title: Biological activities of ophiobolin K and 6-epi-ophiobolin K produced by the endophytic fungus Aspergillus calidoustus.
abstract: Endophytic fungi represent ubiquitous microbial organisms able to live in the tissues of different plants around the world and represent a prolific source of bioactive metabolites. In the present study, the endophytic fungus Aspergillus calidoustus was isolated from the medicinal plant Acanthospermum australe (Asteraceae), and identified using molecular, physiological and morphological methods. A methylene chloride crude extract of A. calidoustus has been produced and subjected to antifungal bioassay-directed fractionation which resulted in the isolation of the two bioactive compounds: ophiobolin K and 6-epi-ophiobolin K. These pure compounds displayed antifungal activity against fungal plant pathogens, protozoal activity against Trypanosoma cruzi, and cytotoxic activity against human tumoral cell lines. The results show that A. calidoustus was able to produce the antifungal and cytotoxic metabolites ophiobolin K and 6-epi-ophiobolin K, which may help the fungus to colonise and occupy the substratum as well as survive in natural environments.
authors: a Department of Microbiology , Federal University of Minas Gerais , Belo Horizonte , Brazil.
authors: Camila Rodrigues
authors: CR
authors: de Carvalho
authors: a Department of Microbiology , Federal University of Minas Gerais , Belo Horizonte , Brazil.
authors: Mariana de Lourdes Almeida
authors: Mde L
authors: Vieira
authors: b USDA-ARS, Natural Products Utilization Research Unit , Oxford , MS , USA.
authors: Charles L
authors: CL
authors: Cantrell
authors: b USDA-ARS, Natural Products Utilization Research Unit , Oxford , MS , USA.
authors: David E
authors: DE
authors: Wedge
authors: c Laboratory of Chemistry of Natural Products, Oswaldo Cruz Foundation , Belo Horizonte , Brazil.
authors: Tânia M A
authors: TM
authors: Alves
authors: c Laboratory of Chemistry of Natural Products, Oswaldo Cruz Foundation , Belo Horizonte , Brazil.
authors: Carlos Leomar
authors: CL
authors: Zani
authors: d Laboratory of Environmental Microbiology, Federal University of Tocantins , Palmas , Brazil.
authors: Raphael Sanzio
authors: RS
authors: Pimenta
authors: e Laboratory of Cellular and Molecular Parasitology, Oswaldo Cruz Foundation , Belo Horizonte , Brazil.
authors: Policarpo A
authors: PA
authors: Sales Junior
authors: e Laboratory of Cellular and Molecular Parasitology, Oswaldo Cruz Foundation , Belo Horizonte , Brazil.
authors: Silvane M F
authors: SM
authors: Murta
authors: e Laboratory of Cellular and Molecular Parasitology, Oswaldo Cruz Foundation , Belo Horizonte , Brazil.
authors: Alvaro J
authors: AJ
authors: Romanha
authors: a Department of Microbiology , Federal University of Minas Gerais , Belo Horizonte , Brazil.
authors: Carlos Augusto
authors: CA
authors: Rosa
authors: a Department of Microbiology , Federal University of Minas Gerais , Belo Horizonte , Brazil.
authors: Luiz H
authors: LH
authors: Rosa
mesh_terms: D000935:Antifungal Agents / Q000737:chemistry* / Q000302:isolation & purification; D000962:Antimalarials / Q000737:chemistry* / Q000302:isolation & purification; D000970:Antineoplastic Agents / Q000737:chemistry* / Q000302:isolation & purification; D001230:Aspergillus / Q000737:chemistry*; D019659:Asteraceae / Q000382:microbiology; D045744:Cell Line, Tumor; D006801:Humans; D054830:Sesterterpenes / Q000737:chemistry*
chemical_list: D000935:Antifungal Agents; D000962:Antimalarials; D000970:Antineoplastic Agents; D054830:Sesterterpenes; C002884:ophiobolins
keywords: Chagas' disease; cancer; endophytic fungi; secondary metabolites