Zanhic acid tridesmoside and other dominant saponins from Alfalfa (Medicago sativa L.) aerial parts.

A zahnic acid tridesmoside, 3-O-[beta-D-gluocpyranosyl(1-2)-beta-D-glucopyranosyl(1-2)-beta-D-glucopyranosyl]-2-beta,3-beta,16-alpha-trihydroxyolean-12-ene-23,28-dioic acid-23-O-alpha-L-arabinopyranosyl-28-O-[beta-D-apiofuranosyl-(1-3)-beta-D-xylopyranosyl(1-4)-alpha-L-rhamnopyranosyl(1-2)-alpha-L-arabinoside], has been identified as the main saponin present in the aerial parts of alfalfa by a combination of chromatographic, chemical, and spectroscopic techniques. Moreover, four medicagenic acid glycosides and soyasaponin I have been isolated from the same source and identified. Three of the medicagenic acid glycosides are identical to those previously found in alfalfa roots, while the fourth has been identified as 2-beta-hydroxy-3-beta-O-glucuronopyranosyl 28-O-[alpha-L-rhamnopyranosyl(1-2)-alpha-L-arabinopyranoside]olean-12-en-23-oic acid. Biological activity was measured using the fungus Trichoderma viride, and hemolytic activity was assessed using a hemolytic test. The zahnic acid glycoside did not inhibit fungal growth over a wide range of concentrations and exhibited only weak hemolytic activity.