Submitted to: Journal of Chromatography A
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 17, 2003
Publication Date: March 28, 2003
Citation: Boue, S.M., Carter Wientjes, C.H., Shih, B.Y., Cleveland, T.E. 2003. Identification of flavone aglycones and glycosides in soybean pods by liquid chromatography-tandem mass spectrometry. Journal of Chromatography A. 991:61-68. Interpretive Summary: The pod of the soybean serves several purposes and is the main protective barrier for the seed preventing insect damage and fungal attack. A class of plant compounds called flavonoids are commonly found in soybeans, however no data exists on their presence in soybean pods. Using several analytical techniques, seven flavonoids in soybean pods were identified. In mature soybean pods, the flavonoid at the highest concentration was identified as apigenin. Two other flavonoids were identified as luteolin and 7,4'-dihydroxyflavone. These flavonoids found in mature soybean pods are indicators of soybean seed maturity and may have antifungal activities. These results indicate that the soybean pod that is discarded during harvesting may have alternative uses. This would enhance the post-harvest value of soybeans and would benefit soybean growers.
Technical Abstract: High-performance liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (HPLC-APCI-MS) was used to identify flavone aglycones and glycosides in soybean pods. Tandem mass spectrometry (MS/MS and MS3) and photodiode array detection were also utilized in flavone characterization. Soybean pod extracts contained the flavones apigenin, 7,4'-dihydroxyflavone, and luteolin. Using tandem mass spectrometric techniques, four flavone glycosides were identified: 7,4'-dihydroxyflavone-7-O-B-D-glucoside, luteolin-7-O-B-D-glucoside, apigenin-7-O-B-D-glucoside, and apigenin-7-O-B-D-glucoside-6"-O-malonate. This is the first report identifying flavones in soybean pods. These results indicate that the soybean pod that is discarded during harvesting may have agricultural value.