Background: Small particles increase airway inflammation upon reaching the alveoli. Here, we investigated the protective or therapeutic
effects of Salvia plebeia R. Br. (SP_R) extracts on airway inflammation.
Methods and Results: To investigate the anti-inflammatory activity of SP_R extracts, we measured their inhibitory effect on the
production of reactive oxygen species (ROS) expression of inflammatory mediators, and immune cell infiltration in MH-S alveolar
macrophage cells and in the ambient particulate matter (APM)-exposed airway inflammation mice model. The SP_R extracts inhibited
the production of ROS and expression of IL-4, IL-10, IL-15, and IL-17A mRNA in APM-stimulated MH-S cells. Oral administration
of SP_R extracts suppressed APM-induced inflammatory symptoms, such as high alveolar wall thickness, excess collagen
fibers, decreased mRNA expression of chemokines (Ccr9, Ccl5, Ccr3), inflammatory cytokines (IL-15, TNF-α), and IL-4 Th2 cytokine
in the lung. The SP_R extracts also inhibited ROS production, granulocyte (CD11b+Gr-1+) infiltration, IL-17A, TNF-α, macrophage
inflammatory protein (Mip-2), and chemokine (C-X-C motif) ligand 1 (Cxcl-1) production in the airway. The specific
compounds in the SR-R extracts that mediate the anti-inflammatory effects were identified.
Conclusions: In this study, SP_R extracts effectively inhibited airway inflammatory responses, such as ROS production and granulocyte
infiltration into the airway, by regulating the expression of chemokines and inflammatory cytokines.