- Background/Objectives. Inflammation, comprising many complex and finely coordinated
immunological processes, represents a vital protective mechanism of the human body.
By regulating inflammatory processes, cytokines play a key role in the modulation of
the immune system. Secondary plant compounds such as polyphenols influence cellular
immunological processes which might contribute to ensuring a physiologically healthy
immune status. Methods/Results. This study investigated eleven polyphenol-rich extracts
from red fruit beverages in terms of potential inhibitory effects on pro-inflammatory
cytokine secretion of leukemic monocyte THP-1 cells. Extracts originating from fruit
juice (apple), fruit juice concentrate (red grape, black currant, pomegranate, elderberry,
aronia), fruit juice puree (cranberry, blueberry) or fruit juice pulp (strawberry, sour cherry)
were obtained by adsorption onto Amberlite® XAD-7 resin. The Folin–Ciocalteu assay
showed a high content of phenolic compounds in the eleven extracts and HPLC-DADESI-
MSn analysis revealed that the extracts contained various anthocyanins in addition to
copigments and polymers. Further screening using Lumit® Immunoassay showed that
all tested extracts caused a reduction in pro-inflammatory cytokine secretion (interleukins
(IL): IL-1β, IL-6, IL-8 and tumor necrosis factor TNF-α). The extracts from red grape and
black currant were the most active ones. Conclusions. Overall, our results showed that
polyphenol-rich fruit extracts can inhibit inflammatory processes in vitro. In vivo studies
on the anti-inflammatory effect of fruit juice will be a promising approach to determine the
fruit juice-dependent, health-promoting effects in humans.
