Daniel Lorenzo

Essential oils of Mentha pulegium and Mentha rotundifolia from Uruguay

Essential oils obtained by hydrodistillation from leaves of Mentha pulegium L. and Mentha rotundifolia (L.) Huds. from Uruguay were analysed by GC-FID and GC-MS. Oxygen-containing monoterpenes were the main group of constituents in both oils. Pulegone, isomenthone and menthone were the major components in the oil of M. pulegium, whereas piperitenone oxide and (Z)-sabinene hydrate were the major ones in M. rotundifolia. Enantiomerically pure (-)-menthone, (+)-isomenthone, (+)-isomenthol, (-)-menthol and (+)-pulegone were detected by multidimensional gas chromatography in the case of M. pulegium oil.

Rosmarinus officinalis L. (Labiatae) Essential Oils from the South of Brazil and Uruguay

Abstract Rosemary oils from cultivars of Rosmarinus officinalis L. growing in different areas of Uruguay and South of Brazil (Rio Grande do Sul State) were analyzed by GC and GC/MS. The oils from Uruguay were found to be rich in αpinene (37.8–46.2%) and 1,8-cineole (13.4–13.8%). The oil from R. officinalis which was cultivated in Brazil contained αpinene (32.2%) and 1,8-cineole (14.7%), while the oil from wild plants found in Brazil contained αpinene (12.4%), myrcene (22.7%) and 1,8-cineole (15.3%).

Liquid phase oxidation of limonene catalyzed by palladium supported on hydrotalcites

Abstract Palladium supported on copper–magnesium–aluminium hydrotalcites (HTs) were prepared by using coprecipitation and impregnation techniques. The different palladium/hydrotalcites solid catalysts were tested in the liquid phase oxidation of pure limonene using molecular oxygen as the sole oxidant agent. Both palladium and copper were found to influence the conversion versus reaction time profile of limonene oxidation. A chain reaction mechanism is proposed to explain the experimental results. Palladium participates in the formation of allylic radicals through activation of carbon–hydrogen bonds of limonene and in the formation of adducts by cleavage of the carbon–carbon double bonds. Copper catalyzes mainly the decomposition of hydroperoxides leading to radical intermediates. Different oxygen containing derivates from limonene were formed (1,2- and 8,9-epoxylimonene, cis and trans carveol and carvone) according to the chain reaction mechanism. Higher reaction rates and final conversion of limonene over 70% were obtained with a suitable content of copper in the hydrotalcite.

Essential oils of camphor tree (cinnamomum camphora nees & eberm) cultivated in Southern Brazil

The essential oils of two varieties of Camphor tree (Cinnamomum camphora Nees & Eberm, Lauraceae), known as Hon-Sho and Ho-Sho cultivated in experimental stands in Southern Brazil were studied. The essential oils were obtained from the leaves and twigs of young plants by hydrodistillation. The identification of the components was performed using GC, GC/MS and retention indexes on methyl silicone and carbowax phases. The main components identified were linalool in the Ho-Sho and camphor in the Hon-Sho.

Asaricin, the main component of Ocotea opifera Mart. essential oil.

Abstract Investigation of the volatile fraction from the stem bark of Ocotea opifera Mart. led to the isolation and characterization of asaricin, a phenolic derivative with antifungal and insecticidal activity, as the main component, which is described for the first time for the genus Ocotea. The structure has been established by a study of its mono-and bidimensional NMR spectra and mass spectrometry.

Uruguayan essential oils. Composition of leaf oil of Myrcianthes cisplatensis (Camb.) Berg. (‘Guayabo colorado’) (Myrtaceae)

Myrcianthes cisplatensis leaf oil, obtained by steam distillation, was analysed by GC–FID and GC–MS. Twenty-six components were identified in the oil (90% of the total composition); the enantiomeric distribution of α-pinene, β-pinene, limonene, linalool, terpinen-4-ol and α-terpineol was studied by multidimensional HRGC–HRGC. The major component was 1,8-cineole (54%). The enantiomeric purity for the (+) enantiomers for the monoterpenes studied was 96% for α-pinene, 49% for β-pinene, 100% for limonene, 94% for linalool, 50% for terpinen-4-ol and 64% for α-terpineol. Copyright

Composition of the essential oil of Porophyllum ruderale (Jacq.) Cass. from Bolivia

The essential oil of aerial parts of Porophyllum ruderale (Jacq.) Cass. was analysed by HRGC, HRGC–MS (quadrupole) and 26 components (93% of the total composition) were identified. The enantiomeric distribution of β-pinene, sabinene, 4-terpineol and α-terpineol was studied by multidimensional HRGC–HRGC. The major component was sabinene (64%) with an enantiomeric purity of 97% for (+)-sabinene. Copyright

Uruguayan essential oils. Part X. Composition of the oil of Citrus clementine Hort.

The composition of the essential oil of Uruguayan Citrus clementine Hort., prepared in the laboratory from the fruit of Nules and Comune cultivars, has been studied. The volatile fraction was analysed by HRGC and HRGC–MS (quadrupole); 69 components were identified; the enantiomeric distribution of β-pinene, sabinene, limonene, linalol and α-terpineol was studied by multidimensional HRGC–HRGC. Polymethoxylated flavones present in the non-volatile residue were analysed by normal-phase HPLC. The results were compared with those of Italian clementine oil.

Uruguayan essential oils. Part VI. Composition of lemon oil

The composition of 31 genuine Uruguayan lemon oils obtained by industrial processing (FMC on line) during the 1995 season is reported. The samples were representative of all production areas situated in the North and South of Uruguay. The volatile fraction was analysed by HRGC‐FID and GC‐MS; the enantiomeric distribution of b-pinene, sabinene, limonene, linalol, terpinen-4-ol and a-terpineol was studied by multidimensional HRGC‐ HRGC; coumarins and psoralens present in the non-volatile residue were analysed by normal phase HPLC. The results relative to the volatile fraction were compared with those obtained for Uruguayan oils produced in the 1992 and 1993 seasons and for Italian FMC oils. Coumarins and psoralens have been analysed for the first time in Uruguayan oils; their content is compared with that of Italian oils. #1997 by John Wiley & Sons, Ltd.

Pesticide Residues in Uruguayan Lemon Oils

Abstract Organophosphorus and organochlorine residues were studied on 31 samples of Uruguayan lemon oils corresponding to the 1995 season from North and South areas of fruit production in the country. Organochlorine pesticides were absent in all die samples analyzed. The average level of contamination for the organophosphorus pesticides (Chlorpyrifos and Methidathion) was 0.80 ppm and 15.05 ppm for die samples corresponding to the North and South areas, respectively. The results were compared with those obtained in 1993 in lemon oils from the same areas of production.