Structural assignment of a heteropolysaccharide isolated from the gum of Cochlospermum religiosum (Katira gum)

A heteropolysaccharide isolated from the gum (Katira) of Cochlospermum religiosum was found to consist of D-galactose, D-galacturonic acid and L-rhamnose in a molar ratio 2:1:3. Structural assignment of the polysaccharide was carried out using total acid hydrolysis, methylation analysis, periodate oxidation, Smith degradation and NMR studies (1H, 13C, DQF-COSY, TOCSY, NOESY, HMBC and HSQC) and the repeating unit of the polysaccharide was established as [Formula: see text].     

Structure of a highly substituted beta-xylan of the gum exudate of the palm Livistona chinensis (Chinese fan)

Structural features of the acidic, highly substituted glycanoxylan (LCP; 87% yield) from the gum exudate of the palm, Livistona chinensis, family Arecaceae, were determined. It had [alpha]D -30 degrees, Mw 1.9x10(5) and a polydispersity ratio Mw/Mn of approximately 1.0. Acid hydrolysis gave rise to Rha, Fuc, Ara, Xyl, and Gal, in a 1:6:46:44:3 molar ratio, and 12% of uronic acid was present. LCP had a highly branched structure with side-chains containing nonreducing end-units (% values are approximate) of Araf (15%), Fucp (4%), Xylp (7%), GlcpA, and 4-Me-GlcpA, and internal 2-O- (5%) and 3-O-substituted Araf (8%), and 2-O-substituted Xylp (14%) units. The (1-->4)-linked beta-Xylp main-chain units of LCP were substituted at O-3 (4%), O-2 (17%), and O-2,3 (16%). Partial acid hydrolysis gave 4-Me-alpha-GlcpA-(1-->2)-[beta-Xylp-(1-->4)](0-2)-Xyl, identified by showing that the uronic acids were single-unit side-chain substituents on O-2. Milder hydrolysis conditions removed from O-3 other side-chains containing Fucp and Araf nonreducing end-units and internal Arap, and 2-O- and 3-O-substituted Araf units. Carboxyl-reduced LCP contained 4-O-methylglucose and glucose in a 3.2:1 molar ratio, arising from GlcpA and 4-OMe-GlcpA nonreducing end-units, respectively. The gum contained small amounts of free alpha-Fucp-(1-->2)-Ara, which corresponds to structures in the polysaccharide. Free myo- and D- or L-chiro-inositol were present in a 9:1 ratio.     

Composition of gum exudates from Anacardium occidentale

The composition and solution properties of Indian and Papuan specimens of the gum from Anacardium occidentale have been studied and found to be closely similar. Contrary to earlier reports by Indian workers, this gum does not contain galacturonic acid. It does, however, contain glucose; this appears to be the first report of the presence of this sugar in a plant gum exudate. A freeze-dried sample of the gum was examined at intervals over a period of 2 months; its weight-average MW increased by a factor of three in that time, and molecular-sieve chromatography showed that self-association occurred with the formation of a small proportion of a very high MW component.     

Phenology, growth, and response to light of ciruela Mexicana (Spondias purpurea L., Anacardiaceae)

The phenology of vegetative and reproductive patterns, shoot growth, and the physiological and anatomical plasticity of leaves of ciruela mexicana (Spondias purpurea L) exposed to different ranges of light are described. Flower and fruit production occur during the dry season. Shoot elongation occurs during late spring and summer. Growth rates of S. purpurea are similar to the rates reported for fast growing plants, when growing on rocky slopes in shallow infertile soils. Leaves exposed to the highest photosynthetic photon flux (PPF) had a thicker mesophyll than leaves that developed under the shade. Midday depression of photosynthesis was observed forS. purpurea. The reduction in the rates of net CO₂ uptake was related to high temperatures, high PPF, and increased leaf starch content. Plasticity in physiological and anatomical traits as observed in S. purpurea may be advantageous in the low-resource rocky environments where it grows.     

The “tortoise’s cajá”—a new species of Spondias (Anacardiaceae) from southwestern Amazonia

Botanical exploration in southwestern Amazonia has revealed a new species, Spondias testudinis J. D. Mitch. & Daly, described and illustrated here. Its distribution appears to be restricted to the Brazilian state of Acre; Pando in Bolivia; and Huánuco and Ucayali in Peru. The sexuality of the flowers of Spondias and its implications regarding their morphology is discussed. A provisional key to the neotropical species is presented.     

Structural investigation of a polysaccharide (Fr. I) isolated from the aqueous extract of an edible mushroom, Volvariella diplasia

A water-soluble polysaccharide, (Fr. I) isolated from the aqueous extract of an edible mushroom, Volvariella diplasia, is composed of D-glucose, D-mannose, and D-galactose in a molar ratio 3:1:1. Compositional analysis, methylation analysis, periodate oxidation study, Smith degradation, and NMR studies (1H, 13C, DQF-COSY, TOCSY, NOESY, ROESY, HMQC, and HMBC) revealed the presence of the following repeating unit in the polysaccharide: [FORMULA: SEE TEXT].     

Structural features of a pectic arabinogalactan with immunological activity from the leaves of Diospyros kaki

A water-soluble acidic heteroglycan, DL-3Bb, isolated from the leaves of Diospyros kaki, had [alpha](D)(20) -19.9 degrees (c 0.30, water), and contained rhamnose, arabinose, xylose, galactose and galacturonic acid in the molar ratio of 1.0:4.5:0.7:1.5:1.0. About 44% of the galacturonic acid existed as its methyl ester, and O-acetyl groups (approx 5.7%) were also identified. Its molecular weight was determined to be 9.0x10(5) Da by high-performance gel-permeation chromatography. Its structural features were elucidated by a combination of methylation analysis, periodate oxidation, two steps of partial acid hydrolysis, and 1H and 13C NMR spectroscopy and ESI mass spectrometry. The data obtained indicated that DL-3Bb possessed a backbone of a disaccharide of [-->4)-alpha-GalAp-(1-->2)-alpha-Rhap-(1-->], with approx 58.7% substitution at O-4 of the rhamnopyranosyl residues by beta-(1-->4)-linked xylopyranosyl residues, and by beta-(1-->3) and beta-(1-->6)-linked galactopyranosyl (galactan) residues. The side chains were further substituted by arabinofuranosyl residues at O-2 by beta-(1-->4)-linked xylopyranosyl residues and at O-3 by beta-(1-->6)-linked galactopyranosyl residues. Preliminary tests in vitro revealed that it could stimulate LPS-induced B lymphocyte proliferation, but not for ConA-induced T lymphocyte proliferation. It was proposed that the acid-labile arabinofuranosyl residues in the side chains would not be needed for the expression of the enhancement of the immunological activity, and that the presence of GalAp in the backbone has an important, but not crucial effect on the expression of the activity.     

Structural elucidation and immuno-stimulating activity of an acidic heteropolysaccharide (TAPA1) from Tremella aurantialba

A novel acidic heteropolysaccharide (TAPA1) was purified from hot water extracts of Tremella aurantialba fruiting bodies by DEAE-Sepharose Fast Flow and Sephacryl S-500 High-Resolution Chromatography. The heteropolysaccharide had a molecular weight of ca. 1.35 × 10⁶ Da, and a carbohydrate content estimated to be ∼98.7% by the phenol-sulfuric acid method. It was composed mainly of d-mannose, d-xylose, and d-glucuronic acid in the ratio of ca. 5:4:1, along with trace amounts of d-galacturonic acid and d-glucose. Monosaccharide compositional analysis and GC-MS of methylated derivatives, combined with ¹H and ¹³C NMR spectroscopies (including COSY, TOCSY, NOESY, HSQC, and HMBC spectra), revealed TAPA1 to consist of an α-(1→3)-linked mannopyranosyl backbone, partially substituted at position 4 with xylose side chains, and at position 2 with side chains composed of either xylose, mannose, and glucuronic acid or of xylose and mannose. Bioactivity testing showed that TAPA1 stimulated the proliferation of mouse spleen lymphocytes in vitro.     

Structure of a heteroxylan of gum exudate of the palm Scheelea phalerata (uricuri)

The polysaccharide isolated from the gum exudate of palm Scheelea phalerata (SPN) was water-insoluble and composed of Fuc, Ara, Xyl, and uronic acid moieties in a 5:34:54:7 molar ratio: 12% of phenolics were also present. A soluble polysaccharide (SPNa) was obtained after alkaline treatment, which contained Fuc, Ara, Xyl and uronic acid in a 7:44:42:7 molar ratio, with only 2% phenolics. SPNa had an M(W) approximately 1.04 x 10(5) g mol(-1) and was almost monodisperse (M(W)/M(N) : 1.25 +/-0.22). It had a branched structure with side chains of 2-O-substituted Xylp (approximately 8%) and 3-O-substituted Araf (12%) units, and a large proportion of nonreducing end-units of Araf (15%), Fucp (10%), Xylp (4%), and Arap (6%). The (1 --> 4)-linked beta-Xylp main-chain units were 3-O- (9%), 2-O- (13%), and 2,3-di-O- (13%) substituted. Its (13)C NMR spectrum contained at least 9 C-1 signals, those at delta 108.6 and 107.7 arising from alpha-Araf units. Others were present at delta 175.4 from C-6 of alpha-GlcpA and delta 15.6 from C-6 of Fucp units. The main chain of SPNa was confirmed by analysis of a Smith-degraded polysaccharide (SPDS): methylation analysis provided a 2,3-Me(2)-Xyl (65%) derivative and its (13)C NMR spectrum showed five main signals typical of a (1 --> 4)-linked beta-Xylp units. Methylation analysis of a carboxy-reduced polysaccharide (SPN-CR) revealed a 2,3,4,6-Me(4)-Glc derivative (4%) arising from nonreducing end-units of GlcpA. Alpha-GlcpA-(1 --> 2)-alphabeta-Xy1p and alpha-GlcpA-(1 --> 2)-beta-Xylp-(1 --> 4)-alphabeta-Xylp were obtained via partial acid hydrolysis of SPN, showing the structure of side-chain substituents on O-2 of the main-chain units.     

Structural analysis of a water-soluble glucan (Fr.I) of an edible mushroom, Pleurotus sajor-caju

A water-soluble glucan was obtained from the fruit bodies of an edible mushroom, Pleurotus sajor-caju, by hot water extraction, ethanol precipitation, dialysis, and Sepharose 6B gel filtration. On the basis of total hydrolysis, methylation analysis, periodate oxidation, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, and HSQC), the structure of the repeating unit of the glucan is determined as [carbohydrate structure: see text].     

Isolation, characterization and structural determination of a unique type of arabinogalactan from an immunostimulatory extract of Chlorella pyrenoidosa

An arabinogalactan was isolated from a hot water extract of freeze-dried cells of the green microalga, Chlorella pyrenoidosa. This hot water extract is a proprietary immunomodulator, with the trademark Respondintrade mark (ONC-107). The arabinogalactan was recovered from the ethanol-soluble fraction of the supernatant resulting from a process that involved controlled ethanol precipitation followed by size exclusion chromatography on Sephadex G-100, then Cetavlon precipitation. Sugar analyses, GC-MS data for (S)-2-octyl glycosides, and 1D and 2D NMR experiments established unambiguously that the repeating unit was -->2)-alpha-L-Araf-(1-->3)-[alpha-L-Araf-(1-->4)]-beta-D-Galp-(1-->. This structure does not fit into any of the known classes of arabinogalactans. SEC/MALS experiments gave a molecular mass for the arabinogalactan isolated as 47 +/- 4 kDa but the original structure was probably larger.     

Structure of the arabinogalactan from gum tragacanth (Astralagus gummifer)

The polysaccharide obtained by ethanol precipitation from an aqueous solution of gum tragacanth contained arabinogalactan and tragacanthic acid, as well as starch ( approximately 0.6%). GC-MS, NMR, and ESI-MS analyses showed the structure of the arabinogalactan to be even more complex than previously determined, with core structures containing Arap, beta-Araf, and alpha-Galp units, as well as known terminal, and 2-O- and 3-O-substituted alpha-Araf units. Analysis was aided by examination of free, reducing oligosaccharides present in the gum. In addition to maltose, maltotriose, maltotetraose, and maltopentaose, the following were characterized: mixed alpha-Araf (1-->2)-alpha-Araf-(1-->4)-Ara and alpha-Araf-(1-->2)-alpha-Araf-(1-->5)-Ara, which correspond to the side chains of the arabinogalactan, beta-Galp-(1-->4)-beta-Galp-(1-->4)-beta-Galp-(1-->4)-Gal; and a mixture of beta-Galp-(1-->4)-beta-Galp-(1-->4)-Gal and beta-Glcp-(1-->4)-beta-Galp-(1-->4)-beta-Galp-(1-->4)-Gal, which did not resemble side-chain structures of the arabinogalactan. The latter are suggested to be related to tragacanthic acid, which has been previously found to contain beta-Galp nonreducing end-units.     

Structural characterization of a water-soluble beta-(1-->6)-linked D-glucan isolated from the hot water extract of an edible mushroom, Agaricus bitorquis

A water-soluble polysaccharide, isolated from the hot aqueous extract of an edible mushroom, Agaricus bitorquis, was found to consist of d-glucose only. On the basis of total hydrolysis, methylation analysis, and NMR studies (¹H, ¹³C, TOCSY, DQF-COSY, NOESY, ROESY, HMQC, and HMBC), the structure of the repeating unit was established as→6)-β-d-Glcp-(1→     

Structural studies of a methyl galacturonosyl-methoxyxylan isolated from the stem of Lagenaria siceraria (Lau)

A water-soluble polysaccharide was isolated from the aqueous extract of the stem of Lagenaria siceraria. The polysaccharide was found to be constituted of methyl d-galacturonate, 2-O-methyl-D-xylose, and d-xylose in a ratio of 1:1:1. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, NMR studies ((1)H, (13)C, 2D-COSY, TOCSY, NOESY, HSQC, and HMBC), and MALDI-TOF MS analysis, the structure of the repeating unit of the polysaccharide is determined as.     

Structural elucidation of the polysaccharide moiety of a glycopeptide (GLPCW-II) from Ganoderma lucidum fruiting bodies

A water-soluble glycopeptide (GLPCW-II) was isolated from the fruiting bodies of Ganoderma lucidum by DEAE-Sepharose Fast-Flow and Sephacryl S-300 High Resolution Chromatography. The glycopeptide had a molecular weight of 1.2x10(4)Da (determined by HPLC), and consisted of approximately 90% carbohydrate and approximately 8% protein as determined using the phenol-sulfuric acid method and the BCA protein assay reagent kit, respectively. The polysaccharide moiety was composed mainly of D-Glc, L-Fuc, and D-Gal in the ratio of 1.00:1.09:4.09. To facilitate structure-activity studies, the structure of the GLPCW-II polysaccharide moiety was elucidated using 1H and 13C NMR spectroscopy including COSY, TOCSY, HMBC, HSQC, and ROESY, combined with GC-MS of methylated derivatives, and shown to consist of repeating units with the following structure: [Formula: see text].     

Structural investigation of a heteroglycan isolated from the fruit bodies of an ectomycorrhizal fungus Astraeus hygrometricus

A polysaccharide fraction (AQS-II) has been isolated from the hot aqueous extract of the fruits of an ectomycorrhizal fungus Astraeus hygrometricus. It was found to contain 63% polysaccharide and 35% protein. The polysaccharide part contains glucose, galactose, and fucose in a 2:1:1 molar ratio. On the basis of total acid hydrolysis, methylation analysis, periodate oxidation, and NMR studies ((1)H, (13)C, DQF-COSY, TOCSY, NOESY, HMBC, and HSQC) the structure of the repeating unit of the polysaccharide was established as [structure: see text].     

An arabinogalactan from the skin of Opuntia ficus-indica prickly pear fruits

The cold-water extract from the skin of Opuntia ficus-indica fruits was fractionated by anion-exchange chromatography. The major fraction, which was purified by size exclusion chromatography, consisted of a polysaccharide composed of galactose and arabinose residues in the ratio 6.3:3.3, with traces of rhamnose, xylose and glucose, but no uronic acid. The results of methylation analysis, supported by (13)C NMR spectroscopy, indicated that this polysaccharide corresponded to an arabinogalactan having a backbone of (1-->4)-linked beta-D-galactopyranosyl residues with 39.5% of these units branched at O-3. The side-groups consisted either of single L-arabinofuranosyl units or L-arabinofuranosyl alpha-(1-->5)-linked disaccharides. This polysaccharide is thus an arabinogalactan that can be classified in the type I of the arabinogalactan family.     

Structural elucidation of the core-lipid A backbone from the lipopolysaccharide of Acinetobacter radioresistens S13, an organic solvent tolerant Gram-negative bacterium

The structure of the core oligosaccharide of the lipopolysaccharide from an organic solvent tolerant Gram-negative bacterium, Acinetobacter radioresistens S13, was investigated by chemical analysis, NMR spectroscopy and MALDI-TOF mass spectrometry. All the experiments were performed on the oligosaccharides obtained either by alkaline degradation or mild acid hydrolysis. The data showed the presence of two novel oligosaccharide molecules containing a trisaccharide of 3-deoxy-D-manno-octulopyranosonic acid in the inner core region and a glucose rich outer core whose structure is the following: [structure: see text] R=H in the main oligosaccharide and beta-Glc in the minor product. The bacterium was grown on aromatic (phenol and benzoic acid) and nonaromatic carbon sources and the core oligosaccharide resulted to occur always with this novel structure.     

Structural investigation of a heteropolysaccharide isolated from the pods (fruits) of Moringa oleifera (Sajina)

A water-soluble polysaccharide was isolated from the aqueous extract of pods of Moringa oleifera. The polysaccharide contains d-galactose, 6-O-Me-D-galactose, D-galacturonic acid, l-arabinose, and l-rhamnose in a molar ratio of 1:1:1:1:1. On the basis of total hydrolysis, methylation analysis, periodate oxidation, and NMR ((1)H, (13)C, TOCSY, DQF-COSY, NOESY, ROESY, HSQC, and HMBC) studies, the repeating unit of the polysaccharide is established as [structure: see text].