Received September 25, 2006. Revised December 26, 2006. Accepted January 4, 2007. This work was supported by grants NSC 93-2320-B- 415-002 and NSC 94-2313-B-415-011 from National Science Council of the Republic of China.

Abstract:

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-B 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-B-driven luciferase assay, LPS-induced NF-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 and C/EBP, only C/EBP expressions were reduced. Thus, these stilbenoids were effective in inhibition of PGE₂- or NO-mediated inflammation and NF-B- or C/EBP-mediated inflammatory gene expression. In comparison, the highest inhibitory activity on LPS-induced PGE₂/NO production, C/EBP gene expression, and NF-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.

Keywords: Arachidin-1; piceatannol; resveratrol; inflammation; transcription factors; macrophages

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