Saponins in Medicago truncatula : structures and activities

Saponins are polar bioactive compounds that contain a triterpene or a steroid aglycone with one or more sugar moieties. They are the most numerous and most diverse molecules generally considered as produced by plants to fight against pathogens and herbivores. Among the sources of saponins, the genus Medicago, a member of the legume family (Fabaceae), comprises 87 species of flowering plants, including the forage plant Medicago sativa (alfalfa) and the legume model Medicago truncatula (barrel medic), is an important reservoir. These bioactive natural products often have a wide range of commercial applications in the food cosmetics and pharmaceutical sector. This review will focus on structural aspects of saponins, and their biological activities with a special attention on saponins from Medicago species and more particularly from M. truncatula.