Publication Date: 2013.
Currently, there is a pressing need for novel antibacterial agents against drug-resistant bacteria, especially those which have been common in our communities and hospitals, such as methicillin-resistant Staphylococcus aureus (MRSA). The South American plant Achyrocline satureioides (Marcela) has been widely used in traditional medicine for a number of diseases, including infections. Several crude extracts from this plant have shown good antimicrobial activities in vitro. In the search for the active principle (s) that confers these antimicrobial activities, we have processed the dichloromethane extract from the aerial parts of the plant. One of the isolated compounds showed extraordinary antibacterial activities against a set of clinically relevant Gram-positive strains that widely differ in their antibiogram profiles. This compound was identified as achyrofuran on the basis of its spectroscopic and physical data.<br />We determined the MIC to be around 0.1 M (0.07 g/ml) for the reference methicillin-resistant and<br />vancomycin-intermediate S. aureus strain NRS402. Moreover, nanomolar concentrations of achyrofuran killed 10 6 bacteria within 12 h. Based on the presence of the 2,2-biphenol core, we further studied whether achyrofuran killed bacteria through a mechanism of action similar to that reported for the naturally occurring antibiotic MC21-A. Indeed, we found that achyrofuran was not bacteriolytic by itself although it greatly compromised membrane impermeability as determined by increased SYTOX Green uptake.
Author affiliation: Casero, Carina Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Rio Cuarto; Argentina. Universidad de la Laguna; España
Author affiliation: Estévez-Braun, Ana. Universidad de la Laguna; España. Instituto Canario de Investigación del Cáncer; España
Author affiliation: Gutiérrez Ravelo, Ángel. Universidad de la Laguna; España. Instituto Canario de Investigación del Cáncer; España
Author affiliation: Demo, Mirta. Universidad Nacional de Rio Cuarto; Argentina
Author affiliation: Méndez Alvarez, Sabastián. Universidad de la Laguna; España. Hospital Universitario Nuestra Señora de Candelaria; España
Author affiliation: Machin, Félix. Hospital Universitario Nuestra Señora de Candelaria; España
Repository: CONICET Digital (CONICET). Consejo Nacional de Investigaciones Científicas y Técnicas