New Acylated Presenegenin Saponins from Two Species of Muraltia

Six new acylated bisdesmosidic triterpene glycosides 1 – 6 were isolated from the roots of Muraltia heisteria (L.) DC., as three inseparable mixtures 1 / 2, 3 / 4 , and 5 / 6 of the ( E )‐ and ( Z )‐3,4,5‐trimethoxycinnamoyl derivatives. The compound pair 1 / 2 along with four known saponins were also isolated from the roots of Muraltia satureioides DC. Their structures were elucidated mainly by spectroscopic experiments including 2D‐NMR techniques as 3‐ O ‐( β ‐ D ‐glucopyranosyl)presenegenin 28‐{ O ‐ β ‐ D ‐apiofuranosyl‐(1→3)‐ O ‐[ β ‐ D ‐xylopyranosyl‐(1→4)]‐ O ‐ α ‐ L ‐rhamnopyranosyl‐(1→2)‐ O ‐[6‐ O ‐acetyl‐ β ‐ D ‐galactopyranosyl‐(1→3)]‐4‐ O ‐[( E )‐3,4,5‐trimethoxycinnamoyl]‐ β ‐ D ‐fucopyranosyl} ester ( 1 ) and its ( Z )‐isomer 2 , 3‐ O ‐( β ‐ D ‐glucopyranosyl)presenegenin 28‐{ O ‐6‐ O ‐acetyl‐ β ‐ D ‐galactopyranosyl‐(1→3)‐ O ‐[3‐ O ‐acetyl‐ α ‐ L ‐rhamnopyranosyl‐(1→2)]‐4‐ O ‐[( E )‐3,4,5‐trimethoxycinnamoyl]‐ β ‐ D ‐fucopyranosyl} ester ( 3 ) and its ( Z )‐isomer 4 , and 3‐ O ‐( β ‐ D ‐glucopyranosyl)presenegenin 28‐{ O ‐3‐ O ‐acetyl‐ α ‐ L ‐rhamnopyranosyl‐(1→2)‐ O ‐[ β ‐ D ‐xylopyranosyl‐(1→3)]‐4‐ O ‐[( E )‐3,4,5‐trimethoxycinnamoyl]‐ β ‐ D ‐fucopyranosyl} ester ( 5 ) and its ( Z )‐isomer 6 , respectively.