David O. Freier, MA, PhD
Tonya Price, DHEd, MS, RDN, CHES, CWP
Price Blair, PhD
The eastern and central North American flowering plant Echinacea purpurea (EP) is used by Native Americans as a traditional remedy for upper respiratory illnesses (URI). Active chemical constituents in EP include caffeic acid derivatives, alkylamides, and polysaccharides. The use of EP extracts have been suggested to shorten the duration of upper respiratory illness symptoms. Most studies suggest an immunomodulatory effect on innate immune responses. This research will test the immunomodulatory effects of a 50:50 glycerol:water extraction of EP stem and leaf on LPS-stimulated RAW 264.7 murine macrophages. Results will be compared to previous work using 75:25 ethanol root and 75:25 ethanol stem and leaf extract to determine differences in direct effect on RAW 264.7 cells. RAW 264.7 cells plated at 4x10^5 cells/well (500uL DMEM) in a 24-well plate are stimulated with bacterial lipopolysaccharide [LPS] (E. coli O55:B5) for 24 hours. Supernatants were reserved for cytokine TNF-alpha ELISA and samples were used to measure nitrites in solution by the Griess reaction to assess inflammatory responses. Preliminary experiments with extract diluted in DMEM at 15 uL/mL (0.75% glycerol), 30 uL/mL (1.5% glycerol) and 60 uL/mL (3% glycerol) showed inhibitory effect in cells stimulated by 100 ng/mL of LPS. Further experiments will examine lower concentrations of glycerol in extract in the culture environment to elucidate solvents effect on cell culture responses.
Garcia, Maxwell D., "Immunomodulatory Effects of Glycerol Echinacea purpurea Stem and Leaf Extract on RAW
264.7 Murine Macrophages" (2023). Undergraduate Theses and Capstone Projects. 286.