Analytical methodologies based on GC and HPLC were developed for the separation and quantification of carnosic acid, ursolic acid, caffeic acid, p-coumaric acid, rosmarinic acid, apigenin, luteolin, quercetin, kaempferol, naringenin, and pinocembrin. These methods were used to characterize essential oils and extracts obtained by solvent (methanol) and by supercritical fluid (CO(2)) extraction from stems and leaves of Lippia (Verbenaceae family) aromatic plants (Lippia alba, Lippia origanoides, Lippia micromera, Lippia americana, Lippia graveolens, and Lippia citriodora). Supercritical CO(2) extraction isolated solely pinocembrin and narigenin from three L. origanoides chemotypes. Solvent extracts possessed a more varied composition that additionally included apigenin, quercetin, and luteolin. Solvent extraction afforded higher overall flavonoid yields from all species in comparison with supercritical CO(2) extraction. Pinocembrin was determined in L. origanoides extract at a concentration of 30 mg/g of plant material, which is more than ten times higher than the amount at which polyphenols are regularly found in aromatic plant extracts.

Headspace (HS), extractive, and distillative methods were employed to isolate volatile and semivolatile compounds from fresh Coffea arabica flowers. Static HS solid-phase microextraction (HS-SPME), microwave-assisted HS-SPME (MW-HS-SPME) with simultaneous hydrodistillation, and extraction with hexane or supercritical CO2 -isolated mixtures in which around 150 different chemical substances were identified or tentatively identified by GC-MS analysis. n-Pentadecane (20-37% relative peak area, RPA) was the most abundant compound in the HS fractions from fresh flowers, followed by 8-heptadecene (8-20% RPA) and geraniol (6-14% RPA). Hydrocarbons (mostly C13 -C30 paraffins) were the predominant compound class in all the sorptive extractions (HS-SPME, MW-HS-SPME, distillate), followed by terpenoids or oxygenated compounds (which varied with the isolation technique). Caffeine, a distinctive component of coffee fruits and beans, was also found in relatively high amounts in the supercritical CO2 extract of C. arabica flowers.

Composición y actividad antioxidante de aceites de lippia 89 Rev. Acad. Colomb. Cienc. 38(Supl.):89-105, 2014 Estudio comparativo de la composición química y la actividad antioxidante de los aceites esenciales de algunas plantas del género Lippia (Verbenaceae) cultivadas en Colombia. Elena E. Stashenko*, Jairo René Martínez, Diego Camilo Durán, Yuri Córdoba, Deyanira Caballero CIBIMOL-CENIVAM, Facultad de Ciencias, Universidad Industrial de Santander, Bucaramanga, Colombia ResumenSe presentan varios resultados obtenidos en investigaciones de aceites esenciales de especies vegetales aromáticas que crecen en Colombia, se destaca la necesidad de investigar una gran variedad de tópicos que permitan brindar el soporte científico para el desarrollo de la agroindustria de aceites esenciales, y se presentan en detalle resultados de la caracterización química y la evaluación de la capacidad antioxidante de 12 aceites esenciales de 7 especies del género Lippia. La determinación de la composición química de 12 aceites esenciales de plantas del género Lippia, por cromatografía de gases acoplada a espectrometría de masas, mostró que los constituyentes más abundantes y más frecuentes son sustancias oxigenadas. La diversidad composicional se manifiesta en la isomería óptica, en la existencia de quimiotipos con pocas sustancias en común, y en los diversos modos de atrapamiento de radicales, según lo evidenciaron los resultados de las evaluaciones de capacidad antioxidante por los métodos ORAC y TEAC. Mientras que el limoneno y el linalol se encontraron en todos los aceites, 19 de los 102 constituyentes identificados en el conjunto de aceites se hallaron en solo una ocasión. Los aceites esenciales de las especies del género Lippia estudiados mostraron una capacidad antioxidante mayor que la exhibida por el α-tocoferol o el BHT, que son utilizados comúnmente como antioxidantes en productos comerciales de consumo humano. Varias especies tuvieron un rendimiento de extracción relativamente alto (1,5 -4,4%), que junto con la alta capacidad antioxidante registrada, convierte a sus aceites esenciales en buenos candidatos para sustituir a antioxidantes sintéticos. AbstractVarious results obtained from research on essential oils of vegetal aromatic species growing in Colombia are presented. In order to offer good scientific support to the essential oils agro-industry, the need for investigating a wide variety of topics is emphasized. Results of the chemical characterization and the antioxidant activity evaluation of 12 essential oils of 7 Lippia species are presented. The determination of the chemical composition of 12 essential oils of plants from genus Lippia, using gas chromatography coupled to mass spectrometry, showed that the most abundant and frequent constituents are oxygenated substances. The compositional diversity is manifested in optical isomers, in the existence of chemotypes with few substances in common, and in the diverse radical trapping modes, as evidenced by the ORAC and TEAC antioxidant capacity evaluations. While...

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