Herbal Combination of Tithonia diversifolia, Moringa oleifera, and Curcuma longa as Antidiabetic Agent Against iNOS and COX-2 Proteins: An in silico Study

Diabetes mellitus (DM) is a condition characterized by chronic hyperglycemia, which is caused by a combination of insulin resistance and pancreatic β-cell dysfunction. These pathological processes are further exacerbated by oxidative stress and chronic inflammation. The enzymes inducible Nitric Oxide Synthase (iNOS) and Cyclooxygenase-2 (COX-2) have been reported to be major contributors to the inflammatory processes associated with DM. Therefore, this study aims to investigate the antidiabetic potential of a herbal combination of Tithonia diversifolia, Moringa oleifera, and Curcuma longa (TMC) using an in silico approach. The study also evaluated the inhibition of iNOS and COX-2 proteins by bioactive compounds in the treatment sample through molecular docking and dynamics simulations. Aqueous extracts of the TMC combination were analyzed using LC-HRMS to identify 17 bioactive compounds. After the screening procedure based on drug similarity and molecular properties, selected compounds were subjected to further analysis. The results showed that xanthurenic acid, piperanine, ferulic acid, and 57-dihydroxy-4-methylcoumarin were major compounds with significant binding affinities towards iNOS (-8.2, -8.8, -7.2, and -8.6 kcal/mol, respectively) and COX-2 (-7.9, -8.1, -7.2, and -8.0 kcal/mol, respectively). Molecular dynamics simulations further showed stable protein-ligand interactions, supporting their potential as alternative treatments for diabetes. In addition, the compounds exhibited relatively low toxicity, good membrane permeability, as well as effective antioxidant, anti-inflammatory, and antidiabetic bioactivities. These results showed the potential of xanthurenic acid, piperanine, ferulic acid, and 5,7-dihydroxy-4-methylcoumarin as effective inhibitors of both iNOS and COX-2, contributing to the treatment of DM.