Anti‐inflammatory Activity of Aronia Berry Polyphenols in Jurkat T Cells

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract resulting from an aberrant immune response to the microbiota. T cells and their cytokines influence contribute to the ongoing inflammation in IBD. Diets rich in fruits and vegetables have been shown to decrease the risk of developing IBD. Dietary polyphenols are considered to be responsible for many of the benefits of fruit and vegetable consumption. Aronia berries are a concentrated source of polyphenols including anthocyanins, proanthocyanidins, and phenolic acids. Polyphenols, in general, have limited intestinal absorption and are extensively metabolized by the gut microbiota. Microbial catabolism may contribute to the health benefits associated with polyphenol consumption. OBJECTIVE The objective of this study was to determine the anti‐inflammatory activities of an aronia berry extract, aronia polyphenol fractions, and microbial polyphenol metabolites in Jurkat T cells. METHODS Aronia anthocyanin and neutral phenols fractions were obtained from an ethanolic aronia extract by elution from a C18 solid phase extraction column. Aronia proanthocyanidin rich fraction was obtained from whole aronia berries extracted with acetone/water/acetic acid (70/29.5/0.5 v/v) followed by elution from a Sephadex LH‐20 column. Polyphenols in the extract and fractions were determined by HPLC. Jurkat T cells were stimulated with 50 ng/mL phorbol myristate acetate and 1 μg/mL ionomycin for 4 h in the presence of a commercial aronia berry extract, aronia berry polyphenol fractions, or known microbial polyphenol metabolites. Tumor necrosis factor (TNF)α in supernatant was determined by immunoassay. Statistical significance was determined by one‐way ANOVA. RESULTS At 250 μg/mL, the aronia extract significantly inhibited TNFα production by 33.6% (p<0.01) without reducing cell viability. At 50 to 100 μg extract/mL, there was no inhibition of TNFα. The anthocyanin and proanthocyanidin rich fractions did not affect TNFα production, but the neutral phenols fraction exhibited dose‐dependent inhibition. 3,4‐Dihydroxyphenylpropionic acid inhibited TNFα production at 100 and 0.1 μM, by 14.1 and 15.1% (p<0.05 and p<0.01, respectively) and 3,4‐dihydroxyphenylacetic acid inhibited TNFα production by 20.6% at 0.1 μM (p<0.0001). 3,4‐Dihydroxybenzoic acid (protocatechuic acid) and ferulic acid did not inhibit TNFα production at any tested concentration. CONCLUSION The aronia extract, neutral phenols fraction, and select microbial metabolites inhibited T cell TNFα without apparent loss of cell viability. The anti‐inflammatory capacity of aronia berry polyphenols may help to prevent and minimize intestinal inflammation associated with IBD by inhibiting T cell TNFα. Support or Funding Information USDA Hatch WIS01836