Jinian Fang

Structural features of immunologically active polysaccharides from Ganoderma lucidum

Three polysaccharides, two heteroglycans (PL-1 and PL-4) and one glucan (PL-3), were solubilized from the fruit bodies of Ganoderma lucidum and isolated by anion-exchange and gel-filtration chromatography. Their structural features were elucidated by glycosyl residue and glycosyl linkage composition analyses, partial acid hydrolysis, acetolysis, periodate oxidation, 1D and 2D NMR spectroscopy, and ESI-MS experiments. The data obtained indicated that PL-1 had a backbone consisting of 1,4-linked alpha-D-glucopyranosyl residues and 1,6-linked beta-D-galactopyranosyl residues with branches at O-6 of glucose residues and O-2 of galactose residues, composed of terminal glucose, 1,6-linked glucosyl residues and terminal rhamnose. PL-3 was a highly branched glucan composed of 1,3-linked beta-D-glucopyranosyl residues substituted at O-6 with 1,6-linked glucosyl residues. PL-4 was comprised of 1,3-, 1,4-, 1,6-linked beta-D-glucopyranosyl residues and 1,6-linked beta-D-mannopyranosyl residues. These polysaccharides enhanced the proliferation of T- and B-lymphocytes in vitro to varying contents and PL-1 exhibited an immune-stimulating activity in mice.

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.

Immunologically active polysaccharides of acanthopanax senticosus

From the alkaline aqueous extract of Acanthopanax (Eleutherococcus) senticosus two homogeneous polysaccharides, a glucan with a mean M, of 150 000 and a heteroxylan with a mean M, of 30 000, have been isolated by DEAE-Sepharose CL-6B and Sephacryl S-400 column chromatography. Their structures were elucidated mainly by permethylation, periodate oxidation, Smith degradation, reduction experiments, partial hydrolysis and 13C NMR. The isolated crude polysaccharide mixture and the heteroxylan enhance phagocytosis in in vitro and in vivo immunological tests.

Structure and potential immunological activity of a pectin from Centella asiatica (L.) Urban.

S3A was a RG-I pectin isolated from Centella asiatica that contained Rha, Ara, Gal, Glc and GalA in molar ratio of 1.0:0.6:1.5:0.2:1.1 and had been found to have a backbone composed mainly of the disaccharide repeat unit, -->4)-alpha-D-GalpA-(1-->2)-alpha-L-Rhap-(1-->. Based on methylation analysis, NaIO4 oxidation, partial acid hydrolysis and lithium-treatment, the structural features were elucidated. Side chains of S3A were predominantly linked to O-4 of 1,2,4-linked alpha-L-Rhap. The side chains are comprised of arabinosyl chains, galactosyl chains, arabinogalactosyl chains and short glucosyl chains. A total of 45% Rhap in the backbone was substituted by side chains. The arabinosyl residues were mostly distributed in the arabinosyl side chains. According to the immunological results of S3A and its degraded derivatives, S3A had no immunological activity, but its derivatives had immuno-stimulating activities to some extent.

Structural characterization of a pectic polysaccharide from Nerium indicum flowers.

A polysaccharide fraction, J6, was isolated from the hot-water extract of flowers of oleander Nerium indicum Mill., using ethanol precipitation, cetyltrimethylammonium bromide (CTAB) complexing, anion-exchange chromatography and gel permeation chromatography. J6 was found to contain L-rhamnose, L-arabinose, D-galactose, and D-galacturonic acid, in the ratio of 10.1:49.8:30.1:10.0. Its structure was investigated by methylation analysis, periodate oxidation, Smith degradation, partial acid hydrolysis, electrospray ionization mass spectrometry and NMR spectroscopic methods. It was found that J6 is an RG-I type polysaccharide, which contains a rhamnogalacturonan backbone, with various branches attached to O-4 of L-rhamnose. The branches probably involve (1-->4)-beta-D-galactan, branched L-arabino-(1-->3)(1-->6)-beta-D-galactan, and (1-->5)-alpha-L-arabinan. J6 stimulated NO production of macrophage RAW264.7 cells in a preliminary test.

Structural features of a heteroxylan from Sophora subprostrata roots

Abstract An acidic heteroxylan, SSb2, was isolated from the alkaline extract of Sophora subprostrata by DEAE-Sephadex A-25 and Sephacryl S-300 chromatography, with an Mr of 4.4×105 and a specific optical rotation of −49.2° (c 0.5, H2O). Its structural features were elucidated by methylation analysis, partial acid hydrolysis, periodate oxidation and 13C NMR spectroscopy. The data obtained indicated that SSb2 has a backbone consisting of 1,4-linked xylopyranosyl residues with branches at O-2 or O-3, composed of l -Araf(1→5) l -Araf(1→, 4-O-Me- d -GlcA(1→ or d -GlcA(1→. SSb-2 exhibited an immunostimulating activity in vivo in pharmacological experiments.

Chemical structure and immunoinhibitory activity of a pectic polysaccharide containing glucuronic acid from the leaves of Diospyros kaki.

Pectin is a family of complex polysaccharides characterized by the presence of 1,4-linked alpha-galacturonic acid residues in the backbone and is more recognized for its potential bioactive properties. Herein we reported the structural and biological features of a pectic fraction DL-4OAC-1 from the leaves of Diospyros kaki. Chemical and spectral analysis revealed this polysaccharide possessed a backbone composed of a repeating disaccharide [-->4)-alpha-GalAp-(1-->2)-alpha-Rhap-(1-->], substituted at some O-4 of Rhap residues and O-3 of GalAp residues by the side chains consisting of Araf, Galp, Xylp, and in particular terminal GlcAp residues. The immunological assay in vitro showed that this distinct pectic fraction could inhibit the LPS-induced B lymphocyte proliferation and had no effect on the ConA-induced T lymphocyte proliferation.

Characterization of a pectic polysaccharide from the leaves of Diospyros kaki and its modulating activity on lymphocyte proliferation

Pectin is a group of carbohydrate polymers constructing the primary cell walls and the middle lamella of terrestrial plants. Herein, we demonstrated the structure and immunomodulatory activity of the major pectic polysaccharide DL-3B(2) isolated from the leaves of Diospyros kaki. Based on composition analysis, methylation analysis, two-step acid hydrolysis, lithium-mediated selective degradation, (13)C NMR spectroscopy, and electrospray ionization mass spectrometry, DL-3B(2) was found to contain an alpha-1, 4-linked galacturonic acid (GalA) backbone with some insertions of alpha-1, 2-linked rhamnose residues. The arabinan- and arabinogalactan-side chains were attached to O-4 of the rhamnose residues, whereas the linear arabinoxylan was probably linked to O-3 of the GalA residues. Immunological tests in vitro showed that DL-3B(2) could help stimulate lipopolysaccharide-induced B lymphocyte proliferation, but not ConA-induced T lymphocyte proliferation, and that the arabinose residues play a role in maintaining this immunological activity.

Two acidic polysaccharides from the flowers of Chrysanthemum morifolium

Two new acidic polysaccharides, F4 and F5, were isolated from the flowers of Chrysanthemum morifolium. Monosaccharide analysis indicated that F4 contained arabinose, galactose and galacturonic acid units in a molar ratio of 1.0:2.3:6.8 and F5 contained arabinose, rhamnose galactose and galacturonic acid units in a molar ratio of 1.0:3.2:1.0:4.3. The results of methylation analysis, partial acid hydrolysis and NMR spectral analysis indicated that F4 had a homogalacturonan main chain with arabinogalactan side chain linked to 3 position of (1 → 3,4)-linked galacturonan and F5 had a rhamnogalacturonan main chain with arabinogalactan side chain linked to 3 position of (1 → 3,4)-linked galacturonan or 4 position of (1 → 2,4)-linked rhamnose. Biological tests revealed that F4 and F5 could simulate the mitogen induced T and B lymphocyte proliferation in vitro.