Trisecocycloartane triterpene dilactones from the cones of Pseudolarix amabilis

Abstract

• Two previously undescribed cycloartane triterpenoids were isolated from the cones of Pseudolarix amabilis . • Compounds 1 - 2 are rare 3(4),8(9),9(10)-trisecocycloartane dilactones. • The structures of new triterpenoids were elucidated by detailed spectral analysis. • The absolute configuration of 1 was determined by single crystal X-ray diffraction (CuK α ). Two previously undescribed 3(4), 8(9), 9(10)-trisecocycloartane triterpene dilactones with a featured eleven-membered ring, pseudoladilactones A and B ( 1 - 2 ), together with three known ones ( 4 - 5 ), were isolated from the 80 % ethanol extract of the cones of Pseudolarix amabilis . The structures of compounds 1 and 2 were determined on the basis of analysis of 1D- and 2D-NMR spectroscopic data. The absolute configuration of pseudoladilactones A ( 1 ) was elucidated by single crystal X-ray diffraction (CuK α ). All isolates were tested for cytototoxicity against four human tumor cell lines A549, HCT116, SK-BR-3, and HepG2.