title: Anti-infective effects of Brazilian Caatinga plants against pathogenic bacterial biofilm formation.
abstract: BACKGROUND
  The local communities living in the Brazilian Caatinga biome have a significant body of traditional knowledge on a considerable number of medicinal plants used to heal several maladies.
  
  
  OBJECTIVE
  Based on ethnopharmacological data, this study screened 23 aqueous plant extracts against two well-known models of biofilm-forming bacteria: Staphylococcus epidermidis and Pseudomonas aeruginosa.
  
  
  METHODS
  Crystal violet assay and scanning electron microscopy (SEM) were used to evaluate the effect of extracts on biofilm formation and measurements of the absorbance at 600 nm to assess bacterial growth. Selected extracts were investigated regarding the cytotoxicity by MTT assay using mammal cells and the qualitative phytochemical fingerprint by thin layer chromatography.
  
  
  RESULTS
  Harpochilus neesianus Mart. ex Nees. (Acanthaceae) leaves, Apuleia leiocarpa Vogel J. F. Macbr. (Fabaceae), and Poincianella microphylla Mart. ex G. Don L. P. Queiroz (Fabaceae) fruits showed non-biocidal antibiofilm action against S. epidermidis with activities of 69, 52, and 63%, respectively. SEM confirmed that biofilm structure was strongly prevented and that extracts promoted overproduction of the matrix and/or bacterial morphology modification. Poincianella microphylla demonstrated toxicity at 4.0 mg/mL and 2.0 mg/mL, A. leiocarpa presented toxicity only at 4.0 mg/mL, whereas H. neesianus presented the absence of toxicity against Vero cell line. Preliminary phytochemical analysis revealed the presence of flavonoids, terpenoids, steroids, amines, and polyphenols.
  
  
  CONCLUSIONS
  This work provides a scientific basis which may justify the ethnopharmacological use of the plants herein studied, indicating extracts that possess limited mammal cytotoxicity in vitro and a high potential as a source of antibiofilm drugs prototypes.
authors.affiliation: Centro de Biotecnologia do Estado do Rio Grande do Sul, Porto Alegre, Universidade Federal do Rio Grande do Sul , Porto Alegre, Rio Grande do Sul , Brazil .
authors.forename: Laura Nunes
authors.initials: LN
authors.lastname: Silva
authors.forename: Danielle da Silva
authors.initials: Dda S
authors.lastname: Trentin
authors.forename: Karine Rigon
authors.initials: KR
authors.lastname: Zimmer
authors.forename: Janine
authors.initials: J
authors.lastname: Treter
authors.forename: Clara Lia Costa
authors.initials: CL
authors.lastname: Brandelli
authors.forename: Amanda Piccoli
authors.initials: AP
authors.lastname: Frasson
authors.forename: Tiana
authors.initials: T
authors.lastname: Tasca
authors.forename: Alexandre Gomes
authors.initials: AG
authors.lastname: da Silva
authors.forename: Márcia Vanusa
authors.initials: MV
authors.lastname: da Silva
authors.forename: Alexandre José
authors.initials: AJ
authors.lastname: Macedo
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D001938:Brazil; D002522:Chlorocebus aethiops; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D010946:Plants, Medicinal; D011550:Pseudomonas aeruginosa / Q000187:drug effects* / Q000502:physiology; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000502:physiology; D014709:Vero Cells
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts
keywords: Antibiofilm; antibacterial; cytotoxicity; medicinal plants