Oligo/polysaccharides from Cyathula officinalis and Achyranthes bidentata: a review of structures and bioactivities.

OBJECTIVES: Oligo-/polysaccharides from Cyathula officinalis Kuan (COPs) and Achyranthes bidentata Blume (ABPs) have attracted researchers' attention in the fields of healthy food supplements and traditional Chinese medicine (Niúxi) due to their multiple bioactivities combined with their nontoxic and highly biocompatible nature. The purpose of this paper was to provide a systematic and comprehensive overview of the extraction, purification, and structural analysis methods, chemical characteristics, biological activities, and structure bioactivity relationship. Furthermore, the possible development trends and perspectives for future research, and traditional uses of Niúxi are also summarized. METHODS: All the information was gathered from a library search and scientific databases. KEY FINDINGS: Although COPs and ABPs are derived from different plants, they have similar structural features in type, structure, and glycosidic linkage patterns and biological activities in vivo and in vitro. However, there are differences in monosaccharide compositions, which can be used as an identification mark. CONCLUSIONS: As traditional Chinese herbal medicine, C. officinalis and A. bidentata have similar pharmacological activities. The COPs and ABP possess wide pharmacological effects such as antitumor, antioxidant, anti-osteoporosis, and anti-inflammatory. Meanwhile, the biological activity and structure-activity relationship of purified COPs and ABPs are less studied, future research should focus on them.

Structure of an unprecedent glucuronoxylogalactoglucomannan from fruit bodies of Auricularia auricula-judae (black woody ear).

An unprecedent glucuronoxylogalactoglucomannan (GXG'G″M), ME-2 (Mw, 2.60 × 105 g/mol; O-acetyl % = 16.7 %), was isolated and purified from water extracts of Auricularia auricula-judae (black woody ear). Firstly, due to much higher O-acetyl contents, we prepared its fully deacetylated products (dME-2; Mw, 2.13 × 105 g/mol) for convenient structure survey. The repeating structure-unit of dME-2 was readily proposed based on Mw determination, monosaccharide compositions, methylation analysis, free-radical degradation and 1/2D NMR spectroscopy. The dME-2 was identified as a highly branched polysaccharide with an average of 10 branches per 10 sugar backbone units. The backbone was only repeating →3)-α-Manp-(1→ residues, substituted at the C-2, C-6 and C-2,6 positions. The side chains included ß-GlcAp-(1→, ß-Xylp-(1→, α-Manp-(1→, α-Galp-(1→ and ß-Glcp-(1→. Secondly, the complex substituted positions of O-acetyl groups in ME-2 were determined to be at C-2, C-4, C-6 and C-4,6 in the backbone and at C-2 and C-2,3 in some side chains. Finally, the anti-inflammatory activity of ME-2 was preliminarily explored on LPS-stimulated THP-1 cells. The above date not only provided the first example for structural studies of GXG'G″M type polysaccharides, but also facilitated development and application of black woody ear polysaccharides as medicinal agents or functional dietary supplements.

Isolation, purification and structural characterization of two pectin-type polysaccharides from Coreopsis tinctoria Nutt. and their proliferation activities on RAW264.7 cells.

Coreopsis tinctoria Nutt. (C.tinctoria) is an annual herb of the Compositae family with many health benefits, such as clearing heat, antioxidant and anticancer activity. In this paper, two polysaccharides were isolated from C.tinctoria, named CTAP-1 and CTAP-2, respectively. Structure of CTAP-1and CTAP-2 were elucidated by high-performance gel permeation chromatography, chemical derivative analyses, GC-MS and NMR techniques. Results reveal that they both CTAP-1 and CTAP-2 consisted of predominant amounts of galacturonic acid residues along with small amounts of arabinose, rhamnose and galactose.Both them contain homogalacturonan and rhammnogalcturan I regions in different ratio, suggesting their pectin-type features. The proliferation activities of CTAP-1 and CTAP-2 on RAW264.7 cells in vitro were detected. Results show both them have the significant proliferation effect on RAW264.7 cells when the concentration from 40 to 200 µg/mL. Given their structural characteristics and proliferation activities, the pectins are expected to be potential natural immune modulators, which need further study.

Isolation, purification, and structural characterization of polysaccharides from Atractylodis Macrocephalae Rhizoma and their immunostimulatory activity in RAW264.7 cells.

Three water-soluble polysaccharides (AMAP-1, AMAP-2 and AMAP-3) were isolated and purified from Atractylodis Macrocephalae Rhizoma by using the combination of ion-exchange chromatography and gel permeation chromatography. The structures of the polysaccharides were characterized by chemical derivatization, HPGC, GC-MS, FT-IR, and NMR techniques. Structural analyses show that the three polysaccharides are pectin-type macromolecules consisting of homogalacturonan (HG) and rhamnogalacturonan type I (RG-I) regions in different ratios. Immunostimulatory assay highlighted that the RG-I-rich AMAP-1 and AMAP-2 with high molecular weights can stimulate RAW264.7 macrophages to release nitric oxide, but HG-rich AMAP-3 with a low molecular weight cannot. This finding suggests that the immune activity may be related to the side chains of the RG-I region, which provides a certain theoretical guidance for further exploring the structure-activity relationship. Meanwhile, AMAP-1 and AMAP-2, especially AMAP-2, from Atractylodis Macrocephalae Rhizoma show potential as immune adjuvants.

Structural characterization and antiviral activity of two fucoidans from the brown algae Sargassum henslowianum.

Purified fucoidans SHAP-1 and SHAP-2 with apparent molecular weights of 6.55 × 105 and 5.89 × 105, respectively, were isolated from Sargassum henslowianum by ion-exchange and gel-filtration column chromatography. They are both composed of fucose and galactose at a ratio of around 3:1 and 31.9% sulfate. The backbone of two fucoidans consists of α-(1→3)-linked L-Fucp residues which are mainly sulfated on the C-2 and C-4 positions. Side chains composed of terminally linked α-L-Fucp and α-D-Galp residues, and (1→2)-, (1→6)-, and (1→2,6)-linked ß-D-Galp residues attach mainly at O-4 position of backbone residues. Antiviral test showed that the IC50 values of SHAP-1 and SHAP-2 against HSV-1 were estimated to be 0.89 and 0.82 µg/mL by plaque reduction assay, respectively, whereas both as low as 0.48 µg/mL against HSV-2. The antiviral mechanism of the fucoidans might be at least through blocking HSV-2 virion adsorption to host cells. These results suggest that the fucoidans have potential clinical applications.

Structural characterization of three polysaccharides from the roots of Codonopsis pilosula and their immunomodulatory effects on RAW264.7 macrophages.

Three polysaccharides were isolated from the roots of Codonopsis pilosula by ion-exchange and gel-filtration chromatography. They were named RCNP, RCAP-1, and RCAP-2, and had apparent molecular weights of 1.14 × 104, 5.09 × 104, and 2.58 × 105, respectively. Their structures were characterized by HPGPC, chemical derivative analysis, GC-MS and NMR analyses. Results showed that RCNP contained arabinan and arabinogalactan regions. The arabinan region had a main chain comprising (1 → 5)-linked Araf residues, and the side chains branched at the O-3 position by the single Araf residues. The arabinogalactan region comprised alternating (1 → 4)-, (1 → 6)- or (1 → 3)-linked Galp along with small amounts of branches mainly at the O-3 position of the (1 → 6)-linked Galp or O-6 position of the (1 → 3)-linked Galp residues by terminally linked Araf residues. RCAP-1 and RCAP-2 were highly methyl-esterified pectin-type polysaccharides with long homogalacturonan regions interrupted by a short rhamnogalacturonan I (RG-I) region. The side chains of the RG-I region consisted of (1 → 2)-linked Rha residues attached to the position O-4 of rhamnose. Their degrees of methyl-esterification were approximately 60.6% and 68.1%, respectively. Bioactivity tests showed that RCAP-1 and RCAP-2 exerted a significant immunostimulatory effect based on NO production from RAW264.7 macrophages. These results suggested that these two pectin-type polysaccharides were potential immunostimulation agents.