title: Phytocompounds and modulatory effects of Anacardium microcarpum (cajui) on antibiotic drugs used in clinical infections.
abstract: BACKGROUND
  The challenge of antibiotic resistance and the emergence of new infections have generated considerable interest in the exploration of natural products from plant origins as combination therapy. In this context, crude ethanolic extract (CEE), ethyl acetate fraction (EAF), and methanolic fraction (MF) from Anacardium microcarpum were tested alone or in combination with antibiotics (amikacin, gentamicin, ciprofloxacin, and imipenem) against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.
  
  
  METHODS
  Antibiotic resistance-modifying activity was performed using the microdilution method by determining the minimal inhibitory concentration (MIC). In addition, phytochemical prospecting analyses of tested samples were carried out.
  
  
  RESULTS
  Our results indicated that all the extracts showed low antibacterial activity against multidrug-resistant strains (MIC =512 μg/mL). However, addition of CEE, EAF, and MF to the growth medium at the subinhibitory concentration (MIC/8=64 μg/mL) significantly modulated amikacin- and gentamicin-resistant E. coli 06. CEE and EAF also demonstrated a significant (P<0.001) synergism with imipenem against S. aureus. In contrast, MF antagonized the antibacterial effect of ciprofloxacin and gentamicin against P. aeruginosa 03 and S. aureus 10, respectively. Qualitative phytochemical analysis of the extracts revealed the presence of secondary metabolites including phenols, flavonoids, xanthones, chalcones, and tannin pyrogallates.
  
  
  CONCLUSIONS
  Taken together, our results suggest that A. microcarpum is a natural resource with resistance-modifying antibacterial activity that needs to be further investigated to overcome the present resistant-infection problem.
authors.affiliation: Departamento de Ciências Biológicas, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Regional do Cariri (URCA), Crato, CE, Brazil ; Programa de Pós-Graduação em Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Valter M
authors.initials: VM
authors.lastname: Barbosa-Filho
authors.affiliation: Programa de Pós-Graduação em Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Emily P
authors.initials: EP
authors.lastname: Waczuk
authors.affiliation: Departamento de Química Biológica, Centro de Ciências Biológicas e da Saúde (CCBS), Crato, CE, Brazil.
authors.forename: Nadghia F
authors.initials: NF
authors.lastname: Leite
authors.affiliation: Departamento de Ciências Biológicas, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Regional do Cariri (URCA), Crato, CE, Brazil.
authors.forename: Irwin R A
authors.initials: IR
authors.lastname: Menezes
authors.affiliation: Departamento de Ciências Biológicas, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Regional do Cariri (URCA), Crato, CE, Brazil.
authors.forename: José G M
authors.initials: JG
authors.lastname: da Costa
authors.affiliation: Departamento de Ciências Biológicas, Centro de Ciências Biológicas e da Saúde (CCBS), Universidade Regional do Cariri (URCA), Crato, CE, Brazil.
authors.forename: Sírleis R
authors.initials: SR
authors.lastname: Lacerda
authors.affiliation: Programa de Pós-Graduação em Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil.
authors.forename: Isaac A
authors.initials: IA
authors.lastname: Adedara
authors.affiliation: Laboratory of Microbiology and Molecular Biology, Universidade Regional do Cariri (URCA), Crato, CE, Brazil.
authors.forename: Henrique Douglas Melo
authors.initials: HD
authors.lastname: Coutinho
authors.affiliation: Campus São Gabriel, Universidade Federal do Pampa, São Gabriel, RS, Brazil.
authors.forename: Thais
authors.initials: T
authors.lastname: Posser
authors.affiliation: Programa de Pós-Graduação em Bioquímica Toxicológica, Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil ; Departamento de Bioquímica, Instituto de Ciências Básica da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: Jean P
authors.initials: JP
authors.lastname: Kamdem
mesh_terms: D031021:Anacardium / Q000737:chemistry*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects*; D004357:Drug Synergism; D004359:Drug Therapy, Combination; D004926:Escherichia coli / Q000187:drug effects; D008826:Microbial Sensitivity Tests; D010936:Plant Extracts / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D064210:Secondary Metabolism; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D010936:Plant Extracts
keywords: A. microcarpum; antibacterial activity; multidrug-resistant