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United States Department of Agriculture

Agricultural Research Service

Research Project: DISCOVERY OF ANTIFUNGAL COMPOUNDS FROM LOW VALUE/UNDERUTILIZED CROPS AND CROP CO-PRODUCTS

Location: Food and Feed Safety Research

2007 Annual Report


1a.Objectives (from AD-416)
Enhance value and utilization of low value/underutilized crops and crop co-products through discovery and purification of novel, constituent antifungal compounds and determine commercial potential of discovered antifungals.


1b.Approach (from AD-416)
Barley and cotton 3-day old cotyledons will be extracted aqueously as will okra fruit and peanut and rice hulls. Filtered, freeze-dried extracts will be tested for fungicidal properties. Active compounds will be purified by HPLC/MS and activity monitored with bioassays using Aspergillus flavus and Fusarium oxysporum. NMR will determine chemical structure of antifungal compounds. Novel compounds will be patented and all active compounds will be tested for their antifungal spectra of activity. Commercial potential of compounds as agricultural fungicides and medical antifungals will be determined by collaborators. Discovered protein antifungals will be cloned. Construct genes will be incorporated into gene expression systems to obtain a protective effect against fungal pathogens.


3.Progress Report
Under a Non-Funded Cooperative Agreement between ARS and Louisiana State University (LSU) (6435-41000-097-01N) research was conducted to discover whether plant extracts studied for fungicidal properties might have anti-insect potential. During FY 2006 a number of plants were sent to collaborators at LSU for prelimary assays against the riceborer. Plants extracted included cayenne and bay leaf. Nether of these extracts showed promise. Due to negative results additional plant extracts have not been provided.

Under a second Non-Funded Cooperative Agreement between ARS and LSU (6435-41000-097-02N) research was conducted to discover novel fungicides produced by Asian plants. One experimental protocol initially tests crude plant extracts for fungicidal properties. One such extract, code name ARW, was found to contain a potent fungicide.


4.Accomplishments
Since fungi can develop resistance to fungicides, the need exists to discover novel, safe, and potent fungicides. We are exploring plants since they have had to develop such compounds to combat infections caused by the microorganisms in their environments.

a) CAY-1 synergy studies, status of other tested plant fungicides. -- In our lab, we discovered that silver is a potent fungicide, but its activity against Aspergillus and Fusarium is enhanced with pure CAY-1 (our patented fungicide from cayenne pepper). Ethylene diamine tetraacetic acid (EDTA) was not synergistic with CAY-1 against these fungi. Bay leaf extracts contain a potent fungicide that is active against Fusarium. We have semipurified the compound, but final purification was not achieved. (National Program 306, Component 1, Problem statement 1.1.1; Crude extraction and initial determination of active agent; and Problem statement 1.1.2; Purification of fungicidal compound)

b) CAY-1 collaborative studies. -- Our patented plant fungicide, CAY-1, continues to be studied both in our lab and that of collaborators. Initial studies by USDA, ARS collaborators (Mosquito and Fly Research Unit, Gainesville, FL) showed that pure CAY-1 kills mosquito larva species (weak activity against Aedes aegypti and Culex quinquefasciatus; strong activity against Anopheles albimanus), but does not kill A. aegypti adults. Our crude bay leaf extract, which has fungicidal properties, was also found to kill A. aegypti mosquito adults. Collaborators at Children’s Hospital (New Orleans) initiated studies of CAY-1 efficacy against the human pathogens, Cryptococcus and Candida species. (National Program 306, Component 2, Determination of commercial potential of discovered antifungal compounds)


5.Significant Activities that Support Special Target Populations
None.


6.Technology Transfer

Number of active CRADAs and MTAs2
Number of non-peer reviewed presentations and proceedings2

Review Publications
De Lucca II, A.J. 2007. Harmful fungi in both agriculture and medicine. Revista Iberoamericana De Micologia. 24:3-13.

De Lucca II, A.J., Bland, J.M., Boue, S.M., Vigo, C.B., Cleveland, T.E., Walsh, T.J. 2006. Synergism of Cay-1 with amphotericin B and itraconazole. Chemotherapy. 52:285-287.

Last Modified: 8/19/2014
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