Novel Sesquiterpenes from Ligularia virgaurea spp. oligocephala

Abstract

AbstractTwo novel sesquiterpene dimers, ligularin A (1) and ligulolide D (2), and one new sesquiterpenoid, 1β,10α‐dihydroxy‐6β‐[(2‐methylpropyl)oxy]furanoeremophil‐9‐one (3), as well as two known sesquiterpenoids, 6β‐[(2‐methylpropyl)oxy]‐furanoeremophil‐1(10)‐en‐9‐one (4) and 1‐hydroxy‐3,7‐dimethyl‐2‐(pent‐3‐enyl)benzofuran (5), were isolated from the petroleum‐ether fraction from an alcoholic extract of the whole plant of Ligularia virgaurea spp. oligocephala. Their structures were elucidated by 1D and 2D‐NMR spectroscopy together with HR‐ESI‐MS analysis, and comparison of the spectroscopic data with those reported for structurally related compounds. In addition, the cytotoxicities against human gastric cancer SGC‐7910 cell were measured in vitro, the results demonstrated that these sesquiterpenes have no cytotoxicity against the selected tumor cell (all IC50 values >200 μM).