Protopanaxadiol modulates LPS-induced inflammatory activity in murine macrophage RAW264.7 cells

Protopanaxadiol (PPD) is a mixture of protopanaxadiol type saponins with a dammarane skeleton, from Korean red ginseng (Panax ginseng C.A. Meyer; Araliaceae). Korean ginseng is well-known herb to treat almost all kinds of diseases in Oriental medicine. This herb was particularly prescribed for treatment various inflammatory diseases, including rheumatoid arthritis, atherosclerosis, and diabetes mellitus, for centuries. To understand the efficacy of ginseng against inflammatory diseases, we aimed to show anti-inflammatory activities of the PPD in murine macrophage cell line, RAW264.7 cells using nitric oxide (NO) production assay and the expressions of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6, and monocyte chemotactic protein-1 (MCP-1). We found that PPD saponin significantly blocked LPS (1 μg/ml)-induced NO production in a dose-dependent manner. In addition, PPD abrogated the expressions of LPS-induced pro-inflammatory cytokines, such as IL-1β and MCP-1. Moreover, cyclooxygenase (COX)-2, a critical enzyme to produce prostaglandin E2 (PGE2), was significantly inhibited by PPD in LPS-activated RAW264.7 cells. Taken together, these results suggested that anti-inflammatory efficacy of Korean red ginseng on inflammatory diseases is, at least, due to the NO inhibitory activity and the inhibition of the expressional level of inflammatory cytokines and/or mediators. KCI Citation Count: 6