Hepatic anti-inflammatory effect of hexane extracts of Dioscorea batatas Decne: Possible suppression of toll-like receptor 4-mediated signaling

Abstract

The hepatic anti-inflammatory potential of hexane extracts of Dioscorea batatas Decne edible part(EDH-1e) and bark(EDH-2b) were investigated in Western-type diet-fed apolipoprotein E null [ApoE(-/-)] mice and HepG2 cells. EDH-1e and EDH-2b suppressed the increased levels of tumor necrosis factor alpha(TNF-α), interleukin(IL)-6, transforming growth factor beta 1(TGF-β1), vascular cell adhesion protein 1(VCAM-1), and monocyte chemoattractant protein-1(MCP-1), and reduced infiltration of monocytes into liver tissue. The protein levels of Toll-like receptor 4(TLR4) were also downregulated by EDH-1e and EDH-2b treatment as were the levels of activator protein 1(AP-1), c-fos, and c-jun in the livers from Western-type diet-fed ApoE(-/-) mice and in lipopolysaccharide-stimulated HepG2 cells. Taken together, EDH-1e and EDH-2b attenuated hepatic inflammation and fibrosis via suppression of the TLR4-AP1-mediated signaling pathway.