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ARS Home » Southeast Area » Oxford, Mississippi » Natural Products Utilization Research » Research » Publications at this Location » Publication #319512
Title: Antifungal compounds from turmeric and nutmeg with activity against plant pathogens

Author
item RADWAN, MOHAMED - University Of Mississippi
item TABANCA, NURHAYAT - University Of Mississippi
item Wedge, David
item TARAWNEH, AMER - University Of Mississippi
item CUTLER, STEPHEN - University Of Mississippi

Submitted to: Fitoterapia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/21/2014
Publication Date: 8/27/2014
Publication URL: http://handle.nal.usda.gov/10113/62241
Citation: Radwan, M.M., Tabanca, N., Wedge, D.E., Tarawneh, A.H., Cutler, S.J. 2014. Antifungal compounds from turmeric and nutmeg with activity against plant pathogens. Fitoterapia. 99:341-346.

Interpretive Summary: Water distilled essential oils from the roots of Angelica dahurica and Angelica pubescentis were investigated for their antifungal activity against plant pathogens Colletotrichum acutatum, C. fragariae, and C. gloeosporioides as well as insecticidal activity against the yellow fever mosquito, Aedes aegypti and azalea lace bugs, Stephanitis pyrioides. Water distilled essential oils from the roots of Angelica dahurica and Angelica pubescentis were investigated for their antifungal activity against plant pathogens Colletotrichum acutatum, C. fragariae, and C. gloeosporioides as well as insecticidal activity against the yellow fever mosquito, Aedes aegypti and azalea lace bugs, Stephanitis pyrioides. Forty-three compounds, representing 92.1% of the A. dahurica total essential oil and 46 components, which made up 86.2% of the A. pubescentis total essential oil, were characterized. A. pubescentis root essential oil demonstrated moderate antifungal activity against Colletotrichum species, whereas A. dahurica root essential oil did not show antifungal activity. Conversely, A. dahurica root essential oil demonstrated deterrent and insecticidal activity against Ae. aegypti and azalea lace bugs, S. pyrioides. Chemical diversity appears to play a role in determining the antifungal and insecticidal activities of essential oils. Chemical diversity appears to play a role in determining the antifungal and insecticidal activities of essential oils.

Technical Abstract: The antifungal activity of twenty-two common spices was evaluated against plant pathogens using direct-bioautography coupled Colletotrichum bioassays. Turmeric, nutmeg, ginger, clove, oregano, cinnamon, anise, fennel, basil, black cumin, and black pepper showed antifungal activity against the plant pathogens Colletotrichum acutatum, Colletotrichum fragariae, and Colletotrichum gloeosporioides. Among the active extracts, turmeric and nutmeg were the most active and were chosen for further investigation. The bioassay-guided fractionation led to the isolation of three compounds from turmeric (1–3) and three compounds from nutmeg (4–6). Their chemical structures were elucidated by spectroscopic analysis including HR-MS, 1D, and 2D NMR as curcumin (1), demethoxycurcumin (2) and bisdemethoxy-curcumin (3), erythro-(7R,8R)-Delta 8'-4,7-dihydroxy-3,3',5'-trimethoxy-8-O-4'-neolignan (4), erythro-(7R,8R)-Delta8'-7-acetoxy-3,4,3',5'-tetra-methoxy-8-O-4'-neolignan (5), and 5-hydroxy-eugenol (6). The isolated compounds were subsequently evaluated using a 96-well microbioassay against plant pathogens. At 30 µM, compounds 2 and 3 possessed the most antifungal activity against Phomopsis obscurans and Phomopsis viticola, respectively.