E. Conde

Low molecular weight polyphenols in leaves of Eucalyptus camaldulensis, E. globulus and E. rudis

Ether soluble polyphenols from leaves of Eucalyptus camaldulensis, E. globulusand E. rudis have been studied. The phenolic aldehyde vanillin, the phenolic acids gallic, protocatechuic and ellagic acids, some flavonol glycosides (rutin, quercetin-3-arabinoside, quercetin-3,7-dirhamnoside, quercitrin, kaempferol-3-arabinoside and their aglycones), one flavanone (naringenin) and two flavones (luteolin and apigenin) were identified and quantified. Some ellagitannins, flavonols and flavanones were recognized according to their ultra-violet spectra. E. camaldulensis and E. rudis showed the highest concentrations and varieties of flavonol glycosides, whilst E. globulus was characterized by high concentrations of ellagitannins.

Chemical Characterization of Reproduction Cork from Spanish Quercus Suber

Abstract The chemical composition of Quercus suber reproduction cork was studied in planks from three different trees at different stages of their industrial processing and in samples collected in seven locations in the three main Spanish production areas. Extracts in chloroform, methanol and water, ne[ugrave]tral and acid fractions of waxes, suberin, lignin, holocellulose and pentosans, and polyphenols (low molecular weight polyphenols and tannins), were quantified. Suberin was the main component in all the samples, followed by lignin and holocellulose in lower concentrations. The most affected variables throughout the industrial processing were: lignin, chloroform and water extracts and the acid fraction of waxes. These variables did not allow one to distinguish the studied trees, which are differentiated by the percentages of methanol extracts, the tannic fraction of polyphenols, the free of suberin residue and the holocellulose content. Four variables were selected as those which provided the greatest...

Suberin Composition of Reproduction Cork from Quercus suber

The monomeric composition of suberins from Spanish Quercus suber was determined by gas chromatography/mass spectrometry in the product of depolymerization of free extractives cork with sodium methoxide-methanol. I-Alkanols (C 20 -C 26 )(1,8-6,4%), alkanoic acids (C 20 -C 24 )(2.2-8,1%), α,ω-alkanedioic acids (C 16 -C 24 )(6,1-10,2%) and ω-hydroxy-alkanoic acids (C 20 -C 26 , being C 22 and C 24 the most abundant) (28,7-37,3%) are identified. The erythro- and threo-9,10-dihydroxyoctadecanedioic (5,4-7,5%), erythro- and threo-9,10,18,-trihydroxyoctadecanoic (7.6-11.8%), 9,10-epoxy-18-hydroxy-octadecanoic (1,2-3,1% and 9,10-epoxy-octadecanodioic acids (1,0-4,4%) and the unsaturated 18-hydroxy-9-octadecenoic (8.1-11,5%) and 9-octadecenedioic (1.5-2.4 %) acids are also important components. Ferulic acid (5,3-9,1%) is the main phenolic component of suberin. The studied samples differ in the relative proportion of the different monomers.

Tannin composition of Eucalyptus camaldulensis, E. globulus and E. rudis. Part I. Wood

In this work, a study on tannins (proanthocyanidins and ellagitannins) is carried out in bark extracts from different Eucalyptus species grown in Spain : E. camaldulensis, E. globulus and E. rudis. The tannin analysis was carried out using HPLC and classical chemical methods. Bark extracts were characterized by the abundance of polymeric proanthocyanidins and by the diversity of ellagitannins, The ellagitannins composition was related with the species and the tree provenance, allowing to discriminate E. globulus from E. camaldulensis and E. rudis.

High Pressure Liquid Chromatographic Analysis of Polyphenols in Leaves of Eucalyptus camaldulensis, E. globulus and E. rudis: Proanthocyanidins, Ellagitannins and Flavonol Glycosides

Polyphenols of adult leaves from Eucalyptus globulus, E. camaldulensis and E. rudis grown in Spain, in two areas with different edaphoclimatical characteristics, were estimated by chemical methods and by high pressure liquid chromatography. Leaf extracts consisted mainly of proanthocyanidins, ellagitannins and flavonol glycosides. Knowledge of the ellagitannins allows the discrimination of the three species, with E. globulus being well differentiated from the other two. However, the pattern of flavonol glycosides only permitted the discrimination of E. rudis with respect to E. camaldulensis and E. globulus.

Polyphenolic composition of bark extracts from Eucalyptus camaldulensis, E. globulus and E. rudis

Polyphenolic composition (flavonoids and phenolic acids and aldehydes) is studied in the Et2O soluble fractions of the methanolic extracts ofEucalyptus camaldulensis, E. globulus andE. rudis bark. Gallic, protocatechuic, vanillic and ellagic acids, and protocatechuic aldehyde were identified in the three species; eriodictyol, quercetin and naringenin, inE. camaldulensis andE. globulus; vanillin, inE. camaldulensis andE. rudis; naringin, quercitrin, luteolin and kaempferol, inE. camaldulensis; taxifolin and apigenin, inE. globulus; and methyl benzoates and cinnamates, inE. rudis. Some unidentified ellagitannins, flavonols and flavanones were also detected. Significant differences in composition among species were found:E. rudis showed the lowest concentration in flavonoids andE. globulus presented higher concentration and variety of ellagitannins than the others.ZusammenfassungDie in Ethylether und Methanol löslichen Extrakte der Rinde von drei Eukalyptusarten wurde hinsichtlich ihre Polyphenolanteile untersucht (Flavanoide, phenolische Säuren und Aldehyde). In allen drei Arten wurden Gallussäure, Protocatechusäure, Vanillinsäure und Ellagsäure identifiziert. Eriodictyol, Quercitin und Naringenin fanden sich inE. camaldulensis undE. globulus, Vanillin inE. camaldulensis undE. rudis. Naringin, Quercitrin, Luteolin und Kampher wurden inE. camaldulensis identifiziert, Taxifolin und Apigenin inE. globulus. Benzoate und Cinnamate wurden inE. rudis entdeckt. Weiterhin wurden einige noch nicht identifizierte Ellagitannine, Flavanole und Flavanone gefunden. Charakteristische Unterschiede zwischen den Arten ware folgende:E. rudis zeigt die niedrigste Konzentration an Flavonoiden;E. globulus weist höhere Konzentrationen und größere Variationen der Ellagitannine auf.

HPLC analysis of flavonoids and phenolic acids and aldehydes in Eucalyptus spp.

SummaryStandards of the polyphenols occurring in wood, bark and leaf extracts ofEucalyptus spp. (i.e. flavonoids and phenolic acids and aldehydes) have been analyzed by HPLC using reversed phase columns, gradient elution and diode-array detection. The conditions used are reported.

Polyphenolic composition of bark extracts fromEucalyptus camaldulensis, E. globulus andE. rudis

Polyphenolic composition (flavonoids and phenolic acids and aldehydes) is studied in the Et2O soluble fractions of the methanolic extracts ofEucalyptus camaldulensis, E. globulus andE. rudis bark. Gallic, protocatechuic, vanillic and ellagic acids, and protocatechuic aldehyde were identified in the three species; eriodictyol, quercetin and naringenin, inE. camaldulensis andE. globulus; vanillin, inE. camaldulensis andE. rudis; naringin, quercitrin, luteolin and kaempferol, inE. camaldulensis; taxifolin and apigenin, inE. globulus; and methyl benzoates and cinnamates, inE. rudis. Some unidentified ellagitannins, flavonols and flavanones were also detected. Significant differences in composition among species were found:E. rudis showed the lowest concentration in flavonoids andE. globulus presented higher concentration and variety of ellagitannins than the others.ZusammenfassungDie in Ethylether und Methanol löslichen Extrakte der Rinde von drei Eukalyptusarten wurde hinsichtlich ihre Polyphenolanteile untersucht (Flavanoide, phenolische Säuren und Aldehyde). In allen drei Arten wurden Gallussäure, Protocatechusäure, Vanillinsäure und Ellagsäure identifiziert. Eriodictyol, Quercitin und Naringenin fanden sich inE. camaldulensis undE. globulus, Vanillin inE. camaldulensis undE. rudis. Naringin, Quercitrin, Luteolin und Kampher wurden inE. camaldulensis identifiziert, Taxifolin und Apigenin inE. globulus. Benzoate und Cinnamate wurden inE. rudis entdeckt. Weiterhin wurden einige noch nicht identifizierte Ellagitannine, Flavanole und Flavanone gefunden. Charakteristische Unterschiede zwischen den Arten ware folgende:E. rudis zeigt die niedrigste Konzentration an Flavonoiden;E. globulus weist höhere Konzentrationen und größere Variationen der Ellagitannine auf.

Variability of Suberin Composition of Reproduction Cork from Quercus suber Throughout Industrial Processing

Summary The chemical composition of suberin was studied in cork planks from three different trees of Spanish Quercus suber at four different stages of the industrial processing of first transformation: stripping (a), first rest (b), boiling followed by open air rest (c1) and boiling followed by store-room rest (c2). The monomeric composition was determined by gas chromatography/mass spectrometry in the product of depolymerization of the free of extractives cork with sodium methoxide-methanol. The average concentrations of the main monomers were: 1-alkanols (C20–C26) 4.17 %; alkanoic acids (C20–C26) 5.99%; α, ω-alkanedioic acids (C16–C24) 6.20%; ω-hydroxy-alkanoic acids (C20–C26) 29.41%; erythro and threo-9,10-dihydroxyoctadecanedioic acids 6.76%, erythro- and threo-9,10,18-trihydroxyoctadecanoic acids 9.50%, 9,10-epoxy-18-hydroxyoctadecanoic acid 2.72% and 9,10-epoxy-octadecanedioic acid 2.93% and ferulic acid 5.05%. Significant differences were observed between samples taken at the stripping and after boiling with store room rest, and both groups of samples differed from those picked after the other two processing stages. Ten components were selected as providing the greatest discrimination among stages: 9-octadecenedioic, 18-hydroxy-9-octadecenoic, eicosanedioic and 9,10-epoxy-18-hydroxy-octadecanoic acids, tetracosanol, and five unidentified components.

Waxes composition of Quercus suber reproduction cork from different Spanish provenances

Summary The chemical composition of waxes was studied in Quercus suber cork planks collected in seven localities of the three main production areas of Spain. Waxes were extracted with chloroform (CHCl3) and the extract was submitted to saponification in order to obtain the neutral and acid fractions. The trimethylsilyl derivatives of both fractions were analysed by GC-MS.The seven populations cannot be distinguished by their total contents of waxes (Chloroform extract) and of the neutral and acid fraction. This lack of differences could be due to the important variability among samples of each population.The neutral fraction was mainly composed of fatty alcohols (all the even members from C18 to C26, with traces of the intermediate odd members and some unsaturated groups) and triterpenes (11 components, among them friedelin, betulin and cerin were identified) and a very small amount of monocarboxylic fatty acids (C16 and C24 members) was also present. The main group of components of the acid fraction was that of fatty acids (saturated even C14–C24 and odd C15, C17, C21 members, accompanied by a great amount of unsaturated terms and some ω-hydroxyacids, 18-hydroxy-9,12-octadecadienoic and 18-hydroxy-9-octadecenoic acids). Four triterpenes and the C20 and C24 alcohols were also detected in the acid fraction. Significant differences were found among the corks of the various provenances in the global contents of alcohols and triterpenes and in these individual components contents of the neutral fraction. Concerning the differences among the various provenances in the contents of the groups of fatty acids, alcohols, and triterpenes in the acid fraction, a higher number of differences were obtained in the comparisons of the contents of acids and triterpenes, whereas the differences were practically null in the case of the alcohols. When the differences were studied considering the individual compounds, the relation with the behaviour of the contents of the groups of components was not as clear as it happens in the neutral fraction. In this case, the differences were scarcer and they did not show a unique pattern, neither in the components, nor the populations. There is no correspondence in the differences among the provenances regarding the components of the neutral fraction or those of the acid fraction. No clear relationship was found between the geographical proximity of the provenances and chemical similarity of the waxes composition.