title: The bioactivity of plant extracts against representative bacterial pathogens of the lower respiratory tract.
abstract: BACKGROUND
  Lower respiratory tract infections are a major cause of illness and death. Such infections are common in intensive care units (ICU) and their lethality persists despite advances in diagnosis, treatment and prevention. In Mexico, some plants are used in traditional medicine to treat respiratory diseases or ailments such as cough, bronchitis, tuberculosis and other infections. Medical knowledge derived from traditional societies has motivated searches for new bioactive molecules derived from plants that show potent activity against bacterial pathogens. Therefore, the aim of this study was to evaluate the effect of hexanic, chloroformic (CLO), methanolic (MET) and aqueous extracts from various plants used in Mexican traditional medicine on various microorganisms associated with respiratory disease.
  
  
  METHODS
  thirty-five extracts prepared from nine plants used in Mexican traditional medicine for the treatment of respiratory infections were evaluated against 15 control bacterial species and clinical isolates.
  
  
  RESULTS
  Both chloroformic (CLO) and methanolic (MET) extracts of Larrea tridentata were active against Methicillin-resistant S. aureus, B. subtilis and L. monocytogenes. A MET extract of L. tridentata was also active against S. aureus, S. pneumoniae, S. maltophilia, E. faecalis and H. influenzae and the CLO extract was active against A. baumannii. An Aqueous extract of M. acumitata and a MET extract of N. officinale were active against S. pneumoniae. CLO and MET extracts of L. tridentata were active against clinical isolates of S. aureus, S. pneumoniae and E. faecalis.
  
  
  CONCLUSIONS
  Overall, our results support the potential use of L. tridentata as a source of antibacterial compounds.
authors.affiliation: Departamento de Biología Molecular y Bioingeniería, UAM Reynosa Aztlán, Universidad Autónoma de Tamaulipas, Reynosa, Mexico. vbocanegg@yahoo.com
authors.forename: Virgilio
authors.initials: V
authors.lastname: Bocanegra-García
authors.forename: María
authors.initials: M
authors.lastname: Del Rayo Camacho-Corona
authors.forename: Mónica
authors.initials: M
authors.lastname: Ramírez-Cabrera
authors.forename: Gildardo
authors.initials: G
authors.lastname: Rivera
authors.forename: Elvira
authors.initials: E
authors.lastname: Garza-González