Chemical Composition of the Essential Oil of Phyllanthus acidus

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 %).

Essential Oil Composition and Antibacterial Activity of Hyptis colombiana from the Venezuelan Andes

Hyptis colombiana is an aromatic shrub native to the Colombian and Venezuelan Andes. Aerial parts were collected in Mérida State at about 3100 m above sea level in February 2005, and May and October 2006. The essential oil was found to contain germacrene D and β-caryophyllene as main constituents (about 50%). The February 2005 and October 2006 oils were found to have antibacterial activity against Staphylococcus aureus, but not the May 2006 oil, probably due to the lack of some minor constituent.

Chemical Composition and Antibacterial Activity of the Essential Oil of Ruilopezia bracteosa

The essential oil from the leaves of Ruilopezia bracteosa was obtained by hydrodistillation, and analyzed by GC-MS. Eighteen components, which made up 99.6% of the oil were identified, the most abundant being β-myrcene (34.2%), α-pinene (24.3%), 7-epi-α-selinene (9.1%), β-pinene (8.5%) and 6,9-guaiadiene (4.4%). Antibacterial activity was tested against Gram-positive and Gram-negative bacteria using broth microdilution and disk agar diffusion methods. MIC values found presented significant differences between both methods, which may be due to diffusion factors.

Chemical Composition of the Essential Oil of Gynoxys meridana from Mérida, Venezuela

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 γ-curcumene (31.9%), fukinanolide (22.3%), β-pinene (9.5%), α-phellandrene (7.1%) and α-pinene (5.7%).

Chemical Composition of the Essential Oil from the Leaves of Carapa guianensis Collected from Venezuelan Guayana and the Antimicrobial Activity of the Oil and Crude Extracts

The essential oil obtained by hydrodistillation of Carapa guianensis Aubl. (Meliaceae) leaves was analyzed by GC-FID and GC-MS. Twenty-three components were identified, which made up 93.7% of the oil. The most abundant constituents were bicyclogermacrene (28.5%), α-humulene (17.2%), germacrene B (11.9%), and trans-β-caryophyllene (9.9%). Antimicrobial activity of the essential oil, as well as the crude extracts of the leaves obtained by refluxing the dried leaves with n-hexane, dichloromethane, and methanol, was determined using the disc diffusion assay. Activity against Staphylococcus aureus ATCC 29923 and Enterococcus faecalis ATCC 29212 was only found for the essential oil and the methanolic extract, at minimal inhibitory concentrations (MIC) of 400 μg/mL and 50 μg/mL.

Chemical Composition and Antibacterial Activity of the Essential Oil of Espeletia nana

The essential oil of the leaves of Espeletia nana Cuatrec, obtained by hydrodistillation, was analyzed by GC-MS, which allowed the identification of 24 components, which made up 99.9% of the oil. The most abundant compounds were α-pinene (38.1%), β-pinene (17.2%), myrcene (15.0%), spathulenol (4.2%), bicyclogermacrene (4.0%), α-zingiberene (4.0%), and γhimachalene (3.7%). Antibacterial activity was tested against Gram-positive and Gram-negative bacteria using the agar disk diffusion method. Activity was observed only against Gram-positive bacteria. MIC values were determined for Staphylococcus aureus ATCC 25923(200 μg/mL) and Enterococcus faecalis ATCC 29212 (600 μg/mL).

Analysis of Chemical Constituents of the Volatile Oil from Leaves of Solanum bicolor

The volatile components from the leaves of Solanum bicolor Roemer & Schultes, was obtained by hydrodistillation and was analizad by GC/MS. A total of 20 compounds, representing 96.3 % of the oil, were identified. The dominant compounds were trans-caryophyllene (23.2%), trans-2-pentadecene (22.6%), germacrene D (12.2%), biciclogermecrene (8.0%) and caryophyllene oxide (4.7%).