An ethyl acetate fraction of flavonoids from Polygonum hydropiper L. exhibits an anti-inflammatory activity in PCV2-infected porcine alveolar macrophages via PI3K/Akt and NF-kappa B pathways

Porcine circovirus type 2 (PCV2) widely exists in swine production systems causing porcine circovirus diseases (PCVD) which is associated with significant economic losses. Polygonum hydropiper L. was used as a traditional Chinese medicine to treat a variety of diseases. This study was carried out to investigate anti-inflammatory activity of the ethyl acetate fraction of flavonoids from Polygonum hydropiper L. (FEA) in PCV2-induced porcine alveolar macrophages (3D4/2 cell line). The production of oxygen species (ROS) and the levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and interleukin-8 (IL-8) were detected to evaluate the anti-inflammatory activities of FEA. The translocation of nuclear factor-kappa B (NF-kappa B) and the phosphatidylinositol 3kinase/protein kinase B (PI3K/Akt) signaling pathways were investigated to document the potential anti-inflammatory mechanisms. In PCV2 induced 3D4/2 cells, FEA treatment significantly reduced the production of ROS, and sharply down-regulated the levels of TNF-alpha, IL-1 beta and IL-8 in both secretion and mRNA expression level. The FEA also decreased the mRNA expression of Akt and NF-kappa B p65, reduced the transfer of p65 to nuclear, and inhibited the activation of PI3K/Akt signaling pathway. The findings suggest that FEA exhibited an anti-inflammatory activity in vitro and could be used as a candidate in treatment of inflammation induced by PCV2 infection. (c) 2022 Urmia University. All rights reserved.