Pascale Bradesi

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.

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.

Constituents of the essential oil of Solidago gigantea Ait. (giant goldenrod)

The hydrodistilled essential oil of aerial parts of S. gigantea was investigated by GC, GC–MS and NMR spectroscopy. Two samples (1990/91, Warsaw, and 1998, Łodź) yielding 0.55% and 70% of essential oil, were analysed in 1992 and 1998. Ninety constituents (96% of the total oil) were identified in the first sample and 85 (98%) in the second. α-Pinene (7.0/4.1%), myrcene (2.5/2.6%), p-cymene (2.2/0.6%), (−)-bornyl acetate (4.4/2.9%), α- (6.1/4.0%) and γ-gurjunene (2.5/2.1%) (−)-germacrene D (21.6/23.5%), (−)-ledol (1.2/2.1%), eudesma-4(15),7-dien-1β-ol (1.9/2.5%) and (−)-cyclocolorenone (8.1/32.4%) are the main constituents. The structures of three new sesquiterpenes were established by NMR data: epi-torilenol (5αH, 6βH, 7αH, 8βH, 10α-6,8-cycloeudesm-4(15)-en-lα-ol, 0.4/0.1%), 1,10-seco-eudesma-4(15),5(10)-dien-1-al (0.9%/trace) and cis-eudesm-4(10)-en-1-one (0.2%/trace). Copyright

Enantiomeric differentiation of oxygenated p‐menthane derivatives by 13C NMR using Yb(hfc)3

The 13C NMR behaviour of 21 p‐menthanic terpene bearing an oxygenated function (alcohol, ketone, acetate) was examined in the presence of a chiral lanthanide shift reagent (Yb(hfc)3). For each monocyclic compound, we measured the lanthanide‐induced shift (LIS) on the signals of the carbons and the splitting of signals allowing the enantiomeric differentiation. Some general features were found about their LIS behaviour: experimental data establishing distinct patterns for carvomenthone‐like compounds and menthone‐like compounds. The enantiomeric splitting was observed for the majority of signals in the spectrum of each compound. In the case of alcohols and acetates, the influence of the relative stereochemistry (cis vs trans) of isopropyl(ene) and the binding function was discussed. Copyright

Composition and chemical variability of Mentha suaveolens ssp. suaveolens and M. suaveolens ssp. insularis from Corsica.

A detailed analysis of two essential oils from individual plants of Mentha suaveolens ssp. suaveolens growing wild in Corsica was carried out by combination of GC(RI), GC/MS, and 13C‐NMR analyses. One oil sample is characterized by the pre‐eminence of piperitenone oxide, and the second is dominated by piperitenone. In contrast, it was reported that the essential oil of M. suaveolens ssp. insularis, an endemic species to Corsica and Sardinia, contained pulegone and cis‐cis‐p‐menthenolide as main components. A principal‐component analysis (PCA) carried out on the composition of the essential oil of 59 individual plants of M. suaveolens sp. allowed the classification into three well‐defined groups. All the oil samples from Mentha suaveolens ssp. insularis belonged to the same group, while the oils from M. suaveolens ssp. suaveolens were distributed in the two other groups. The composition of the essential oil isolated from aerial parts of M. suaveolens ssp. has been shown to be an additional tool to differentiate the botanically close subspecies suaveolens and insularis.

Detailed analysis of the essential oil from Cistus albidus L. by combination of GC/RI, GC/MS and 13C-NMR spectroscopy

The composition of the essential oil of Cistus albidus (L.) obtained from plants growing wild in Provence (France) has been investigated using GC–RI (RI = retention indices), GC/MS and 13C-NMR. Eighty-eight components were reported accounting for 81.8% of the essential oil. This essential oil was characterized by a high content of sesquiterpenes with α-zingiberene (12.8%), α-curcumene (7.7%), (E)-β-caryophyllene (5.9%), α-cadinol (5.4%), α-bisabolol (4.1%), caryophyllene oxide (3.8%), allo-aromadendrene (3.4%), δ-cadinene (3.4%), and germacrene D (3.1%) being the main components.

Identification of Dihydrocarveol Stereoisomers and Their Acetates Using Carbon-13 NMR Spectroscopy

Abstract The Carbon-13 NMR spectra of dihydrocarveol and dihydrocarvyl acetate stereoisomers are characterized. The chemical shifts are assigned taking account the steric and electronic substituent effects, the lanthanide induced shifts and the proton-carbon correlation.

Enantiomeric Differentiation of Oxygenated Bicyclo[2.2.1]heptane Derivatives by 13C NMR Spectroscopy Using Yb(hfc)3

ABSTRACT The 13C NMR behavior of 10 oxygenated compounds (ketones, alcohols, acetates) bearing the bicyclo[2.2.1]heptane skeleton was examined in the presence of a chiral lanthanide shift reagent (Yb(hfc)3). For each compound, we measured the lanthanide-induced shift (LIS) on the signals of the carbons and the splitting of signals, enabling the enantiomeric differentiation. The enantiomeric splitting was observed for the majority of signals in the spectrum of each compound.