Molecular mechanisms underlying the in vitro anti-inflammatory effects of a flavonoid-rich ethanol extract from chinese propolis (poplar type)

Inhibition of Inflammatory Response by Artepillin C in Activated RAW264.7 Macrophages

Artepillin C (3,5-diprenyl-4-hydroxycinnamic acid) is the main bioactive component of Brazilian green propolis. The aim of this study was to investigate the anti-inflammatory effect of artepillin C on LPS + IFN- γ - or PMA-stimulated RAW264.7 macrophages. The cell viability was evaluated by MTT and LDH assays. The radical scavenging ability was determined using DPPH(•) and ABTS(•+). ROS and RNS generation was analyzed by chemiluminescence. NO concentration was detected by the Griess reaction. The release of various cytokines by activated RAW264.7 cells was measured in the culture supernatants using a multiplex bead array system based on xMAP technology. NF- κ B activity was confirmed by the ELISA-based TransAM NF- κ B kit. At the tested concentrations, the compound did not decrease the cell viability and did not cause the cytotoxicity. Artepillin C exerted strong antioxidant activity, significantly inhibited the production of ROS, RNS, NO, and cytokine IL-1 β , IL-3, IL-4, IL-5, IL-9, IL-12p40, IL-13, IL-17, TNF- α , G-CSF, GM-CSF, MCP-1, MIP-1 α , MIP-1 β , RANTES, and KC, and markedly blocked NF- κ B expression in stimulated RAW264.7 macrophages. Our findings provide new insights for understanding the mechanism involved in the anti-inflammatory effect of artepillin C and support the application of Brazilian green propolis in complementary and alternative medicine.