Targeted isolation of dimeric sesquiterpene lactones and sesquiterpene derivatives from the roots of Inula helenium.

LC-HRMS/MS-based molecular networking was applied to investigate the bioactive sesquiterpene lactones and their analogs contained in Inula helenium, enabling the isolation of four undescribed eudesmane-eudesmane sesquiterpene dimers (1-4), a sesquiterpene-amino acid adduct (5), and 17 known sesquiterpenes (6-22). The structures were determined based on 1D, 2D NMR, and HRESIMS data analysis, as well as DP4+ probability analyses and ECD calculations. The biosynthetic pathway of the sesquiterpene dimers is postulated to proceed via the Diels-Alder reaction as the key step. The inhibitory activity of all isolates on LPS-induced nitric oxide (NO) production in RAW 264.7 macrophages was evaluated. Compounds 4, 17, and 20 exhibited significant inhibitory activity against NO production, with IC50 values of 8.4, 5.5, and 9.1 μM, respectively.

Han JS ，Kim JG ，Cho YB ，An BK ，Lee D ，Lee MK ，Hwang BY ... -  《-》

Five new sesquiterpene lactones from Inula hupehensis.

Ren J ，Qin JJ ，Cheng XR ，Yan SK ，Jin HZ ，Zhang WD ... -  《-》

Targeted isolation of sesquiterpene lactone dimers from Aucklandia lappa guided by LC-HRMS/MS-based molecular networking.

An LC-HRMS/MS-based molecular networking strategy was applied to investigate the potential sesquiterpene dimers of Aucklandia lappa, leading to the isolation of three undescribed guaiane-guaiane dimers and one guaiane-eudesmane dimer together with six known sesquiterpenes. The structures were determined by analyzing their 1D, 2D NMR, and HRESIMS data as well as ECD calculations. The biogenetic pathway of the sesquiterpene dimers was postulated to involve the Diels-Alder cycloaddition as the key step. All compounds exhibited their inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages with IC50 values ranging from 0.3 to 25.1 μM.

Han JS ，Kim JG ，Linh Le TP ，Cho YB ，Lee D ，Hong JT ，Lee MK ，Hwang BY ... -  《-》

Japonicones E-L, dimeric sesquiterpene lactones from Inula japonica Thunb.

Eight new dimeric sesquiterpene lactones (japonicones E-L, 1- 8), including a novel sesquiterpene dimer bearing a rare hydroperoxide group (japonicone E, 1), were isolated from the aerial part of Inula japonica Thunb. Their structures were determined mainly by the use of 1D and 2D NMR spectroscopic techniques including HSQC, (1)H-(1)H COSY, HMBC, and NOESY. All the isolates were tested for inhibitory effects against LPS-induced NO production in RAW264.7 macrophages. Among the compounds tested, japonicone F (2) showed the strongest activity with the IC(50) value of 4.1 microg/mL.

Qin JJ ，Jin HZ ，Zhu JX ，Fu JJ ，Hu XJ ，Liu XH ，Zhu Y ，Yan SK ，Zhang WD ... -  《-》

Characterization of Sesquiterpene Dimers from the Flowers of Inula japonica and the Structural Revisions of Related Compounds.

Niu Z ，Chen CY ，Zhou Y ，Liu GK ，Zhang BY ，Oppong MB ，Zhang DQ ，Yao T ，Qiu F ... -  《-》