Suppression of inducible nitric oxide production by indole and isothiocyanate derivatives from Brassica plants in stimulated macrophages

In this study, the effects of bioactive compounds derived from vegetables of the Brassica genus (Brassicaceae) including 2-phenylethyl isothiocyanate (PEITC), indole-3-carbinol (13C), and indolo[3,2-b]carbazole (ICZ), on the inhibition of NO production in RAW 264.7 cells were explored. The results indicated that PEITC and 13C inhibited lipopolysaccharide (LPS)- and interferon-γ (IFN-γ)-induced NO production in RAW 264.7 cells, and this inhibition was in accordance with lowering the expression of iNOS protein and mRNA. On the contrary, ICZ, a derivative of 13C, had no significant effect on the stimulated NO production. In conclusion, the Brassica plants derivatives, PEITC and, to a lesser extent, 13C inhibit the LPS/IFN-γ-induced NO production by lowering iNOS protein and mRNA expression in RAW 264.7 cells, in which the PEITC had a more potent inhibitory effect. Nevertheless, ICZ exhibits no inhibitory effect on the activated NO production (Indole-3-carbinol = indole-3-methanol).