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 A-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.