Two Novel Guaiane Sesquiterpenes from the Whole Plant of Youngia japonica

Abstract

Two new guaiane-type sesquiterpenes ( 1 and 2) together with eight related sesquiterpenoidal constituents ( 3 – 10) were isolated from the whole extract of Youngia japonica. The chemical structures of 1 – 10 were established by spectroscopic analyses as 4- epi -isolipidiol ( 1), 4′- p -hydroxyphenylacetyl crepiside E ( 2), isolipidiol ( 3), isoambeboin ( 4), grosheimin ( 5), annuionone D ( 6), loliolide ( 7), youngiajaponicoside A ( 8), crepiside H ( 9), and crepiside E ( 10), respectively. Among the isolated components, 5 exhibited a significant inhibitory effect on the proliferation of cultured human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15).