Safe therapeutics of murine melanoma model using a novel antineoplasic, the partially methylated mannogalactan from Pleurotus eryngii.

A heteropolysaccharide was isolated by cold aqueous extraction from edible mushroom Pleurotus eryngii ("King Oyster") basidiocarps and its biological properties were evaluated. Structural assignments were carried out using mono- and bidimensional NMR spectroscopy, monosaccharide composition, and methylation analyses. A mannogalactan having a main chain of (1→6)-linked α-d-galactopyranosyl and 3-O-methyl-α-d-galactopyranosyl residues, both partially substituted at OH-2 by ß-d-Manp (MG-Pe) single-unit was found. Biological effects of mannogalactan from P. eryngii (MG-Pe) were tested against murine melanoma cells. MG-Pe was non-cytotoxic, but reduced in vitro melanoma cells invasion. Also, 50mg/kg MG-Pe administration to melanoma-bearing C57BL/6 mice up to 10days decreased in 60% the tumor volume compared to control. Additionally, no changes were observed when biochemical profile, complete blood cells count (CBC), organs, and body weight were analyzed. Mg-Pe was shown to be a promising anti-melanoma molecule capable of switching melanoma cells to a non-invasive phenotype with no toxicity to melanoma-bearing mice.

Polysaccharides from peach pulp: structure and effects on mouse peritoneal macrophages.

Pulp from peaches contained polygalacturonic acid and arabinogalactan as main polysaccharides, which were isolated and characterised. The polygalacturonic acid (AE-CWI) contained 95% GalA and its (13)C NMR spectrum showed signals at δ 98.9, 78.0, 71.4, 69.1, 68.4, and 175.1 from C-1, C-4, C-5, C-3, C-2, and C-6 respectively, from (1→4)-linked α-GalpA units. Methylation-MS analysis of carboxy-reduced material (AE-CWI-CR) gave 90% of 2,3,6-Me(3)-galactitol acetate. The arabinogalactan (AE-AG) was composed mainly of Ara (41%) and Gal (50%) and was characterised (methylation analysis and (13)C NMR) as a type II-arabinogalactan. It induced peritoneal macrophage activation in mice, ~70% of cells treated with this fraction (1-50 µg/mL) having morphology of activated cells. However, NO production in macrophages treated with AE-AG was not affected. This suggests a new biological activity for peach polysaccharides.

Exopolysaccharides, proteins and lipids in Pleurotus pulmonarius submerged culture using different carbon sources.

For many years mushrooms have been consumed and appreciated by their nutritional value, and medicinal properties. The traditional mushroom cultivation takes too long and the macrofungi biotechnology has not been explored in its full potential yet. The goal of this work was to observe if different carbon sources could improve the yield and diversify fungi nutrient composition in submerged culture. Pleurotus pulmonarius mycelia and exopolysacharide productions were evaluated using glucose, galactose, xylose and arabinose. The mycelia yield varied depending on the culture medium, and galactose showed to be the best carbon source to produce EPS. Samples that showed the highest protein contents were grown with xylose (19.44%) and arabinose (26.05%). Furthermore, the biomass cultivated with these carbohydrates and with galactose showed five essential amino acids. All cultured biomass showed low lipid contents (∼1%), being composed mainly of unsaturated fatty acids. All EPS fractions showed as main structures glucans and mannogalactans.

Evaluation of the antischistosomal activity of sulfated α-D-glucan from the lichen Ramalina celastri free and encapsulated into liposomes

The antischistosomal activity of the sulfated polysaccharide α-D-glucan (Glu.SO4) extracted from Ramalina celastri was evaluated after encapsulation into liposomes (Glu.SO4-LIPO) in Schistosoma mansoni-infected mice. The effect of treatment with Glu.SO4 and Glu.SO4-LIPO (10 mg/kg) on egg elimination, worm burden and hepatic granuloma formation was assessed using female albino Swiss mice, 35-40 days of age, weighing 25 ± 2 g, infected with 150 cercariae/animal (Biomphalaria glabrata, BH strain). Four groups (N = 10) were studied, two controls (empty liposomes and NaCl) and two treated groups (Glu.SO4-LIPO and Glu.SO4) using a single dose. Parasitological analysis revealed that Glu.SO4-LIPO was as efficient as Glu.SO4 in reducing egg elimination and worm burden. Treatment with free Glu.SO4 and Glu.SO4-LIPO induced a statistically significant reduction in the number of granulomas (62 and 63 percent, respectively). Lectin histochemistry showed that wheat germ agglutinin intensely stained the egg-granuloma system in all treated groups. On the other hand, peanut agglutinin stained cells in the control groups, but not in the treated groups. The present results suggest a correlation between the decreasing number of hepatic egg-granulomas and the glycosylation profile of the egg-granuloma system in animals treated with free Glu.SO4 or Glu.SO4-LIPO.

Evaluation of the antischistosomal activity of sulfated α-D-glucan from the lichen Ramalina celastri free and encapsulated into liposomes.

The antischistosomal activity of the sulfated polysaccharide α-D-glucan (Glu.SO(4)) extracted from Ramalina celastri was evaluated after encapsulation into liposomes (Glu.SO(4)-LIPO) in Schistosoma mansoni-infected mice. The effect of treatment with Glu.SO(4) and Glu.SO(4)-LIPO (10 mg/kg) on egg elimination, worm burden and hepatic granuloma formation was assessed using female albino Swiss mice, 35-40 days of age, weighing 25 ± 2 g, infected with 150 cercariae/animal (Biomphalaria glabrata, BH strain). Four groups (N = 10) were studied, two controls (empty liposomes and NaCl) and two treated groups (Glu.SO(4)-LIPO and Glu.SO(4)) using a single dose. Parasitological analysis revealed that Glu.SO(4)-LIPO was as efficient as Glu.SO(4) in reducing egg elimination and worm burden. Treatment with free Glu.SO(4) and Glu.SO(4)-LIPO induced a statistically significant reduction in the number of granulomas (62 and 63%, respectively). Lectin histochemistry showed that wheat germ agglutinin intensely stained the egg-granuloma system in all treated groups. On the other hand, peanut agglutinin stained cells in the control groups, but not in the treated groups. The present results suggest a correlation between the decreasing number of hepatic egg-granulomas and the glycosylation profile of the egg-granuloma system in animals treated with free Glu.SO(4) or Glu.SO(4)-LIPO.

Some biomolecules and a partially O-acetylated exo-galactomannan containing ß-Galf units from pathogenic Exophiala jeanselmei, having a pronounced immunogenic response.

The pathogenic fungus Exophiala jeanselmei (Ej4) was grown in submerged MM medium, glucose being consumed after six days with maximum biomass and EPS production. Cells were extracted with CHCl3-MeOH (2:1, v/v) yielding a product containing 10% lipid, with high levels of unsaturated C(18:1) (43.6%) and C(18:2) (21.0%), 2D-TLC showed the presence of PE (17.7%), PS (11.6%), PC (35.8%), PI (1.2%) and lyso-phospholipids, LPE (10.7%), LPC (2.0%), PA (10.4%), cardiolipin (10.5%) and glucosyl-ceramide. Analysis of EPS-1 (120 kDa) showed a galactomanan, containing a main chain of Manp-(1→2) (24.2%), substituted by side chains containing terminal Galf (16.8%) and Manp (3.5%) and acetyl groups attached at O-6 of terminal Galf. An immune response against antigens was obtained using Balb/C mice. Anti-EPS-1 antibodies recognized purified fraction containing cellular walls very titer and higher than 1:20,000 for EPS. The studied biomolecules showed biotechnological potential and point to important perspectives in diagnosis of fungi and immunomodulatory products.

Chemical composition of lipopolysaccharides isolated from various endophytic nitrogen-fixing bacteria of the genus Herbaspirillum.

Bacteria from the genus Herbaspirillum are endophytes responsible for nitrogen fixation in gramineous plants of economic importance such as maize, sugarcane, sorghum, rice, and wheat. Some species are known to produce plant growth substances. In contrast, Herbaspirillum rubrisubalbicans strains are known to be mild plant pathogens. The molecular communication between the plant and the microbes might involve lipopolysaccharides present in the outer membrane of these gram-negative bacteria. Phenol-water extraction was used to obtain lipopolysaccharides from 7 strains of Herbaspirillum seropedicae (SmR1, Z67, Z78, ZA95, and M2) and H. rubrisubalbicans (M1 and M4). The electrophoretic profiles and chemical composition of the lipopolysaccharides obtained in the phenol and aqueous extracts were shown herein.

A procedure for characterizing glucans synthesized by purified enzymes of cariogenic Streptococcus mutans.

Extracellular polysaccharide is a virulence factor of the most cariogenic bacteria, Streptococcus mutans. We describe a procedure for chemical analysis of this polysaccharide of S. mutans, using a well-known glucan synthesized by purified enzymes of cariogenic streptococci. Soluble and insoluble glucan from glucosyltransferase D and B respectively, were prepared and analyzed by nuclear magnetic resonance spectroscopy and methylation. Soluble alpha-glucan contained 60% of (1-->6)-linkages and 17% of branching while insoluble alpha-glucan was composed of 57% of (1-->3)- and 28% of (1-->6)-linkages with 8% branching. The described procedure could be important focusing future studies on in vivo biofilm.

A 3-O-methylated mannogalactan from Pleurotus pulmonarius: structure and antinociceptive effect.

A polysaccharide (Mw 2.39x10(4)g/mol) was extracted with cold water from the basidiomycete Pleurotus pulmonarius, and its antinociceptive and anti-inflammatory properties were evaluated. It was a mannogalactan (MG), whose structure was characterized using mono- and two-dimensional NMR spectroscopy, methylation analysis, and a controlled Smith degradation. It had a main chain of (1-->6)-linked alpha-D-galactopyranosyl and 3-O-methyl-alpha-D-galactopyranosyl units, both of which are partially substituted at O-2 by beta-D-mannopyranosyl non-reducing ends. The MG was tested for its effects on the acetic acid-induced writhing reaction in mice, a typical model for inflammatory pain, causing a marked and dose-dependent inhibition of the nociceptive response, with ID50 of 16.2 (14.7-17.7)mg/kg and inhibition of 93+/-3% at a dose of 30mg/kg. An inflammatory response was not inhibited.

Anticoagulant and antithrombotic activities of a chemically sulfated galactoglucomannan obtained from the lichen Cladonia ibitipocae.

A galactoglucomannan (GGM), isolated from the lichen Cladonia ibitipocae, consisted of a (1-->6)-linked main chain of alpha-mannopyranose units, substituted by alpha- and beta-D-galacto (alpha- and beta-D-Galp)-, beta-D-gluco (beta-D-Glcp)- and alpha-D-mannopyranosyl (alpha-D-Manp) groups, and was sulfated giving a sulfated polysaccharide (GGM-SO4) with 42.2% sulfate corresponding to a degree of substitution of 1.29. NMR studies indicated that after sulfation, the OH-6 groups of galactopyranosyl and mannopyranosyl units were preferentially substituted. GGM-SO4 was investigated in terms of its in vitro anticoagulant and in vivo antithrombotic properties. Those of the former were evaluated by its activated partial thromboplastin (APTT) and thrombin time (TT), using pooled normal human plasma, and compared with that of 140 USP units mg(-1) for a porcine intestinal mucosa heparin. Anticoagulant activity was detected in GGM-SO4, but not in GGM. The in vivo antithrombotic properties of GGM-SO4 were evaluated using a stasis thrombosis model in Wistar rats, intravenous administration of 2 mg kg(-1) body weight totally inhibiting thrombus formation. It caused dose-dependent increases in tail transection bleeding time. The results obtained showed that this sulfated polysaccharides is a promising anticoagulant and antithrombotic agent.

Sulfonoglycolipids from the lichenized basidiomycete Dictyonema glabratum: isolation, NMR, and ESI-MS approaches.

Two distinct sulfonoglycolipid fractions were isolated from the basidiolichen Dictyonema glabratum by chromatography on Diethylaminoethyl (DEAE)-Sepharose, which resulted in rapid elution, followed by partition between aqueous sulfuric acid and an ethyl acetate-methanol-chloroform mixture and the content of the organic layer chromatographed of a column of silicic acid. The products were examined by nuclear magnetic resonance spectroscopy in their native rather than their acetylated forms, as in previous investigations. Each was methanolyzed to give the same methyl glycoside, Me-G. On electrospray ionization mass spectrometry (ESI-MS), it provided a pseudomolecular ion at m/z 303 in the positive-ion mode and a molecular ion at m/z 257 with a daughter ion at m/z 146 in the negative-ion mode, showing the presence of a sulfonate group S-linked to a hexosyl ring. An exclusively alpha-glucopyranosyl configuration was indicated by (1)H, (1)H correlation spectroscopy (COSY) and (1)H, (1)H total correlation spectroscopy (TOCSY). S-substitution occurred at CH(2)-6, because a high-field (13)C signal at delta 52.6 gave an inverted distortionless enhancement by polarization transfer (DEPT) signal and (1)H, (3)C heteronuclear multiple quantum coherence (HMQC) showed correlation with two H-6 signals. This 6-sulfono-alpha-quinovopyranoside group was present in the glycolipid fractions, O-alpha-D-Quip-6-sulfono-(1'<-->1)-2,3-diacyl-D-glycerol (polar fraction 1a; PF1a) and O-alpha-D-Quip-6-sulfono-(1'<-->1)-2- or -3-monoacyl-D-glycerol (polar fraction 1b; PF1b), the monoacyl derivatives not having been previously completely characterized in other systems. All components are typical of plant glycolipids. The most abundant fatty acid ester in PF1a and PF1b was C(16:0). Other esters present in PF1a were C(14:0), C(17:0), C(18:0), C(18:1) (oleic), C(20:0), C(21:0), and C(24:0), in contrast with C(14:0), C(17:0), C(18:0), and C(20:0) in PF1b. HMQC and TOCSY data can be used as fingerprints for detection of glycosylacylglycerides and sulfonoglycolipids and the positive ESI-MS ions at m/z 329 and 271 for identification of the latter.

Characterization of lyso-galactolipids, C-2 and C-3 O-acyl trigalactosylglycerol isomers, obtained from the lichenized fungus Dictyonema glabratum.

A mixture of two lyso isomers of a galactolipid was obtained from Dictyonema glabratum. Aqueous hydrolysis gave rise to galactose and glycerol in a 3:1 molar ratio. ESI-MS spectroscopy gave, in the positive-ion mode, a pseudomolecular ion at m/z 839 and daughter ions with m/z 677, 600, 515 and 353, suggesting three galactosyl units linked to a glycerol moiety, substituted by one O-acyl group. 1D and 2D NMR experiments were used to characterize the glycolipid, and HMQC examination showed three anomeric signals, corresponding to two alpha-Galp and one beta-Galp residue liked to glycerol. The glycolipid structure was shown to be O-alpha-D-Galp-(1-->6)-O-alpha-D-Galp-(1-->6)-O-beta-D-Galp-(1<-->1)-2- and -3-monoacyl-D-glycerol, the latter structures not having been previously found in nature. The fatty acid composition was determined by GC-MS of derived methyl esters: that of palmitic acid C(16:0) was the most abundant, although the presence of C(12:0), C(14:0), C(16:1) and C(18:0) esters was observed.

Comparative studies of the polysaccharides isolated from lichenized fungi of the genus Cladonia: significance as chemotypes.

Beta-D-glucans of the laminaran type were prepared from 15 Cladonia spp., Cladonia bellidiflora, Cladonia boryi, Cladonia clathrata, Cladonia connexa, Cladonia crispatula, Cladonia furcata, Cladonia gracilis, Cladonia ibitipocae, Cladonia imperialis, Cladonia miniata, Cladonia penicillata, Cladonia salmonea, Cladonia signata, Cladonia substellata and Cladonia uncialis. They were extracted with 10% aqueous KOH at 100 degrees C, giving polysaccharides with varying yields and proportions of mannose, galactose and glucose. Their aqueous solutions were freeze-thawed giving precipitates of mixed alpha-glucan (nigeran) and beta-glucans, which were isolated and suspended in aqueous 0.5% KOH at 50 degrees C, which preferentially dissolved the beta-glucan. In the case of the C. uncialis product, it was subjected to methylation analysis, which gave rise to 2,4,6-tri-O-methylglucitol acetate only, corresponding to (1-->3)-linkages. Its specific rotation (+4 degrees ) and one- and two-dimensional nuclear magnetic resonance (NMR) spectra were consistent with beta-linkages. 13C and (1)H-1 signals were observed, respectively, at delta 102.8 (C-1), 86.0 (C-3), 76.2 (C-5), 72.6 (C-2), 68.3 (C-4) and 60.7 (C-6), and 4.55 (H-1), 3.31 (H-2), 3.49 (H-3), 3.27 (H-4), 3.27 (H-5), 3.48 (H-6) and 3.72 (H-6'). Similar (13)C-NMR spectra were obtained from the glucans from the other 14 Cladonia spp. The beta-D-glucans of the laminaran type seems to be present in all Cladonia spp. being significant for chemotyping since it was observed in every species studied.

Cytotoxic effects against HeLa cells of polysaccharides from seaweeds.

Polysaccharides extracted from several red and brown seaweeds growing along the South American coasts were evaluated regarding their cytotoxic effects against HeLa cells. Sulfated galactans were isolated and purified from the red algae Bostrychia montagnei (BHW and B4 fractions, 17 and 22% SO3Na, respectively) and Porphyra columbina (PC75 fraction, 15.6% SO3Na). At maximum concentration of 80 microg/mL, these fractions promoted atypical mitoses in HeLa cells, presence of atypical nuclei and blebs. Alginic acid (160.0 microg/mL) isolated from the brown seaweed Laminaria brasiliensis (molar ratio M/G 1.2) and its M and G blocks (40.0 microg/mL; DP = 20), promoted similar morphologic alterations besides the presence of acidophilic material in the cellular cytoplasm and occurrence of multinuclear cells present in the monolayer. The polysaccharide fraction SF isolated from the brown seaweed Sargassum stenophyllum containing mainly fucose and presenting molar ratio of sulfate/sugar 1.9, promoted very accentuated morphologic modifications in HeLa cells at low concentrations. SF (2.5 microg/mL) caused significant alterations in the cellular morphology and reduction of the growth, such effects being dose dependent. At 40.0 microg/mL, accentuated decrease of the number of mitosis illustrations accompanied by an increase in the number of condensed cells, atypical nuclei, number of clusters and blebs. These results demonstrated that among the anionic polysaccharides tested, the sulfated fucans were those which caused greater cytotoxic effects in HeLa cells.

Galactomannoglucans of lichenized fungi of Cladonia spp.: significance as chemotypes.

The chemical structures of the glucans, galactoglucomannans and galactomannoglucans of two species of the Cladonia, section Cocciferae, Cladonia miniata and Cladonia salmonea, were determined and compared. alpha-D-Glucans of the nigeran type were isolated from both species, in common with all Cladonia spp., along with galactoglucomannans containing (1-->6)-linked main-chains of alpha-D-Manp units substituted by structurally different and typical side-chains. Isolated were previously unreported galactomannoglucans, with (1-->3)-linked main-chains of beta-D-Glcp units, substituted at O-2,6 by side-chains. These consisted of beta-D-Galf, 6-O-substituted beta-D-Galf and 2-O-, 4-O-, 6-O- and 2, 3-di-O-substituted alpha-D-Manp units. According to (13)C NMR spectroscopy, a similar galactomannoglucan was isolated from the Cladonia spp. Cladonia signata, Cladonia crispatula, Cladonia penicillata, Cladonia imperialis, Cladonia clathrata, Cladonia connexa, Cladonia substellata and Cladonia ibitipocae. Its presence could also contribute to the classic taxonomy of lichenized fungi.

The free reducing oligosaccharides of angico branco (Anadenanthera colubrina) gum exudate: an aid for structural assignments in the heteropolysaccharide.

A novel method is described for the determination of sequential side-chain structures in the complex, high-arabinose polysaccharide of the gum exudate of angico branco (Anadenanthera colubrina), using as basis the structurally similar reducing oligosaccharides present in small quantities. Of the ten detected, eight were characterized as disaccharides (2, 3, and 9), linear trisaccharides (1 and 4), branched pentasaccharides (5 and 6), and a doubly branched heptasaccharide (8). The oligosaccharides are substituents of the polysaccharide, which has a (1-->3)-linked beta-D-galactopyranosyl main chain, and with two exceptions they had 6-O-substituted galactopyranosyl reducing ends, probably corresponding to its main-chain units. Characterization was effected through their 1D and 2D NMR correlation spectra, which were better resolved and more readily interpretable than those of the polysaccharide. These spectral data were supported by monosaccharide composition and rotation values. Controlled Smith degradations and methylation analyses were carried out when it was necessary. These data were confirmed by field-desorption MS.

"Linkage region" sequences of heparins and heparan sulfates: detection and quantification by nuclear magnetic resonance spectroscopy.

The (13)C NMR spectra of most heparin and heparan sulfate preparations display minor signals not attributable to the glycosaminoglycan chains of these polysaccharides. These signals have been "concentrated" in oligosaccharides isolated from an acid hydrolyzate of heparin and shown to arise from the sequence GlcA-Gal-Gal-Xyl of the "linkage region" (LR) connecting the carbohydrate chains to the peptide chains in the original proteoglycans. Mono- and two-dimensional (1)H and (13)C NMR analysis of the major oligosaccharide (LR-OLIGO) indicated the prevalent structure GlcA-GlcNAc-GlcA-Gal-Gal-Xyl, where GlcNAc is partially 6-O-sulfated. (13)C NMR signals at 84.6 and 85.0 ppm, arising from C-3 of the two Gal residues, lend themselves to easy detection and quantification of the linkage region in heparins and heparan sulfates and can be used to assess the importance of the LR in the modulation of various biological activities of these glycosaminoglycans.

Glycosyldiacylglycerolipids from the lichen Dictyonema glabratum.

Three glycolipids (1-3) were isolated from the basidiolichen Dictyonema glabratum. Their carbohydrate and lipid components were structurally characterized using 1D 1H and 13C and 2D NMR spectroscopy, complemented by mass spectrometry, as were the carbohydrate moieties formed on saponification. These were O-alpha-D-Galp-(1''-->6')-O-beta-D-Galp-(1'<-->1)-2, 3-diacyl-D-glycerol (2) and two others not previously found in lichens, O-beta-D-Galp-(1'<-->1)-2,3-diacyl-D-glycerol (1) and O-alpha-D-Galp-(1'''-->6'')-O-alpha-D-Galp-(1' '-->6')-O-beta-D-Galp-(1'<-->1)-2,3-diacyl-D-glycerol (3). Each was saponified to give the free carbohydrates and its fatty acid methyl esters. The most abundant fatty acid esters in 1-3 was palmitic C16:0, but there was a wide variation of ester composition. Others present were C8:0 and C14:0 in 1, C14:0, C15:0, C17:0, C18:0, C18:1 (oleic), C18:2 (linoleic), C22:0, and C24:0 in 2, and C8:0, C14:0, C18:0, C18:1 (oleic), C18:2 (linoleic), and C18:3 (linolenic) in 3. As in ascolichens, the glycolipids appear to arise from the phycobiont.

Novel structures in galactoglucomannans of the lichens Cladonia substellata and Cladonia ibitipocae: significance as chemotypes.

The galactoglucomannans of two species of the lichen genus Cladonia, C. substellata and C. ibitipocae, were compared. They were homogeneous on gel-filtration chromatography and structurally related, having (1-->6)-linked alpha-D-mannopyranosyl main-chains, but were substituted in different patterns by alpha- and beta-D-galacto-, beta-D-gluco- and alpha-D-mannopyranosyl groups. The C-1 portions of their 13C-NMR spectra are typical of the lichen species and indicate differences between the two polysaccharides. Partial acetolysis of the galactoglucomannan from C. substellata gave rise to oligosaccharides and three were identified, namely alpha-D-Manp-(1-->3)-alpha beta-D-Galp, alpha-D-Manp-(1-->2)-alpha beta-D-Manp and alpha-D-Manp-(1-->2)-[beta-D-Glcp-(1-->4)]-alpha beta-D-Manp, whereas only the latter two were obtained from that of C ibitipocae. Methylation and Smith degradation data confirmed these results. Whereas the mannobiose represents a common structure in lichen heteropolysaccharides, it is the first time that the other oligosaccharides have been isolated from those of lichens.

Gum heteropolysaccharide and free reducing mono- and oligosaccharides of Anadenanthera colubrina.

The gum from Anadenanthera colubrina consists mainly of a complex high-arabinose heteropolysaccharide with a (1-->3)-linked beta-D-Galp main-chain and many different side-chains. These contain beta-D-Galp-[(1-->6)-beta-D-Galp]m-(1-->6)-, substituted in turn at O-3 by alpha-L-Araf-[(1-->3)-alpha-L-Araf-]0-2. Also present are (1) main-chain units substituted at O-4 and O-6 by alpha-L-Araf units, (2) side-chains of Rhap-(1-->4)-beta-D-GlcpA-(1-->6)-beta-Galp-groups, (3) alpha-L-Arap non-reducing end-units linked (1-->6) to D-Galp, and (4) beta-Araf and beta-Arap structures. For the first time, a plant gum exudate was found to contain in the natural state, reducing low M(r) carbohydrates. These were rhamnose (0.6%), arabinose (4.7%), mannose (0.1%), galactose (0.8%) and many oligosaccharides (0.6%; 11 with different RFs, with the majority containing arabinose). They were all mixtures with the exception of alpha-Rhap-(1-->4)-beta-D-GlcpA-(1-->6)-alpha beta-Gal and an incompletely identified hexasaccharide, probably having alpha-L-Araf-(1-->4)-beta-D-Galp- and -alpha-L-Araf-(1-->3)-beta-D-Galp- structures. The mono- and oligosaccharides do not appear to arise via in situ autohydrolysis of the gum.