The essential oils from fresh aerial parts of Monticalia greenmaniana (Hieron) C. Jeffrey (Asteraceae) collected in March, were analyzed by GC/MS. Oil yields (w/v) of 0.1% (flowers), 0.07%, (stems) and 0.1% (leaves) were obtained by hydrodistillation. Thirteen, sixteen and eighteen components, respectively, were identified by comparison of their mass spectra with those in the Wiley GC-MS Library data base. The major components of the flower and stem oils were 1-nonane (38.8% flowers; 33.5% stems), α-pinene (29.0% flowers; 14.8% stems) and germacrene D (15.6% flowers; 18.6% stems). However, in the leaf oil, germacrene D was observed at 50.7%, followed by β-cedrene at 8.4 %. The leaf essential oil showed a broad spectrum of antibacterial activity against the important human pathogenic Gram-positive and Gram-negative bacteria Staphylococcus aureus (ATCC 25923), Enterococcus faecalis (ATCC 19433), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and Klebsiella pneumoniae (ATCC 25955) with MIC values ranging from 75 to 6000 ppm.

The essential oil of Aniba hostmanniana (Nees) Mez, family Lauraceae, was obtained from fresh leaves by hydrodistillation. The chemical composition of the oil was assessed using gas chromatography with mass spectrometric detection (GC-MS). The antimicrobial activity of the essential oil was tested against Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumonia) and the Gram-positive bacterium Staphylococcus aureus. GC-MS analysis revealed the presence of 35 compounds in the essential oil, the predominant ones being benzyl benzoate (29.3%), δ-cadinene (12%), β-caryophyllene (10.5%), bicyclogermacrene (5.9%), and α-copaene (3.9%). The oil showed activity against most of the bacterial strains studied.

El aceite esencial (AE) obtenido de las hojas y flores de Hyptis suaveolens (L.) Poit. recolectado en Guasdualito, Estado Apure, Venezuela, fue obtenido por hidrodestilación empleando una trampa de Clevenger. El aceite se analizó mediante cromatografía de gases acoplada a espectrometría de masas (GC/MS), se identificaron treinta y cinco compuestos en las hojas (91.9% de la muestra) y treinta compuestos en las flores (97.0% de la muestra), con los siguientes compuestos principales: 1,8-cineol (19.1% hojas, 13.3% flores), fenchona (18.5% hojas, 16.1% flores), biciclogermacreno (12.7% hojas, 18.8% flores), D-Germacreno (6.3% hojas, 10.0% flores). La actividad antibacteriana se evaluó por el método de difusión en agar con discos contra Staphylococcus aureus ATCC 25923, Enterococcus faecalis ATCC 29212, Escherichia coli ATCC 25922, Klebsiella pneumoniae ATCC 23357, Salmonella typhi CDC 57, Pseudomonas aeruginosa ATCC 27853. Ambos AE inhibieron el desarrollo de E. coli, K. pneumoniae y S. typhi, con una concentración inhibitoria mínima (CIM) que osciló entre 300 μL/mL y 450 μL/mL. Estos resultados representan un aporte al estudio del AE de H. suaveolens, siendo el primer reporte sobre la actividad antibacteriana del AE de las flores de esta especie.

The volatile components from the fresh leaves of Gynoxys meridana Cuatrec. were obtained by hydrodistillation and analyzed by GC/MS. A total of 25 compounds, representing 99.3% of the oil, were identified. The dominant compounds were -curcumene (31.9%), fukinanolide (22.3%), β-pinene (9.5%), α-phellandrene (7.1%) and α-pinene (5.7%).

El género Peperomia (Piperaceae), es bien conocido por sus especies ornamentales y usos etnomedicinales. En el presente trabajo se describe la caracterización química y la actividad antibacteriana del aceite esencial de Peperomia acuminata Ruiz & Pav. proveniente del Estado Mérida Venezuela. El aceite esencial se obtuvo por hidrodestilación de las hojas y la separación de los componentes se realizó por Cromatografía de gases-Espectrometría de Masas (CG/EM). Se logró la elucidación de ocho compuestos (96,7%), siendo el 2E-dodecenal el componente mayoritario (65%) seguido de dodecanal (14,8%) y tetradecanal (9,2%). Esta investigación muestra el potencial del aceite esencial de P. acuminata frente a bacterias Gram positivas (Staphylococcus aureus ATCC 25923 y Enterococcus faecalis 29212), con un valor de Concentración inhibitoria mínima de 1μL/mL. Este es el primer reporte sobre la composición química del aceite esencial de esta especie, por lo tanto una contribución importante al estudio del género Peperomia.

The essential oil from the leaves of Kalanchoe pinnata (Lam.) Pers. (Crassulaceae), collected in the Venezuelan Andes, was obtained by hydrodistillation and its composition determined by gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). Nineteen compounds were identified, representing 95.2% of the oil. The most abundant components were α-curcumene (44.7%), 1-octen-3-ol (18.1%), β-curcumene (4.9%), and β-caryophyllene (3.7%).

Aniba cinnamomiflora C. K. Allen is a tree species of Lauraceae family that produces essential oil. A study on the hydrodistillation product of wood pieces from branches of Aniba cinnamomiflora is presented. A 0.05% of essential oil was obtained. The essential oil was analyzed by gas chromatography and Mass spectrometry. Fifteen compounds were identified (98.55%) of the total retrieved. The major component (54.00%) corresponds to the lipid γ-palmitolactone, followed by 1-epi-cubenol (9.56%), δ-cadinene (6.05%), t-cadinol (5.00%), and chamazulene (3.53%). This is the first study on the wood essential oil of Aniba cinnamomiflora.

The essential oil from the leaves of Phyllanthus acidus (Phyllanthaceae) was obtained by hydrodistillation and its composition determined by GC and GC/MS. Twenty-one compounds were identified, representing 92.8 % of the oil. The most abundant components were t-muurolol (20.4 %), α-cadinol (14.6 %), β-cadinene (8.9 %) and α-muurolene (7.5 %).