ISOLATION AND IDENTIFICATION OF ALFALFA (MEDICAGO-SATIVA L) ROOT SAPONINS - THEIR ACTIVITY IN RELATION TO A FUNGAL BIOASSAY

Nine triterpene glycosides have been isolated from alfalfa (Medicago sativa) roots and their structures elucidated by using chromatographic, chemical, and spectroscopic techniques. Six of these saponins were identified as being glycosides of medicagenic acid, two of hederagenin, and one of soyasapogenol B. The compounds containing medicagenic acid could be further subdivided into analogues of either 3-O-glucoside or 3-O-glucuronide of medicagenic acid. The presence of the latter group has not been previously reported. Activity against the fungus Trichoderma viride has been determined for each of the saponins, and their structure-activity relationship is discussed with regard to a fungal bioassay routinely used for saponin determination. © 1990, American Chemical Society. All rights reserved.