S-deoxydihydroglyparvin from Glycosmis parva inhibits lipopolysaccharide induced murine macrophage activation through inactivating p38 mitogen activated protein kinase

Abstract

Macrophages play major roles to produce several pro-inflammatory and inflammatory mediators in chronic inflammatory diseases. All current anti-inflammatory drugs target these mediators to alleviate inflammation. Searching for new anti-inflammatory agents is always needed due to problems from the clinical use of current anti-inflammatory drugs. We intended to evaluate the anti-inflammatory potential of three main compounds, arborinine, methylatalaphylline, and S-deoxydihydroglyparvin (DDGP), from Glycosmis parva leaves and branches on macrophage stimulated by lipopolysaccharide (LPS). Only DDGP demonstrated a potent inhibitor of LPS-activated macrophages. Results indicated that the mRNA level of inducible nitric oxide synthase (iNOS) was inhibited by the treatment in accompany with the decreased nitric oxide (IC50 at 3.47 ± 0.1 μM). DDGP was shown to suppress tumor necrosis factor-α, interleukin (IL)-1, and IL-6 at the mRNA expression and at the released protein levels. In addition, DDGP inhibited the several chemokines, monocyte chemoattractant protein-1 and macrophage inflammatory proteins-1α, and enzymes for prostaglandin (PG) synthesis. It also inhibited PGE2 production. On LPS signaling pathways, DDGP profoundly decreased phosphorylation of p38 mitogen-activated protein kinase (MAPK) in the LPS-treated cells. It had little or no effect on the activation of JNK, ERK and nuclear factor kappa B. In conclusion, results suggested that DDGP from G. parva inhibited expression and production of inflammatory molecules in LPS-activated macrophages through suppressing p38 MAPK activation. DDGP should be a good candidate anti-inflammatory agent in the future.

Keywords: Anti-inflammation; Glycosmis parva; S-deoxydihydroglyparvin; lipopolysaccharide; macrophage.

Figure 1

Structures of compounds isolated from ethyl acetate extracts of Glycosmis parva leaves and branches

Figure 2

Effects of N-methylatalaphylline, arborinine, and S-deoxydihydroglyparvin on nitric oxide production (a) and cell viability (b) in lipopolysaccharide-activated RAW 264.7 macrophages

Figure 3

Effects of S-deoxydihydroglyparvin on nitric oxide production (a) and inducible nitric oxide synthase expression (b) in lipopolysaccharide-activated RAW 264.7 macrophages

Figure 4

Effects of S-deoxydihydroglyparvin on pro-inflammatory cytokine expression and production. The expression of tumor necrosis factor-α (A), interleukin-1β (B), and interleukin-6 (C) was determined after 4 h (4.1) and 24 h (4.2) of treatment. The cytokine levels were determined after 24 h exposure (4.3)

Figure 5

Effects of S-deoxydihydroglyparvin on the expression of chemokines, monocyte chemoattractant protein-1 (a), and macrophage inflammatory proteins-1α. (b) In lipopolysaccharide-activated RAW 264.7 macrophages

Figure 6

Effects of S-deoxydihydroglyparvin on the expression of cyclooxygenase-2 (a), mPGES-1 (b), and the production of PGE2 (c) in lipopolysaccharide-activated RAW 264.7 macrophages

Figure 7

Effects of S-deoxydihydroglyparvin on lipopolysaccharide-induced phosphorylation of ERK (a), JNK (b), and p38 MAPK in RAW264.7 cells. GAPDH was used as a loading control

Figure 8

Effects of S-deoxydihydroglyparvin on lipopolysaccharide-induced the degradation of cytosolic iκB (a) and the activation of nuclear factor kappa B p65 in the nucleus (b). GAPDH and PCNA were used as loading controls of cytosolic and nuclear proteins, respectively

Figure 9

Proposed mechanisms of anti-inflammatory action of S-deoxydihydroglyparvin