Inhibitory Effect of Jing-Fang Powder n-Butanol Extract and Its Isolated Fraction D on Lipopolysaccharide-Induced Inflammation in RAW264.7 Cells

Abstract

The Jing-Fang powder n-butanol extract (JFNE) has anti-inflammatory properties; however, its active ingredient remains unknown. In addition, the mechanism by which JFNE exerts its anti-inflammatory effects on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells is yet to be explored. In this study, JFNE was isolated by chromatography to obtain fraction D. We found that pretreatment of LPS-induced RAW264.7 cells with JFNE and fraction D for 3 hours significantly reduced the levels of nitric oxide (NO), interleukin (IL)-1β, and tumor necrosis factor-α (TNF-α) in the supernatant of cell cultures, and fraction D could also reduce the level of IL-6. In addition, JFNE and fraction D significantly reduced the mRNA expression of inducible NO synthase (iNOS), IL-6, IL-1β, and TNF-α JFNE and fraction D significantly inhibited the phosphorylation of proteins and mRNA expression levels of phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB/AKT). Moreover, JFNE and fraction D significantly decreased the mRNA expression of iNOS, v-rel reticuloendotheliosis viral oncogene homolog A (RELA), and nuclear factor of κ light polypeptide gene enhancer in B cells 1 (NF-κB1), whereas an increase in the mRNA expression of conserved helix-loop-helix ubiquitous kinase (CHUK) was observed. In addition, JFNE and fraction D downregulated the protein expression of iNOS, nuclear factor-κB (NF-κB) (p50), and phosphorylated NF-κB (p65). These results show that JFNE and its isolated fraction D exert specific anti-inflammation properties in LPS-stimulated RAW264.7 cells that are regulated by inhibition of the PI3K/Akt and NF-κB signaling pathways.