Rheological behavior of high methoxyl pectin from the pulp of tamarillo fruit (Solanum betaceum).

Rheological behavior of a high methyl-esterified pectic fraction (STW-A) from tamarillo was evaluated at different concentrations in water and with sucrose (50% w/w, pH 3). STW-A dispersions at 3, 5, and 8% (w/w) showed low apparent viscosities, shear-thinning and liquid-like behaviors. They were well fitted using the Ostwald-de Waele model and obey the Cox-Merz rule. The viscosity and the viscoelastic behavior were greatly modified by the presence of sucrose. STW-A at 1% (+ sucrose) showed shear-thinning and concentrated solution behavior. Pronounced shear-thinning and gel-like behaviors were obtained with STW-A at 2 and 3% (+ sucrose). Their flow curves profiles were better fitted using the Hershel-Bulkley model and not followed the Cox and Merz rule. Temperature sweeps (5-80°C) showed that STW-A formed thermostable gels. Altogether, our results suggested tamarillo can be a new source of pectin with potential applications as thickeners/gelling agents depending on solvent or applied processes.

Monosaccharide composition of glycans based on Q-HSQC NMR.

Glycans have essential functions related to structural architecture and specific cell surface phenomena, such as differentiation, biosignalling, recognition and cell-cell interaction, with the carbohydrate structure determining main function in the cell. Due to the importance of the primary structure, the monosaccharide composition is crucial to show the glycan structure. We now present a method for complex carbohydrates based on NMR spectroscopy, which has shown to give similar results to those obtained by the classic GC-MS-carboxy-reduction/deuterium labeling approach. Quantitative HSQC, through JCH dependence showed 155 Hz as the best value for (1)H/(13)C anomeric aldoses, allowing milli-microM detection using conventional inverse probe heads. Combining the quantification of native monosaccharide units of the glycan and those from the hydrolyzed product, a strong correlation occurs between the molecular mobility of the monosaccharide units, giving rise to some insights on the dynamic properties of the parent glycan.

Fucomannogalactan and glucan from mushroom Amanita muscaria: structure and inflammatory pain inhibition.

A fucomannogalactan (FMG-Am) and a (1→3), (1→6)-linked ß-D-glucan (ßGLC-Am) were isolated from Amanita muscaria fruiting bodies. These compounds' structures were determined using mono- and bi-dimensional NMR spectroscopy, methylation analysis, and controlled Smith degradation. FMG-Am was shown to be a heterogalactan formed by a (1→6)-linked α-D-galactopyranosyl main chain partially substituted at O-2 mainly by α-L-fucopyranose and a minor proportion of ß-D-mannopyranose non-reducing end units. ßGLC-Am was identified as a (1→3)-linked ß-D-glucan partially substituted at O-6 by mono- and a few oligosaccharide side chains, which was confirmed after controlled Smith degradation. Both the homo- and heteropolysaccharide were evaluated for their anti-inflammatory and antinociceptive potential, and they produced potent inhibition of inflammatory pain, specifically, 91±8% (30 mg kg(-1)) and 88±7% (10 mg kg(-1)), respectively.

Lactarius rufus (1→3),(1→6)-ß-D-glucans: structure, antinociceptive and anti-inflammatory effects.

Medicinal health benefits uses of edible as well as non-edible mushrooms have been long recognized. The pharmacological potential of mushrooms, especially antitumor, immunostimulatory and anti-inflammatory activities has been documented. Wild ectomycorrhizal mushroom, Lactarius rufus had the anti-inflammatory and antinociceptive potential of their polysaccharides evaluated using the formalin model. Two structurally different (1→3),(1→6)-linked ß-D-glucans were isolated from fruiting bodies. Soluble (FSHW) ß-D-glucan 1-30 mg kg(-1) produced potent inhibition of inflammatory pain caused by formalin when compared with the insoluble one (IHW), suggesting that solubility and/or branching degree could alter the activity of ß-glucans. Their structures were determined using mono- and bi-dimensional NMR spectroscopy, methylation analysis, and controlled Smith degradation. They were ß-D-glucans, with a main chain of (1→3)-linked Glcp residues, substituted at O-6 by single-unit Glcp side chains (IHW), on average to every fourth residue of the backbone, or by mono- and few oligosaccharide side chains for soluble ß-glucan.

Cytotoxic effect of Agaricus bisporus and Lactarius rufus ß-D-glucans on HepG2 cells.

The cytotoxic activity of ß-D-glucans isolated from Agaricus bisporus and Lactarius rufus fruiting bodies was evaluated on human hepatocellular carcinoma cells (HepG2). NMR and methylation analysis suggest that these ß-d-glucans were composed of a linear (1→6)-linked and a branched (1→3), (1→6)-linked backbone, respectively. They both decreased cell viability at concentrations of up to 100 µg mL(-1), as shown by MTT assay. The amount of LDH released and the analysis of cell morphology corroborated these values and also showed that the ß-D-glucan of L. rufus was more cytotoxic to HepG2 cells than that of A. bisporus. The treatment of HepG2 cells with L. rufus and A. bisporus ß-D-glucans at a dose of 200 µg mL(-1) for 24h promoted an increase of cytochrome c release and a decrease of ATP content, suggesting that these polysaccharides could promote cell death by apoptosis. Both ß-D-glucans were tested against murine primary hepatocytes at a dose of 200 µg mL(-1). The results suggest that the L. rufus ß-d-glucan was as cytotoxic for hepatocytes as for HepG2 cells, whereas the A. bisporus ß-D-glucan, under the same conditions, was cytotoxic only for HepG2 cells, suggesting cell selectivity. These results open new possibilities for use of mushroom ß-D-glucans in cancer therapy.

Chemical and biological properties of a highly branched ß-glucan from edible mushroom Pleurotus sajor-caju.

Hot aqueous extraction of the basidiocarps of the mushroom Pleurotus sajor-caju provided a cold water-soluble, gel-like glucan, which was characterized chemically, and its effects on RAW 264.7 cell line (mouse leukaemic monocyte macrophage) activation were determined. NMR spectroscopy, HPSEC, methylation analysis, and a controlled Smith degradation showed it to have a branched structure with a (1→3)-linked ß-Glcp main-chain, substituted at O-6 by single-unit ß-Glcp side-chains, on the average of two to every third residues of the backbone, with a molar mass of 9.75 × 10(5) g mol(-1). In macrophage cell culture, the ß-glucan induced production of NO and the cytokines TNF-α, IL-1ß, these effects being very similar as those of Escherichia coli serotype 0111:B4 Sigma-Aldrich lipopolysaccharide (LPS), although not modifying the response of LPS-activated macrophages. The results suggest that the (1→3), (1→6)-linked ß-glucan from P. sajor-caju may have potential for immunological activities, although additional experiments are necessary for a better understanding of the mechanisms involved.

Structure and degree of polymerisation of fructooligosaccharides present in roots and leaves of Stevia rebaudiana (Bert.) Bertoni.

Fructooligosaccharides have been isolated from roots and leaves of Stevia rebaudiana, by hot aqueous extraction, followed by precipitation with ethanol. Their structure has been determined using methylation and NMR analysis, MALDI-TOF, and ESI-MS. Fructooligosaccharides contained almost exclusively (2→1)-linked ß-fructofuranosyl, with terminal α-glucopyranosyl and ß-fructofuranosyl units. MALDI-TOF and ESI-MS analyses showed the wide range of degree of polymerisation (DP) present in various extracts. From roots and leaves, three different fractions gave profiles of homologous series, with DPs ranging up to 17 with MALDI-TOF and 19 using ESI-MS. These inulin-type fructooligosaccharides were the major component of extracts from S. rebaudiana roots and significant components from the leaves.

In vitro antiherpetic and antirotaviral activities of a sulfate prepared from Mimosa scabrella galactomannan.

A chemically sulfated galactomannan (BRS) from seeds of Mimosa scabrella had in vitro antiviral activity against Herpes simplex virus 1 (HSV-1), but not against Simian rotavirus A/SA11 (SiRV-A/SA11). It was examined by (13)C NMR spectroscopy, which showed the sulfate groups to be mainly at C-6 of galactose residues. BRS had a selective inhibition against HSV-1 during its attachment step, having an IC(50) lower than 2.5microg/ml, determined by plaque reduction, and a selectivity index of greater than 181, suggesting that the antiviral effect is likely due to interactions between the virus and BRS, being influenced its overall surface charge.

Fatty acid composition of the tropical lichen Teloschistes flavicans and its cultivated symbionts.

Fatty acid components, in both the free and combined form of the intact tropical lichen Teloschistes flavicans, and its isolated photobiont and mycobiont, were analyzed by GC-MS of derived methyl esters. Its rDNA analysis confirmed that the isolated cultured symbionts belong to the genera Trebouxia and Teloschistes, respectively. The fatty acid composition of the lichen did not correspond to those found in the isolated symbionts, suggesting that the fatty acid metabolism is markedly influenced by the symbiosis. Differences in the fatty acid composition in the lichen were observed during the summer (27 degrees C), when the main fatty acids were saturated and in the winter (22 degrees C) when an increase of unsaturated fatty acids occurred. Similar differences of composition were also observed for the cultured mycobiont at different temperatures. The increase in the unsaturation level at low temperatures would maintain the membrane fluidity. Our results are the first on the fatty acids of a tropical lichen and suggest that it is sensitive to small temperature variations, which influences its saturated and unsaturated fatty acid composition.

Chemotypes significance of lichenized fungi by structural characterization of heteropolysaccharides from the genera Parmotrema and Rimelia.

Galactoglucomannans were isolated from the lichenized fungi of the genus Parmotrema (Parmotrema austrosinense, Parmotrema delicatulum, Parmotrema mantiqueirense, Parmotrema schindlerii, and Parmotrema tinctorum and that of Rimelia (Rimelia cetrata and Rimelia reticulata) via successive hot alkaline extraction and precipitation with Fehling solution. The structure of each polysaccharide was investigated using 13C NMR and HSQC-DEPT spectroscopy, methylation analysis, and HPSEC-MALLS. The galactoglucomannans had a (1-->6)-linked main chain of alpha-Manp units, substituted preferentially at O-2 and O-4 by alpha-Galp and beta-Galp nonreducing end-units, respectively. The C-1 region of the 13C NMR spectra of these heteropolysaccharides is typical of the lichen species, and is an additional tool in lichenized fungi classification.

Identification of lactose and D-volemitol in the lichen Sticta damaecornis

We now describe the identification, in the lichen Sticta damaecornis, of lactose, not previously found in lichens, and of D-volemitos which was unexpected taxonomically