The carotenoid extract from Dunaliella salina was used to evaluate the suppressive effects on lipopolysaccharide (LPS)-induced pro-inflammatory mediators in RAW264.7 cells. The extract composed all-trans forms of α-carotene (28.8 mg/g extract), β-carotene (471.1 mg/g extract), lutein (7.1 mg/g extract) and zeaxanthin (7.2 mg/g extract), 13- or 13′-cis-β-carotene (12.1 mg/g extract), 9- or 9′-cis-α-carotene (19.1 mg/g extract) and 9- or 9′-cis-β-carotene (440.3 mg/g extract) dose-dependently reduced the production of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α (TNF-α), the protein expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and the secretion of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-activated RAW264.7 cells. Its attenuation of LPS-induced inflammatory responses was closely related to inhibition of the nuclear NF-κB p50 subunit translocation by blocking inhibitor of κBα (IκB) phosphorylation and degradation correlated with suppressing IκB kinase (IKK) α/β phosphorylation, as well as down-regulation of the c-Jun NH2-terminal kinase (JNK) activation.
