A new bisdesmosidic spirostanol saponin, along with three known saponins, w
ere isolated from Agave americana (Agavaceae). The structure of the new sap
onin was elucidated as (25R)-3 beta,6 alpha-dihydroxy-5 alpha-spirostan-12-
one 3,6-di-O-beta-D-glucopyranoside. Among the isolated saponins, hecogenin
tetraglycoside showed cytotoxic activity against HL-60 human promyelocytic
leukemia cells with an IC50 value of 4.3 mu g/ml.