Physicochemical, functional, and biological properties of water-soluble polysaccharides from Rosa roxburghii Tratt fruit

Proximate composition, nutritional evaluation and functional properties of a promising food: Arabian wax Cissus (Cissus rotundifolia Forssk) leaves

Cissus rotundifolia is a wild plant, extensively used during scarcity and famine; however, the information about its chemical and nutritional properties still limited. In this work, C. rotundifolia was evaluated for its chemical, nutritional and functional properties. The results revealed that C. rotundifolia mainly contained carbohydrates (72.54%), proteins (12.16%), ash (12.53%), dietary fiber (14.10%), in addition to adequate amounts of essential amino acids and minerals. Fructose, glucose, galactose, and arabinose were the major monosaccharides with a percentage of 23.32, 13.60, 1.24, and 0.25 g/100 g DW, respectively. Furthermore, it was found that C. rotundifolia contained important vitamins, including thiamin (5.37 mg/100 g DW), riboflavin (1.19 mg/100 g DW), pyridoxine (0.46 mg/100 g DW) and folic acid (0.20 mg/100 g DW). The findings of functional properties revealed good water and oil absorption capacities of 2.74 and 1.63 g/g, respectively. Foaming capacity and water solubility index were 14 and 18.74%, respectively. From these results, it can be stated that C. rotundifolia has high nutritional values, which could be used widely in food applications.

Longan pulp polysaccharides relieve intestinal injury in vivo and in vitro by promoting tight junction expression

The integrity of the intestinal mucosal barrier is important for the health of the host. In this study, longan pulp polysaccharides (LP) prevented the intestinal mucosal injury by increasing the expression of mucin 2, tight junction proteins zonulae occludens-1 (ZO-1), claudin-1, claudin-4, and adherens junction E-cadherin in cyclophosphamide-treated mice. To further identify the principle bioactive component of LP, four acidic polysaccharides (LPIa, LPIIa, LPIIIa, and LPIVa) were purified, and their intestinal protection activity in vitro was compared. LPIa, LPIIa, and LPIIIa displayed an ability to increase mRNA expression of ZO-1, claudin-1, occludin, and E-cadherin in differentiated Caco-2 cells, especially LPIa. LPIa has specific structure characteristics: porous surface structure, a high molecular weight (1.47 × 10⁵ Da), and two specific glycosidic linkages of α-Araf-(1→ and →5)-α-Araf-(1→. These structure characteristics might primarily contribute to greater intestinal barrier protective effect of LPIa.

Physicochemical characterization, potential antioxidant and hypoglycemic activity of polysaccharide from Sargassum pallidum

A polysaccharide, designated as PSP-1, was isolated and purified from Sargassum pallidum. Physicochemical characterization showed that PSP-1 with the average molecular weight of 1.036 × 106 Da was composed of fucose, arabinose, galactose, glucose, xylose, mannose, galacturonic acid and glucuronic acid in a molar ratio of 18.45:2.15:19.06:1.89:16.07:1.00:5.74:20.09. The results of antioxidant assays indicated that PSP-1 had good DPPH radical scavenging activity, hydroxyl radical scavenging activity, cellular antioxidant activity, and reactive oxygen species inhibition activity, and could significantly improve cellular antioxidant enzymes of ABAP-induced HepG2 cell model. The results of hypoglycemic assays showed that PSP-1 possessed favorable α-amylase and α-glucosidase inhibitory activities, and could remarkably enhance glucose consumption, glycogen synthesis and the activities of pyruvate kinase and hexokinase in insulin-resistance HepG2 cells. The results suggest that PSP-1 can be exploited as a potential antioxidant and hypoglycemic candidate for functional and nutraceutical applications.

Structural characteristics, rheological properties, and biological activities of polysaccharides from different cultivars of okra (Abelmoschus esculentus) collected in China

In order to well understand the physicochemical characteristics and biological activities of polysaccharides (OPPs) from different cultivars of okra collected in China, the chemical characteristics, rheological properties, antioxidant activities, in vitro binding properties, and in vitro inhibitory effects on α-glucosidase of polysaccharides from five representative okra cultivars, including 'Lvjian', 'Kalong8', 'Shuiguo', 'Taiwanwufu', and 'Kalong3', were investigated and compared. Results showed that the constituent monosaccharides of OPPs were similar, which composed of rhamnose, galacturonic acid, galactose, and arabinose. However, their weight-average molecular weights varied from 2.76 × 10³ to 4.20 × 10³ kDa, and from 0.11 × 10³ to 0.90 × 10³ kDa, respectively. The uronic acids and degrees of esterification of OPPs ranged from 39.32% to 61.68%, and from 21.66% to 30.02%, respectively. OPPs exhibited typical shear-thinning behavior and viscoelastic properties. Furthermore, OPPs exhibited remarkable antioxidant activities, in vitro binding capacities, and inhibitory effects on α-glucosidase, which might be attributed to their relatively high content of uronic acids, high degrees of esterification, and high molecular weights. Results are helpful for better understanding of the physicochemical structures and bioactivities of OPPs, and OPPs had good application prospects as functional food ingredients for industrial applications.

Possible Metabolic Pathway of a Novel Bioactive Polysaccharide Extracted from Dendrobium aphyllum: An In Vivo Study

Our previous study characterized the structure-associated immunomodulatory effects of an edible Dendrobium aphyllum polysaccharide (DAP), and the in vitro gastrointestinal digestions highlighted DAP could be digested by the GI tract in some extent. Therefore, the present study further explored the digestive properties in vivo to infer the metabolic pathway with health mice model. Results revealed that DAP-treated group showed slightly lower blood glucose levels and significantly higher (P < 0.05) enzyme activities, namely G6Pase and GDH with an increment of about 0.4 to 0.9 and 45 to 91 U/mL, respectively. Meanwhile, DAP up-regulated the expression of glucose transporters, GLUT1 and GLUT2 in the increment rates of 56.34% to 68.28% and 76.63% to 83.03%, in colon. Furthermore, the beneficial effects of DAP on colon were confirmed by the increment of four types short chain fatty acids and the health-promoting microbiota diversity. The above results successfully identify the metabolic pathways after the oral administration of bioactive DAP. PRACTICAL APPLICATION: The metabolic pathways of Dendrobium aphyllum polysaccharide, after artificially stimulated oral administration, were characterized. The most of the unabsorbed portion of DAP were utilized by the colon microbiota, resulting in the significantly increasing production of four health-promoting SCFAs. The unabsorbed portion of DAP upregulated the diversity of various beneficial microbiota genus, and meanwhile downregulated kinds of harmful microbiota genus.

Physicochemical characterization, antioxidant and hypoglycemic activities of selenized polysaccharides from Sargassum pallidum

This study was carried out to study the effects of selenylation on physicochemical and biological properties of polysaccharide (SPP) extracted from Sargassum pallidum. The selenized derivative of SPP (Se-SPP) with the selenium content of 2419 μg/g was synthesized by sodium selenite/dilute nitric acid method. Physicochemical characterization indicated that selenylation modification resulted in some changes in chemical composition, monosaccharide composition, molecular weight and surface morphology of polysaccharides. FT-IR spectroscopy showed that a new absorption peak appeared at 675 cm-1 in Se-SPP probably due to the substitution of selenyl groups. Bioactivity assay showed that Se-SPP exhibited higher scavenging radical activities and ferrous ion chelating activities than native SPP. Compared with SPP and acarbose, Se-SPP showed more significantly inhibitory effect on α-glucosidase activity in a noncompetitive inhibition type. The IC50 values of SPP, Se-SPP and acarbose were determined as 1.579, 0.896 and 2.742 mg/mL, respectively. These results suggest that Se-SPP can be used to develop a new selenium-complementary ingredient in functional foods.

Structure and in vitro hypoglycemic activity of a homogenous polysaccharide purified from Sargassum pallidum

This study aimed at investigating the structure, hypoglycemic activity and the underlying mechanism of a homogeneous polysaccharide (PSP-2) purified from Sargassum pallidum. Structural characterization revealed that PSP-2 with a molecular weight of 144.8 kDa was composed of fucose (21.6%), arabinose (2.5%), galactose (22.4%), glucose (2.2%), xylose (18.8%), mannose (1.2%), glucuronic acid (7.7%) and galacturonic acid (23.6%). The backbone chain of PSP-2 was composed of →1)-β-d-Xylp-(3→, →1,3)-β-l-Fucp-(4→, →1)-α-d-Galp-(6→, and →1)-α-d-GlcpNAc-(2→, and the side chains were composed of →1,3,6)-α-d-Galp-(2→, →3)-β-l-Fucp-(1,4→, β-d-GalpNAc-(1→, and α-d-Manp-(1→. In vitro hypoglycemic assays indicated that PSP-2 could significantly enhance glucose consumption, glycogen synthesis, and pyruvate kinase (PK) and hexokinase (HK) activities of insulin-resistant HepG2 cells. Furthermore, the underlying mechanistic studies revealed that PSP-2 could ameliorate insulin resistance by up-regulating the expression levels of insulin receptor substrate-1 (IRS-1), glycogen synthase (GS), phosphoinositide-3-kinase (PI3K) and glucose transporter-4 (GLUT4). These results suggested that PSP-2 may be a potential candidate for the prevention and treatment of Type 2 diabetes mellitus.

Physicochemical, Structural, and Biological Properties of Polysaccharides from Dandelion

The edible and medicinal perennial herb dandelion is known to have antitumor, antioxidant, and anticomplement properties. However, the structural characterization and biological effects of its polysaccharides are not well understood. Here, we aimed to extract and investigate a novel polysaccharide from dandelion. A water-soluble polysaccharide, PD1-1, was successfully obtained from dandelion through ultrasonic-assisted extraction and purification using diethylaminoethyl (DEAE)–Sepharose fast flow and Sephadex G-75 columns. The results showed that PD1-1 is an inulin-type polysaccharide with a molecular weight of 2.6 kDa and is composed of glucose (52.39%), and mannose (45.41%). Glycosidic linkage analysis demonstrated that PD1-1 contains terminal α-d-Man/Glcp-(1→ and →1)-β-d-Man/Glcf-(2→ glycosidic linkage conformations. A physicochemical analysis indicated that PD1-1 has a triple helix structure and exhibits important properties, including good swelling, water-holding, and oil-holding capacities. Furthermore, PD1-1 showed good antioxidant activities in DPPH and hydroxyl free radical scavenging abilities, with IC₅₀ values of 0.23 mg/mL and 0.25 mg/mL, respectively, and good hypoglycemic activities in α-amylase and α-glucosidase inhibition, with IC₅₀ values of 0.53 mg/mL and 0.40 mg/mL, respectively, in a concentration-dependent manner. Results suggest that PD1-1 possesses efficacious antioxidant and hypoglycemic properties and has potential applications as a functional food ingredient.

Polysaccharide-Rich Fractions from Rosa rugosa Thunb.-Composition and Chemopreventive Potential

The huge health-beneficial potential of polysaccharides encourages the search for novel sources and applications of these compounds. One poorly explored source of polysaccharides is the rose. The content and biological activity of polysaccharides in rose organs is an almost completely unaddressed topic, therefore, polysaccharide-rich extracts (crude polysaccharides, CPLs) from petals, leaves, hips, and achenes of Rosa rugosa Thunb. were studied for their composition and the influence on various cellular processes involved in the development of cancer and other civilization diseases. The study revealed the presence of water-soluble and -insoluble polysaccharides (including β-glucans) and protein-polysaccharide conjugates in rose organs. Rose hips were found to be the most abundant source of polysaccharides. Different polysaccharide-rich extracts showed the ability to inhibit pro-inflammatory enzymes (COX-1, COX-2, hyaluronidase), a radical scavenging effect (against DPPH^• and ABTS^•+), and antiproliferative activity (in the A549 lung and SW480 colon cancer cell lines) in in vitro assays. Therefore, rose crude polysaccharides are very promising and can potentially be used as natural chemopreventive agents.

Modified QuEChERS purification and Fe3O4 nanoparticle decoloration for robust analysis of 14 heterocyclic aromatic amines and acrylamide in coffee products using UHPLC-MS/MS

Based on QuEChERS dispersed purification, Fe₃O₄ nanoparticle decoloration and UHPLC-MS/MS, a robust and sensitive method was established for simultaneous analysis of 14 heterocyclic aromatic amines (HAAs) and acrylamide (AA) in coffee products. Sample was extracted by 90% acetonitrile water (v/v), dispersed with primary secondary amine (PSA) and further purified with Fe₃O₄ nanoparticle. Then, 15 analytes were detected using ESI positive ion under MRM mode. Good linearity was observed for all analytes in the range of 0.2-100 μg/L with the determination coefficients being above 0.996. Limits of detection (S/N ≥ 3) and limits of quantification (S/N ≥ 10) were in the range of 0.02-0.15 µg/L and 0.2-0.7 µg/L, respectively. The intra-day average recoveries were between 81.6% and 100%, and the intra-day precisions ranged from 4.3% to 9.0%. The inter-day average recoveries were in the range of 81.0-101% with precisions ranging from 5.0% to 7.8%. Results indicated that the combination of PSA and Fe₃O₄ exhibited superior purification and adsorption effects for removing pigments and acid compounds. Real samples analysis indicated that coffee products were widely contaminated with AA, harman and norharman.

GLABROUS1 from Rosa roxburghii Tratt regulates trichome formation by interacting with the GL3/EGL3 protein

GLABROUS1 is an R2R3 MYB homolog that is essential for the initiation of trichome development. In this study, we used RACE to clone a full-length cDNA from Rosa roxburghii Tratt, termed RrGL1, which was 1013 bp, including an open reading frame of 792 bp that encoded 263 amino acids. In situ hybridization, corresponding with qRT-PCR results, revealed that RrGL1 transcripts were mainly expressed in petiole, leaf, and stem. RrGL1 expression levels at various fruit developmental stages in R. roxburghii were also evaluated. RrGL1 was highly expressed in young fruit, and the expression level decreased with fruit maturation. The overexpression of RrGL1 was able to functionally complemented the Arabidopsis thaliana gl1^-/- mutant in trichome formation. RrGL1 was located in the cell nucleus with analysis of subcellular localization and physically interacted with A. thaliana GL3/EGL3 in the yeast two-hybrid assay, implying that RrGL1 might exert functions by forming a MYB-basic helix-loop-helix complex in trichome initiation. The formation of prickles in R. roxburghii is similar to that of Arabidopsis trichome. These results provided a foundation for further research on the molecular mechanisms underlying the formation and development of prickles that could assist and cultivate in the genetic engineering of prickle-free fruits.

Bioaccessibility, antioxidant activity and modulation effect on gut microbiota of bioactive compounds from Moringa oleifera Lam. leaves during digestion and fermentation in vitro

This study aims to investigate the bioaccessibility, bioactivity and gut microbiota modulation effect of Moringa oleifera Lam. leaves after in vitro gastrointestinal digestion and colonic fermentation.

Structural characterization and immunoregulatory activity of a new polysaccharide from Citrus medica L. var. sarcodactylis

A new homogeneous heteropolysaccharide (CMSPA90-1) was purified from bergamot by DEAE sepharose fast flow and Sephadex G-75 columns, and was shown to have a molecular weight of 17.6 kDa. Its chemical structure was elucidated by acid hydrolysis and methylation analysis, along with high-performance anion-exchange chromatography, Fourier transform infrared spectroscopy coupled with gas chromatography-mass spectrometry, NMR spectroscopies, the Congo red test, and circular dichroism. CMSPA90-1 consisted of a pyranoside and funanside with branches containing α- and β-configurations simultaneously. Arabinose and glucose might form an arabinoglucan backbone. The ultrastructure of CMSPA90-1 was further characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results of thermogravimetric analysis (TGA) revealed that CMSPA90-1 had good thermal stability. The results of DPPH˙ and ABTS⁺˙ radical scavenging assays indicated that CMSPA90-1 exhibited free-radical-scavenging properties. Otherwise, CMSPA90-1 could promote the proliferation of mouse splenocytes and the neutral red phagocytosis of RAW264.7 cells, which indicated that CMSPA90-1 could be researched and developed as one of the potential functional foods or natural medicines.

A new homogeneous heteropolysaccharide (CMSPA90-1) was purified from bergamot by DEAE sepharose fast flow and Sephadex G-75 columns, and was shown to have a molecular weight of 17.6 kDa.

Sulfated modification, characterization, antioxidant and hypoglycemic activities of polysaccharides from Sargassum pallidum

The aim of this study was to investigate the effect of sulfated modification on the in vitro antioxidant and hypoglycemic activities of Sargassum pallidum polysaccharides (SPP). Three sulfated derivatives (S-SPP1-4, S-SPP1-6 and S-SPP1-8) were prepared using chlorosulfonic acid-pyridine method under different reaction conditions. Physicochemical characterization indicated that sulfated modification had successfully occurred. The degrees of substitution (DS) of S-SPP1-4, S-SPP1-6 and S-SPP1-8 were determined to be ranging from 0.85 to 1.19. Sulfated modification resulted in some changes in chemical component, molecular weight and monosaccharide composition of SPP. Among these sulfated polysaccharides, S-SPP1-4 exhibited the best DPPH and ABTS radical scavenging activities, while S-SPP1-8 exhibited the best α-glucosidase inhibitory activity and promoting-effect on glucose consumption in insulin resistant (IR)-HepG2 cells. Furthermore, all the sulfated derivatives exhibited better hypoglycemic ability than native SPP. These results suggest that appropriately sulfated modification could enhance the antioxidant and hypoglycemic activities of S. pallidum polysaccharides, which might be used as an alternative derivative of natural antioxidant and hypoglycemic agent.

Isolation and Characterization of Pectic Polysaccharide Fraction from In Vitro Suspension Culture of Fumaria officinalis L

In the current study, an acidic polysaccharide from the in vitro suspension culture of Fumaria officinalis L. was obtained by extraction with 0.8% (w/v) aqueous ammonium oxalate. The polysaccharide fraction mainly consisted of galacturonic acid (41.0%), followed by galactose (7.3%) and arabinose (5.6%). This suggests the presence of arabinogalactan side chains in the rhamnogalacturonan-I segment of the studied pectin, which was mainly built up by homogalacturonan segments. The pectin was evaluated as low-methyl-esterified (45.0%) with degree of acetylation 3.4%. The polymer fraction was consisted of different molecular weight populations in the range of 6–600 kDa. The high amount of 4-L-hydroxyproline (11.7% of total protein) and the specific positive reaction to Yariv’s phenylglycoside reagent indicated the presence of an arabinogalactan protein in the cell walls. The functional properties of the polysaccharide fraction were evaluated, as it possessed better water-holding capacity than oil-holding capacity. The studied pectin demonstrated significant foaming ability and promising emulsifying properties in a concentration 1%. Therefore, the isolated polysaccharide fraction could be successfully used as emulsifier and foaming agent in food products and pharmaceutical supplements.

Structural characterization of a novel acidic polysaccharide from Rosa roxburghii Tratt fruit and its α-glucosidase inhibitory activity

An acidic polysaccharide (RTFP-3) extracted from Rosa roxburghii Tratt fruit can inhibit the activity of α-glucosidase.