The Chemical Educator
ISSN: 1430-4171 (electronic version)
Abstract Volume 12
Issue 3 (2007) pp 179-184
Isolation and Characterization of Osajin and Pomiferin: Discovery Laboratory Exercises for Organic Chemistry
Whaley, W. L.,*, Rummel, J. D.,, Zemenu, E., Li, W., Yang, P., Rodgers, B. C., Bailey, J., Moody, C. L., Huhman, D. V., Maier, C. G.-A.,§ Sumner, L. W., Starnes, S.D.
Department of Chemistry, Texas A&M
University-Commerce, Commerce, Texas 75429-3011, William_Whaley@tamu-commerce.edu,
Division of Plant
Sciences, The Noble Foundation, Ardmore, Oklahoma, §Department of
Biology, Texas Womans University, Denton, Texas.
Published online: 4 June 2007
Abstract. 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.
Key Words: Laboratories and Demonstrations; organic chemistry; natural products
(*) Corresponding author. (E-mail: William_Whaley@tamu-commerce.edu)
The supporting materials (807 KB) include the following:
· Student instructions for Laboratory Exercises #1, #2, and #3.
· 1H-NMR spectra for osajin and pomiferin.
· Example 1H-NMR spectra for determining composition of osajin and pomiferin in typical student samples.
· 1H-NMR 2D-COSY spectra for osajin and pomiferin.
· Summary of signal assignments for 1H-NMR spectra for osajin and pomiferin.
· 1H-NMR 1D-NOESY spectra for pomiferin.
· 13C-NMR (1D), 13C-NMR DEPT spectra for osajin and pomiferin.
· 13C-NMR APT spectra for pomiferin.
· HPLC/Tandem Mass Spectra of osajin and pomiferin.
· Example DPPH radical scavenging assay results for vitamin E, pomiferin, and osajin.
Issue date: June