Characterization of immunological activities of peanut stilbenoids, arachidin-1, piceatannol, and resveratrol on lipopolysaccharide-induced inflammation of RAW 264.7 macrophages

Biological activities of peanut stilbenoids, mainly resveratrol and its derivatives, have attracted increased attention and interest because of peanut being a potent producer and a dietary channel to convey these polyphenols to the human body. As arachidin-1 and piceatannol are structurally close to resveratrol, it is worthy to investigate their immunological activities on inhibition of lipopolysaccharide (LPS)-induced production of PGE(2) and NO and mediation of the related transcription factors (NF-kappa B and C/EBP) of RAW 264.7 macrophage cells. Productions of PGE(2) and NO were inhibited by all the test stilbenoids in a dose-dependent manner while gene and protein expressions of COX-2 and iNOS were not inhibited. As shown by NF-kappa B-driven luciferase assay, LPS-induced NF-kappa B activities were also reduced by the stilbenoids. In further, when these stilbenoids were subjected to monitoring their inhibitory effectiveness on LPS-induced transcription factor expressions of C/EBP delta and C/EBP beta, only C/EBP delta expressions were reduced. Thus, these stilbenoids were effective in inhibition of PGE(2)- or NO-mediated inflammation and NF-kappa B- or C/EBP delta-mediated inflammatory gene expression. In comparison, the highest inhibitory activity on LPS-induced PGE(2)/NO production, C/EBP delta gene expression, and NF-kappa B activation was piceatannol which was followed in order by arachidin-1 and resveratrol. The observed anti-inflammatory activities of these peanut stilbenoids are of merit in further consideration for nutraceutical applications.