The leaves of the annual plant Impatiens parviflora DC., a herbal medicine in Asian countries and invasive in managed forests and natural environments in Central Europe, have the potential as a source of bioactive phenolic compounds and polysaccharides. Extractives accounted for ∼22% of the leaves, whereby, the methanolic extract contains mainly caffeic acid, ferulic acid, kaempferol, and quercetin derivatives, and 1,2,4-trihydroxynaphthalene-1-O-glucoside. From the pre-extracted leaves, non-cellulosic polysaccharides were isolated by a five-step extraction procedure using as extractants cold water, 0.05 M EDTA, and DMSO in the first three steps, and 1% and 5% NaOH in the last two steps. The isolated polysaccharide fractions were characterized by chemical, physicochemical, and spectroscopic analyses (FTIR and (1)H NMR). The first three fractions contained mainly pectin and the alkali-extracted ones methylglucuronoxylan and arabinogalactan. The suggested structural features were confirmed using HSQC NMR and COSY experiments for polysaccharides of the EDTA-fraction and the Pronase-treated 5% NaOH-fraction. The EDTA fraction comprised a pectin with low degree of methyl-esterification (DM, 37%) with few rhamnogalacturonan RG I segments bearing β-1,4-galactan as side chains. The alkali-extracted fraction comprised a degraded methylglucuronoxylan and type II 3,6-arabinogalactan in about equal amounts.
Tamarind seed xyloglucan was subjected to different radiation sources-ultrasound, gamma-radiation, and microwave heating, and the effects of these energies upon its molecular and structural properties were characterised by gel permeation chromatography, viscometry, sugar analysis, FT-IR and NMR spectroscopic techniques. In dependence on the degradation methods and experimental conditions used, the decrease of the relative molecular mass (RMM) was accompanied with alteration of the primary structure. Depolymerisation by ultrasound at a frequency of 20 kHz yielded after 120 min products with RMM of about 131 x 10(3) without significant alteration of the primary structure of the polysaccharide. Intense degradation of XG started by microwave heating at pH 1.5 yielding polymers with RMM in the range of higher oligosaccharides, however, with changed sugar composition due to cleavage of the glycosyl side chains. At gamma-irradiation doses >40 kGy, next to chain cleavage, very high-molecular mass components exhibiting UV(254)-absorption were formed, and the RMM decreased to about 50 x 10(3) at the highest applied dose (100 kGy). The results of the comparative study suggest that ultrasonication was the most convenient procedure to decrease the RMM of xyloglucan to 130 x 10(3) and preserve the primary structure of the polysaccharide.
The composition, main structural features and molecular properties of exopolysaccharides (EP) produced by Cryptococcus laurentii var. laurentii CCY 17-3-16 under optimal (EPo) and NaCI-stress conditions (EPs) as well as their subfractions isolated by gel chromatography were studied using chemical, FT-IR and NMR spectroscopy methods. The results showed that under stress conditions the yeast produced EP with a lower content of protein and phosphorus. In comparison to EPo, the EPs exhibited a substantially larger proportion of high molecular mass populations. NMR analysis of EPs revealed a higher degree of branching with single xylose side chains of the heteromannan components. The increase of the molecular mass and degree of branching of the macromolecular chains of the heteromannan components might in part be related to the function of EPs to protect the yeast cells from water loss and maintain growth conditions under the salt stress.
- MeSH
- adjuvancia imunologická aplikace a dávkování farmakologie terapeutické užití MeSH
- finanční podpora výzkumu jako téma MeSH
- fytoterapie terapeutické užití MeSH
- kostní dřeň účinky léků MeSH
- léčivé rostliny MeSH
- mitogeny aplikace a dávkování farmakologie MeSH
- myši MeSH
- rostlinné extrakty farmakologie terapeutické užití MeSH
- stavba rostlin MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
