Acylated Triterpene Saponins from Atroxima liberica Stapf

The four new acylated triterpene saponins 1 – 4 , isolated as two pairs of isomers and named libericosides A₁/A₂ and B₁/B₂, one pair of isomers 5 / 6 , the (Z)‐isomer libericoside C₂ ( 5 ) being new, one new sucrose ester, atroximoside ( 7 ), and eight known compounds were isolated from the roots of Atroxima liberica by repeated MPLC and VLC on normal and reversed‐phase silica gel. Their structures were elucidated on the basis of extensive 1D‐ and 2D‐NMR studies (¹H‐ and ¹³C‐NMR, DEPT, COSY, TOCSY, NOESY, HSQC, and HMBC) and mass spectrometry as 3‐O‐β‐D ‐glucopyranosylpresenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1→3)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 1 ) and its (Z)‐isomer 2 , 3‐O‐β‐D ‐glucopyranosylpresenegenin 28‐{O‐α‐L ‐arabinopyranosyl‐(1→4)‐O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[O‐β‐D ‐xylopyranosyl‐(1→3)‐β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 3 ) and its (Z)‐isomer 4 , 3‐O‐β‐D ‐glucopyranosylpresenegenin 28‐{O‐β‐D ‐xylopyranosyl‐(1→4)‐O‐α‐L ‐rhamnopyranosyl‐(1→2)‐O‐[6‐O‐acetyl‐β‐D ‐glucopyranosyl‐(1→3)]‐4‐O‐[(Z)‐3,4‐dimethoxycinnamoyl]‐β‐D ‐fucopyranosyl} ester ( 5 ), and 3‐O‐[(Z)‐feruloyl]‐β‐D ‐fructofuranosyl α‐D ‐glucopyranoside ( 7 ). Compounds 1 – 6 and the known saponins 8 / 9 were evaluated against the human colon cancer cells HCT 116 and HT‐29 and showed moderate to weak cytotoxicity.