Judith Velasco

Chemical Composition and Antibacterial Activity of the Essential Oil of Coleus amboinicus Lour., Against Enteric Pathogens

Abstract The chemical composition of the essential oil from the leaves of Coleus amboinicus Lour., an aromatic shrub with ethnobotanical uses was analyzed by GC-FID and GC-MS. Fifteen components were identified by GC-MS and carvacrol (65.2 %)was found to be the major constituent. The essential oil showed antibacterial activity against important enteric pathogens (Salmonella sp., Shigella sp., diarrheagenic Escherichia coli and Vibrio sp.), with MIC values of 10 μg/ml.

Composition and in vitro Antibacterial Activity of Essential Oil of Oyedaea verbesinoides D.C. from Venezuela

Abstract The essential oil of Oyedaea verbesinoides D.C. (Asteraceae), obtained by hydro-distillation, was analysed by gas chromatography-mass spectrometry (GC-MS) and evaluated for antimicrobial activity. Twenty seven components accounting for 98.9 % of the oil were identified. The most abundant components were β-caryophyllene (27.1 %), germacrene D (24.4 %), eugenol (9.3 %), bicyclogermacrene (6.0 %) and α-pinene (5.7 %). The oil of Oyedaea verbesinoides showed to be active against Staphylococcus aureus.

Chemical composition and antibacterial activity of Piper lenticellosum C.D.C essential oil collected in Ecuador

The essential oil of the leaves and spikes of Piper lenticellosum C. DC. (Piperaceae) was isolated by hydrodistillation and analyzed by GC/MS. A yield of 2.06 % was obtained. Twenty eight components were identified by comparison of their mass spectra with Wiley GC-MS library data and the retention indices (RI) calculated for every compounds. The major constituents were Piperitone (33.97 %), 1,8 cineole (11.92 %), limonene (11.07 %), safrole (8.18 %) and alpha-pinene (4.49 %). Antibacterial activity of the essential oil was evaluated against five important human pathogenic bacterial strains using the disk diffusion agar method. The results showed at moderate activity against Staphylococcus aureus ATCC (25923), Escherichia coli ATCC (25922) and Klebsiella pneumoniae ATCC (233357) with minimal inhibitory concentration (MIC) values of 100, 200 y 300 µL/mL, respectively. According to the literature consulted, this is the first report on chemical composition and antibacterial activity of the essential oil of Piper lenticelosum C. DC. from Ecuador.

Construcción de mutantes de Salmonella enterica por inactivación de los genes invG/invE y ssaJ/ssaK de las islas de patogenicidad 1 y 2

Several methods have been described for manipulating and producing mutant genomic DNA having specific characteristics in an attempt to understand the genetic basis for Salmonella pathogenicity. This study reports the construction of mutants from several S. enterica serotypes, the substitution and inactivation of invG/invE