Structural characterization of a pectic polysaccharide from Nerium indicum flowers

A structure defined pectin SA02B from Semiaquilegia adoxoides is metabolized by human gut microbes

Polysaccharide is one of the major factors for shaping the gut microbiota. However, bioactivity of polysaccharide isolated from Semiaquilegia adoxoides on human gut microbiota remains unclear. Thus, we hypothesize gut microbes may act on it. Herein, pectin SA02B from the roots of Semiaquilegia adoxoides with molecular weight 69.26 kDa was elucidated. The backbone of SA02B was composed of alternate 1, 2-linked α-Rhap and 1, 4-linked α-GalpA, with branches of terminal (T) -, 1, 4-, 1, 3- and 1, 3, 6-linked β-Galp, T-, 1, 5- and 1, 3, 5-linked α-Araf and T-, 1, 4-linked-β-Xylp substituted at C-4 of 1, 2, 4-linked α-Rhap. Bioactivity screening showed SA02B promoted the growth of Bacteroides spp. which deconstructed it into monosaccharide. Simultaneously, we observed competition might exist between Bacteroides spp. and probiotics. Besides, we found that both Bacteroides spp. and probiotics could generate SCFAs grown on SA02B. Our findings highlight SA02B may deserve as a prebiotic to be explored to benefit the health gut microbiota.

Structural characterization and immunoregulatory activity of a neutral polysaccharide from the roots of Apocynum venetum L

The structural characteristics and immunoregulatory activities of neutral heteropolysaccharide (AVRP-N) separated from the roots of Apocynum venetum L. were extensively investigated. The results showed that the weight average molecular mass (Mw) of AVRP-N was 6.430 × 10³ Da. Moreover, the backbone is composed of natural acetylated (1 → 4)-β-D-Man and (1 → 5)-α-L-Ara domains. The mannan is composed of →4)-β-D-Manp-(1→, →4)-β-D-Glcp-(1→, and the terminal group α-D-Galp-(1→ attached to →4,6)-β-D-Manp-(1→ at O-6. Araban is composed of →5)-α-L-Araf-(1→; the terminal group α-L-Araf-(1→attached to→2,3,5)-α-L-Araf-(1→ at O-2, O-3 and →3,5)-α-L-Araf-(1→ at O-3. In addition, the senior structure shows that AVRP-N has a triple-helix conformation. Furthermore, AVRP-N exhibited immunomodulatory effects, which could significantly regulate the proliferation of mouse splenic lymphocytes by enhancing the secretion of the cytokines (IFN-γ, IL-2, IL-4, and IL-10). Our results provide new structural and immunoregulatory information for natural polysaccharides derived from Apocynum venetum L.

The structure elucidation of novel arabinogalactan LRP1-S2 against pancreatic cancer cells growth in vitro and in vivo

The fruit of Lycium ruthenicum Murr is used as traditional medicine and functional food. Previously we reported that one RG-I pectin from this fruit might inhibit pancreatic cancer cells growth. We further hypothesized that there might be other type of polysaccharides in this fruit also have anti-tumor effect. Here, we showed novel structure of a homogeneous polysaccharide named LRP1-S2 from this fruit and its anti-pancreatic cancer effect. Structure analyses suggested that LRP1-S2 was a novel arabinogalactan with the molecular weight (Mw) of 17.0 kDa. Bioactivity test showed that LRP1-S2 might attenuate the proliferation of pancreatic cancer cells in vitro and in vivo without significant cytotoxicity to normal pancreatic HPDE6-C7 cells and LO2 liver cells. Mechanism study indicated that it might induce apoptosis of BxPC-3 by inactivating P38 MAPK/NF-κB and GSK-3β/β-Catenin signaling pathways. These results suggested that LRP1-S2 could be a potential anti-tumor leading compound for functional food and new drug development. CHEMICAL COMPOUNDS: arabinogalactan, pectin, galactan, arabinan, RN-1, HH1-1, LRP1-S2, LRP3-S1.

Rethinking the impact of RG-I mainly from fruits and vegetables on dietary health

Rhamnogalacturonan I (RG-I) pectin is composed of backbone of repeating disaccharide units →2)-α-L-Rhap-(1→4)-α-D-GalpA-(1→ and neutral sugar side-chains mainly consisting of arabinose and galactose having variable types of linkages. However, since traditional pectin extraction methods damages the RG-I structure, the characteristics and health effects of RG-I remains unclear. Recently, many studies have focused on RG-I, which is often more active than the homogalacturonan (HG) portion of pectic polysaccharides. In food products, RG-I is common to fruits and vegetables and possesses many health benefits. This timely and comprehensive review describes the many different facets of RG-I, including its dietary sources, history, metabolism and potential functionalities, all of which have been compiled to establish a platform for taking full advantage of the functional value of RG-I pectin.

A new heteropolysaccharide from the seed husks of Plantago asiatica L. with its thermal and antioxidant properties

A new heteropolysaccharide (PMH) with a molecular weight of 1.4 × 10³ kDa was isolated from the seed husks of Plantago asiatica L. The monosaccharide composition of PMH was determined as glucose, xylose, arabinose, rhamnose, galactose and galacturonic acid with a molar ratio of 1.0 : 1.8 : 2.4 : 3.8 : 4.9 : 8.5. The backbone of PMH consisted of 1,4-β-d-GalpA with the side chains mainly composed of 1,3-α-d-Galp and 1,2-α-d-Galp which were attached to the O-3 of GlapA. The thermal analysis using the Flynn-Wall-Ozawa (FWO) method revealed that PMH had an apparent activation energy (E_a) of 173.1 kJ mol^-1. PMH experienced a major decomposition during the heating process at a temperature of 91.1 °C with a dry weight loss of 31.1%. Moreover, PMH exhibited stronger antioxidant ability than commercial psyllium, partially due to its higher content of uronic acid. The results suggested that PMH could be used in functional foods due to its structural, thermal and antioxidant characteristics.

Structural characterization of a polysaccharide from the flower buds of Tussilago farfara, and its effect on proliferation and apoptosis of A549 human non-small lung cancer cell line

In present study, we purified a polysaccharide, TFPB1, from the flower buds of Tussilago farfara using DEAE-cellulose 52 anion-exchange and Sephacryl S-300 HR gel filtration chromatography. TFPB1 was a homogeneous polysaccharide with a molecular weight of 37.8kDa and composed of rhamnose, galacturonic acid, glucose, galactose, and arabinose, in a ratio of 13:13:1:7:12. Methylation and NMR results demonstrated that TFPB1 contained a rhamnogalacturonan I backbone consisting of a repeat disaccharide unit →4)-α-_D-GalAp-(1→2)-α-_L-Rhap-(1→, substituted by various type II arabinogalactan branches including terminal galactose, (1→3)-β-_D-galactan and (1→5)-α-_L-arabinan, attached to the O-4 of (1→2)-α-_L-Rhap. TFPB1 was found to inhibit cell proliferation of A549 cells and induce cell apoptosis in vitro. Furthermore, TFPB1 downregulated the phosphorylation of Akt, and upregulated caspase-3, Fas, FasL, and Bax expression, but downregulated Bcl-2 expression. Therefore, TFPB1 exhibited anti-proliferative and anti-apoptotic effect partly depending on the suppression of Akt signaling pathway. These findings provided us a potential chemotherapeutic strategy for the treatment of human non-small cell lung cancer.

Polysaccharides from Moringa oleifera gum: structural elements, interaction with β-lactoglobulin and antioxidative activity

Structural highlights of an antioxidative arabinogalactan from Moringa oleifera gum that interacts with β-lactoglobulin.

Structural analysis of ginseng polysaccharides extracted by EDTA solution

Polysaccharides extracted from Panax ginseng by EDTA solution are composed of both starch-like glucan and pectin.

Structural elucidation of a polysaccharide from Chrysanthemum morifolium flowers with anti-angiogenic activity

The flowers of Chrysanthemum morifolium were extracted with 5% sodium hydroxide, yielding a neutral polysaccharide (JHB0S2) with a molecular weight of 16 kDa by anion-exchange chromatography on a DEAE-cellulose column and gel permeation chromatography on a Sephacryl S-200 HR column. JHB0S2 was found to contain glucose, xylose, arabinose and galactose in molar ratio of 2.9:2.3:1.0:1.2. Through the linkage analysis, partial acid hydrolysis and NMR spectra and so forth, indicated that its backbone consisted of 1,4-linked β-Glcp, nearly 50% of which was substituted at O-6 by 1,2-linked α-Xylp terminated with Galp or Xylp. Furthermore, some of 1,2-linked α-Xylp was substituted at O-4 by α-Araf-(1→5)-α-Araf-(1→6)-β-Galp. The biological test showed that JHB0S2 could inhibit the tube formation of HMEC-1 cells.

Structural, thermal, and anti-inflammatory properties of a novel pectic polysaccharide from alfalfa (Medicago sativa L.) stem

A pectic polysaccharide (APPS) was purified from the cold alkali extract of alfalfa stem and characterized to be a rhamnogalacturonan I (RG-I) type pectin with the molecular weight of 2.38 × 10(3) kDa and a radius of 123 nm. The primary structural analysis indicated that APPS composed of a →2)-α-l-Rhap-(1→4)-α-d-GalpA-(1→ backbone with 12% branching point at C-4 of Rhap forming side chains by l-arabinosyl and d-galactosyl oligosaccharide units. Transmission electron microscopy (TEM) analysis revealed a primary linear-shaped structure with a few branches in its assembly microstructures. The thermal decomposition evaluation revealed the stability of APPS with an apparent activation energy (Ea) of 226.5 kJ/mol and a pre-exponential factor (A) of 2.10 × 10(25)/s, whereas its primary degradation occurred in the temperature range from 215.6 to 328.0 °C. In addition, APPS showed significant anti-inflammatory effect against mRNA expressions of the pro-inflammatory cytokine genes, especially for IL-1β, suggesting its potential utilization in functional foods and dietary supplement products.

An arabinogalactan from flowers of Panax notoginseng inhibits angiogenesis by BMP2/Smad/Id1 signaling

Angiogenesis plays an essential role in tumor development. Blocking angiogenesis in tumor has become a promising tactic in limiting cancer progression. Here, an arabinogalactan polysaccharide, RN1 was isolated from flowers of Panax notoginseng. Its structure was determined to possess a backbone of 1,6-linked Galp branched at C3 by side 1,3-linked Galp, with branches attached at position O-3 of it. The branches mainly contained 1,5-linked, 1,3,5-linked, terminal Arabinose and terminal Galactose. RN1 could inhibit microvessel formation in the BxPC-3 pancreatic cancer cell xenograft tumor in nude mice. The antiangiogenesis assay showed that RN1 could reduce the migratory activity of endothelial cells and their ability of tube formation on matrigel, but no effect on endothelial cells growth. Further studies revealed that RN1 could inhibit BMP2/Smad1/5/8/Id1 signaling. All those data indicated the RN1 had an antiangiogenic effect via BMP2 signaling and could be a potential novel inhibitor of angiogenesis.

A RG-II type polysaccharide purified from Aconitum coreanum alleviates lipopolysaccharide-induced inflammation by inhibiting the NF-κB signal pathway

Korean mondshood root polysaccharides (KMPS) isolated from the root of Aconitum coreanum (Lévl.) Rapaics have shown anti-inflammatory activity, which is strongly influenced by their chemical structures and chain conformations. However, the mechanisms of the anti-inflammatory effect by these polysaccharides have yet to be elucidated. A RG-II polysaccharide (KMPS-2E, Mw 84.8 kDa) was isolated from KMPS and its chemical structure was characterized by FT-IR and NMR spectroscopy, gas chromatography-mass spectrometry and high-performance liquid chromatography. The backbone of KMPS-2E consisted of units of [→6) -β-D-Galp (1→3)-β-L-Rhap-(1→4)-β-D-GalpA-(1→3)-β-D-Galp-(1→] with the side chain →5)-β-D-Arap (1→3, 5)-β-D-Arap (1→ attached to the backbone through O-4 of (1→3,4)-L-Rhap. T-β-D-Galp is attached to the backbone through O-6 of (1→3,6)-β-D-Galp residues and T-β-D-Ara is connected to the end group of each chain. The anti-inflammatory effects of KMPS-2E and the underlying mechanisms using lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages and carrageenan-induced hind paw edema were investigated. KMPS-2E (50, 100 and 200 µg/mL) inhibits iNOS, TLR4, phospho-NF-κB-p65 expression, phosphor-IKK, phosphor-IκB-α expression as well as the degradation of IκB-α and the gene expression of inflammatory cytokines (TNF-α, IL-1β, iNOS and IL-6) mediated by the NF-κB signal pathways in macrophages. KMPS-2E also inhibited LPS-induced activation of NF-κB as assayed by electrophorectic mobility shift assay (EMSA) in a dose-dependent manner and it reduced NF-κB DNA binding affinity by 62.1% at 200 µg/mL. In rats, KMPS-2E (200 mg/kg) can significantly inhibit carrageenan-induced paw edema as ibuprofen (200 mg/kg) within 3 h after a single oral dose. The results indicate that KMPS-2E is a promising herb-derived drug against acute inflammation.

Evaluation of antioxidant and antiulcerogenic activities of Opuntia ficus indica f. inermis flowers extract in rats

The Opuntia ficus indica f. inermis methanolic flowers extract (OMFE) was phytochemical studied, in vitro tested for their potential antioxidant activity using 2,2-diphenyl-1-picrylhydrazyl (DPPH), reducing power, linoleic acid peroxidation assays and in vivo evaluated for its ability to prevent ethanol-induced gastric ulcer in rats. The OMFE was rich in polysaccharide, phenolics and flavonoids contents and exhibited a moderate in vitro antioxidant activity when compared with (+)-catechin and ascorbic acid. Pre-treatment with OMFE at oral doses 250, 500 and 1000 mg/kg body weight was found to provide a dose-dependent protection against ethanol-induced gastric ulcer by averting the deep necrotic lesions of the gastric epithelium, by preserving normal antioxidant enzymes activities, by inhibiting the lipid peroxidation, the oxidation of protein and the DNA fragmentation in gastric mucosa. The antiulcerogenic activity of OMFE might be due to a possible synergistic antioxidant and antihistaminic-like effects.