Taraxacum officinale inhibits tumor necrosis factor-α production from rat astrocytes

Substance P (SP) can stimulate production of tumor necrosis factor-α (TNF-α) from astrocytes stimulated with lipopolysaccharide (LPS). The objective of the current study was to determine the effect of Taraxacum officinale (TO) on the production of TNF-α from primary cultures of rat astrocytes. TO (100 and 1000 μg/ml) significantly inhibited the TNF-α production by astrocytes stimulated with LPS and SP. Interleukin-1 (IL-1) has been shown to elevate TNF-α production from LPS-stimulated astrocytes while having no effect on astrocytes in the absence of LPS. We therefore examined whether IL-1 mediated inhibition of TNF-α production from primary astrocytes by TO. Treatment of TO (100 and 1000 μg/ml) to astrocytes stimulated with both LPS and SP decreased IL-1 production significantly. Moreover, the production of TNF-α by LPS and SP in astrocytes was progressively inhibited with increasing amount of IL-1 neutralizing antibody. Our results suggest that TO may inhibit TNF-α production by inhibiting IL-1 production and that TO has an antiinflammatory activity in the central nervous system.