Browsing by Author "Armstrong, Veronica"

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    Characterization of the Fungitoxic Activity on Botrytis cinerea of N-phenyl-driman-9-carboxamides
    (2021) Melo, Ricardo; Armstrong, Veronica; Navarro, Freddy; Castro, Paulo; Mendoza, Leonora; Cotoras, Milena
    A total of 12 compounds were synthesized from the natural sesquiterpene (-) drimenol (compounds 4 to 15). The synthesized compounds corresponded to N-phenyl-driman-9-carboxamide derivatives, similar to some fungicides that inhibit the electron-transport chain. Their structures were characterized and confirmed by H-1 NMR, C-13 NMR spectroscopy, and mass spectrometry. Compounds 5 to 15 corresponded to novel compounds. The effect of the compounds on the mycelial growth of Botrytis cinerea was evaluated. Methoxylated and chlorinated compounds in the aromatic ring (compounds 6, 7, 12, and 13) exhibited the highest antifungal activity with IC50 values between 0.20 and 0.26 mM. On the other hand, the effect on conidial germination of B. cinerea of one methoxylated compound (6) and one chlorinated compound (7) was analyzed, and no inhibition was observed. Additionally, compound 7 decreased 36% the rate of oxygen consumption by germinating conidia.
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    New cyclic acetals related to Ambergris and their olfactory evaluation
    (SAGE PUBLICATIONS LTD, 2006) Benites, Julio; Armstrong, Veronica; Cortes, Manuel
    Hemisyntheses of cyclic acetals (11-18) were performed using (-)-polygodial and (+)-confertifolin as chiral starting materials. The acetals obtained were evaluated for their odoriferous properties.
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    Trypanosoma cruzi: Activities of lapachol and alpha- and beta-lapachone derivatives against epimastigote and trypomastigote forms
    (PERGAMON-ELSEVIER SCIENCE LTD, 2008) Salas, Cristian; Tapia, Ricardo A.; Ciudad, Karina; Armstrong, Veronica; Orellana, Myriam; Kemmerling, Ulrike; Ferreira, Jorge; Maya, Juan Diego; Morello, Antonio
    Derivatives of natural quinones with biological activities, such as lapachol, alpha- and beta-lapachones, have been synthesized and their trypanocidal activity evaluated in vitro in Trypanosoma cruzi cells. All tested compounds inhibited epimastigote growth and trypomastigote viability. Several compounds showed similar or higher activity as compared with current trypanocidal drugs, nifurtimox and benznidazole. The results presented here show that the anti-T Cruzi activity of the alpha-lapachone derivatives can be increased by the replacement of the benzene ring by a pyridine moiety. Free radical production and consequently oxidative stress through redox cycling or production of electrophilic metabolites are the potential biological mechanism of action for these synthetic quinones. (c) 2007 Elsevier Ltd. All rights reserved.