Polysaccharides from the infusions of P. tridentatum, F. angustifoliaand M. suaveolens

The use of plant infusions for medicinal purposes is present in secular traditions of all civilizations. In Portugal, in Trás-os-Montes region, the small shrub (Pterospartum tridentatum), the narrow-leafed ash (Fraxinus angustifolia), and the apple mint (Mentha suaveolens) are plants used for such purposes. According to the popular tradition, the infusions of P. Tridentatum, F. Angustifolia, and M. suaveolens protect against diabetes, high blood pressure, high levels of cholesterol, and uric acid [1].These health benefits are associated with the presence of phenolic compounds, essential oils, and polysaccharides, among others. Although phenolic compounds and essential oils have been studied in detail for more than two decades, the structures of the polysaccharides present in plant infusions and their involvement in the health benefits is still incipient. Infusions were prepared in two different ways: a traditional method, consisting in the infusion of the vegetal material with boiling water during five minutes (Method A), and a more intensive method, consisting in the infusion of the vegetal material with boiling water during four hours (Method B). The high molecular weight material was obtained by concentrating and dialyzing the extracts obtained by Methods A and B. The high molecular weight material obtained with the Method B contained more glycosidic material than the obtained with Method A. The high molecular weight material was fractionated using ethanol precipitation yielding fractions especially rich in uronic acids besides considerable amounts of arabinose, galactose, glucose and rhamnose, suggesting the presence of pectic polysaccharides. Detailed monomeric composition and glycosidic linkages of each fraction will be presented

Monomeric composition and linkage analysis of the polysaccharides present in the infusions of Fraxinus angustifolia leaves

In the Trás-os-Montes region, the use of infusions of Fraxinus angustifolia dried leaves as a protection against high levels of cholesterol, blood pressure and uric acid is widespread. Pectic polysaccharides isolated from the infusions of some medicinal plants have been reported as biologically active [1,2]. Pectic poly-saccharides have been described as structurally complex polymers, exhibiting different polymeric building blocks: homogalacturonans (HG), rhamnogalacturonans-I (RG-I), rhamnogalacturonans-II (RG-II) and xylogalacturonans (XG) [3]. The backbone of RG-I can be partly substituted with various side chains, such as arabinans, type-I and type-II arabinogalactans (AG-I and AG-II). The aim of this work is to provide a first insight of the nature of the pectic polysaccharides present in the infusions of F. angustifolia dried leaves

Composição glicosídica e actividade antioxidante de extractos de infusões de folhas de freixo (Fraxinus angustifolia)

Neste trabalho foram preparadas infusões de folhas de freixo secas. Cada infusão foi dividida em duas fracções, tendo uma sido utilizada para a obtenção do material polimérico por diálise (Dial) e a outra submetida a uma extracção em fase sólida C18, sendo a fase aquosa recolhida composta pelo material não retido (C18 H2O) e a fracção de metanol composta pelo material retido e eluído neste solvente (C18 MeOH). A análise da composição glicosídica mostrou que a fracção C18 H2O era rica em glucose e manose; a fracção C18 MeOH era rica em glucose e a fracção Dial era rica em ácidos urónicos, arabinose, galactose e glucose. A fracção C18 H2O era a mais pobre em compostos fenólicos e a que apresentou menor actividade antirradicalar. As fracções C18 MeOH e Dial apresentaram actividades antirradicalares semelhantes entre si, apesar de possuírem quantidades de compostos fenólicos totais distintas. A fracção Dial, constituída por material de peso molecular superior a 12-14 kDa, foi ainda sujeita a uma análise de ligações glicosídicas, através da análise por GC-MS dos respectivos acetatos de alditol parcialmente metilados. O resultado obtido permitiu inferir a presença de resíduos glicosídicos característicos de arabinogalactanas do tipo II, xiloglucanas e xilanas

Polysaccharides from the infusions of P. tridentatum, F. angustifolia, and M. suaveolens

The use of plant infusions for medicinal purposes is present in secular traditions of all civilizations. In Portugal, in Trás-os-Montes region, the small shrub (Pterospartum tridentatum), the narrow-leafed ash (Fraxinus angustifolia), and the apple mint (Mentha suaveolens) are plants used for such purposes. According to the popular tradition, the infusions of P. Tridentatum, F. Angustifolia, and M. suaveolens protect against diabetes, high blood pressure, high levels of cholesterol, and uric acid [1].These health benefits are associated with the presence of phenolic compounds, essential oils, and polysaccharides, among others. Although phenolic compounds and essential oils have been studied in detail for more than two decades, the structures of the polysaccharides present in plant infusions and their involvement in the health benefits is still incipient. Infusions were prepared in two different ways: a traditional method, consisting in the infusion of the vegetal material with boiling water during five minutes (Method A), and a more intensive method, consisting in the infusion of the vegetal material with boiling water during four hours (Method B). The high molecular weight material was obtained by concentrating and dialyzing the extracts obtained by Methods A and B. The high molecular weight material obtained with the Method B contained more glycosidic material than the obtained with Method A. The high molecular weight material was fractionated using ethanol precipitation yielding fractions especially rich in uronic acids besides considerable amounts of arabinose, galactose, glucose and rhamnose, suggesting the presence of pectic polysaccharides. Detailed monomeric composition and glycosidic linkages of each fraction will be presented

Polysaccharide composition of Fraxinus angustifolia Leave infusions

The use of plant infusions with medicinal purposes, such as the ones from members of the Fraxinus genus, is an ancient practice that has been reported by popular medicine [1]. The health benefits are associated with the presence of phenolic compounds and polysaccharides, among others [2]. Although phenolic compounds have been studied in detail for more than two decades, the characterization of the polysaccharides present in plant infusions and their involvement in the health benefits is still incipient. The polysaccharides of F. angustifolia dried leaves were recovered by dialysis (12-14 kDa cut-off). The high molecular weight material comprised approximately 2% of the total soluble material obtained from the infusions. Total sugars in fraction were 27%, with a monomeric composition rich in Ara (15.2 ± 1.9 %), Gal (17.7 ± 0.4 %), Glc (30.1 ± 1.3 %) and uronic acids (18.9 ± 2.9 %). Analysis of the glycosidic linkage composition showed the presence of (1→6)-, (1→3,6)- and (1→3)-Gal with a proportion of 5:3:1, respectively, and also a high percentage of Ara terminally linked, diagnostic of the presence of Type II arabinogalactans [3]. Similar features have been reported in biological active Type II pectic arabinogalactans obtained from aqueous extracts of the roots of C. tinctorium [4]. The EC50 for the antioxidant activity (DPPH radical assay) was 0.34±0.04 mg/mL, showing lower antioxidant activity than that reported for aqueous extracts of hazel leaves (0.16-0.20 mg/mL) [5], but higher than that reported for the table olives ‘‘alcaparras’’ aqueous extracts (0.47± 0.03) [6]. The high molecular weight material was fractionated by ethanol precipitation in four distinct fractions: WI, a cold water insoluble residue (20.3% yield); Et50, material precipitated with 50% ethanol (17.9%); Et75, material precipitated with 75% ethanol (21.1%); and SN, material that remained soluble in 75% ethanol solution (40.7%). Fractions Et50, Et75 and SN were submitted to solid phase extraction (C18 cartridge). The Et50 and Et75 C18 non-retained fractions were rich in Ara (13.5-17.2%), Gal (27.1-35.7%) and uronic acids (25.9-35.2%), suggesting the occurrence of heterogeneous pectic arabinogalactans. NMR experiments are in progress in order to evaluate the detailed structure of the type II pectic arabinogalactans isolated from the infusions of dried leaves of F. angustifolia

Caracterização dos polissacarídeos das paredes celulares da grainha de uva com vista à valorização do óleo por aplicação de enzimas exógenas

ISBN 972-9372-29-