Bioactive sesquiterpenoids from the flowers of Inula japonica. (September 2016) - Wu, Xing-De
Abstract: Phytochemical investigation of the flowers of Inula japonica led to isolation of nine sesquiterpenoids, inujaponins A-I, as well as eighteen known ones. These sesquiterpenoids belong to six skeletal-types, including eudesmane, 1, 10-seco-eudesmane, germacrane, guaiane, 4, 5-seco-guaiane, and pseudoguaiane sesquiterpenoids. Their structures were established by extensive spectroscopic analysis. The absolute configurations of inujaponin A, eupatolide, and deacetylovatifolin were determined by Cu-Kα X-ray crystallographic analysis. Most of the isolated compounds exhibited potent cytotoxicity against HL-60, SMMC-7721, A-549, MCF-7, and SW-480 cancer cell lines, with IC50 values ranging from 1.57 to 22.58 μ M. Some selected compounds also possessed significant inhibitory activity against LPS-induced NO production in RAW264.7 macrophages with IC50 values ranging from 1.42 to 8.99 μ M. Graphical abstract: Nine sesquiterpenoids, inujaponins A-I, along with eighteen known ones, were isolated from the flowers of Inula japonica . Their cytotoxicity and inhibitory effect against LPS-induced NO production in RAW264.7 macrophages were evaluated. Highlights: Twenty-seven sesquiterpenoids were isolated from the flowers of Inula japonica. Nine previously undescribed sesquiterpenoids were characterized. Nine compounds exhibited potent cytotoxicity against five cancer cell lines. Six compounds exhibited inhibition against NO production.