Félix Tomi

Chemical variability of peel and leaf essential oils of 15 species of mandarins.

Peel and leaf oils of 58 mandarin cultivars, belonging to 15 different species were obtained from fruits and leaves collected on mandarin-trees submitted to the same pedoclimatic and cultural conditions. Their chemical composition was investigated by capillary GC, GC/MS and 13C NMR and the results were submitted to a cluster analysis and a discriminant analysis. Three major chemotypes, limonene, limonene/gamma-terpinene and linalyl acetate/limonene, were distinguished for peel oils while three other chemotypes, sabinene/linalool, gamma-terpinene/linalool and methyl N-methylanthranilate, were observed for leaf oils.

Chemical variability of peel and leaf essential oils of mandarins from Citrus reticulata Blanco

Abstract Peel and leaf oils of 41 mandarin cultivars, belonging to the Citrus reticulata Blanco species, were obtained from fruits and leaves collected on mandarin trees submitted to the same pedoclimatic and cultural conditions. Their chemical composition was investigated by capillary GC, GC/MS and 13 C NMR and the results were submitted to a cluster analysis and a discriminant analysis. Two major chemotypes, limonene and limonene/ γ -terpinene, were distinguished for peel oils while three major chemotypes, sabinene/linalool, linalool/ γ -terpinene and methyl N-methylanthranilate, were observed for leaf oils.

Chemical composition of myrtle leaf essential oil from Corsica (France)

Abstract Collective and individual samples of myrtle leaf oil from Corsica were analyzed by GC, GC/MS and Carbon-13 NMR spectroscopy. Corsican myrtle was found to contain α-pinene (47.9–59-5%) and 1,8-cineole (19.8–28.1%) as major components. It belongs to the α-pinene/l,8-cineole chemotype.

Essential oils from four piper species

Abstract The essential oils from Piper capense , P. nigrum , P. guineense and P. umbellatum from S. Tome e Principe were investigated for the first time. They were analysed by GC, GC-mass spectrometry and 13 C NMR. Monoterpene hydrocarbons were the main group of constituents in three of the samples ( P. capense, P. nigrum and P. umbellatum ), whereas for the other species ( P. guineense ) phenylpropanoid derivatives were the most important ones. β -Pinene (32.5%) and β -caryophyllene (12.6%) were the major compounds in the volatile oil of P. capense . Dillapiole (44.8%), followed by myristicin (9.8%), were the main constituents of P. guineense . The most important constituents in the essential oil of P. nigrum were limonene (18.8%), β -caryophyllene (15.4%), sabinene (16.5%) and β -pinene (10.7%). The essential oil of P. umbellatum was characterised by its high β -pinene (26.8%), α -pinene (17.6%) and (E)-nerolidol (12.4%) content.

Chemical polymorphism of the essential oil of Thymus carnosus from portugal

Abstract The composition of the essential oils of 11 populations of Thymus carnosus from Portugal and their infraspecific variability were investigated by GC, GC-MS and 13CNMR. The results obtained were submitted to Principal Component and Chemometric Cluster Analyses. Borneol was the main constituent in all the populations except in one, which had a high content of linalool. This compound showed high percentages in samples originating from the region of Estremadura. Multivariate analysis allowed the distinction between three different groups of essential oils, (i) borneol/cis-sabinene hydrate/terpinen-4-ol, (ii) linalool/borneol/trans-sabinene hydrate and (iii) borneol/camphene.

Chemical variability of peel and leaf essential oils of sour orange

Peel and leaf oils of 30 sour orange cultivars, belonging to four different species (C. aurantium L., C. myrtifolia Raf., C. natsudaidai Hay. and C. neo-aurantium Tan.) were obtained from fruits and leaves collected on sour orange trees submitted to the same pedoclimatic and horticultural conditions. Their chemical composition was investigated by capillary GC, GC–MS and 13C-NMR. Two chemotypes, limonene and limonene/β-pinene, were distinguished for peel oils, while four chemotypes, linalool/linalyl acetate, sabinene/(E)-β-ocimene, limonene/β-pinene and β-pinene/linalool, were observed for leaf oils. Copyright

Variability of essential oils of Thymus caespititius from portugal

Abstract The composition and variability of the essential oils of several populations of Thymus caespititius from Portugal were investigated by GC, GC-mass spectrometry and 13 C NMR. All samples from NW Portugal were characterized by their high α-terpineol content, while the main components in the oil sample from Pico island (Azores archipelago) were carvacrol and thymol. The analytical data of individual samples from NW Portugal showed no chemical polymorphism in this area. The different areas of distribution (NW Portugal and Azores) that show great climatic and soil variation conditions may be the origin of the α-terpineol-type oil from NW Portugal and the carvacrol/thymol-type oil from the Azores. 13 C NMR spectra of the essential oil, previously fractionated by column chromatography, led to the identification of trans -dihydroagarofuran, a new oxygenated sesquiterpene for the genus Thymus and a characteristic compound of T.caespitiuius .

DIRECT QUALITATIVE AND QUANTITATIVE ANALYSIS OF CARBOHYDRATE MIXTURES USING 13C NMR SPECTROSCOPY : APPLICATION TO HONEY

A method is described which allows the identification of individual carbohydrates of multi‐component artificial mixtures using the computer‐aided analysis of their 13C NMR spectra, without previous separation. Quantitation of mono‐, di‐ and trisaccharides was carried out after improvement of the experimental procedure and using an internal standard. The procedure was then applied to authentic honeys of different floral types, harvested in Corsica (France). Several oligosaccharides (identification of some of these is not easy by chromatographic techniques) were observed at levels ranging from 0.4 to 3.3%. In addition, the fructose/glucose ratio, which has an influence on crystallization, was easily obtainable.

Identification and quantitative determination of furanodiene, a heat-sensitive compound, in essential oil by 13C-NMR.

A method based on 13C-NMR has been used as a tool for the identification and quantitative determination of two furanic sesquiterpenes: a heat-sensitive compound, furanodiene, and its rearrangement product, furanoelemene. Following a preliminary study using artificial mixtures which permitted the construction and verification of calibration curves for each compound, the method was used for the qualitative and quantitative analysis of furanodiene and furanoelemene in the essential oil of Smyrnium olusatrum.

Essential Oil Composition of Eryngium foetidum from S. Tomé e Príncipe

Abstract The essential oil of Eryngium foetidum leaves from S. Tomé e Príncipe was investigated for the first time. The oils were obtained by hydrodistillation of the leaves, from two different sites, and subsequently analyzed by GC, GC/MS and 13C-NMR. The oils were characterized by the presence of small amounts of monoterpene hydrocarbons and sesquiterpenoids, and by a large number of aromatic and linear aldehydes in high proportions, with 2,3,6-trimethylbenzaldehyde (5.5–23.7%), (E)-2-dodecenal (15.9–37.5%) and (E)-2-tetradecenal (18.7–25.3%) being the most dominant.