Effects of crude extract of Capparis spinosa L. fruit alkaloids on the maturation of murine dendritic cells

Abstract

Objective To investigate the effects of crude extract of Capparis spinosa L. fruit alkaloids (CSFA) on the maturation of murine bone marrow-derived dendritic cells (DCs). Methods CSFA was prepared and the contents were determined by high performance liquid chromatography. DCs were treated with different doses (1, 2, 3 mg/ml) of CSFA. The viability of DCs, the expression of surface molecules and the ability of phagocytosis were detected by flow cytometry. The secretion of cytokines was measured by ELISA. Western blot assay was performed to analyze the activation of key molecules in mitogen-activated protein kinases (MAPK) and nuclear factor-kappa B (NF-κB) signaling pathways. Results The results showed that CSFA alone had no significant influence on the expression of surface molecules and cytokines in DCs. However, it significantly decreased the expression of CD40, CD80, CD86 and MHC Ⅱ as well as the secretion of IL-12p40 and TNF-α that were induced by lipopolysaccharides (LPS), but increased IL-10 secretion and the ability of phagocytosis after treating DCs with both CSFA and LPS. Further, the phosphorylation of p38, extracellular signal-regulated kinase (ERK) and c-Jun NH2-terminal kinase (JNK) and the nuclear translocation of NF-κBp65 induced by LPS were inhibited by CSFA. Conclusion CSFA could inhibit the maturation of DCs and the secretion of pro-inflammatory cytokines induced by LPS while increasing the secretion of the anti-inflammatory cytokine IL-10 and the ability of phagocytosis, which might involve MAPK and NF-κB signaling pathways. This study suggests that CSFA could be used as a potential immunosuppressant. Key words: Capparis spinosa L.; Alkaloid; Dendritic cell; Cytokine; Immunosuppression