A galactose-rich heteropolysaccharide extracted from "jaboticaba" (Plinia cauliflora) peels.

The objective of this work was to extract, identify and characterize a galactose-rich heteropolysaccharide (GH) from "jaboticaba" peel. The best conditions to extract the GH according to a 23 full-factorial experimental design were 90 °C/30 min/pH 1.0, resulting in a 32.32 % yield using lyophilized sample. The chemical structure analyzed by GC/MS and NMR spectra (HSQC/HSQC-TOCSY) showed that the main chain of GH consists of a (1→4) galactoside branched at carbon 3, containing galactose (67.21 %), glucose (15.78 %), arabinose (9.78 %), rhamnose (2.26 %) and traces of esterified and non-esterified uronic acids. Rheological studies revealed that GH suspensions behave as a Newtonian fluid, with calculated molecular mass of 1.48 × 105 Da. The absolute viscosity of 1 % (w/v) aqueous suspension of GH decreased from 25 mPa s to 10 mPa s in NaCl and 7 mPa s in CaCl2, indicating the polyelectrolyte character of GH.

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.

Structure of Agaricus spp. fucogalactans and their anti-inflammatory and antinociceptive properties.

Fucogalactans from Agaricus brasiliensis (EPF-Ab) and A. bisporus var. hortensis (EPF-Ah) were prepared via by aqueous extraction and a purification procedure. EPF-Ab had M(w) 19.4 x 10(3)g/mol and EPF-Ah M(w) 31.1 x 10(3)g/mol. EPF-Ab had a (1-->6)-linked alpha-D-Galp main-chain partially substituted in O-2 by non-reducing end-units of alpha-L-Fucp. EPF-Ah had a similar main-chain with O-2 substitution, but was partially methylated at HO-3, as well as having 2.5% non-reducing end-units of beta-D-Gal. In mice, EPF-Ab gave 39% antinociceptive inhibition (ID(50)>100mg/kg) and no anti-inflammatory activity. EPF-Ah also gave an inhibition of 39% at ID(50) 0.33 mg/kg and also inhibited by 61% (ID(50) 5.0mg/kg) total cell migration and by 32% peritoneal capillary permeability, which is related to the anti-inflammatory effect. The small differences in chemical structure in these polysaccharides thus modified their biological activities.

Chemical and immunological modifications of an arabinogalactan present in tea preparations of Phyllanthus niruri after treatment with gastric fluid.

An arabinogalactan (AG) obtained from tea preparations of Phyllanthus niruri was previously investigated and presented immunological properties when tested with peritoneal mice macrophages. AG was now submitted to acidic and neutral gastric conditions using human gastric fluids and aq. HCl solution. Since the acidic procedures gave rise to the same free monosaccharidic composition, the acid hydrolyzate of AG at pH 2.00 was treated with ethanol to form insoluble (AG-P) and soluble fractions (AG-S). These were analyzed using (13)C NMR, HPSEC, and GC-MS for monosaccharide composition and methylation analyses. The results showed an intense partial degradation, including cleavages of the main chain. AG-S presented the monosaccharides released from the native polymer and some oligosaccharides as shown by methylation data. AG-P contained larger molecular fragments comprising the internal units from AG, which were not attacked by the hydrolysis condition. Both fractions were tested in peritoneal mice macrophages and remained active, promoting an increase of superoxide anion production of 2.0 and 2.3-fold, at 250 microg/mL, for AG-S and AG-P, respectively. When compared to AG, a slight diminished response was observed, revealing a structure-activity relation. The significance of the results is that most plant extracts are orally ingested and will reach the gastrointestinal tract before performing a biological function, so checking these changes is crucial to propose future clinical therapies based on the rational use of phytomedicine.

Unusual partially 3-O-methylated alpha-galactan from mushrooms of the genus Pleurotus.

Indistinguishable partially 3-O-methylated galactans were isolated from the edible basidiomycetes Pleurotus eryngii and Pleurotus ostreatoroseus. They were obtained via successive aqueous extraction, freeze-thawing, precipitation with Fehling solution of soluble material, and ultrafiltration. Mono- and bidimensional 13C and 1H-nuclear magnetic resonance spectroscopy (HMBC, HETEROTOCSY, COSY, and HMQC), and methylation analysis were used to determine their structures. They were linear, partially 3-O-methylated, (1-->6)-linked alpha-d-galactans containing Gal and 3-Me-Gal, in a 3:1 molar ratio (GC-MS of alditol acetates).

Chemical and biological properties of an arabinogalactan from Phyllanthusniruri.

Phyllanthus niruri is a well-known herb widely used medicinally in Asia, Africa, and South America. Aqueous extraction of the intact plant provided an acidic arabinogalactan, which was characterized chemically, and its effects on peritoneal macrophage activation were determined. Methylation analyses and (13)C NMR spectroscopy showed it to have a complex structure with a (1-->4)-linked beta-Galp main chain, substituted by rhamnose, galacturonic acid, arabinose, xylose, galactose, and glucose-containing side chains, with nonreducing end-units of arabinofuranose, xylopyranose, galactopyranose, and glucopyranose. In immunological studies, the arabinogalactan stimulated superoxide anion production, when tested using peritoneal macrophages of mice, but did not interfere with the nitric oxide pathway. Thus, traditional aqueous extraction methods, such as decoction and infusion, provide a major polysaccharide, which stimulates an intense biological response in macrophages: this could represent an interesting approach in phytotherapeutic treatments.

Xylans from the medicinal herb Phyllanthus niruri.

Phyllanthus niruri is a well-known medicinal herb that is widely used in Asia, Africa, and South America. The characterization of two purified polysaccharides from the whole plant has been investigated. Methylation analysis and (13)C NMR spectroscopy showed the chemical structure of two xylans. A hot 15% aqueous KOH fraction yielded a linear beta-(1-->4)-linked xylan, and 2% aqueous KOH afforded a complex acidic heteroxylan, with a (1-->4)-linked beta-Xylp main chain, substituted by rhamnose, arabinose, and 4-O-methylglucuronic acid side chains. These contained nonreducing end-units of arabinose, xylose, galactose, glucose, and nonmethylated glucuronic acid.

Effect of a soluble alpha-D-glucan from the lichenized fungus Ramalina celastri on macrophage activity.

An alpha-glucan from the lichen Ramalina celastri has previously been demonstrated to have cytotoxic effects against HeLa cells. This polysaccharide was studied using Sarcoma-180 cells as tumoral model, and its effects on peritoneal exudate cells, namely, hydrogen peroxide production, phagocytic activity and cell eliciting activity are evaluated. Tumors developing in animals treated with the glucan at a dose of 200 mg kg(-1), had a tumor size approximately 80% smaller than that of the control group, showing an impairment of tumor establishment. The polysaccharide was injected into mice not bearing a tumor and after 7, 15 and 30 days the cells were collected from the peritonea. The number of peritoneal cells increased approximately 130% 7 days after inoculation, and then gradually decreased. Hydrogen peroxide production was 75% greater 7 and 15 days after inoculation, on in vitro phorbol myristate acetate (PMA) triggering. Without PMA, the difference in hydrogen peroxide production was not significant. Phagocytic assays using fluorescent beads showed that the uptake increased 7 and 15 days after inoculation, when compared with the control. These results thus suggest a possible role of the R. celastri glucan as a biological response modifier (BRM).