A critical component of the body’s immune response to pathogens, damaged cells, or irritants is inflammation. Chronic inflammation, however, can promote the development of chronic inflammatory disorders. Findings from a new study suggest that pterostilbene, a polyphenolic compound present in blueberries, can reduce the risk of developing chronic inflammatory disorders by altering the activity of dendritic cells and T cells.

Pterostilbene is a polyphenolic compound that demonstrates antioxidant, anti-inflammatory, and anti-cancer properties, as well as many other beneficial effects. Closely related to resveratrol, pterostilbene is found in blueberries and a tropical tree commonly known as heartwood.

Dendritic cells and T cells are key elements of the body’s immune responses. Dendritic cells initiate the adaptive immune response, which in turn activates T cells. Activated T cells produce interleukin (IL)‐2 to facilitate their proliferation and subsequent differentiation into various helper T cells, including Th1, Th2, Th17, or regulatory T cells (Tregs). Over-activation of Th1, Th2, and Th17 cells can lead to immune disorders, such as inflammatory bowel diseases, atopic dermatitis, and psoriasis. Conversely, Treg cells produce IL‐10, an anti-inflammatory protein, to reduce inflammation and impair disease progression.

The authors of the study used an in vitro cell culture system to assess the effects of pterostilbene and related compounds on immune cell response. They looked at the activity of dendritic cells and T cells in the presence or absence of the compounds to evaluate their immunosuppressive activity.

They found that pterostilbene suppressed T cell‐proliferation and decreased the Th1 and Th17 population in a dose‐dependent manner but did not affect the population of Th2 cells. The presence of pterostilbene markedly increased Treg differentiation was markedly increased.

Then the authors of the study assessed the effects of pterostilbene on mice that had ulcerative colitis, a type of inflammatory bowel disease. They gave the mice pterostilbene in their drinking water for a week. They found that the mice that consumed the pterostilbene had fewer symptoms associated with their disease and lower levels of tumor necrosis factor-alpha, a type of pro-inflammatory protein.

Taken together, these findings indicate that pterostilbene exhibits immunosuppressive activity by directing T cell differentiation toward Treg cells rather than Th1 and Th17 cells. Furthermore, oral consumption of pterostilbene may reduce colonic inflammation associated with an inflammatory bowel disease.

• Link to full study.