A genome-wide microarray analysis reveals anti-inflammatory target genes of paeonol in macrophages

Objective: Paeony root has long been used for its anti-inflammatory effects. In this study, the effects of albiflorin, paeoniflorin, and paeonol, compounds from paeony root, on gene expression profiles were examined in macrophages challenged with the inflammation inducer lipopolysaccharide (LPS). Methods: The RAW264.7 macrophages were treated with LPS in the presence or absence of albiflorin, paeoniflorin, or paeonol. Global mRNA expression levels were detected by using an oligonucleotide microarray platform covering the mouse whole genome. Results: Treatment with LPS caused expression level changes in 1,270 genes by 2 folds or more. Paeonol attenuated the induction level of 355 LPS-responsive genes. Classification of the genes targeted by paeonol according to the Panther group analysis revealed 20 biological processes, 24 molecular functions, and 22 signaling pathways. The Panther signaling pathways highly affected by paeonol included the 'inflammation mediated by chemokine and cytokine signaling', 'interleukin signaling', and 'Toll receptor signaling'. Conclusion: Our results demonstrate that paeonol has extensive inhibitory effects on the regulation of inflammation associated gene expression by LPS in macrophages. In addition, the predominant effect of paeonol among the tested compounds suggests that paeonol may be a major ingredient for the anti-inflammatory effect of paeony root.