Analysis of the essential oil of Mexican oregano (Lippia graveolens HBK)

Metabolite profiling of the ripening of Mangoes Mangifera indica L. cv. 'Tommy Atkins' by real-time measurement of volatile organic compounds

Real-time profiling of mango ripening based on proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) of small molecular weight volatile organic compounds (VOCs), is demonstrated using headspace measurements of 'Tommy Atkins' mangoes. VOC metabolites produced during the ripening process were sampled directly, which enabled simultaneous and rapid detection of a wide range of compounds. Headspace measurements of 'Keitt' mangoes were also conducted for comparison. A principle component analysis of the results indicated that several mass channels were not only key to the ripening process but could also be used to distinguish between mango cultivars. The identities of 22 of these channels, tentatively speciated using contemporaneous GC-MS measurements of sorbent tubes, are rationalized through examination of the biochemical pathways that produce volatile flavour components. Results are discussed with relevance to the potential of headspace analysers and electronic noses in future fruit ripening and quality studies.

Phytochemical diversity of the essential oils of Mexican Oregano (Lippia graveolens Kunth) populations along an Edapho-climatic gradient

Mexican oregano (Lippia graveolens) is an important aromatic plant, mainly used as flavoring and usually harvested from non-cultivated populations. Mexican oregano essential oil showed important variation in the essential-oil yield and composition. The composition of the essential oils extracted by hydrodistillation from 14 wild populations of L. graveolens growing along an edaphoclimatic gradient was evaluated. Characterization of the oils by GC-FID and GC/MS analyses allowed the identification of 70 components, which accounted for 89-99% of the total oil composition. Principal component and hierarchical cluster analyses divided the essential oils into three distinct groups with contrasting oil compositions, viz., two phenolic chemotypes, with either carvacrol (C) or thymol (T) as dominant compounds (contents >75% of the total oil composition), and a non-phenolic chemotype (S) dominated by oxygenated sesquiterpenes. While Chemotype C was associated with semi-arid climate and shallower and rockier soils, Chemotype T was found for plants growing under less arid conditions and in deeper soils. The plants showing Chemotype S were more abundant in subhumid climate. High-oil-yield individuals (>3%) were identified, which additionally presented high percentages of either carvacrol or thymol; these individuals are of interest, as they could be used as parental material for scientific and commercial breeding programs.

Essential oils from neotropical Myrtaceae: chemical diversity and biological properties

Myrtaceae family (121 genera, 3800-5800 spp.) is one of the most important families in tropical forests. They are aromatic trees or shrubs, which frequently produce edible fruits. In the neotropics, ca. 1000 species were found. Several members of this family are used in folk medicine, mainly as an antidiarrheal, antimicrobial, antioxidant, cleanser, antirheumatic, and anti-inflammatory agent and to decrease the blood cholesterol. In addition, some fruits are eaten fresh or used to make juices, liqueurs, and sweets very much appreciated by people. The flavor composition of some fruits belonging to the Myrtaceae family has been extensively studied due to their pleasant and intense aromas. Most of the essential oils of neotropical Myrtaceae analyzed so far are characterized by predominance of sesquiterpenes, some with important biological properties. In the present work, chemical and pharmacological studies carried out on neotropical Myrtaceae species are reviewed, based on original articles published since 1980. The uses in folk medicine and chemotaxonomic importance of secondary metabolites are also briefly discussed.

Volatile components from mango (Mangifera indica L.) cultivars

The volatile components of 20 mango cultivars were investigated by means of simultaneous distillation-extraction, GC, and GC-MS. Three hundred and seventy-two compounds were identified, of which 180 were found for the first time in mango fruit. The total concentration of volatiles was approximately 18-123 mg/kg of fresh fruit. Terpene hydrocarbons were the major volatiles of all cultivars, the dominant terpenes being delta-3-carene (cvs. Haden, Manga amarilla, Macho, Manga blanca, San Diego, Manzano, Smith, Florida, Keitt, and Kent), limonene (cvs. Delicioso, Super Haden, Ordonez, Filipino, and La Paz), both terpenes (cv. Delicia), terpinolene (cvs. Obispo, Corazon, and Huevo de toro), and alpha-phellandrene (cv. Minin). Other qualitative and quantitative differences among the cultivars could be demonstrated.

Analysis of Origanum vulgare volatiles by direct thermal desorption coupled to gas chromatography-mass spectrometry

Volatile components of samples of a population of Spanish Origanum vulgare have been analyzed by direct thermal desorption coupled to GC-MS. The method is fast and reliable and requires a low amount of sample, allowing analysis of leaves and flowers from a single individual plant. Volatile yield is highly variable among individual plants and concentration also presents a high variation for most Origanum volatile compounds, linalool being the main component in most samples. Statistical analyses are applied in order to find patterns in composition data.

Galloylglucosides from berries of Pimenta dioica

Three new galloylglucosides, (4S)-alpha-terpineol 8-O-beta-D-(6-O-galloyl)glucopyranoside (1); (4R)-alpha-terpineol 8-O-beta-D-(6-O-galloyl)glucopyranoside (2), and 3-(4-hydroxy-3-methoxyphenyl)propane-1,2-diol 2-O-beta-D-(6-O-galloyl)glucopyranoside (3), were isolated from the berries of Pimenta dioica together with three known compounds, gallic acid (4), pimentol (5), and eugenol 4-O-beta-D-(6-O-galloyl)glucopyranoside (6). The structures of 1-3 were elucidated on the basis of MS and NMR spectral data and enzymatic hydrolysis. These galloylglucosides (1-3, 5, and 6) showed radical-scavenging activity nearly equivalent to that of gallic acid (4) against 1,1-diphenyl-2-picrylhydrazyl radical.