Andrograpanin, a compound isolated from anti-inflammatory traditional Chinese medicine Andrographis paniculata, enhances chemokine SDF-1alpha-induced leukocytes chemotaxis

Andrographis paniculata is a traditional Chinese medicine (TCM) that has been effectively used for treatment of Infection, inflammation, cold, fever, and diarrhea in China. However, mechanism of its therapeutic function is not well known. In the current study, we showed one of its components, andrograpanin, could enhance chemokine stromal cell-derived factor-1alpha (SDF-1alpha) induced chemotaxis in Jurkat and THP-1 cells. Further study demonstrated that this kind of effect was CXC chemokine receptor-4 (CXCR4) specific, since andrograpanin could not enhance other chemokines, such as RANTES, monocyte chemotactic protein-1 (MCP-1), etc. induced cell chemotaxis. Mechanisms of andrograpanin exerting its effect were not directly in the receptor and G protein coupling level because it had no effect on the binding of SDF-1 to CXCR4, SDF-1 induced G protein activation and adenyly cyclase inhibition. However, receptor internalization might be involved, since we found it significantly reduced SDF-1alpha-induced CXCR4 internalization.