Ameliorating Effects of Phlomis umbrosa Turcz. Root in Ovalbumin-Induced Allergic Asthma: Modulation of IL-33-Mediated Inflammation and TGF-β/Smad-Dependent Fibrosis

Our study aimed to evaluate the therapeutic potential of a 20% ethanolic extract of the Phlomis umbrosa Turcz. (EPT) herb and its associated bioactive compounds in an ovalbumin (OVA)-induced allergic asthma mouse model. We used phytochemical analysis and identified sesamoside, shanzhiside methyl ester, 8-O-acetyl shanzhiside methyl ester, and isoacteoside as the bioactive components. We validated and quantitatively analyzed shanzhiside methyl ester as a major compound. The treatment with EPT significantly attenuated the T helper type 2 (Th2)-based immune response, eosinophilia, histopathological changes, and biochemical parameters. Furthermore, EPT inhibited interleukin (IL)-33-mediated activation of the nuclear factor kappa B (NF-κB) and transforming growth factor beta (TGF-β) signaling pathways, as well as reduced fibrosis and apoptosis associated with inflammation. The findings of our study suggest that EPT is a promising natural substance for alleviating symptoms of allergic asthma.