Phytochemistry and Preliminary Assessment of the Antibacterial Activity of Chloroform Extract ofAmburana cearensis(Allemão) A.C. Sm. againstKlebsiella pneumoniaeCarbapenemase-Producing Strains

Abstract

The chloroform extract of the stem bark ofAmburana cearensiswas chemically characterized and tested for antibacterial activity.The extract was analyzed by gas chromatography and mass spectrometry. The main compounds identified were 4-methoxy-3-methylphenol (76.7%), triciclene (3.9%),α-pinene (1.0%),β-pinene (2.2%), and 4-hydroxybenzoic acid (3.1%). Preliminary antibacterial tests were carried out against species of distinct morphophysiological characteristics:Escherichia coli,Salmonella entericaSerotype Typhimurium,Pseudomonas aeruginosa,Staphylococcus aureus,Listeria monocytogenes, andBacillus cereus. The minimum inhibitory concentration (MIC) was determinate in 96-well microplates for the chloroform extract and an analogue of themain compound identified, which was purchased commercially.We have shown that plant’s extract was only inhibitory (but not bactericidal) at the maximum concentration of 6900 μg/mL againstPseudomonas aeruginosaandBacillus cereus. Conversely, the analogue 2-methoxy-4-methylphenol produced MICs ranging from215 to 431 μg/mL against all bacterial species.New antibacterial assays conducted with such chemical compound againstKlebsiella pneumoniaecarbapenemase-producing strains have shown similarMICresults and minimumbactericidal concentration (MBC) of 431 μg/mL.We conclude thatA. cearensisis a good source of methoxy-methylphenol compounds,which could be screened for antibacterial activity againstmultiresistant bacteria fromdifferent species