Immunomodulatory Activity of Sambucus mexicana and Trichostema lanatum on LPS Stimulated RAW 264.7 Macrophage Cells
Mentor:P. Matthew Joyner, Assistant Professor of Biochemistry, Pepperdine University
The Chumash Native Americans of Southern California have well-documented traditions of using plants for medicinal purposes. If a specific plant has traditionally been used for the treatment of cuts, wounds and infections, it may contain chemicals with immunomodulatory properties that promote wound healing and reduce inflammation. Two plants that fit these criteria are Sambucus mexicana (Mexican elderberry) and Trichostema lanatum (woolly blue curls). We tested extracts of these plants for their ability to alter the production of pro- and anti-inflammatory cytokines in macrophage cells. Tumor necrosis factor alpha (TNF-α) is secreted by activated macrophages and has been shown to promote inflammation. Interleukin-10 is a cytokine which can act as an anti-inflammatory modulator when produced by alternatively activated macrophages. RAW 264.7 macrophage cells were used to test the immunomodulatory properties of our methanolic plant extracts. Macrophage proliferation assays were performed using a CCK-8 colorimetric assay, and TNF-α and IL-10 production by macrophages were quantified using ELISA. Bacterial lipopolysaccharide (LPS) was used to activate a pro-inflammatory response in the macrophages. Modulation of the macrophage response to LPS was tested by treating LPS induced RAW 264.7 cells with plant extracts at concentrations of 0.001 mg/μL and 0.01 mg/μL. Production of cytokines TNF-α and IL-10 were measured using ELISA 12 hours and 24 hours after activation with LPS. Treatment with T. lanatum and S. mexicana at concentrations of 0.01 mg/μL resulted in reduced pro-inflammatory macrophage response, as indicated by significant reduction in the concentration of TNF-alpha in vitro in comparison to the control. However, no significant change was observed in the concentration of IL-10 after treatment with the plant extracts, indicating that these extracts do not stimulate the production of this anti-inflammatory cytokine.