Polyhydroxylated eudesmane sesquiterpenoids and sesquiterpenoid glucoside from the flower buds of Tussilago farfara

Chemical fractionation of the n-BuOH partition, which was generated from the EtOH extract of the flower buds of Tussilago farfara, afforded a series of polar constituents including four new sesquiterpenoids ( 1 – 4 ), one new sesquiterpenoid glucoside ( 5 ) and one known analogue ( 6 ) of the eudesmane type, as well as five known quinic acid derivatives ( 7 – 11 ). Structures of the new compounds were unambiguously characterized by detailed spectroscopic analyses, with their absolute configurations being established by X-ray crystallography, electronic circular dichroism (ECD) calculation and induced ECD experiments. The inhibitory effect of all the isolates against LPS-induced NO production in murine RAW264.7 macrophages was evaluated, with isochlorogenic acid A ( 7 ) showing significant inhibitory activity.