Isolation and Characterization of Osajin and Pomiferin: Discovery Laboratory Exercises for Organic Chemistry

TCE

The Chemical Educator

ISSN: 1430-4171 (electronic version)

Table of Contents

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 Woman’s University, Denton, Texas.
Received February 7, 2007. Accepted April 16, 2007.

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)

Article in PDF format (374 KB) HTML format

Supporting Materials:

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.