Antimicrobial Activity of Three Species of Verbeneceae Family

PÉREZ ZAMORA, CRISTINA; TORRES, CAROLA; VONKA, CARLOS; AGUADO, MARÍA INÉS; NUÑEZ, MARÍA BEATRIZ

Rosario

Congreso; 2° Reunión Internacional de Ciencias Farmacéuticas; 2012

Departamento Farmacia, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario y Departamento de Farmacia, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba

Verbenaceae family has 34 genera and 1175 species of which 26 genera and 191 species live in Argentina. This family includes genera that are grown as ornamentals and other species provide essential oils, gums and tannins (1). Lippia alba (Mill.) N. E. Brown (salvia morada) is used in folk medicine to treat digestive disorders, upper respiratory ailments (colds, coughs and bronchitis) also like sedative and anti-inflammatory. Its essential oil has antimicrobial activity (2). Lippia turbinata (Griseb.) (poleo) is used for digestive disorders, as a diuretic, emmenagogue, abortifacient, in dyspepsia, dysmenorrhea and oliguria, with anti-inflammatory and hypotensive dose-dependent and antimicrobial activity (2, 3). Aloysia polystachya (Griseb.) Mold. (burrito) leaves are used in folk medicine to treat digestive disorders, liver troubles and as a sedative. (4-6) The aim of this work was to evaluate the antimicrobial activity of hidroalcoholic extract of leaves of L. alba, L. turbinata and A. polystachya against pathogenic bacteria. The powdered samples of plants were extracted with ethanol of 70° by percolation. Then these extracts were filtered and stored at -20 °C. Antimicrobial activity was assayed with agar disk diffusion method. Ampicillin and gentamicin were used as positive controls. The microorganisms tested were: Staphylococcus aureus ATCC 29213, S. aureus ATCC 25923, S. epidermidis ATCC 12228, Enterococcus faecalis ATCC 29212, E. coli ATCC 35218 and Pseudomonas aeruginosa ATCC 27853 and clinical isolates of S. aureus provided by a service of publish health. Bioautography was developed by the Nieva-Moreno et al. technique (1999) using thin-layer chromatography with chloroform-methanol (9:1) as solvent system. The plates were covered with brain–heart infusion medium (BHI) containing 105 CFU of S. aureus ATCC 25923 and P. aeruginosa ATCC 27853, it was incubated at 35 °C for 16-20 hours. The plates were sprayed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium solution (MTT). Thin-layer chromatography used silica gel G60 F254 sheets and the same solvent system in bioautography. The UV-active compounds were detected at UV light and revealed with ammonia vapors and NP reagent and compared to reference publications (7, 8). The disk diffusion method demonstrated that the mentioned ethanolic extracts were active against Gram-positive. The different strains of S. aureus and S. epidermidis showed equal halos or superior to 10 mm and it was considered significant for antimicrobial activity. The bioautography showed the reduction of MTT salt with a yellow color in the inhibition of microbial growth areas. The assays revealed three to five bands with microbial growth inhibition and could correspond to components of flavones and free flavonols 3’ and 3’4’ hydroxylated. The three assayed extracts showed antimicrobial activity and the same would be related to some flavonoids components. Our group is working to confirm the identification of these components with other analytical techniques specific.