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 PGE2 and NO and mediation of the related transcription factors (NF-kappaB and C/EBP) of RAW 264.7 macrophage cells. Productions of PGE2 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-kappaB-driven luciferase assay, LPS-induced NF-kappaB 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/EBPdelta and C/EBPbeta, only C/EBPdelta expressions were reduced. Thus, these stilbenoids were effective in inhibition of PGE2- or NO-mediated inflammation and NF-kappaB- or C/EBPdelta-mediated inflammatory gene expression. In comparison, the highest inhibitory activity on LPS-induced PGE2/NO production, C/EBPdelta gene expression, and NF-kappaB 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.