Combined Anti-Inflammatory Effects of Curcumin and Evodiamine: In Vitro Synergy, Docking, and Molecular Orbital Insights

Combining plant-derived bioactives could produce effective anti-inflammatory interventions for myofascial inflammation. This study evaluated in vitro synergy and computational mechanisms of curcumin–evodiamine activity against TNF-α, IL-1β, iNOS and COX-2, with frontier molecular orbital analysis to inform putative mechanisms. Evodiamine and curcumin were identified/quantified by HPLC–PDA and LC–MS (λmax 226 nm and 426 nm; RT 8.61 and 9.53 min; [M−H]−m/z 302.2 and 367.2). Purities were 98.08 ± 1.92% and 98.04 ± 1.86%. Noncytotoxic concentrations in RAW264.7 cells were determined, then LPS-stimulated cells were treated with evodiamine (0.01 µM), curcumin (0.01 µM) and a 1:1 mixture (0.001 µM). Molecular docking against TNF-α, IL-1β, iNOS and COX-2 and HOMO–LUMO calculations were performed. Curcumin and the combination significantly reduced TNF-α and NO; curcumin and the combination reduced IL-1β, whereas evodiamine alone showed limited effects. Docking predicted stronger binding for curcumin and evodiamine than ibuprofen across targets (e.g., curcumin ΔG −10.18 kcal·mol−1 for TNF-α; evodiamine ΔG −10.02 kcal·mol−1 for COX-2). Frontier orbital energies indicated differing electronic profiles (ibuprofen ΔE 8.62 eV; evodiamine 9.65 eV; curcumin 9.89 eV), suggesting complementary reactivity. The curcumin–evodiamine combination exhibits in vitro anti-inflammatory activity with supportive docking and orbital data, providing mechanistic rationale for further development.