Effects of Various Phytochemicals on Indoleamine 2,3-Dioxygenase 1 Activity: Galanal Is a Novel, Competitive Inhibitor of the Enzyme
Figure 4
Inhibition by galanal of the NFκ-B signal transduction pathway.
(A) L-Kyn formation in LPS (50 ng/ml)-treated THP-1 cells with and without various concentrations (1-5 µM) of galanal. L-Kyn formed after 24-hr incubation was measured by HPLC. Data are the mean ± SD. ***P<0.001. (B) Expression of IDO1 mRNA in LPS-treated THP-1 cells with and without galanal after 24 hrs incubation. The mRNA expressed was measured using RT-PCR. (C) Cytoplasmic expression of IDO1 and Iκ-Bα proteins in LPS (50 ng/ml)-treated THP-1 cells with and without galanal after 24 hrs incubation. (D) The phosphorylation of IKK-α, IκB-α, and NFκ-B in LPS (50 ng/ml)-treated THP-1 cells with and without galanal after 60-min incubation. Data are the mean ± SD. ***P<0.001.