Chemical Constituents of the Roots of Polygala tenuifolia and Their Anti-Inflammatory Effects.

Increasing scientific evidence has demonstrated that the roots of Polygala tenuifolia Willd. have pharmacological effects related to anti-inflammation. Therefore, the aim of this study is to investigate the chemical constituents from P . tenuifolia roots as anti-inflammatory drug candidates. In the present work, twenty-three compounds were isolated from P . tenuifolia roots, including three saponins ( 1 - 3 ), ten phenylpropanoid sucrose esters ( 4 - 12 ), one benzoic acid sugar ester derivative ( 13 ), four xanthones ( 14 - 17 ), two hydroxy benzophenone derivatives ( 18 and 19 ), two phenolic derivatives ( 20 and 21 ), and two ionones ( 22 and 23 ). All isolates were tested for their inhibitory effects of LPS-stimulated NO and PGE 2 production in RAW 264.7 macrophages. Among these, 3- O -(3,4,5-trimethoxy-cinnamoyl),6'- O -( p -methoxybenzoyl) sucrose ester (TCMB; 11 ) together with compounds 3 and 21 exhibited significant inhibitory effects on NO production, while TCMB and compounds 17 , 19 , and 21 showed strong inhibitory effects on PGE 2 production. Specifically, TCMB ( 11 ) downregulated the protein levels of iNOS and COX-2 in LPS-induced RAW 264.7 macrophages. In addition, TCMB ( 11 ) dose-dependently diminished the relative mRNA expression levels of iNOS, PGE 2 , and proinflammatory cytokines (TNF-α, IL-1β, and IL-6). A molecular docking study showed that TCMB ( 11 ) has strong binding affinities with iNOS and COX-2.