title: Biologically active tetranorditerpenoids from the fungus Sclerotinia homoeocarpa causal agent of dollar spot in turfgrass.
abstract: Nine new tetranorditerpenoid dilactones (2-10), together with two previously reported norditerpenoids dilactones (1, 11), and two known putative biosynthetic intermediates, oidiolactone-E (12) and 13, were isolated from an ethyl acetate extract of a culture medium of Sclerotinia homoeocarpa. Structures and absolute configurations of these compounds were determined by spectroscopic methods and confirmed by X-ray crystallographic analysis of representative compounds. Compounds were evaluated for herbicidal, antiplasmodial, and cytotoxic activities. Compounds 1, 2, 6, 7, and 11 were more active as growth inhibitors in a duckweed bioassay (I(50) values of 0.39-0.95 microM) than more than half of 26 commercial herbicides previously evaluated using the same bioassay. Some of these compounds exhibited strong antiplasmodial activities as well, but they also had cytotoxic activity, thus precluding them as potential antimalarial agents.
authors.affiliation: National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, and Department of Medicinal Chemistry, School of Pharmacy, University of Mississippi, University, Mississippi 38677, USA.
authors.forename: H M T Bandara
authors.initials: HM
authors.lastname: Herath
authors.forename: Wimal H M W
authors.initials: WH
authors.lastname: Herath
authors.forename: Paulo
authors.initials: P
authors.lastname: Carvalho
authors.forename: Shabana I
authors.initials: SI
authors.lastname: Khan
authors.forename: Babu L
authors.initials: BL
authors.lastname: Tekwani
authors.forename: Stephen O
authors.initials: SO
authors.lastname: Duke
authors.forename: Maria
authors.initials: M
authors.lastname: Tomaso-Peterson
authors.forename: N P Dhammika
authors.initials: NP
authors.lastname: Nanayakkara
mesh_terms: D000962:Antimalarials / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D000972:Antineoplastic Agents, Phytogenic / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D001203:Ascomycota / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology*; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006801:Humans; D008922:Mississippi; D008968:Molecular Conformation; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D010963:Plasmodium falciparum / Q000187:drug effects*; D006109:Poaceae / Q000382:microbiology*
chemical_list: D000962:Antimalarials; D000972:Antineoplastic Agents, Phytogenic; D004224:Diterpenes