Immunomodulatory activities of Gelidium amansii gel extracts on murine RAW 264.7 macrophages

The objective of this study was to investigate the effects of Gelidium amansii, a red algae cultivated in the northeastern coast of Taiwan, on immune regulatory activities in RAW 264.7 macrophages. G. amansii gel was prepared by boiling and filtering the dried G. amansii algae. Phosphate-buffered saline (PBS) and ethanol extracts of the freeze-dried gel were then used to treat the cells. The results showed that the PBS extracts of G. amansii gel activated the macrophage by increasing cell proliferation and by enhancing the production of nitric oxide (NO), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-6; the ethanol extracts did not show such effects. By contrast, neither PBS nor ethanol extracts of G. amansii gel affected NO production in lipopolysaccharide (LPS)-stimulated macrophages, although the ethanol extracts suppressed LPS-stimulated TNF-α, IL-1β, and IL-6 production. In conclusion, the PBS extracts of G. amansii gel activated the macrophage by enhancing the production of immune mediators, whereas the ethanol extracts showed anti-inflammatory activities by suppressing the cytokine production in LPS-stimulated RAW 264.7 macrophages.