Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2006
Publication Date: 2/16/2006
Citation: Sobolev, V.S., Deyrup, S.T., Gloer, J.B. 2006. New peanut (arachis hypogaea) phytoalexin with stilbene and but-2-enolide moieties. Journal of Agricultural and Food Chemistry. 54(6:2111-2115.
Interpretive Summary: Peanut is a worldwide economically important crop. Peanuts are often infected by the fungi Aspergillus flavus and A. parasiticus and, as the result, become contaminated with the carcinogenic aflatoxins. Peanuts can resist fungal infection by producing antifungal compounds called phytoalexins. Knowledge of the role of phytoalexins in peanuts is limited and cannot explain why the antifungal activity of known phytoalexins does not fully correlate with peanut resistance to fungal infection. This suggests that other, yet unidentified compounds may be involved in peanut resistance. The purpose of this work was to search for new substances that may serve as peanut phytoalexins together with known compounds. As the result of this research, a new pigmented compound, termed SB-1, has been isolated and characterized by modern spectroscopic methods. SB-1 is accumulated in peanuts at high concentrations in response to a fungal attack and may be an important representative of a new class of peanut phytoalexins.
Technical Abstract: A new pigmented, optically active, low-molecular weight metabolite has been isolated from peanut (Arachis hypogaea) kernels challenged by a soil fungal isolate. The structure of the new compound, termed SB-1, was elucidated by analysis of 1H NMR, 13C NMR, and mass spectral data. The SB-1 molecule bears stilbene and but-2-enolide moieties and represents an unusual class of compounds. The closest known analog to SB-1 was isolated from heartwood of Pericopsis elata. Both A. hypogaea and P. elata belong to the family Leguminosae. The new metabolite is accumulated in different peanut genotypes challenged by different fungal species and may be an important representative of a new class of peanut phytoalexins. SB-1 production often exceeds production of major known stilbenes.