Pectic polysaccharides from purple passion fruit peel: A comprehensive study in macromolecular and conformational characterizations

Screening of Poria cocos polysaccharide with immunomodulatory activity and its activation effects on TLR4/MD2/NF-κB pathway

PCP-W1, the Poria cocos polysaccharide with the strong immunomodulatory activity, was isolated through column chromatography and screened for in vitro immune activity in RAW 264.7 cells in this study. The structure analysis results revealed that the PCP-W1 were composed of galactose, glucose, fucose and mannose in a molar percentage of 35.87: 28.56: 21.77: 13.64. And it exhibited a random coil and branched conformational features with a molecular weight of 18.38 kDa. The main chain consisted of residues→3)-β-D-Glcp-(1 → 3,6)-β-D-Glcp-(1 → 3)-β-D-Glcp-(1 → 6)-β-D-Glcp-(1 → 6)-α-D-Galp-(1 → 6)-α-D-Galp-(1 → 2,6)-α-D-Galp-(1→6)-α-D-Galp-(1 → 6)-α-D-Galp-(1 → , while branching occurred at β-D-Glcp-(1→, α-D-Manp-(1→, and α-L-Fucp-(1 → 3)- α-L-Fucp-(1→. The pharmacodynamic studies demonstrated that PCP-W1 activated the release of NO, IL-6, IL-β, TNF-α, CD86, and ROS to induce polarization of RAW 264.7 murine macrophages towards M1-type through modulation of the TLR4/MD2/NF-κB pathway. The molecular docking results showed that PCP-W1 could primarily dock onto the hydrophobic binding site of TLR4/MD2 complex via its galactose chain. Furthermore, molecular dynamics simulation displayed stable modeling for TLR4-MD2-PCP-W1 complex. Overall, we screened the most immunoactive components of the polysaccharide, analyzed its structure, demonstrated its impact on TLR4/MD2/NF-kB pathway, and studied the interaction between TLR4/MD2 and the polysaccharide fragments. These results provide further support for the structure-activity relationship study of the immunomodulatory effects of Poria cocos polysaccharide.

Influence of Temperatures on Physicochemical Properties and Structural Features of Tamarind Seed Polysaccharide

Due to the high content of impurities such as proteins in tamarind seed polysaccharide (TSP), they must be separated and purified before it can be used. TSP can disperse in cold water, but a solution can only be obtained by heating the mixture. Therefore, it is important to understand the dispersion and dissolution process of TSP at different temperatures to expand the application of TSP. In this study, pasting behavior and rheological properties as a function of temperature were characterized in comparison with potato starch (PS), and their relationship with TSP molecular features and microstructure was revealed. Pasting behavior showed that TSP had higher peak viscosity and stronger thermal stability than PS. Rheological properties exhibited that G' and G'' of TSP gradually increased with the increase in temperature, without exhibiting typical starch gelatinization behavior. The crystalline or amorphous structure of TSP and starch was disrupted under different temperature treatment conditions. The SEM results show that TSP particles directly transformed into fragments with the temperature increase, while PS granules first expanded and then broken down into fragments. Therefore, TSP and PS underwent different dispersion mechanisms during the dissolution process: As the temperature gradually increased, TSP possibly underwent a straightforward dispersion and was then dissolved in aqueous solution, while PS granules initially expanded, followed by disintegration and dispersion.

Methods of study on conformation of polysaccharides from natural products: A review

Polysaccharides from natural products play multiple roles and have extensive bioactivities in life process. Bioactivities of polysaccharides (e.g., Lentinan, Schizophyllan, Scleroglucan, Curdlan, Cinerean) have a close relation to their chain conformation. Compared to other types of polysaccharides, the conformation of β-glucan has been studied more. The major research methods of conformation of polysaccharides from natural products (Congo red experiment, circular dichroism spectrum, viscosity method, light scattering method, size exclusion chromatography, atomic force microscope), corresponding experimental schemes, and the external factors affecting polysaccharide conformation were reviewed in this paper. These research methods of conformation have been widely used, among which Congo red experiment and viscosity method are the most convenient ones to study the morphological changes of polysaccharide chains.

Xylooligosaccharides from corn cobs alleviate loperamide-induced constipation in mice via modulation of gut microbiota and SCFA metabolism

This study aimed to optimize the structure and efficacy of xylooligosaccharides (XOSs) from corn cobs in constipated mice. Structural analysis revealed that XOSs from corn cobs were composed of β-Xyl-(1 →4)-[β-Xyl-(1→4)]n-α/β-Xyl (n = 0-5) without any other substituents. XOS administration significantly reduced the defecation time, increased the gastrointestinal transit rate, restored the gastrointestinal neurotransmitter imbalance, protected against oxidative stress, and reversed constipation-induced colonic inflammation. Fecal metabolite and microbiota analysis showed that XOS supplementation significantly increased short chain fatty acid (SCFA) levels and improved the gut microbial environment. These findings highlighted the potential of XOSs from corn cobs as an active ingredient for functional foods or as a therapeutic agent in constipation therapy.

NADES assisted integrated biorefinery concept for pectin recovery from kinnow (Citrus reticulate) peel and strategic conversion of residual biomass to L(+) lactic acid

The present study aims to establish an integrated strategy for valorization of kinnow peel waste. A total of ten natural deep eutectic solvents (NADESs) were exploited for extraction of pectin. The highest yield of pectin enriched material was reported 35.66 % w/dw using choline chloride-Maltose based NADES. The extraction process parameters and chemical composition of NADES influenced the yield and different associated physico-chemical attributes of the pectin enriched material. All the recovered pectin enriched materials found to be composed of low methoxy pectin (degree of methylation: 18.41-40.26 %) and galacturonic acid (GalA) content was in range of 67.56-78.22 %. The Principal Component Analysis (PCA) was used to categorise isolated pectin enriched materials based on similarities and differences. The liquid fraction upon pectin extraction presented a considerable amount of fermentable sugar which was further utilized for lactic acid production by microbial intervention. The microbial strain Lactobacillus amylophilus GV6 was exploited for lactic acid fermentation where the highest yield reached 55.59 g/L. A sustainable and straight-forward biorefinery concept was developed for extraction of pectin enriched material and lactic acid production from kinnow peel waste with potential application in food and biotechnological sectors.

The structures of two acidic polysaccharides from Gardenia jasminoides and their potential immunomodulatory activities

This study identified two homogeneous acidic polysaccharides from Gardeniae fructus, GJP50-3 and GJP50-4, which exhibited potential immunomodulatory activities in macrophage activation assays, via liquid-chip technology, and in a zebrafish model. Monosaccharide composition analysis and gel permeation chromatography revealed that GJP50-3 and GJP50-4 were composed of Rha, GalA, Glc, Gal, and Ara in specific ratios and had molecular weights of 91.5 kDa and 140.3 kDa, respectively. Based on FT-IR, GC-MS, and NMR analyses, these polysaccharides were identified as typical pectin polysaccharides with methylation degrees of 24.7 % and 21.4 %, respectively. The primary structures of GJP50-3 and GJP50-4 included linear HG domains and branched RG-I domains with arabinans and AG side chains. In vitro, GJP50-3 and GJP50-4 could stimulate NO release and increase the secretion of TNF-α in a RAW 264.7 macrophage model. Luminex liquid suspension chip detection revealed that GJP50-3 significantly promoted the secretion of multiple interleukins [IL-6, IL-9, IL-10, IL-12 (p40), IL-12 (p70), IL-13], TNF-α, and chemokines (G-CSF, GM-CSF, MCP-1 and RANTES). In vivo, these polysaccharides could also increase NO release and neutrophil count in a zebrafish model. These findings suggested that GJP50-3 and GJP50-4 might have the potential to be used as immunomodulators in the food and pharmaceutical industries.

Structural characterization and antioxidant activity of pectic polysaccharides from Veronica peregrina L

Background

Pectins are a class of acidic polysaccharides with complex structures. Different pectin molecules are composed of different domains, which have an important impact on their biological activity.

Objective

This study aimed to determine the structural features and the antioxidant activities of the pectic polysaccharides isolated from Veronica peregrina L.

Methods

The polysaccharide was isolated from Veronica peregrina L by water extraction and fractionated by ion exchange chromatography and gel permeation chromatography. The structure features of the pectic polysaccharides were determined by Fourier transforminfrared spectroscopy (FT-IR) and Nuclear magnetic resonance (NMR). The antioxidant activities was evaluated by the DPPH, OH and ABTS radical scavenging ability.

Results

WVPP-A2b and WVPP-A3b, with molecular weights of 48.7 × 10⁴ and 77.6 × 10⁴  kDa, respectively, contained homogalacturonan (HG), rhamnogalacturonan I (RG-I), and rhamnogalacturonan II (RG-II) domains with a mass ratio of 2.08:2.64:1.00 and 3.87:4.65:1:00, respectively. The RG-I domain contained an arabinogalactan II backbone and arabinans consisting of t-Araf, (1→5)-α-Araf, and (1→3,5)-α-Araf. WVPP-A3b also contained short chains consisting of the [t-Araf-(1→5)-α-Araf-(1→] structural unit. WVPP-A3b showed stronger ability to scavenge DPPH, hydroxyl, and ABTS radicals, which was potentially associated with its high content of galacturonic acid and presence of the HG domain.

Conclusion

The results provide information for enhancing knowledge of the structureactivity relationship of pectic polysaccharides from V. peregrina and their potential application in the healthcare food field.

Structure characterization and biological activities evaluation of two hetero-polysaccharides from Lepista nuda: Cell antioxidant, anticancer and immune-modulatory activities

Polysaccharides LNP-1 and LNP-2 were extracted and purified from Lepista nuda, and their structural characteristics and biological activities were evaluated. The molecular weights of LNP-1 and LNP-2 were determined to be 16,263 Da and 17,730 Da, respectively. The monosaccharide composition analysis showed that LNP-1 and LNP-2 were composed of fucose, mannose, glucose, and galactose in a molar ratio of 1.00:2.42:1.09:4.04 and 1.00:2.39:1.61:4.23, respectively. The structure analysis revealed that these two polysaccharides were mainly composed of T-Fuc, T-Man, T-Glc, 1,6-Glc 1,6-Gal, and 1,2,6-Man, 1,2,6-Gal. Additionally, LNP-2 contained an additional 1,4-Glc glycosidic linkage in comparison to LNP-1. Both LNP-1 and LNP-2 exhibited anti-proliferation effects on A375 cells, but not on HepG2 cells. Furthermore, LNP-2 showed better cellular antioxidant activity (CAA) than LNP-1. RT-PCR results indicated that LNP-1 and LNP-2 could induce macrophages to secrete immune-modulatory factors NO, IL-6, and TNF-α by regulating their mRNA expression. Overall, this study provides a theoretical basis for the further development of the structure-function relationship of polysaccharides from L. nuda.

Partial enzymolysis affects the digestion of tamarind seed polysaccharides in vitro: Degradation accelerates and gut microbiota regulates

Two hydrolyzed fractions of tamarind seed polysaccharide (TSP), denoted ETSP1 (176.68 kDa) and ETSP2 (34.34 kDa), were prepared by partial degradation via endo-xyloglucanase, and then characterized and evaluated by simulated gastrointestinal digestion in vitro. The results showed that the hydrolyzed TSPs remained indigestible in gastric and small intestinal media, and were fermented by gut microbiota, similar to the native TSP (M_w = 481.52 kDa). Although the degradation of hydrolyzed TSPs was accelerated during fermentation with a decreasing degree of polymerization, the content of produced total short-chain fatty acids (SCFAs) decreased. After fermentation, the gut microbiota composition was modified, esp. the Firmicutes/Bacteroidetes ratio decreased (1.06 vs. 0.96 vs. 0.80) with a decreasing degree of polymerization, which implied that the potential anti-obesity prebiotic effect was enhanced. At the genus level, hydrolyzed TSPs maintained similar roles as native TSP, including promoting beneficial bacteria (Bifidobacterium, Parabacteroides, and Faecalibacterium) and inhibiting enteropathogenic bacteria (Escherichia-Shigella and Dorea). Moreover, ETSP1 had additional potential due to abundant Bacteroides vulgatus (LDA = 4.68), and ETSP2 might perform better as related to Bacteroides xylanisolvens (LDA = 4.40). All these results indicated the prebiotic potential of hydrolyzed TSP with detailed information about changes in degradation and gut microbiota based on enzyme-hydrolysis.

Acidic polysaccharide from corn silk: Structural & conformational properties and hepatoprotective activity

This study aimed to investigate the structural characterization, conformational properties, and hepatoprotective activity of corn silk acidic polysaccharide (CSP-50E). CSP-50E with molecular weights of 1.93 × 10⁵ g/mol was composed of Gal, Glc, Rha, Ara, Xyl, Man and uronic acid with a weight ratio of 12:25:1:2:2:5:21. Structural analysis with methylation indicated that CSP-50E mainly contained T-Manp, 4-substituted-_D-Galp/GalpA, and 4-substituted-_D-Glcp. CSP-50E presented random coils conformation in an aqueous solution based on the analysis of HPSEC. In vitro experiments showed that CSP-50E exhibited significant hepatoprotective effects, CSP-50E reduce IL-6, TNF-α content, and AST, ALT activity to protect ethanol-induced damage liver cells (HL-7702), while the polysaccharide functioned mainly through the caspase cascade and mediate the mitochondrial apoptosis pathway. In this study, we describe a novel acidic polysaccharide from corn silk with hepatoprotective activity that facilitates the development and utilization of corn silk resources.

Acetylation modification improved the physicochemical properties of xyloglucan from tamarind seeds

Acetylation modification was conducted to improve the water-solubility and solution properties of xyloglucan from tamarind seeds (TSX). Three acetylated TSX with different degree of substitution (DS) were successfully prepared, and their structure and molecular parameters were investigated by FT-IR, NMR, and high-performance size exclusion chromatography (HPSEC). Further, the effects of acetylation on the thermal stability, solubility, and rheological properties of TSX were studied. Results showed that acetyl groups were mainly substituted at the O-6 position of terminal galactose with DS of 0.2, 0.47, and 0.36 for AC-2, AC-5, and AC-10, respectively. HPSEC analysis indicated that molecular weight of acetylated derivatives decreased slightly, and the solution conformation became more flexible as the DS increase. By comparing with TSX, the thermal stability, water-solubility, solution transmittance, and ζ-potential of acetylated TSX were significantly improved as the DS increase. In addition, rheological studies demonstrated that acetylation reduced the shear viscosity, but high DS of acetylation could induce the weak gelling property of TSX. In conclusion, acetylation modification could be applied to improve the physicochemical properties of TSX and promote its further application in food and pharmaceutical industries.

Effects of various degrees of esterification on antioxidant and immunostimulatory activities of okra pectic-polysaccharides

Pectic-polysaccharides are considered as one of the most abundant bioactive components in okra, which possess various promising health-promoting effects. However, the knowledge regarding the structure-bioactivity relationship of okra pectic-polysaccharides (OPP) is still limited. In this study, effects of various degrees of esterification (DEs) on in vitro antioxidant and immunostimulatory activities of OPP were analyzed. Results displayed that OPP with high (42.13%), middle (25.88%), and low (4.77%) DE values were successfully prepared by mild alkaline de-esterification, and their primary chemical structures (compositional monosaccharide and glycosidic linkage) and molecular characteristics (molecular weight distribution, particle size, and rheological property) were overall stable. Additionally, results showed that the notable decrease of DE value did not significantly affect antioxidant activities [2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and nitric oxide (NO) radical scavenging abilities as well as ferric reducing antioxidant power (FRAP)] of OPP, suggesting that the DE was not closely related to its antioxidant activity. In fact, the slight decrease of antioxidant activity of OPP after the alkaline de-esterification might be attributed to the slight decrease of uronic acid content. Nevertheless, the immunostimulatory effect of OPP was closely related to its DE, and a suitable degree of acetylation was beneficial to its in vitro immunostimulatory effect. Besides, the complete de-acetylation resulted in a remarkable reduction of immune response. The findings are beneficial to better understanding the effect of DE value on antioxidant and immunomodulatory activities of OPP, which also provide theoretical foundations for developing OPP as functional foods or health products.

Acetyl-glucomannan from Dendrobium officinale: Structural modification and immunomodulatory activities

To understand the mechanisms of immunomodulatory effect, Dendrobium Officinale polysaccharides (DOP) were treated by ultrasound and mild base separately to generate fractions of various weight-average molecular weight (Mw) and degrees of acetylation (DA). The structural features, conformational properties, functional properties and immunomodulatory activities of original and modified DOPs were investigated. Ultrasonic treatment decreased the Mw and apparent viscosity and improved the water solubility of DOP. Mild base treatment remarkably reduced the DA and the water solubility, while the overall apparent viscosity was increased. Conformational analysis by triple-detector high performance size-exclusion chromatography showed that the molecular chain of DOP turned more compact coil conformation with decreased DA. Results from the macrophages RAW 264.7 analysis showed that samples sonicated for 200 min (Mw 34.2 kDa) showed the highest immune-regulation effects. However, the immunomodulatory effects of the samples after de-acetylation were all compromised compared to the original DOP. This study inspires further research to establish the structural-immunomodulatory relationships, which promote the application of DOP in both the food and medicine fields.

Efficient and selective adsorption of methylene blue and methyl violet dyes by yellow passion fruit peel

As an important biomass resource, agricultural waste is of great significance to improve the application value. In this study, the yellow passion fruit peel (Y-PFP) was used as a biosorbent to remove cationic dyes (methylene blue (MB) and methyl violet (MV)) by the simple treatment process. And the effects of pH, contact time, initial dye concentration, ionic strength, and temperature on the adsorption performance of Y-PFP were studied. The adsorption process was consistent with the pseudo-second-order kinetic model and Langmuir isotherm. What's more, the maximum adsorption capacity for MB and MV was 324.7 and 485.4 mg·g^-1, respectively. And Y-PFP still exhibited high removal efficiency after five desorption-adsorption cycles. Thus, Y-PFP had highly valuable for the removal of cationic dyes from wastewater with a simple preparation process, low cost, excellent adsorption capacity and selectivity.

Biogenetic nanocarriers with enhanced pH stability formed by zein and selectively depolymerized mushroom hyperbranched β-glucans

Hyperbranched polysaccharide from Pleurotus tuber-regium (PTR-HBPS) is a β-glucan with high degree of branching (DB, 0.69) and a molecular weight (Mw) of 31.2 × 10⁵ g/mol with mixed β-1, 4/β-1, 4, 6/β-1, 6 glucosidic linkages. PTR-HBPS was depolymerized by cellulase and β-glucosidase under optimized conditions to form PC (PTR-HBPS depolymerized by cellulase) and PG (PTR-HBPS depolymerized by β-glucosidase) fractions with a minimum Mw of 2.74 × 10⁵ and 3.98 × 10⁵ g/mol, respectively. PC fractions had no significant changes for its primary structure in terms of glycosidic linkages, DB, and triple helical structure, while the DB of PG fractions was reduced to 0.63 with the loss of triple helical structure. Nanoparticles fabricated by PC fractions with zein showed better stability under different pH conditions. Enzymatic depolymerized low Mw β-glucan derived from PTR-HBPS with similar structural characteristics as the native one has potential as nanocarriers for food bioactive substances.

Waste Passion Fruit Peel as a Heterogeneous Catalyst for Room-Temperature Biodiesel Production

A low-cost, green, and highly active catalyst which could transesterify oil under ambient conditions is required to reduce the biodiesel production cost. A novel heterogeneous catalyst derived from the waste agroproduct has been developed from passion fruit peel. The catalytic activity of calcined waste passion fruit peel (WPFP) which mainly contains potassium in the form of chloride and carbonate has been evaluated using factorial design to determine the interaction of molar ratio of oil to methanol, catalyst weight, and reaction time with three different reaction conditions such as 65, 45 °C, and room temperature. The transesterification of palm oil to biodiesel achieved a conversion of >90% for all variables determined at a reaction temperature of 45 and 65 °C, respectively, while a maximum biodiesel conversion of 95.4 ± 2.8% was obtained at room temperature and a reaction time of 30 min. The addition of certain amounts of the catalyst is required to reuse the catalyst as the leaching study showed the reduction of 22% of catalyst weight. The ability of calcined WPFP to catalyze transesterification at room temperature opens up the possibility to reduce biodiesel production cost.

Pectic polysaccharides from Biluochun Tea: A comparative study in macromolecular characteristics, fine structures and radical scavenging activities in vitro

In this study, two acidic Biluochun Tea polysaccharides (BTP-A₁₁ and BTP-A₁₂) were investigated comparatively, which mainly consisted of Rha, Ara, Gal and GalA, possibly suggesting their pectic nature. Structurally, their galacturonan backbones composed of →4)-α-D-GalpA-(1→ and →2)-α-L-Rhap-(1→ were revealed similar, while Ara- and Gal-based branches attached to the O-2 of →2)-α-L-Rhap-(1→ were in distinctive types, proportions, extensibilities and branching degrees. This could lead to their different macromolecular characteristics, where BTP-A₁₁ with higher M_w presented a more hyper-branched chain conformation and relatively higher structural flexibility/compactness, thereby resulting in a lower exclusion effect and an insufficient hydrodynamic volume. Besides, better radical scavenging activities in vitro were also determined for Gal-enriched BTP-A₁₁, where a larger surface area containing more H-donating groups were related to its higher M_w, more hyper-branched conformation, lower DM and higher DA. Therefore, the understanding of structure-property-activity relationships was improved to some degrees for acidic Biluochun Tea polysaccharides, which could be potentially required for more applications in food, medical and cosmetic fields.

Structural characteristics of tamarind seed polysaccharides treated by high-pressure homogenization and their effects on physicochemical properties of corn starch

In this work, structural characteristics of TSPs treated by high-pressure homogenization (HPH) and their effects on physicochemical properties of corn starch were analyzed. HPH induced monosaccharides change, Gal/Glc ratio decrease from 0.32 to 0.25, and molecular weight (M_w) decrease from 10.55 to 4.47 × 10⁵ Da through damaging glycosidic linkages in the backbone and side-chain of TSPs. Furthermore, 90 MPa homogenized TSP (higher Gal removal) showed inhibitory effects on starch paste retrogradation, and TSPs with a lower M_w (homogenized at 60 and 90 MPa) could limit water precipitation during the long-term storage. Moreover, M_w and Gal/Glc ratio were the major factors for the determined effects of TSPs on physicochemical properties of corn starch. The results could provide new insights into the relationship between TSP structure and their effects on the physicochemical properties of starch.

Macromolecular and thermokinetic properties of a galactomannan from Sophora alopecuroides L. seeds: A study of molecular aggregation

The molecular aggregation of a galactomannan (NSAP-25) from Sophora alopecuroides L. seeds was investigated, where three polydisperse systems were confirmed during particle size analysis, indicating existence of different aggregates composed of random coil chains revealed by circular dichroism. Morphologically, NSAP-25 aggregate of various sizes (200-1200 nm) was possibly multi-stranded and formed by ellipsoid-like particles (20-60 nm) composed of compact coil chain, exhibiting extended amorphous structure with chain-like branches intertwined. Hence, NSAP-25 aggregation was inevitable, which exerted an unignorable effect on augmenting flexibility (β↓, γ↓, α↓ and L_p/M_L↓) and compactness (ρ↓, d_f↑ and C_∞↓) of branched random coil chain based on macromolecular analysis, especially when concentration increased. Moreover, it could be relevant to thermokinetic behavior of random nucleation and subsequent growth (A² model and negative ΔS*) as well as good thermal stability (IPDT, ITS, t_0.05, T_m and T_p), thus conferring potential applications for NSAP-25 in food and pharmaceutical industries.

Purification, Structural Characterization and Immunomodulatory Effects of Polysaccharides from Amomumvillosum Lour. on RAW 264.7 Macrophages

Amomum Villosum Lour. (A. villosum) is a folk medicine that has been used for more than 1300 years. However, study of the polysaccharides of A. villosum is seriously neglected. The objectives of this study are to explore the structural characteristics of polysaccharides from A. villosum (AVPs) and their effects on immune cells. In this study, the acidic polysaccharides (AVPG-1 and AVPG-2) were isolated from AVPs and purified via anion exchange and gel filtration chromatography. The structural characteristics of the polysaccharides were characterized by methylation, HPSEC-MALLS-RID, HPLC, FT-IR, SEM, GC-MS and NMR techniques. AVPG-1 with a molecular weight of 514 kDa had the backbone of → 4)-α-d-Glcp-(1 → 3,4)-β-d-Glcp-(1 → 4)-α-d-Glcp-(1 →. AVPG-2 with a higher molecular weight (14800 kDa) comprised a backbone of → 4)-α-d-Glcp-(1 → 3,6)-β-d-Galp-(1 → 4)-α-d-Glcp-(1 →. RAW 264.7 cells were used to investigate the potential effect of AVPG-1 and AVPG-2 on macrophages, and lipopolysaccharide (LPS) was used as a positive control. The results from bioassays showed that AVPG-2 exhibited stronger immunomodulatory activity than AVPG-1. AVPG-2 significantly induced nitric oxide (NO) production as well as the release of interleukin (IL)-6 and tumor necrosis factor alpha (TNF-α), and upregulated phagocytic capacities of RAW 264.7 cells. Real-time PCR analysis revealed that AVPG-2 was able to turn the polarization of macrophages to the M1 direction. These results suggested that AVPs could be explored as potential immunomodulatory agents of the functional foods or complementary medicine.

Selective Adsorption of CR (VI) onto Amine-Modified Passion Fruit Peel Biosorbent

This study aimed to prepare surface amino-riched passion fruit peel (DAPFP) by amination reaction with low-cost biomaterials and use it as a biosorbent to adsorb Cr (VI). The specific physicochemical and structural properties of DAPFP were characterized by SEM, EDS, XRD, TG, Zeta, XPS, and FT-IR. The effects of pH value, initial concentration, adsorption time, coexisting ions, and temperature on the adsorption of Cr (VI) were systematically investigated. The results showed that within 90 min, DAPFP could reduce the concentration of Cr (VI) solution (1 mg/L−1) to an allowable safe level of drinking water (0.05 mg/L−1) specified by the World Health Organization. The adsorption process complies with pseudo-second-order kinetics and the Langmuir isotherm model. The adsorption capacity of the prepared biosorbent could reach 675.65 mg/g−1. The results of thermodynamic studies confirmed that the adsorption process was a self-discharging heat process. DAPFP also showed good reusability; even after being used repeatedly five times, it still showed excellent adsorption performance. FT-IR and XPS analyses showed that electrostatic attraction and reduction were the main reasons for the adsorption. By virtue of its low cost and excellent adsorption performance, DAPFP has a potential practical application as an adsorbent in treating Cr (VI) containing wastewater.

Triple-helix polysaccharides: Formation mechanisms and analytical methods

Triple helix conformation of polysaccharides is generally believed to be associated with their biological activities. However, the formation mechanisms and analytical methods for the triple helix polysaccharides, to our best knowledge, have not been systematically investigated. This article reviews specifically the literature on the formation and characterization of triple-helix polysaccharides. The formation mechanisms and related structural-conformation-bioactivity relationships are discussed; various analytical methods for characterizing triple-helix polysaccharides are summarized. This review devotes to a better understanding of the formation of polysaccharides based triple-helix structure and related analytical methods. These could provide some insights and inspirations for their applications in both food and pharmaceutical industries.

The structure, conformation, and hypoglycemic activity of a novel heteropolysaccharide from the blackberry fruit

A novel heteropolysaccharide fraction (BBP-24-3) with a relative molecular weight of 145.1 kDa was isolated from blackberry fruits. The BBP-24-3 was mainly composed of arabinose, glucose, and galacturonic acid with a ratio of 5.30 : 3.60 : 91.10 mol%. Structural analysis showed that BBP-24-3 possessed a 1,6-linked β-d-Glcp, 1, 2, 3, 5 linked α-l-Araf, and 1, 4 linked α-d-GalpA backbone with branches substituted at the C-2 and C-5 positions of arabinose units, which included 1, 2, 3, 4 linked β-d-Glcp and T-linked β-d-GalpA. The conformation analysis indicated that BBP-24-3 exhibited a solid spherical structure with a uniform distribution in 0.1 M NaCl solution. The BBP-24-3 exhibited excellent α-glucosidase inhibitory activity with an IC50 value of 3.70 mg mL-1, which was due to the structural change, including α-helix and random coil of α-glucosidase caused by BBP-24-3. The current work suggests the potential utilization of BBP-24-3 as an α-glucosidase inhibitor in healthy food for reducing the postprandial blood glucose level.

An ultrasonic-extracted arabinoglucan from Tamarindus indica L. pulp: A study on molecular and structural characterizations

In this study, an ultrasonic-extracted polysaccharide (nCPTP-55) was obtained with the highest yield (61.08%, w/w) from tamarind pulp, which consisted chiefly of total sugar (85.98%, w/w) with few protein (2.10%, w/w). Monosaccharide analysis showed nCPTP-55 was mainly composed of arabinose (39.19 mol%) and glucose (50.48 mol%) with negligible GlcA (2.05 mol%), indicating the neutral nature of nCPTP-55, which was further elucidated structurally via GC-MS and NMR, i.e., an arabinoglucan composed of →3)-β-D-Glcp-(1→ backbone with only T-α-L-Araf-(1→ branched at O-4 (27.82%) and O-6 (39.99%), resulting in relatively high A/G ratio (0.68-0.70). Based on MM2 minimized energy, the 3D schematic structures of nCPTP-55 could be considered as structural basis for its conformational behavior, which was preliminarily estimated via HPSEC-MALLS as between compact sphere and loosely hyper-branched chain (ρ = 0.84). Therefore, the relationship between molecular structure and conformational behavior was basically established for nCPTP-55, which was in a bid to have a better knowledge of its structure-property and structure-bioactivity relationships potentially required for more applications in food, cosmetic and pharmaceutical fields.