Abstract
Twelve triterpene saponins were isolated by successive MPLC over silica gel from four species of Polygalaceae: From Polygala ruwenzoriensis, five new saponins 1–5 of which 1–4 as two pairs of (E)/(Z)‐isomers, together with the four known compounds tenuifoline, (E)‐ and (Z)‐senegasaponin b, (E)‐ and (Z)‐senegin II, and polygalasaponin XXVIII, from the genus Carpolobia, one new saponin 6 from C. alba and the known arilloside (11) from C. lutea, and another new triterpene glycoside 7 from Polygala arenaria. Their structures were established mainly by 600‐MHz 2D‐NMR techniques (^1^H,^1^H‐COSY, TOCSY, NOESY, HSQC, HMBC) as 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐{O‐α‐L‐arabinopyranosyl‐(1 → 4)‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐4‐O‐[(E)‐4‐methoxycinnamoyl]‐β‐D‐fucopyranosyl} ester (1) and its (Z)‐isomer 2, 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐{O‐α‐L‐arabinopyranosyl‐(1 → 4)‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐4‐O‐[(E)‐3,4‐dimethoxycinnamoyl]‐β‐D‐fucopyranosyl} ester (3) and its (Z)‐isomer 4, 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐[O‐β‐D‐galactopyranosyl‐(1 → 4)‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐β‐D‐fucopyranosyl] ester (5), 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐{O‐α‐L‐arabinopyranosyl‐(1 → 3)‐O‐[β‐D‐galactopyranosyl‐(1 → 4)]‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐O‐[β‐D‐apiofuranosyl‐(1 → 3)]‐4‐O‐acetyl‐β‐D‐fucopyranosyl} ester (6), and 3‐O‐(β‐D‐glucopyranosyl)presenegenin 28‐{O‐β‐D‐galactopyranosyl‐(1 → 4)‐O‐[β‐D‐glucopyranosyl‐(1 → 3)]‐O‐β‐D‐xylopyranosyl‐(1 → 4)‐O‐α‐L‐rhamnopyranosyl‐(1 → 2)‐β‐D‐fucopyranosyl} ester (7) (presenegenin = (2__β__,3__β__,4__α__)‐2,3,27‐trihydroxyolean‐12‐ene‐23,28‐dioic acid).