Ligustilide prevents LPS-induced iNOS expression in RAW 264.7 macrophages by preventing ROS production and down-regulating the MAPK, NF-κB and AP-1 signaling pathways

Angelica sinensis (AS), an herb used in traditional Chinese medicine, is thought to have anti-inflammatory activities. Ligustilide is its most abundant ingredient. This study sought to determine ligustilide's effects on lipopolysaccharide (LPS)-induced inflammation in RAW 264.7 macrophages. Ligustilide significantly suppressed the production of nitric oxide (NO), prostaglandin E-2 (PGE(2)) and tumor necrosis factor-alpha (TNF-alpha). The inhibition of NO was concomitant with a decrease in the protein and mRNA levels of LPS-induced nitric oxide synthase (iNOS). Furthermore, activation of activator protein-1 (AP-1) and nuclear factor kappa B (NF-kappa B) in the nucleus and the cytosolic degradation of I kappa B alpha were abrogated by ligustilide. Ligustilide also inhibited the phosphorylation of I kappa B kinase (IKK) and mitogen-activated protein kinases (MAPKs), including p38 MAPK, extracellular signal-regulated kinase (ERK1/2) and c-Jun N-terminal kinase (JNK). The intracellular reactive oxygen species (iROS) level was also significantly decreased. These results suggest that ligustilide exhibits anti-inflammatory activities by blocking the activation of MAPKs/IKK and the downstream transcription factors AP-1 and NF-kappa B, which may result from ligustilide's down-regulation of iROS production. (C) 2011 Elsevier B.V. All rights reserved.