Aim: To study the effects of alpha-pinene on nuclear translocation of nuclear factor-kappa B (NF-kappa B) and the expression of the inhibitor of NF-kappa B (I kappa B alpha) in human monocyte THP-1 cell line.
Methods: THP-1 cells were incubated with alpha-pinene (1, 10, and 100 mg/L, for 30 min) before being stimulated with lipopolysaccharide (LPS, 1 mg/L, 30 min). The location of NF-kappa B p65 subunit (NF-kappa B/p65) in THP-1 cells was detected by immunofluorescence and laser scanning confocal microscope (LSCM). The expression of NF-kappa B/p65 in nuclei and that of I kappa B alpha in cytoplasm were measured by Western-blot analysis.
Results: The majority of FITC-labelled NF-kappa B/p65 was located in the nuclei being stimulated with LPS. Whereas, no such fluorescence was seen in the nuclei of the groups pretreated with alpha-pinene or control cells. alpha-Pinene pretreatment decreased the NF-kappa B/p65 nuclear translocation in LPS-stimulated THP-1 cells, and this effect was dose-dependent, but there was no reaction in LPS-unstimulated THP-1 cells. alpha-Pinene pretreatment increased I kappa B alpha protein level in cytoplasm, compared with that in LPS-stimulated THP-1 cells.
Conclusion: In a dose-related fashion, alpha-pinene inhibits the nuclear translocation of NF-kappa B induced by LPS in THP-1 cells, and this effect is partly due to the upregulation of I kappa B alpha expression.