Anti-inflammation Mechanisms of Flavones Are Highly Sensitive to the Position Isomers of Flavonoids: Acacetin vs Biochanin A

Acacetin (ACA) and biochanin A (BCA) are isomeric monomethoxyflavones with different structural positions of the 4'-methoxy-phenyl group. Both of them are present in many commonly consumed foods, such as citrus fruits and vegetables, and have been discovered with anti-inflammatory activities, but their mechanisms of action are not clearly elucidated at the molecular level. Herein, we reported the structure-activity relationship of ACA and BCA regarding their potency in inhibiting nitric oxide (NO) production, proinflammatory enzyme expression, and mRNA expression of proinflammatory cytokines in the lipopolysaccharide (LPS)-induced RAW 264.7 cells. Furthermore, transcriptome analysis was conducted to map out the overall pathways impacted by these two isomers. Our results showed that ACA possessed higher suppressive activity in nitric oxide (NO) production (IC