Seco-type β-Apocarotenoid Generated by β-Carotene Oxidation Exerts Anti-inflammatory Effects against Activated Macrophages.

β-Apocarotenoids are the cleavage products of β-carotene. They are found in plants, carotenoid-containing foods, and animal tissues. However, limited information is available regarding the health benefits of β-apocarotenoids. Here, we prepared seco-type β-apocarotenoids through the chemical oxidation of β-carotene and investigated their anti-inflammatory effects against activated macrophages. Oxidation of β-carotene with potassium permanganate produced seco-β-apo-8'-carotenal, in which one end-group formed an "open" β-ring and the other was cleaved at the C-7',8' position. In lipopolysaccharide-stimulated murine macrophage-like RAW264.7 cells, seco-β-apo-8'-carotenal inhibited the secretion and mRNA expression of inflammatory mediators such as nitric oxide, interleukin (IL)-6 and IL-1β, and monocyte chemoattractant protein-1. Furthermore, seco-β-apo-8'-carotenal suppressed phosphorylation of c-Jun N-terminal kinase and the inhibitor of nuclear factor (NF)-κB as well as the nuclear accumulation of NF-κB p65. Notably, since seco-β-apo-8'-carotenal exhibited remarkable anti-inflammatory activity compared with β-apo-8'-carotenal, its anti-inflammatory action could depend on the opened β-ring structure. These results suggest that seco-β-apo-8'-carotenal has high potential for the prevention of inflammation-related diseases.