Antiyeast steroidal saponins from Yucca schidigera (Mohave yucca), a new anti-food-deteriorating agent

A saponin fraction from the stems of Yucca schidigera (Mohave yucca) exhibi ted potent growth-inhibitory activities against certain food-deteriorating yeasts, film-forming yeasts, and dermatophytic yeasts and fungi. From this fraction, a number of new anti-yeast monodesmosidic spirostanol saponins, n amed schidigera-saponins A1 (1), A2 (2), A3 (3), B1 (4), C1 (5),C2 (6); 25( R and S) schidigera-saponins D1 (7), D2 (8), E1 (12), F1 (13); and 25(S) sc hidigera-saponins D3 (9), D4 (10), D5 (11), and F2 (14) were isolated, toge ther with several related known saponins, and the structures were elucidate d by spectroscopic methods (see Chart 1). The relationship between the anti yeast activities and the structures of these saponins is described.