Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2009
Publication Date: 12/18/2009
Citation: Sobolev, V.S., Neff, S.A., Gloer, J.B. 2009. New Dimeric Stilbenoids from Fungal-Challenged Peanut (Arachis hypogaea) Seeds. Journal of Agricultural Food & Chemistry. 58(2):875-881. Interpretive Summary: In response to fungal infection, under favorable conditions peanuts can produce defensive chemicals, so called phytoalexins. However, despite considerable progress in peanut research, relatively little is known about other aspects of peanut phytochemistry. Detailed knowledge of peanut plant chemistry, particularly knowledge regarding phytoalexin production, may help to reveal mechanisms of peanut disease and/or pest resistance. It is conceivable that such mechanisms could be manipulated to improve early natural field resistance of the plant to pests. In addition, the potential medical importance or health benefits of phytoalexins from peanuts have been acknowledged by several researchers. Our previous investigations of the peanut plant ability to produce phytoalexins revealed production of unidentified compounds. Those compounds were suggested to be new peanut defensive phytoalexins as they were only produced by infected peanut seeds. The structures of two new isolated compounds were deduced by modern spectroscopic means. As no reference to these compounds was found in the literature, they were considered new natural compounds and were termed arahypin-6 and arahypin-7. Both compounds were synthesized from corresponding monomeric, simple units. The synthetic compounds were similar to the natural compounds in every respect. New compounds may play a protective role against fungi and may represent a new class of peanut phytoalexins. Investigation of biological activity of the new compounds is planned.
Technical Abstract: Two new prenylated stilbene dimers named arahypin-6 and arahypin-7 have been isolated from wounded peanut seeds challenged by an Aspergillus caelatus strain. The structures of these new putative phytoalexins were determined by analysis of NMR, MS, and UV spectral data. Together with other known peanut stilbenoids that were also produced in the challenged seeds, these new compounds may play a defensive role against invasive fungi.