Isolation and Characterization of Osajin and Pomiferin

The isoflavones are a class of natural products that exhibit biological activities associated with health benefits. Osage orange, Maclura pomifera (Moraceae), has been naturalized throughout North America and its fruit contains high concentrations of two isoflavones, osajin and pomiferin. A series of discovery-based laboratory exercises, involving the isolation and structural confirmation of these isoflavones, were developed for the undergraduate organic chemistry laboratory. The exercises were based on a classic series of articles published in the Journal of the American Chemical Society. Instructions were written to help students read these articles and glean pertinent information to write a protocol for small-scale extraction of osajin and pomiferin in a common solvent fraction. Students identified optimum conditions for chromatographic purification of these compounds in quantities sufficient for analyses by the spectroscopic methods usually introduced in organic chemistry courses.