Antibacterial activity against antibiotic-resistant Gram negative human pathogenic bacteria of hydroxychalcone isolated from Zuccagnia punctata Cav

ZAMPINI I.C., VATTUONE M., ISLA M.I.

JOURNAL OF ETHNOPHARMACOLOGY

Elsevier

Lugar: Europa; Año: 2005 vol. 102 p. 450 - 456

0378-8741

The present study was conducted to investigate antibacterial activity of Zuccagnia punctata ethanolic extract against 47 strains of antibiotic-resistant Gram negative bacteria and to identify bioactive compounds. Inhibition of bacterial growth was investigated using agar diffusion, agar macrodilution, broth microdilution and bioautographic methods. Z. punctata extract was active against all assayed bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens, Morganella morganii, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia) with minimal inhibitory concentration (MIC) values ranging from 25 to 200 µg/mL. Minimal bactericidal concentration (MBC) values were identical or twofold higher than the corresponding MIC values. Contact bioautography, indicated that Z. punctata extracts possess one major antibacterial component against P. aeruginosa and at least three components against K. pneumoniae and E. coli. Activity-guided fractionation of the ethanol extract on a silica gel column yielded a compound (2’,4’-dihydroxychalcone) which exhibited strong antibacterial activity with MIC values between 0.10 and 1.00 µg/mL for P. mirabilis, E. cloacae, S. marcescens, M. morganii, A. baumannii, P. aeruginosa, S. maltophilia. These values are lower than imipenem (0.25 to 16 µg/mL). Z. punctata might provide promising therapeutic agents against infections with multiresistant Gram negative bacteria.