Joaquín L. Esteban

Evaluation and optimization of the automatic thermal desorption method in the gas chromatographic determination of plant volatile compounds

Abstract The automatic thermal desorption (ATD) method was used in the gas chromatographic determination of the volatile components of plants. The reproducibility of the method was evaluated for several operating conditions; the results were better than those obtained with other sample preparation methods (simultaneous distillation-extraction and solvent extraction). Some applications of the ATD method in the gas chromatographic determination of volatile components of Umbelliferae seeds are also presented, including the determination of the enantiomeric forms of limonene.

Rapid identification of volatile compounds in aromatic plants by automatic thermal desorption — GC-MS

SummaryThermal desorption is a valuable method for the fractionation of plant volatile components, which can be carried out on-line with GC analysis. The use of coupled GC-MS affords additional qualitative information, of special interest for plant species whose composition has not been previously studied. Some examples of the application of automatic thermal desorption, coupled to GC-MS to the identification and characterization of volatile components of plants of different families are given.

Composition of the Essential Oils of Ocimum basilicum var. glabratum and Rosmarinus officinalis from Turkey

ABSTRACT Water-distilled volatiles of Ocimum basilicum var. glabratum and Rosmarinus officinalis gathered in Turkey were analyzed by means of GC, GC/MS, 1H-NMR and 13C-NMR. O. basilicum oil was found to contain linalool (43.73%) and (E)-methyl cinnamate (27.28%) as the major constituents whereas 1,8-cineole (36.91%), borneol (17.50%) and p-cymene (10.50%) were shown to dominate R. officinalis oil.

Essential oils of Calamintha nepeta (L.) Savi and Mentha aff. suaveolens Ehrh., grown in Cordoba, Argentina

ABSTRACT As a part of our research on aromatic plants from Cordoba, Argentina (1–4), we have examined the oil composition of the leaves of Calamintha nepeta(L.) Savi and Mentha off. suaveolens Ehrh., grown in Argentina, using GC and GC/MS. The major constituents of die leaf oil of Calamintha nepeta were pulegone (34.28%), neomenthol (30.61%) and menthone (17.12%) while that of Mentha off. suaveolens had menthol (48.32%), pulegone (20.27%) and menthone (8.90%) as the major components.

The volatiles of five Micromeria species endemic to the Canary Islands

Abstract The chemical composition of the volatiles from five Micromeria species (section Micromeria ) gathered in the Canary Islands is reported. These species were found to contain bornane and pinane types of bicyclic monoterpenes as the most important components of their essential oils. The analysis showed that the Micromeria species studied could be grouped according to the monoterpene skeleton type. M. lachnophylla and M. lasiophylla subsp. palmensis were characterized by larger amounts of bornane type monoterpenes than pinane type monoterpenes. M. lasiophylla subsp. palmensis in addition to those compounds, contained linalool as the other main constituent. The volatile oils of M. varia and M. hyssopffolia were found to contain similar quantities of bornane and pinane type components. M. varia also accumulated large amounts of (E)-nerolidol. Two samples of M. herpyllomorfa were characterized by larger amounts of pinane type monoterpenes than bornane type monoterpenes.

Volatile constituents of Hyptis mutabilis (Rich.) Briq

ABSTRACT As a part of our research on aromatic plants from Cordoba, Argentina, we have examined the oil composition of Hyptis mutabilis (Rich.) Briq. using GC and GC/MS. The main constituents found were camphor (14.37%), myrcenone (14.85%), cis-dihydrocarvone (11.38%) and trans-dihydrocarvone (32.91%).

Essential Oil of Lepechinia floribunda (Benth.) Epl.

ABSTRACT The hydrodistilled oil of Lepechinia floribunda (Benth.) Epl., was studied by means of GC and GC/MS. Thirty-seven components were characterized. Major constituents of the oil were borneol (21.44%), β-caryophyllene (15.14%), aromadendrene (5.50%) and ledyl acetate (16.86%).

Essential oil of Satureja boliviana Briq. from Peru

ABSTRACT The essential oil of Satureja boliviana Briq., was studied by GC and GC/MS. The main constituents found were: menthone (54.11%), isomenthone (15.12%), carvacrol (6.76%) and isopulegone (5.45%)

Chemosystematic study on leaf volatile compounds of Saxifraga L. series Ceratophyllae (Saxifragaceae)

Extracts from 65 samples corresponding to 13 species and 18 taxa of Saxifraga series Ceratophyllae s. l. were analysed by GC and GC/MS. This paper provides the first chemosystematic information on volatile composition of a seemingly natural group in the Saxifragaceae. Diterpenoids and n-alkanes appear to be the most important constituents and some of them are associated to different species and taxonomic series. The application of multivariate analysis techniques to GC and GC/MS data has allowed the classification of samples into two groups, corresponding approximately to the series Ceratophyllae s. str. and Pentadactyles, previously proposed on the basis of morphological and cytotaxonomical information. Therefore, the use of volatile composition as chemotaxonomic markers in Saxifraga is highly recommended because of its diagnostic value even at specific level.

Validación estadística de la presencia en plantas de quimiotipos caracterizados por la concentración de componentes volátiles obtenida mediante GC-MS

Se denomina “quimiotipo” a un grupo de individuos de una especie que se distingue de forma significativa del resto por su composicion quimica. Mientras que la existencia de polimorfismo quimico es bien conocida para diversas especies, el significado estadistico de la diferencia entre sus composiciones no ha recibido suficiente atencion. Se propone, para la asignacion de un nivel de significado a la existencia de un quimiotipo caracterizado por un compuesto, un metodo basado en la formacion de agrupaciones mediante el procedimiento de k-medias, el calculo de la distancia de Mahalanobis Dmah como estimacion de la separacion entre grupos, y la comparacion de este valor con valores Dmah calculados a partir de datos simulados con una distribucion normal. El metodo se aplica a los datos de concentracion obtenidos por GC-MS de compuestos volatiles de muestras de Thymus zygis subsp. zygis, Thymus zygis subsp. sylvestris y Lavandula luisieri.