Studies on Medicago lupulina saponins. 2. Isolation, chemical characterization and biological activity of saponins from M. lupulina tops

Abstract

Two pure saponin fractions from the tops of M. lupulina were isolated and characterized. The fractions named Ma and Ss varied in composition and biological activity. It was shown by TLC that fraction Ma contained 5 components. In the acid hydrolysates of that fraction only one aglycone (medicagenic acid) and 4 sugars: rhamnose, xylose, arabinose, glucuronic acid were found. The Ss fraction contained 11 components. In its acid hydrolysates, soyasapogenols B, C, D, E, F and two new aglycones N and An were found. The same sugars as above and additionally glucose and galactose were identified. It was found that the Ma fraction of saponins (medicagenic acid glycosides) was highly fungistatic, haemolytic and toxic to fishes. The Ss fraction of saponins (soyasapogenol glycosides) showed no such activity.

Keywords

• Medicago lupulina
• saponins
• isolation
• biological activity