Psoralen Isolated from the Roots of Welw. Modulate Th1/Th2 Cytokines and Inflammatory Enzymes in LPS-Stimulated RAW 264.7 Macrophages.

is a widely used plant spice in traditional African medicine to treat pain-related conditions. However, the anti-inflammatory mechanisms underlying this activity and the main active ingredients of have not yet been fully characterized. This study aimed to isolate and identify the main active anti-inflammatory constituents of the extract and to investigate the underlying anti-inflammatory mechanisms in murine macrophages. Chromatographic techniques and spectroscopic data were used for compound isolation and structure elucidation. The Griess reagent method and the ferrous oxidation-xylenol orange assay were used to evaluate the inhibition of NO production and 15-lipoxygenase activity, respectively. Cyclooxygenase activity was assessed using the fluorometric COX activity assay kit, and Th1/Th2 cytokine measurement was performed using a flow cytometer. The results indicated that the extract and fractions of inhibit NO production and proliferation of RAW 264.7 macrophage cells. Bioguided fractionation led to the identification of psoralen, a furocoumarin, as the main bioactive anti-inflammatory compound. Psoralen inhibited NO production and 15-lipoxygenase activity and reduced pro-inflammatory Th1 cytokines (IFN-, TNF-, and IL-2) while increasing the secretion of anti-inflammatory cytokines (IL-4, IL-6, and IL-10) in activated RAW 264.7 macrophage cells. The encouraging results obtained in this study suggest that psoralen-based multiple modulation strategies could be a useful approach to address the treatment of inflammatory diseases.