Bioactive Compounds of Oroxylum indicum L. Kurz Stem Bark and Their Anti-Inflammatory Significance

The anti-inflammatory potential of Oroxylum indicum (OI), a traditional medicinal plant, was evaluated through in vitro, ex vivo, and molecular docking studies. The stem bark extract exhibited a significant, dose-dependent inhibition of protein denaturation in both egg albumin and bovine serum albumin assays at concentrations of 10, 30, and 100µg/mL. Molecular docking revealed strong binding affinities of key bioactive compounds, especially Oroxylin B (docking score -8.79), to the cyclooxygenase-2 (COX-2) enzyme, suggesting a mechanistic basis for anti-inflammatory effects. The extract exhibited no cytotoxicity on human lymphocytes across tested concentrations (20-200µg/mL) in the MTT assay, indicating safety. Ex vivo, OI extract significantly reduced COX-2 enzyme levels from 124.66 ± 0.16ng/mL in radiation controls to 107.33 ± 0.10ng/mL, comparable to diclofenac (106.36 ± 0.08ng/mL). Furthermore, IL-6 and TNF-alpha pro-inflammatory cytokine levels were substantially elevated by radiation but significantly decreased upon treatment with OI extract; IL-6 levels were reduced to 21.74 ± 0.95pg/mL compared to 27.45 ± 0.82pg/mL in radiation controls and TNF-alpha levels were similarly lowered, comparable to the diclofenac-treated group. These findings support the notion that the extract derived from the stem bark of Oroxylum indicum holds considerable strong possibility as a natural anti-inflammatory agent with modulatory effects on key inflammatory enzymes and cytokines, meriting further pharmacological and clinical evaluation.