained in Curcuma extract was the initial step of this study, followed by molecular docking analysis. The results of all molecule interactions were then visualized through Pymol and analyzed by Discovery Studio Visualizer software. The docking visualization results showed that the amino acid residues from iNOS that had the most interactions with ligands were His (421), LYS (261), Trp (203). Molecular docking results of the four active compounds showed that Bisdemethoxycurcumin had the lowest free energy (ΔG) value (-8.00 kcal/mol). The stable conformation location of two ligands (bisdemethoxycurcumin and curcumin) differs from sodium diclofenac, so the type of activity can be said to be a non-competitive inhibition. These results indicated that bisdemethoxycurcumin and curcumin have the potential as anti-inflammatory agents