Red ginseng extract regulates differentiation of monocytes to macrophage and inflammatory signalings in human monocytes

This study was aimed to investigate the effect of red ginseng extract (RGE) on monocyte to macrophage differentiation and inflammatory signalings in THP-1 human monocytes. In HPLC analysis, RGE contained saponin level of 516 μg/mg (extract) with 14 ginsenosides. RGE effectively suppressed the monocyte-to-macrophage differentiation induced by phorbol 12-myristate 13-acetated (PMA) by inhibiting the THP-1 cell adhesion. This result is evidenced by the down-regulation of cluster of differentiation molecule β (CD11β) and CD36. RGE significantly reduced translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) (78%), while cytosolic NF-κB was increased (53%), compared with LPS group. In addition, RGE significantly increased the protein abundance of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and its target protein, hemoxygenase-1 (HO-1), but, Kelch-like ECH-associated protein 1 (KEAP1), a negative regulator of Nrf2, was greatly decreased by RGE. Furthermore, RGE effectively mediated the regulation of Nrf2 level in nucleus and cytoplasm of THP-1.