title: Antifungal compounds from turmeric and nutmeg with activity against plant pathogens.
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)-Δ(8')-4,7-dihydroxy-3,3',5'-trimethoxy-8-O-4'-neolignan (4), erythro-(7R,8R)-Δ8'-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.
authors.affiliation: National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS 38677, USA.
authors.forename: Mohamed M
authors.initials: MM
authors.lastname: Radwan
authors.affiliation: National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS 38677, USA.
authors.forename: Nurhayat
authors.initials: N
authors.lastname: Tabanca
authors.affiliation: United States Department of Agriculture, Agricultural Research Service, Natural Products Utilization Research Unit, The University of Mississippi, University, MS 38677, USA.
authors.forename: David E
authors.initials: DE
authors.lastname: Wedge
authors.affiliation: Department of Medicinal Chemistry, School of Pharmacy, The University of Mississippi, University, MS 38677, USA.
authors.forename: Amer H
authors.initials: AH
authors.lastname: Tarawneh
authors.affiliation: National Center for Natural Products Research, School of Pharmacy, The University of Mississippi, University, MS 38677, USA; Department of Medicinal Chemistry, School of Pharmacy, The University of Mississippi, University, MS 38677, USA. Electronic address: cutler@olemiss.edu.
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Cutler
mesh_terms: D001203:Ascomycota / Q000187:drug effects; D020231:Colletotrichum / Q000187:drug effects; D030024:Curcuma / Q000737:chemistry*; D005659:Fungicides, Industrial / Q000737:chemistry* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D026323:Myristica / Q000737:chemistry*
chemical_list: D005659:Fungicides, Industrial
keywords: Antifungal; Curcuminoids; Neolignans; Nutmeg; Plant pathogens; Spices; Turmeric