Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/28/2008
Publication Date: 6/17/2008
Citation: Cantrell, C.L., Case, B.P., Mena, E., Kniffin, T.M., Duke, S.O., Wedge, D.E. 2008. Isolation and Identification of Antifungal Fatty Acids from the Basidiomycete Gomphus floccosus. Journal of Agricultural and Food Chemistry. 56:5062-5068. Interpretive Summary: Evolved microbial resistance to commercially available agrochemicals has led to a need for new pesticides. Furthermore, the desire for safe and more effective agrochemicals with reduced environmental and/or mammalian toxicity remains important. Natural product-based pesticides offer advantages, in that some can be specific towards a target species, and they often have unique modes of action with little mammalian toxicity. An additional benefit is that they generally have a relatively short environmental half life compared to synthetic pesticides. Our current research efforts are directed towards identifying natural product-based fungicides. The fruiting bodies of Gomphus floccosus (Schw.) Singer was investigated because preliminary screening data indicated the presence of fungitoxic compounds against the plant pathogens Colletotrichum fragariae, C. gloeosporioides, and C. acutatum. Three bioactive compounds were isolated, characterized, and evaluated for their antifungal activity.
Technical Abstract: Bioassay-guided fractionation of an ethyl acetate crude extract of the fruiting bodies of Gomphus floccosus (Schw.) Singer was performed because preliminary screening data indicated the presence of fungitoxic compounds against the plant pathogens Colletotrichum fragariae, C. gloeosporioides, and C. acutatum. Fractionation was directed using bioautography methods, resulting in the isolation of the bioactive fatty acids (10E,12Z)-9-hydroxy-10,12-octadecadienoic acid (1), (9E,11Z)-13-oxo-9,11-octadecadienoic acid (2), and (10E,12E)-9-oxo-10,12-octadecadienoic acid (3). These three fatty acids were evaluated for activity against a greater range of fungal plant pathogens (C. fragariae, C. gloeosporioides, C. acutatum, Botrytis cinerea, Fusarium oxysporum, Phomopsis abscurans and P. viticola) in a growth inhibition bioassay at 45, 90, and 145 uM.