Article

Phytotoxic constituents from Nimbya alternantherae

Depto Fitopatologia, Universidade Federal de Viçosa, 36571-000 Viçosa, MG, Brazil
Biochemical Systematics and Ecology (Impact Factor: 1.17). 11/2006; 34(11):790-795. DOI: 10.1016/j.bse.2006.06.008

ABSTRACT A phytotoxic compound identified as 6-(3,3-dimethylallyloxy)-4-methoxy-5-methylphthalide (1), was isolated from the phytopathogenic fungus Nimbya alternantherae, cultivated on solid media. Catalytic hydrogenation of 1 resulted in the quantitative formation of second compound (2). Both compounds (1, 2) act by inhibiting the ATP synthesis in spinach thylakoids. A detailed investigation on the mechanism of action indicates that compound 1 acts as a Hill reaction inhibitor and uncoupler of photosynthesis.

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    • "Initially, aliquots of culture filtrates, mycelium or colonized solid media are extracted using solvents of different polarities followed by phytotoxicity assays of the obtained organic extracts for selecting the solvent best capable of most efficiently extracting the phytotoxins. If phytotoxicity is observed for more than one organic extract, extraction of the material can be performed using solvents in order of increasing polarity, thereby allowing an initial fractionation of the phytotoxic metabolites (Maiero et al., 1991; Demuner et al., 2006; Berestetskiy et al., 2010). When seeking to improve the efficiency of extraction from culture filtrates, the volume of the filtrates is commonly reduced before organic extractions. "
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    • "Initially, aliquots of culture filtrates, mycelium or colonized solid media are extracted using solvents of different polarities followed by phytotoxicity assays of the obtained organic extracts for selecting the solvent best capable of most efficiently extracting the phytotoxins. If phytotoxicity is observed for more than one organic extract, extraction of the material can be performed using solvents in order of increasing polarity, thereby allowing an initial fractionation of the phytotoxic metabolites (Maiero et al., 1991; Demuner et al., 2006; Berestetskiy et al., 2010). When seeking to improve the efficiency of extraction from culture filtrates, the volume of the filtrates is commonly reduced before organic extractions. "
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    • "Burvenich), two of Chenpodiaceae (Beta vulgaris L. and Spinocia oleracea L.) and one of the Portulacaceae (Portulaca halimoides L.) (Pomella et al., 2007). This fungus thus has potential as a useful biological control agent of A. philoxeroides (Gilbert et al., 2005; Demuner et al., 2006; Cox, 2011). However, intensive studies are still needed on the environmental impact and application technology on the efficiency of N. alternantherae as a mycoherbicide for the problems caused by this weed. "
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