Triterpenoid saponins: A focus on polygalaceae

Abstract

The aim of this chapter is to give the newest results on the chemistry and pharmacological properties of Polygalaceae saponins during the period 2005–2012. Around 60 new triterpene saponins were isolated and characterized, having mainly presenegenin, medicagenic acid, their 2-oxo or 11-oxo structural analogs, and bayogenin as aglycone. The sequence 3-O-(β-d-glucopyranosyl)presenegenin 28-{O-β-d-xylopyranosyl-(1→4)-α-l-rhamnopyranosyl-(1→2)-β-d-fucopyranosyl} ester often encountered in the genera Polygala, Securidaca, and Atroxima supported our previous conclusions that they may represent a chemotaxonomic marker for the Polygalaceae family. Additional glycosylations and acylations with 4-methoxy-, 3,4-dimethoxy-, or 3,4,5-trimethoxycinnamoyl groups contribute to the great chemical diversity of these saponins. The promising potential of the Polygalaceae saponins as immunoadjuvant, antiproliferative, anti-inflammatory, hypolipidemic, antidepressant, neuroprotective, and cognitive enhancer compounds has been highlighted.