António Proença da Cunha

Physicochemical attributes and pollen spectrum of Portuguese heather honeys

Abstract The qualities of selected honey samples of “Serra da Lousa” (Portugal) from three consecutive harvests (20 samples from each harvest) were evaluated by determing the pollen spectrum and physicochemical attributes. The following determinations were carried out: moisture, electrical conductivity, hydroxymethylfurfural, diastase activity, pH, acidity (free, lactone and total), formol number, reducing sugars, apparent sucrose, insoluble material and ash. The samples were found to meet all major national and international honey specifications. Honeys were considered to be monofloral whenever the dominant pollen was found to be over 45% of total pollen. From the 60 studied samples, 70% were monofloral honeys from Erica sp., 17% monofloral honeys from Ericaceae (Erica sp. and Calluna vulgaris (L.) Hull) and 13% multifloral honeys with a high percentage of Erica sp.

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.

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 .

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.

Composition and variability of the essential oils of Thymus species from section Mastichina from Portugal

The composition and chemical polymorphism of the essential oils of several populations of Thymus mastichina subsp. mastichina, T. mastichina subsp. donyanae and T. albicans, which belong to the Section Mastichina of the genus Thymus, were investigated by GC and GC-MS. All representative population samples of these three taxa were characterized by their high 1,8-cineole content, which is a discriminatory and common feature of the essential oils of the Section Mastichina. Linalool is another major constituent of the essential oils of some populations of T. mastichina subsp. mastichina and T. albicans. The essential oil of T. mastichina subsp. donyanae is also characterized by large amounts of borneol. This feature distinguishes its essential oil from the type subspecies. To study the infraspecific variability of each taxon, the results obtained in the GC analyses of the volatile oil of several idtividual plants from each population were submitted to a Principal Component Analysis and a Cluster Analysis, which showed that the essential oils of the only population investigated of T. mastichina subsp. donyanae have no chemical polymorphism, whereas the oils of T. mastichina subsp. mastichina and T. albicans have infraspecific variability. Some correlation between the amount of linalool in the essential oil of T. mastichina subsp. mastichina and the Atlantic humidity was established.

Estudo comparativo dos óleos voláteis de algumas espécies de Piperaceae

O presente trabalho teve por objetivo a analise comparativa dos oleos volateis de especies da familia Piperaceae. As especies estudadas foram as seguintes: Piper aduncum, P. amalago, P. arboreum, P. cernuum, P. hispidum, P. regnelii, P. submarginalum, P. vicosanum e Pothomorphe umbellata. A analise dos oleos volateis foi efetuada pela combinacao de tecnicas de Cromatografia de Fase Gasosa (CG) e de Cromatografia de Fase Gasosa acoplada a Espectrometria de Massa (CG/EM). A porcentagem de identificacao dos constituintes nas analises dos oleos volateis de Piper aduncum, P. amalago, P. vicosanum, P. submarginalum e Pothomorphe umbellata, atingiu valores superiores a 80%. Houve predominância de compostos de natureza sesquiterpenica nas composicoes quimicas das especies analisadas, com excecao de P. hispidum, P. submarginalum e P. vicosanum onde a predominância na composicao foi de monoterpenos. Pelos dados apresentados observou-se que, dentre os compostos majoritarios, os mais frequentes, nas 9 especies estudadas, foram b-pineno (9/9) e espatulenol (9/9), seguidos por E-cariofileno (8/9), oxido de cariofileno (8/9), germacreno D (7/9), a-pineno (7/9) e limoneno (6/9). Pela primeira vez se relata a composicao dos oleos volateis de P. submarginalum e P vicosanum.

Composition and infraspecific variability of essential oil from Thymus camphoratus

Abstract The composition of the essential oils of seven populations of Thymus camphoratus from Portugal and their infraspecific variability were investigated by GC, GC-mass spectrometry and 13C NMR. The results obtained from GC analyses of the volatile oils from individual plants were submitted to Principal Component and Chemometric Cluster analyses. 1,8-Cineole, linalool, borneol, α-pinene, camphene, trans-sabinene hydrate, and terpinen-4-ol were the main constituents. 13 C NMR spectra of the essential oil, previously fractioned by column chromatography, let to the identification of two new oxygenated sesquiterpenes for the genus Thymus: intermedeol, which is reported for the first time in the Lamiaceae, and homalomenol-D. Multivariate analysis enabled four different groups of essential oils to be distinguished: (i) linalool, (ii) borneol, (iii) 1,8-cineole and (iv) 1,8-cineole/borneol.

Chemotaxonomic study on Thymus villosus from Portugal

The composition of the essential oils of four populations of Thymus villosus subsp. lusitanicus (Boiss.) Coutinho from Portugal was investigated by GC and GC-MS. To study the chemical polymorphism the results obtained from GC analyses of the volatile oils from individual plants from four populations were submited to Principal Component and Cluster analyses. A comparision with the essential oil of T. villosus subsp. villosus, previously studied by us was done. Important differences with regard to the major constituents in these two taxa were found. Linalool, geranyl acetate, geraniol and terpinen-4-ol were the main components of the essential oils of T. villosus subsp. lusitanicus, whereas in the oil of T. villosus subsp. villosus p-cymene, myrcene and alpha-terpineol were the major ones. Although, both taxa showed chemical polymorphism, different types of essential oils were characterized in each one: linalool; linalool/ terpinen-4-ol/trans-sabinene hydrate; linalool/1,8-cineole; geranyl acetate/geraniol; geranyl acetate/geraniol/1,8-cineole in T. villosus subsp. lusitanicus and p-cymene/camphor/linalool; p-cymene/borneol; linalool/geraniol/geranyl acetate; alpha-terpineol/camphor/myrcene in T. villosus subsp. villosus. Thus, the two subspecies of T. villosus can be easely differenciated by the composition of their essential oils.

The Essential Oil of Thymus villosus L. ssp. villosus and its Chemical Polymorphism

The composition of the essential oils of six populations of Thymus villosus L. ssp. villosus, an endemic species of Portugal belonging to the section Pseudothymbra Bentham of the genus Thymus (Lamiaceae), was investigated mainly by GC and GC-MS. In order to study the infraspecific variability, the results obtained by the analysis of individual plants were submitted to a principal component analysis and a cluster analysis. Four types of essential oils were found: p-cymene/camphor/linalol, p-cymene/borneol, linalol/geraniol/geranyl acetate, and α-terpineol/ camphor/myrcene.

Contribution for the Characterization of Portuguese Fennel Chemotypes

ABSTRACT Essential oils were obtained from the dried fruit of Foeniculum vulgare Miller subsp. piperitum (Ucria) Coutinho collected from various locations in central Portugal. Gas chromatographic analysis of the oils revealed that the major components, fenchone (6.8–30.8%), methyl chavicol (2.6–36.3%) and (E)-anethole (44.2–74.0%), varied widely. No relationship between component concentrations and fruit ripeness was found. Based on the variation in oil composition between the various taxa, the existence of three chemotypes is proposed.