Anti- inflammatory effects of Andrographis paniculata (Burm.f.) Wall. Ex Nees leaf in LPS-Induced RAW264.7 macrophages

The inflammatory response is a protective biological response to harmful stimuli involving immune cells and inflammatory mediators. However, chronic inflammation can trigger a variety of inflammatory diseases. In this study, we screened natural products for anti-inflammatory materials. Andrographis paniculata (Burm.f.) Wall. ex Nees (A. paniculata) is used to treat inflammatory diseases in Asia. However, the mechanism of its anti-inflammatory effect is unclear. We analyzed the anti-inflammatory effect of A. paniculata boiling water extract (APW) and A. paniculata 70% EtOH extract (AP70E) and the underlying mechanisms of action. Interestingly, 100 µg/mL AP70E suppressed lipopolysaccharide (LPS)-induced inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nitric oxide (NO) production to a significantly greater degree than APW. In addition, 100 µg/mL AP70E significantly inhibited the LPS-induced production of the pro-inflammatory cytokines interleukin (IL)-1β and IL-6 and suppressed the mitogen-activated protein kinase (MAPK) and Janus kinase (JAK)/signaling transducer and activator of transcription (STAT) signaling axes. Moreover, it significantly reduced the activity of the JAK/STAT axis independently of its reduction of pro-inflammatory cytokine production. In conclusion, AP70E has potential as an anti-inflammatory agent.