Abstract
Vernonia amygdalina is rich in palmitic acid (PA), a bioactive known for its anti-inflammatory capabilities. Yet, there is a paucity of scientific information on the immunostimulatory effect of the compound on the immune response. Therefore, this study assessed the potential of PA to modulate the immune cell function with potential implications in immune-mediated diseases. Bioinformatic techniques, including retrieval of regulatory cytokine structure and PA, molecular docking, and visualisations, were conducted using Protein Databank, PubChem database, Chimera, PyRx, and Biovia Discovery studio software. To assess the cell-mediated immune response in vivo, sheep red blood cells (SRBCs) were administered intraperitoneally to Mus musculus (mice). This was followed by PA treatments at various concentrations. Paw thickness and phagocytic activity and index were measured at intervals. Furthermore, the primary and secondary antibody titres were measured to assess the humoral immune response as a follow-up to the SBRC and PA treatments at varying concentrations. PA bound favourably with the cytokines, including TNF-α, IFN-γ, IL-12, IL-6, TGF-β, and IL-10, showing a binding affinity score range of - 6.1 kcal/mol to - 3.5 kcal/mol. In the mouse model, PA-treated groups of 2 and 5 mg/kg showed a significant increase in paw thickness, whereas no significant change was observed at 10 mg/kg. Furthermore, PA induced a significant increase in macrophage phagocytic index and activity in a dose-dependent manner. The PA-treated group of 10 mg/kg showed the highest primary humoral response, while no significant changes were observed in secondary responses. Overall, the potential of palmitic acid to immunomodulate the innate and cell-mediated immunity in a dose-dependent manner with limited effect on antibody-mediated immune response holds promising benefit to treat inflammatory diseases and enhance vaccine efficacy.