Berry anthocyanin fractions repress pro‐inflammatory gene expression and secretion by inhibiting nuclear translocation of NF‐κB in RAW 264.7 macrophages

Abstract

Antioxidant capacity of anthocyanins is known to be associated with their anti‐inflammatory properties. We examined the association between antioxidant capacity of three berry anthocyanin fractions and their anti‐inflammatory potency in lipopolysaccharide (LPS)‐stimulated RAW 264.7 macrophages. The anthocyanin fractions of three berries contain different major anthocyanin compounds: blueberry (BB, 16% malvidin‐3‐glucoside), blackberry (BK, 98% cyanidin‐3‐glucoside) and blackcurrant (BC, 44% delphinidin‐3‐rutinoside). BK showed a significantly higher total antioxidant capacity compared with BB and BC in a non‐cell based assay. At 10 and 20 μg/mL concentrations, all of the three berry anthocyanin fractions significantly decreased interleukin‐1β and tumor necrosis factor α (TNFα) mRNA levels in LPS‐treated macrophages to a similar degree. TNFα secretion to cell culture medium was also significantly decreased by the berry fractions although BK showed the least potency. Increased nuclear factor κB (NF‐κB) p65 translocation to the nucleus by LPS was markedly attenuated by treatment with BB, BK and BC. LPS did not increase cellular ROS levels. In conclusion, anti‐inflammatory functions of berry anthocyanins are primarily attributed to their inhibitory role in NF‐κB nuclear translocation with a minimal contribution from their antioxidant capacity in LPS‐stimulated RAW 264.7 macrophages.