CHUNCHEON, Republic of Korea—According to Korean researchers, phenethyl isothiocyanate (PITC), which is found in cruciferous vegetables, effectively inhibited inflammatory responses in vivo and in vitro, possibly mediated via the inhibition of AKT and ERK1/2 activation, leading to subsequent inhibition of the trangascriptional activity of NF-k;B (J Med Food. 2011;14(4):377-85). Topical application of 5 nmol of 12-O-tetradecanoylphorbol-13-acetate (TPA) to mouse ears markedly increased the ear weight, expression of the inducible nitric oxide synthase (iNOS) and cyclooxygenase (COX)-2 protein and phosphorylation of the inhibitor of kB (IkB)-alpha, AKT and extracellular signal-regulated protein kinase (ERK) 1/2 and reduced IkB-alpha protein levels. Pretreatment with PITC (150 to 450 nmol) significantly suppressed these TPA-induced inflammatory responses.
Researchers also determined whether low concentrations of PITC (0.5 to 5 mol/L) inhibited lipopolysaccharide (LPS)-stimulated inflammatory responses in Raw264 cells. PITC dose-dependently reduced the LPS-induced secretion of nitric oxide (NO) prostaglandin E2, interleukin (IL)-1beta, IL-6 and tumor necrosis factor (TNF)-alpha, as well as COX-2 and iNOS protein expression. PITC also attenuated LPS-induced increases in iNOS, COX-2, IL- 6, IL-1beta and TNF-alpha mRNA levels, as well as the promoter-dependent trangascriptional activation of the genes for iNOS and COX-2. PITC inhibited LPS-induced IkB-alpha phosphorylation and degradation and subsequently reduced LPS-induced p65 nuclear translocation and the trangascriptional activity of nuclear factor kB (NFkB), which was accompanied by a reduction in ERK1/2 and AKT phosphorylation.