Submitted to: Lipids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/29/2001
Publication Date: 6/29/2001
Interpretive Summary: Commercial corn oil is obtained by extracting the oil-rich "germ" portion of corn kernels. Recently we have shown that another type of corn oil, "corn fiber oil" could be obtained from corn fiber, the outer portions of the corn kernel. Corn fiber oil contains very high levels of "phytosterols," compounds that have been shown to lower cholesterol in the blood of laboratory animals and humans. The current study demonstrated that when corn fiber oil is prepared in certain ways, it contains high levels of a second type of natural product, polyamines. Some types of polyamines have been shown to serve as natural fungicides or natural insecticides. Other types of polyamines have been demonstrated to be effective in the treatment of certain types of cancer. This first report of the presence of high levels of polyamines in corn should alert the scientific community that corn is a good source of polyamines, and should cause others to consider possible uses for these unusual compounds.
Technical Abstract: Extraction of corn bran or corn fiber with polar solvents such as methylene chloride, ethanol, or chloroform-methanol yielded common lipids and two unknown HPLC peaks, each with an UV absorbance maximum at 320 nm. HPLC-mass spectrometry revealed that the unknowns were diferuloylputrescine (DFP) and p-coumaroyl-feruloylputrescine (CFP). When compared to extracts of corn fiber (a pericarp enriched fraction from the wet milling of corn), comparable extracts of corn bran (a pericarp enriched fraction from the dry milling of corn) yielded 3 to 8-fold higher levels of DFP and CFP. Extraction of corn bran or fiber with an accelerated solvent extractor revealed that elevated temperatures greatly enhanced the extraction of DFP and CFP by methylene chloride and ethanol. "Corn bran oil," prepared by extraction of corn bran with hot methylene chloride contained 14 wt% DFP and 3 wt% CFP. However, when hexane was used as a solvent, accelerated solvent extraction of the corn bran or fiber did not extract any DFP or CFP. Extraction of wheat bran or psyllium hulls with hot methylene chloride did not yield any detectable DFP or CFP. Because it has been suggested that polyamine conjugates such as DFP and CFP may function as natural pesticides, a rapid method was developed to purify them so that their biological activity could be evaluated.