In vitro and animal studies have shown that carrot juice containing bioactive natural products, such as falcarinol (FaOH) and falcarindiol (FaDOH), can affect inflammation. The present study was designed to test whether oral intake of carrot juice containing the bioactive acetylenic oxylipins FaOH and FaDOH affects mediators of acute inflammation or the innate immune response 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. Next, the blood samples were split in two, and one sample was stimulated ex vivo with lipopolysaccharide (LPS) and incubated at 37 °C for 24 h. The concentrations of 44 inflammatory cytokines and chemokines were examined using multiplex electrochemiluminescence analysis. In blood samples not stimulated with LPS, a significant increase in IL-15 was measured 1 h after carrot juice intake. Cytokines like IFN-ɣ, IL-12/IL-23(p40), IL-23, IL-17A, IL-17B, IL-17D, and IL-22 were significantly increased in LPS-stimulated blood samples after carrot juice intake. The upregulation of the immunostimulating cytokines belonging to the IL-23/IL-17 Th17 axis suggests that carrot juice intake could benefit diseases where inflammation plays a role, like in the early stages of diabetes or cancers.
Keywords:carrots; cytokines; ex vivo; falcarindiol; falcarinol; inflammation; lipopolysaccharide.