Thin layer and anion exchange chromatography of soybean saponins

Twenty‐two solvent systems were evaluated for TLC of soybean saponins on silica gel. A maximum of four fractions separated by single development with the different solvents. Six successive developments with chloroformmethanol‐water (65:25:4) separated soybean saponins into 10 or more fractions. Column chromatography of soybean saponins on an anion exchange resin with a linear gradient of acetic acid yielded seven fractions. Multiple development TLC of the saponins separated by column chromatography showed that a definite fractionation occurred. Several column chromatographic fractions contained components with identical TLC Rf values, but the components were clearly different on the basis of colors detected with sulfuric acid and on the basis of their elution positions from the ion exchange resin. Soybean saponins are more complex mixtures than previously recognized but can be fractionated by chromatography on thin layer plates and anion exchange resins.