Evaluation of the antibacterial activity of different extractive forms of Guayacán ritidome

SGARIGLIA, M.A.; SOBERÓN, J.R; QUIROGA E.N.; SAMPIETRO, D.A.; VATTUONE, M.A.

Molecular Medicinal Chemistry

Idecefyn

Lugar: Buenos Aires. Argentina; Año: 2006 vol. 11 p. 21 - 23

1666-888X

The phytochemical research based on ethnopharmacologic data is an effective approach for the discovery of new metabolites with possible application as antimicrobials. Popular wisdom atributes to Caesalpinia paraguariensis, also called ‘Guayacán’, vulnerary properties, among others. The aim of this study is to evaluate the antibacterial activity of Caesalpinia paraguariensis extracts and validate the medicinal use of this argentinian native tree. Aqueous extracts, infusion and decoction were prepared (10 %, w/v) from powered ritidoma according to the Pharmacopeia. The antibacterial activity of these extracts was evaluated on ATCC strains, using the agar dilution method and microdilution test. MIC and MBC were determined.  The macrodilution test showed that the three extracts of C. paraguariensis were active on all tested bacterial species, and provided orientative data concerning effective extract concentrations for each bacterial species. The results of the microdilution test indicated how potent the extracts were against bacteria. The ranges of MIC and MBC values were: infusion 39.76-634.25 and 79.53-1,272; decoction 78.28-1,252 and 78.28-1,252; tincture 30.7-982.5 and 61.4-491.25; respectively. Antibacterial power varied according to the considered species. Aqueous extracts showed similar MIC values, which suggested a similar composition. When evaluating the MIC values of the positive controls, amoxiciline and ciprofloxacine, most Gram negative tested species, were resistant to amoxiciline. P. mirabilis (F304) and P. aeruginosa (F305) were resistant to ciprofloxacine while plant extracts showed an overwhelming activity on this latter group. Gram-positive species were more susceptible to the extracts than Gram-negative species, likewise against amoxiciline, and in general were very sensitive to ciprofloxacine.Our results suggest that the antibacterial properties of the extracts may have potential uses as antiinfectious agents and preservatives of medicines and food.