Bioactive compounds of Oroxylum indicum ( L.) Kurz stem bark and their anti-inflammatory significance

The anti-inflammatory potential of Oroxylum indicum ( O.indicum), a traditional medicinal plant, was evaluated through in vitro, ex vivo, and in silico 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 100 µg/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 possible molecular basis for anti-inflammatory activity of the extract. The extract exhibited no cytotoxicity on human lymphocytes across tested concentrations (20-200 µg/mL) in the MTT assay, indicating the absence of detectable cytotoxity under the conditions tested. Ex vivo, O.indicum extract significantly reduced COX-2 enzyme levels from 124.66 ± 4.13ng/mL in radiation controls to 107.33 ± 2.04 ng/mL, comparable to diclofenac (106.36 ± 0.11 ng/mL). Furthermore, IL-6 and TNF-alpha pro-inflammatory cytokine levels were substantially elevated by radiation but significantly decreased upon treatment with O.indicum extract; IL-6 levels were reduced to 21.74 ± 0.95 pg/mL compared to 27.45 ± 0.82 pg/mL in radiation controls and TNF-alpha levels were similarly lowered, comparable to the radiation control group. These findings support the notion that the extract derived from the stem bark of O.indicum shows considerable potential as a natural anti-inflammatory agent with modulatory effects on key inflammatory enzymes and cytokines, meriting further pharmacological and clinical evaluation.