Immunomodulatory Activity of Pine Needle (Pinus densiflora) Extracts in Macrophages

Pinus densiflora belongs to the Pinaceae family which has been widely used for health promoting purposes as folk medicine or as a food. Various curative effects of different parts of the pine have been reported including as a remedy for carcinoma. We examined the effects of pine needle water extracts (PNE) on macrophage function using peritoneal macrophage, pre-osteoclast bone macrophage (Raw 264.7 cell) and brain macrophage (C6 microglia). When peritoneal macrophages were treated with various concentrations of PNE ($1{\sim}100{\mu}g/mL$) for 24 hours, phagocytic activity was significantly increased, whereas it had no effect on tumoricidal activity and NO production. However, the treatment of Raw 264.7 with PNE resulted in the enhancement of NO production at high concentration ($100{\mu}g/mL$). Furthermore, the treatment of C6 with PNE increased the production of NO in a concentration-dependent manner, whereas PNE suppressed NO production in $LPS/IFN-{\gamma}-stimulated$ microglia. These results suggest that PNE has differential immunomodulatory effects on macrophages.