Browsing by Author "a1b2c98f-d48f-42a4-9568-a562d2085fe2"

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    • 1,4-benzoxazin-3-one, 2-benzoxazolinone and gallic acid from Calceolaria thyrsiflora Graham and their ... 
      Bravo, Héctor R.; Copaja, Sylvia V.; Figueroa-Duarte, Sebastián; Lamborot, Madeleine; San Martín, Joxsé (Verlag der Zeitschrift fur Naturforschung, 2005)
      Secondary metabolites, DIBOA, HBOA, 7-OH-HBOA, BOA and gallic acid, were isolated and quantified from Calceolaria thyrsiflora Graham, a native medicinal plant of Chile belonging to the Scrophulariaceae family. The highest ...
    • Accumulation of hydroxamic acids during wheat germination 
      Copaja, Sylvia V.; Nicol, Dave; Wratten, Steve D. (1999)
      Hydroxamic acids, quantified by HPLC, varied in concentration between three cultivars of wheat. Seeds, roots, leaves and the entire plants were analysed separately. No hydroxamic acids were present in seeds throughout the ...
    • Adsorption of fungicides in chilean soils incubated with biosolids 
      Copaja, Sylvia V.; Bravo, Héctor R.; Muñoz, Paola (Sociedad Chilena de Quimica, 2012)
      The efficiency of the adsorption process of the fungicides Captan and Thiram was studied in four Chilean soils from the VI [O'Higgins, (HGS)], VII [Talcarehue, (THL)], VIII [Diguillin, (DIG)] and Metropolitan [Maipo, (MAO)] ...
    • Antimicrobial Activity of Natural 2-Benzoxazolinones and Related Derivatives 
      Bravo, Héctor R.; Copaja, Sylvia V.; Lazo, Waldo (American Chemical Society, 1997)
      Natural 2-benzoxazolinones BOA and MBOA and related synthetic derivatives inhibited the growth of Staphylococcus aureus, Escherichia coli, and Candida albicans. Both the electrophilic character of the nitrogen atom of the ...
    • Changes in hydroxamic acid levels of wheat plants induced by aphid feeding 
      Niemeyer, Hermann M.; Pesel, Erika; Copaja, Sylvia V.; Bravo, Héctor R.; Franke, Stephan; Francke, Wittko (1989)
      Seedlings of four wheat cultivars were infested with Metopolophium dirhodum nymphs. After aphids had fed for 40 hr on the plants, the levels of the defense metabolite 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one had changed. ...
    • Chemical Basis for the Antifeedant Activity of Natural Hydroxamic Acids and Related Compounds 
      Bravo, Héctor R.; Copaja, Sylvia V.; Argandoña, Victor H. (2004)
      Natural hydroxamic acids and related compounds derived from the 1,4-benzoxazin-3-one structure show antifeedant activity against the aphid Rhopalosiphum padi. This antifeeding activity is based on the electrophilic character ...
    • Chemical basis for the phytotoxicity of N-aryl hydroxamic acids and acetanilide analogues 
      Bravo, Héctor R.; Villarroel, Elisa; Copaja, Sylvia V.; Argandoña, Victor H. (Verlag der Zeitschrift fur Naturforschung, 2008)
      Germination inhibition activity of N-aryl hydroxamic acids and acetanilide analogues was measured on lettuce seeds (Lactuca sativa). Lipophilicity of the compounds was determined by HPLC. A correlation between lipophilicity ...
    • Contents of 1,4-benzoxazin-3-ones and 2-benzoxazolinone from Stenandrium dulce (Nees) 
      Bravo, Héctor R.; Copaja, Sylvia V.; San Martín, José (Verlag der Zeitschrift fur Naturforschung, 2004)
      Secondary metabolites, DIBOA, HBOA, 7-OH-HBOA and BOA, were isolated and quantified from S. dulce (Nees), a native species in Chile belonging to the Acanthaceae family. The highest DIBOA and HBOA contents were determined ...
    • Hydroxamic acids accumulation by wheat callus 
      Zúñiga, Gustavo E.; Copaja, Sylvia V.; Bravo, Hector R.; Argandoña, Victor H. (1990)
      Hydroxamic acids were quantified by HPLC in leaves of one-week-old seedlings and in 30 day-old callus tissues of four wheat cultivars. Leaves accumulated preferentially 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA). ...
    • Relationships between salicylic acid content, phenylalanine ammonia-lyase (PAL) activity, and resistance ... 
      Chaman, Mercedes E.; Copaja, Sylvia V.; Argandoña, Victor H. (2003)
      It has been suggested that salicylic acid (SA) is a signal in acquired resistance to pathogens in several plants. Also, it has been suggested that infestation of plants causes an increase in the activity of phenylalanine ...