ARS | Publication request: Anti-inflammatory activity of hydroxycinnamic acid derivtives isolated from corn bran in lipopolysaccharide-stimulated raw 264.7 macrophages

Submitted to: Food and Chemical Toxicology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 9, 2012
Publication Date: March 1, 2012
Citation: Kim, E., Kwon, T., Um, B., Moreau, R.A., Choi, S. 2012. Anti-inflammatory activity of hydroxycinnamic acid derivtives isolated from corn bran in lipopolysaccharide-stimulated raw 264.7 macrophages. Food and Chemical Toxicology. 50:1309-1316.

Interpretive Summary: Previous research from our laboratory and others have demonstrated that corn bran contains several phenolic compounds that have antioxidant properties and other bioactive properties. In the current study, four phenolic compounds from corn bran were each purified and their anti-inflammatory properties were measured using two new tests. One of these four compounds,diferuloylputrescine, was found to be the most potent of the four compounds using both anti-inflammatory tests. This suggests that this natural compound from corn may be a new potential anti-inflammatory therapeutic compound.

Technical Abstract: In this study, the effect of the 80 percent ethanolic extract of corn bran (EECB) on inhibition of nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in lipopolysaccharide (LPS)-stimulated Raw 264.7 cells was investigated. The EECB inhibited LPS induced NO production and iNOS expression in a dose-dependent manner. Four hydroxycinnamic acid derivatives (HADs), including two free cinnamic acids, p-coumaric acid (CA) and ferulic acid (FA), and their conjugate phenolic amides, p-dicoumaroyl-putrescine (DCP) and diferuloylputrescine (DFP), were found to be present in the EECB by LC-MS analysis, and DFP (378.66 ug/g) was the predominant phenolic compound, followed by DCP (7.83 ug/g) > CA (5.58 ug/g) > FA (1.84 ug/g). The four HADs significantly inhibited NO production and iNOS expression in a dose-dependent manner. Among the four HADs tested, DFP showed the most potent inhibition on NO production and iNOS mRNA and protein expression, followed by DCP > FA = CA. DFP also exhibited the strongest inhibition on LPS induced iNOS and NF-kB luciferase activity, which was followed by DCP = FA (CA) > CA (FA). Thus, these results suggest that phenolic amides in the corn bran may be a potential source of natural anti-inflammatory agents.