Anti-Inflammatory Effects of the Fraction from the Leaves of Pyrus pyrifolia on LPS-Stimulated THP-1 Cells

Pyrus pyrifolia Nakai (P. pyrifolia) has been traditionally used in East Asia to treat diseases such as phlegm, cough, hangover, and fever. However, there is no investigation that evaluates the biological activities of the leaves of P. pyrifolia. This study aims at describing the anti-inflammatory effects of PP, a bioactive fraction from the leaves of P. pyrifolia, in lipopolysaccharide (LPS)-stimulated THP-1 cells. Initially, PP decreased the protein and RNA expression of TNF-α, MCP-1, IL-8, and IL-6 induced by LPS. Moreover, PP attenuated the phosphorylation of p38, JNK, and ERK. In addition, after stimulation with LPS, the degradation of IκB-α was suppressed by PP, and the phosphorylation of IκB-α and p65 was suppressed by PP. Additionally, PP increased HO-1, which controls the production of inflammatory molecules, by activating Nrf2. These results indicated that PP could be used as an anti-inflammatory drug to promote wellness.