In vitro studies and animal studies have shown that chemical compounds contained in carrots, such as
falcarinol and
falcarindiol, can prevent
inflammation. The present study was designed to test whether the oral intake of carrot juice containing
falcarinol and
falcarindiol affects the activity of
cyclooxygenase (COX)
enzymes and the secretion of inflammatory
cytokines in human blood. Carrot juice (500 mL) was administered orally to healthy volunteers, and blood samples were drawn before and 1 h after juice intake at the time point when peak concentrations of
falcarinol and falcariondiol have been shown in the blood. The blood samples were divided, and one sample was allowed to coagulate for 1 h at room temperature before analyzing the synthesis of
thromboxane B2 (TBX2) by the COX1
enzyme using an
enzyme linked
immunosorbent assay (ELISA). The other blood samples were stimulated ex vivo with
lipopolysaccharide and incubated at 37 °C for 24 h. The ELISA and
cytokine multiplex analysis assessed the levels of COX-2-induced
prostaglandin E2 (
PGE2) and inflammatory markers
interleukin (IL) 1α, IL1β,
IL6,
IL16, and
tumor necrosis factor α (TNFα). Inflammatory
cytokines such as IL1α and
IL16 were significantly reduced in the LPS stimulated blood samples with higher concentrations of
falcarinol and falcariondiol compared to the control samples taken before the intake of carrot juice. The levels of TBX2,
PGE2, IL1β,
IL6, and TNFα were not affected by the carrot juice intake blood samples not stimulated with LPS. In conclusion, carrot juice rich in the polyacetylens
falcarinol and
falcarindiol affects blood leukocytes, priming them to better cope with inflammatory conditions, evident by the reduced secretion of the proinflammatory
cytokines IL1α and
IL16.