Four new sesquiterpenoids from Ligularia cymbulifera.

Four new highly oxygenated bisabolane sesquiterpenoids were obtained from the EtOH extract from Ligularia cymbulifera, and their structures were elucidated by interpretation of spectroscopic data. Their relative configurations were clarified by a detailed analysis of ¹H NMR coupling constants, nuclear overhauser effect (NOE) experiments and two-dimensional NMR spectra. These four new compounds were assayed for their antimicrobial activities against four Gram-positive and Gram-negative bacteria, as well as against one human pathogenic fungus.