Effect of sandalwood oil on inhibition of reactive oxygen species generation and lipopolysaccharide-induced inflammation through down-regulation of the nuclear factor-κB signaling pathways

Abstract

We investigated the antioxidative and anti-inflammatory effects of sandalwood oil and attempted to elucidate its underlying mechanism of action. The antioxidant activities of sandalwood oil were assessed using various methods: 1.1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS+) radical scavenging assays, as well as DNA protection ability and reactive oxygen species (ROS) generation. The cell viability of sandalwood oil in RAW 264.7 cells (murine macrophage) was investigated by tetrazolium salt (MTT) assay. The nuclear factor kappa B (NF-κB) activation was analyzed by western blot analysis in LPS-induced RAW 264.7 cells. NF-κB nuclear translocation was evaluated by immunofluorescence staining. Furthermore, we examined ROS generation using DCF-DA in H2O2-stimulated RAW 264.7 cells. Sandalwood oil inhibited IκBα phosphorylation and NF-κB activation and its translocation into the nucleus. Sandalwood oil shows antioxidant activity in vitro, suggesting that it may inhibit the promotion of the NF-κB-mediated inflammatory signaling pathway induced by ROS.