Soybean Saponins : III. Fractionation And Characterization

A method—consisting of column chromatography on acid washed Al 2 O 3 and subsequent paper chromatography—for the fractionation of soybean saponin extract (SBSE) has been elaborated. SBSE could be separated into 5 fractions, the homogeneity of which has been established by ascending paper chromatography and horizontal paper electrophoresis. Four of these fractions were proved to be saponins by the following criteria: a) Haemolytic and foam‐forming abilities; b) Characteristic bitter taste; and c) Identification of the known soybean sapogenins A, B, C and D as well as reducing sugars, in the acid hydrolysates. A colorimetric method, based on a modified Lieberman‐Burchard reagent, for the quantitative determination of the various saponins present in SBSE has been developed. Saponin b , the strongest haemolytic agent of the four, is present only in small amounts in SBSE, whereas c , which composes 75% of SBSE, has moderate haemolytic activity. Since it has been found that the ratio of haemolytic and foam‐forming activity is inversely correlated, it seems that the two activities involve different active sites.