Chemical constituents from the rhizomes of Polygonatum sibiricum Red. and anti-inflammatory activity in RAW264.7 macrophage cells

Chemical investigation of the rhizomes of Polygonatum sibiricum Red. led to the identification of 27 constituents. Among them, a total of 16 compounds were obtained from Polygonatum for the first time, in which, 3 and 4 were also firstly isolated as natural products. Anti-inflammatory activity studies on 13 isolated compounds showed that β-carboline constituents, especially compounds 1 and 2, significantly inhibited the expression of NO, TNF-α, IL-6 and IL-1β in lipopolysaccharide (LPS)-treated RAW264.7 macrophage cells. Moreover, western blotting analysis demonstrated that compound 1 significantly inhibited the expression of COX-2, iNOS and the activation of NF-κB, suggesting that β-carboline structures may play an important role in inhibition of NF-κB signaling pathway, which thereby inhibits the production of inflammatory factors. The present research may not only help further elucidation of the anti-inflammatory mechanism of P. sibiricum Red., but also provide the potential bioactive molecules for inflammatory diseases research.