Diversity of Sesquiterpenoids from Carpesium cernuum

Two new sesquiterpene lactones, 6b-hydroxy-8a-ethoxyeremophil-7(11)-en-12,8β-olide (1) and 4β,10β-dihydroxy-1aH,5αH,11αH-guaian-12,8β-olide (2), together with 22 known sesquiterpenoids with various structural types, were isolated from Carpesium cernuum (Compositae). Their structures and configurations were elucidated by extensive 1D- and 2D-NMR spectroscopic analysis in combination with MS experiments, and comparison with literature data of related compounds.