Aim of the study
Investigate the effects and molecular mechanisms of SZ-A on inflammation, and identify anti-inflammatory active components in SZ-A. Materials and
Conclusions
SZ-A attenuates inflammation at least partly by blocking the activation of p38 MAPK, ERK, and JNK signaling pathways. DNJ, FAG, DAB, and ARG are the main constituents in SZ-A that exert anti-inflammatory effects.
Methods
The major ingredients in SZ-A were analyzed by HPLC and sulfuric acid - anthrone spectrophotometry. The inhibitory activities of SZ-A on lipopolysaccharide (LPS)-stimulated inflammation were determined in bone marrow-derived macrophage (BMDM) and RAW264.7 cells. The cytokine levels of IL-6 and TNF-α in cell culture supernatant were measured by enzyme-linked immunosorbent assay (ELISA). Gene expression levels of IL-6 and TNF-α were detected by qRT-PCR. The levels of protein phosphorylation of p38 MAPK, ERK, and JNK were analyzed by Western blot.
Results
The main components in SZ-A were found to be 1-deoxynojirimycin (DNJ), 1,4-dideoxy-1,4-imino-D-arabinitol (DAB), fagomine (FAG), polysaccharide (APS), and arginine (ARG). SZ-A reduced the levels of IL-6 and TNF-α secreted by LPS-induced RAW264.7 and BMDM cells. Simultaneously, the mRNA expression levels of IL-6 and TNF-α were all significantly suppressed by SZ-A in a concentration-dependent manner. Furthermore, SZ-A inhibited the phosphorylation of p38 MAPK, ERK, and JNK in BMDM and the activation of ERK and JNK signaling in RAW264.7 cells. We also observed that DNJ, DAB, FAG, and ARG markedly downregulated IL-6 and TNF-α cytokine levels, while APS did not have an obvious effect. Conclusions: SZ-A attenuates inflammation at least partly by blocking the activation of p38 MAPK, ERK, and JNK signaling pathways. DNJ, FAG, DAB, and ARG are the main constituents in SZ-A that exert anti-inflammatory effects.