Actividad biológica de extractos de tres plantas sobre bacterias patógenas para el humano

Abstract

The citotoxicity of extracts and fractions obtained from three plants was determined, and their antibacterial activity was evaluated through a colorimetric assay with tetrazolium 3-(4,5-dimethilthiazol-2yl)-2,4-diphenilbromide (MTT)), using only innocuous concentrations in all the assays carried out. The MIC was determined by the MTT micro dilution assay, and the activity of the possible antimicrobial agents by the Kirby-Bauer agar diffusion test. The MIC of a methanol extract from Couepia paraensis, and a dichloromethanol/ethanol from Parinari sprucei over S. aureus was 25 μg/mL, while the MIC with the ethanol extract from P. sprucei was 50 μg/mL. The MIC of fraction 19 of Lantana camara L. over A. haemolyticus and S. aureus was 50 μg/mL. The inhibition halos obtained with the C. paraensis methanol extracts, and the P. sprucei over S. aureus dichloromethanol/methanol and ethanol extract, were 8, 9 and 7 mm respectively. The Verbenaceae family extracts did not present any antibacterial activity, while those of the Chrysobalanaceae family inhibited replication of gram positive bacteria.