Panax notoginseng attenuates LPS-induced pro-inflammatory mediators in RAW264.7 cells

Herbals or dietary supplements are not regulated as drugs by the United States Food and Drug Administration (USFDA) although many may have associated therapeutic effects and toxicities. Therefore, the immunomodulatory effects of the herbal extract Panax notoginseng on cultured macrophages (RAW264.7 cells) were investigated to address potential therapeutic or toxic effects. Cells were stimulated with LPS (1 μg/ml) and treated with notoginseng at 5, 25 and 50 μg/ml. Notoginseng inhibited the LPS-induced production of TNF-α and IL-6 by the cultured macrophages in a concentration-dependent manner. The expression of COX-2 and IL-1β mRNA was also attenuated by notoginseng. TNF-α production was inhibited in samples treated with notoginseng 24 h before, or at the same time as LPS stimulation, but not in samples treated 8 h after LPS stimulation. Notoginseng reduced expression of the accessory molecules CD40 and CD86 on the RAW264.7 cells while CD14 and TLR4 expression remained unaffected. Furthermore, Rb1 and Rg1 ginsenosides also inhibited macrophage production of TNF-α, but to a lesser extent than did the whole notoginseng extract. Collectively, these results indicate that notoginseng inhibits LPS-induced activation of RAW264.7 macrophages and demonstrates that notoginseng possesses anti-inflammatory and immunosuppressive properties in vitro.