Inhibitory effects of lupane-type triterpenoid saponins from the leaves of Acanthopanax gracilistylus on lipopolysaccharide-induced TNF-α, IL-1β and high-mobility group box 1 release in macrophages

Abstract

Acanthopanax gracilistylus (AGS) has long been used in traditional Chinese medicine for the treatment of various inflammatory diseases. 3-O-β-D-glucopyranosyl 3α, 11α-dihydroxylup-20(29)-en-28-oic acid, acantrifoside A, acankoreoside D, acankoreoside B and acankoreoside A are major lupane-type triterpenoid saponins derived from AGS. In the present study, these five saponins were isolated from AGS by chromatography and their anti-inflammatory activities were investigated in lipopolysaccharide (LPS)-treated RAW264.7 macrophages. Cell viability was evaluated by MTT assay. Tumor necrosis factor (TNF)-α, interleukin (IL)-1β and NF-κB p65 were measured by ELISA. The gene expression levels of TNF-α and IL-1β was detected by reverse-transcription polymerase chain reaction. And high-mobility group box 1 (HMGB1) were analyzed by western blotting. The results demonstrated that these five saponins significantly suppressed LPS-induced expression of TNF-α and IL-1β at the mRNA and protein level in RAW264.7 cells. Further analysis revealed that acankoreoside A and acankoreoside B were able to reduce the secretion of HMGB1 and NF-κB activity induced by LPS in RAW264.7 macrophages. Taken together, these results suggested that the anti-inflammatory activity of AGS-derived saponins may be associated with the downregulation of TNF-α and IL-1β, and the 'late-phase' proinflammatory cytokine HMGB1, via negative regulation of the NF-κB pathway in RAW264.7 cells.