Effects of Gelidium amansii gel extracts on immune responses in RAW 264.7 macrophages

Abstract

The objective of this study was to investigate the effects of Gelidium amansii (GA), a red agar cultivated in the North coast of Taiwan, on immune modulatory activities in murine RAW 264.7 macrophages. Dried GA was boiled in water and filtered to obtain the GA gel. The freeze‐dried GA gel was then extracted with PBS or ethanol, and the extracts were used to treat with RAW 264.7 cells in the presence or absence of lipopolysaccharide (LPS). After 24h treatment, the released immune mediators, including nitric oxide (NO), tumor necrosis factor‐α (TNF‐α), IL (interleukin)‐1β, and IL‐6 were determined. Results showed that the PBS extract not only increased the proliferation of the macrophages, but also enhanced the secretion of NO, TNF‐α, IL‐1β, and IL‐6, whereas the ethanol extract showed no such effects. On the other hand, neither PBS nor ethanol extracts showed NO‐suppressive effects in LPS‐activated macrophages. In conclusion, the PBS extract of GA gel possessed mitogenic effect and immune regulatory activities in RAW 264.7 macrophages, but neither PBS nor ethanol extracts affected LPS‐stimulated NO production.