Methyl 4-(β-D-glucopyranosyloxy)-3-hydroxy-5- methoxybenzoate, isolated from Sanguisorba officinalis, inhibits CpG-DNA-induced inflammation

Purpose: To evaluate the anti-inflammatory effect of methyl-4-(β-D-glucopyranosyloxy)-3-hydroxy-5- methoxybenzoate (comp-1) on immune cells. Methods: Comp-1 was isolated from Sanguisorba officinalis. After treating with comp-1, cell viability and levels of pro-inflammatory cytokines were assessed utilizing MTT assay and ELISA, respectively. Besides, the effects of comp-1 on nuclear factor kappa B (NF-κB), mitogen-activated protein kinase (MAPK), and iNOS were determined using western blotting. Moreover, nitric oxide production was assessed using the Griess reagent. Results: Treatment of dendritic cells (DCs) with CpG DNA upregulated cytokine expression. Comp-1 markedly downregulated the expressions of IL-12 p40, IL-6, and TNF-α, with 50% inhibitory concentrations (IC50) of 1.077 ± 0.04 (p < 0.01), 0.28 ± 0.01 (p < 0.01), and 0.79 ± 0.02 μM (p < 0.01), respectively. Treatment of DCs with CpG DNA upregulated NF-κB and MAPK activation. However, pretreatment of the cells with Comp-1 suppressed CpG DNA-induced NF-κB and MAPK activation. Moreover, comp-1 exhibited a strong anti-inflammatory effect by inhibiting nitric oxide production and iNOS expression. Conclusion: These results reveal that comp-1 has significant anti-inflammatory effect on immune cells.