Search Results (108)

Decoctions of stem barks from Aucoumea klaineana, Canarium schweinfurthii, Pentadesma butyracea and Scorodophloeus zenkeri are used against affections of irritable bowel syndrome in Gabonese traditional medicine. In the present study, we aim to determine whether the bark polysaccharides may contribute to the activity of these plants against the symptoms of gastrointestinal disorders. To this end, we investigated the structure and the pharmacological activity of polysaccharides extracted from their stem barks. The pectic and hemicellulose polysaccharides were isolated, and their sugar compositions were determined by gas chromatography. In addition, analysis by MALDI-TOF mass spectrometry of oligosaccharides released after digestion with an endo-xylanase indicated that glucuronoarabinoxylans are the main hemicellulose of stem barks. We then evaluated the influence of the polysaccharide fractions on the spontaneous contractile activity of rat ileal smooth muscle and the cholinergic system. Spasmolytic activity of pectic fractions from all stem barks, as well as lemon polygalacturonic acid, were observed, indicating that these extracts exhibit a myorelaxant activity. In contrast, the bark hemicellulose fractions, as well as commercially available beechwood glucuronoxylan and wheat arabinoxylan, were demonstrated to be able to increase the basal contractile activity of smooth muscle. These data show that, beyond physicochemical effects affecting the bowel water content, plant polysaccharides have also an impact on the spontaneous smooth muscle contractility, the main mechanism involved in the pathophysiology of gastrointestinal disorders. Full article

This review examines sustainable cascading biorefinery strategies for the green alga Ulva, which is globally prevalent in eutrophic marine waters and often forms extensive “green tides.” These blooms cause substantial environmental and economic damage to coastal communities. The primary target products within an Ulva biorefinery typically encompass salts, lipids, proteins, cellulose, and ulvan. Each of these components possesses unique properties and diverse applications, contributing to the economic robustness of the biorefinery. Salts can be repurposed for agricultural or even human consumption. Lipids offer high-value applications in nutraceuticals and animal feed. Proteins present significant potential as plant-based nutritional supplements. Cellulose can be transformed into various advanced materials. Finally, ulvan, a polyanionic oligosaccharide unique to Ulva, holds promise due to its distinct properties, particularly in the biomedical field. Furthermore, state-of-the-art chemical modifications of ulvan are presented with the aim of tailoring its properties and broadening its potential applications. Future research should prioritize optimizing these integrated extraction and fractionation processes. Furthermore, a multi-product biorefining approach, integrated with robust Life Cycle Assessment studies, is vital for transforming this environmental challenge into a significant opportunity for sustainable resource valorization and economic growth. Full article

Four new minor monosulfated triterpene penta- and hexaosides, cladolosides S (1), S₁ (2), T (3), and T₁ (4), were isolated from the Vietnamese sea cucumber Cladolabes schmeltzii (Sclerodactylidae, Dendrochirotida). The structures of the compounds were established based on extensive analysis of 1D and 2D NMR spectra as well as HR-ESI-MS data. Cladodosides S (1), S₁ (2) and T (3), T₁ (4) are two pairs of dehydrogenated/hydrogenated compounds that share identical carbohydrate chains. The oligosaccharide chain of cladolosides of the group S is new for the sea cucumber glycosides due to the presence of xylose residue attached to C-4 Xyl1 in combination with a sulfate group at C-6 MeGlc4. The oligosaccharide moiety of cladolosides of the group T is unique because of the position of the sulfate group at C-3 of the terminal sugar residue instead of the 3-O-Me group. This suggests that the enzymatic processes of sulfation and O-methylation that occur during the biosynthesis of glycosides can compete with each other. This can presumably occur due to the high level of expression or activity of the enzymes that biosynthesize glycosides. The mosaicism of glycoside biosynthesis (time shifting or dropping out of some biosynthetic stages) may indicate a lack of compartmentalization inside the cells of organism producers, leading to a certain degree of randomness in enzymatic reactions; however, this also offers the advantage of providing chemical diversity of the glycosides. Analysis of the hemolytic activity of a series of 26 glycosides from C. schmeltzii revealed some patterns of structure–activity relationships: the presence or absence of 3-O-methyl groups has no significant impact, hexaosides, which are the final products of biosynthesis and predominant compounds of the glycosidic fraction of C. schmeltzii, are more active than their precursors, pentaosides, and the minor tetraosides, cladolosides of the group A, are weak membranolytics and therefore are not synthesized in large quantities. Two glycosides from C. schmeltzii, cladolosides D (18) and H₁ (26), display selectivity of cytotoxic action toward triple-negative breast cancer cells MDA-MB-231, while remaining non-toxic in relation to normal mammary cells MCF-10A. Quantitative structure–activity relationships (QSAR) were calculated based on the correlational analysis of the physicochemical properties and structural features of the glycosides and their hemolytic and cytotoxic activities against healthy MCF-10A cells and cancer MCF-7 and MDA-MB-231 cell lines. QSAR highlighted the complexity of the relationships as the cumulative effect of many minor contributions from individual descriptors can have a significant impact. Furthermore, many structural elements were found to have different effects on the activity of the glycosides against different cell lines. The opposing effects were especially pronounced in relation to hormone-dependent breast cancer cells MCF-7 and triple-negative MDA-MB-231 cells. Full article

Prebiotics are food ingredients that result in specific changes in the composition and/or activity of the gastrointestinal microbiota, thus conferring benefits upon host health. Xylooligosaccharides (XOS) are prebiotic fibers made from xylan. Commercial XOS are mixtures of oligosaccharides containing β-1,4–linked xylose residues. Though they are widely added to foods at different doses, the molecular mechanisms of the catabolism and growth promotion of XOS in the innate gut microbes Lactobacillus spp. remain unknown. In this study, we evaluated the growth-promoting effect using a human fecal isolate, Lactiplantibacillus plantarum strain B20 (Lb. plantarum B20). Assays of bacterial growth and lactic acid production showed stronger growth promotion of XOS than other oligosaccharides did, in a dose- and fraction-dependent pattern. Using the Lb. plantarum strain SK151 genome as a reference, bioinformatic analysis failed to identify any previously characterized genes responsible for the uptake and catabolism of XOS. However, transcriptomic analysis of Lb. plantarum B20 yielded numerous differentially expressed genes (DEGs) during fermentation of XOS. Among these, an oligopeptide ABC transporter (RS03575-03595, composed of five proteins) and a hydrolase (RS06170) were significantly upregulated. Molecular docking analysis indicated that the substrate-binding protein RS03575 may mediate the import of XOS into the cell. Enzymatic assays further demonstrated that RS06170 possesses β-xylosidase activity and can effectively degrade XOS. In addition, functional enrichment analysis suggested that the growth-promoting effect of XOS may be attributed to the upregulation of genes involved in cellular component biogenesis and cell division, potentially through modulation of ribosome function and carbohydrate metabolism in Lb. plantarum B20. These results provide valuable insights into the mechanisms by which XOS promote growth and highlight potential targets for enhancing prebiotic–probiotic interactions. Full article

During the conventional biomass fractionation, the degradation and dissolution of lignin and hemicellulose result in a complex extract which remains very challenging for the thorough separation and purification of a wide variety of fractionated products, limiting their further utilization. Herein, we proposed a facile and efficient strategy for fractionating biomass and simultaneously in situ converting of both lignin and hemicellulose into single products using a formic acid–phloroglucinol system. The introduced phloroglucinol could react with lignin fragments and hemicellulose-derived products, and the generated intermediate product from hemicellulose can be further condensed with lignin fragments, finally forming single lignin-based functional biopolymers containing heterocyclic structures. Only small amounts of hemicellulosic derivatives, such as oligosaccharides, monosaccharides, furfural, and 5-HMF, were detected in the extracted solution, indicating a highly directional and effective in situ conversion process of hemicellulose. The constructed specific structures on fabric surfaces by using the chelation between lignin-based functional biopolymers and metal ions achieved the preparation of functional fabrics with stable hydrophobicity. The dynamic contact angle of water droplets on the surface of prepared fabric only decreased from 122° to 116.8° over 30 min. This work strategy provides an ideal route to maximize the utilization of both lignin and hemicellulose without involving complex separation and purification procedures. This strategy is the first demonstration of using the targeted fractionation system to achieve the simultaneous conversion of hemicellulose and lignin into single functional biopolymers directly from lignocellulosic biomass. Full article

Purification and characterization of milk oligosaccharides is a challenging process due to the complexity of the constituent oligosaccharides, which behave differently under various chemical treatment procedures and often lose their structural properties in the process. Rathi cow’s milk is widely used in the Rajasthan region of India for its nutritional and medicinal benefits. Here, we aim to present an optimized method for the purification and analysis of oligosaccharides present in Rathi cow milk. Contrary to the freeze transport methods used earlier, we treated the collected milk with ethanol for preservation, followed by microfiltration, lyophilization, and fractionation on silica gel (60–120 mesh size) column chromatography (CC) coupled with chloroform/methanol-mediated gradient elution. Fractions 31–45 (1.78 g), 71–80 (470 mg), and 106–120 (498 mg) from CC-1 and fractions 26–49 (1.14 g) from CC-2 were analysed for sugar content via the phenol–sulfuric acid method. Fraction homogeneity was confirmed using high-performance liquid chromatography. Isolated analytes were treated with acetic anhydride/pyridine (1:1, v/v) to form less polar oligosaccharide derivatives, which could then be easily visualized and semi-quantitated using partition chromatography (thin later and paper) with chloroform/methanol. Structural identities of the purified oligosaccharides were determined using a combination of mass spectrometry and NMR (¹H, ¹³C, HSQC, TOCSY, COSY, HMBC) techniques. Our results clearly demonstrate that the ethanol-based preservation, transport, and purification of oligosaccharides is a simple and robust method for the analysis of Rathi cow’s milk oligosaccharides. Furthermore, using the acetylation, purified oligosaccharides allow for rapid analysis on thin-layer chromatography, which is quite cost effective compared with other analytical methods. Full article

The depolymerized products and oligosaccharide fractions from sea cucumber fucosylated glycosaminoglycans (FGs) are promising anticoagulant candidates, and more novel FG-derived oligosaccharides from low-priced sea cucumbers are expected to be obtained. This study isolated 5−12 oligomers (OF1−OF3) with unusual branches from β-eliminative depolymerized products of Colochirus quadrangularis FG (CqFG). Detailed NMR analyses showed that OF1−OF3 consisted of a chondroitin 4,6-sulfates backbone and some sulfated fucosyl branches (FucS), including monosaccharides (α-l-Fuc_2S4S, α-l-Fuc_3S, α-l-Fuc_4S, α-l-Fuc_2S3S4S, and α-l-Fuc_2S) and a disaccharide D-Gal_3S4S-α1,3-l-Fuc_2S4S with the ratio of ~36:35:10:7:3:9, attached to the C-3 position of β-d-GlcA or its derivatives, such as α-l-Δ4,5GlcA and β-d-GlcA-ol. Unusually, α-l-Fuc_3S was the main FucS branch; no α-l-Fuc_3S4S branch was found, and α-l-Fuc_2S3S4S and α-l-Fuc_2S branches were also found in OF1–OF3. The OF2 and OF3 could strongly inhibit the intrinsic and common coagulation pathways. Intrinsic FXase is a target of OF2 and OF3 inhibiting the intrinsic coagulation pathways, and the unusual side chains may increase the intrinsic FXase inhibitory activity. OF2 and OF3 showed negligible bleeding risk, and less bleeding than heparin (HP), low-molecular-weight heparins (LMWHs), and CqFG. These findings support novel FG oligosaccharides with some unusual branches from low-priced sea cucumbers to be prepared as safer anticoagulants. Full article

Cereals are among the foods rich in myo-inositol hexakisphosphate (phytic acid, IP6), lower myo-inositol phosphates (IPx), a wide range of phenolic compounds, as well as vitamins, minerals, oligosaccharides, phytosterols and para-aminobenzoic acid, and are attributed with multiple bioactivities, particularly associated with the prevention of metabolic syndrome and colon cancer. The bran fraction of wheat, maize, brown rice and other cereals contains high levels of phytate, free and total phenolics, and endogenous enzymes such as amylases, phytase, xylanase, β-glucanase and feruloyl esterase, whose activities can be increased by germination. The preliminary steps of digestion begin in the oral cavity where substrates for the action of endogenous cereal and salivary enzymes start to be released from the food matrix. IP6 released from phytate complexes with arabinoxylans, starch and protein bodies would eventually enhance the absorption of nutrients, including phenolics, by regulating tight junctions and, together with ferulic acid (FA), would maintain cell barrier integrity and epithelial antibacterial immunity. In addition, both IP6 and FA exert potent and complementary antioxidant effects, while FA together with IPx generated through advanced hydrolysis of IP6 by endogenous and microbial phytases may affect digestive enzyme activity and incretin secretion, resulting in modulated insulin and glucagon release and prevention of various diabetic complications. Contrary to widespread negative attitudes towards phytate, in this review, we present the strategy of selecting cereals with high phytate and phenolic content, as well as high endogenous phytase, feruloyl esterase and endoxylanase activities, to produce value-added health-promoting foods. The advanced hydrolysis of phytate and phenolic compounds by cereal and/or microbial enzymes would generate substantial amounts of “enzymatically generated inositol” (EGI), including IP6, IPx and myo-inositol, the compounds that, together with free FA, provide enhanced bioavailability of cereal nutrients through multiple synergistic effects not previously realised. Full article

A rise in antimicrobial resistance coupled with consumer preferences towards natural preservatives has resulted in increased research towards investigating antimicrobial compounds from natural sources such as macroalgae (seaweeds), which contain antioxidant, antimicrobial, and anticancer compounds. This study investigates the antimicrobial activity of compounds produced by the Irish seaweed Alaria esculenta against Escherichia coli and Listeria innocua, bacterial species which are relevant for food safety. Microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), ultrasound–microwave-assisted extraction (UMAE), and conventional extraction technologies (maceration) were applied to generate extracts from A. esculenta, followed by their preliminary chemical composition (total phenolic content, total protein content, total soluble sugars) and antimicrobial activity (with minimum inhibitory concentration determined by broth microdilution methods), examining also the molecular weight distribution (via high performance size exclusion chromatography) and oligosaccharide fraction composition (via high-performance liquid chromatography) of the polysaccharides, as they were the predominant compounds in these extracts, aiming to elucidate structure–function relationships. The chemical composition of the extracts demonstrated that they were high in total soluble sugars, with the highest total sugars being seen from the extract prepared with UAE, having 32.68 mg glucose equivalents/100 mg dried extract. Extracts had antimicrobial activity against E. coli and featured minimum inhibitory concentration (MIC) values of 6.25 mg/mL (in the case of the extract prepared with UAE) and 12.5 mg/mL (in the case of the extracts prepared with MAE, UMAE, and conventional maceration). No antimicrobial activity was seen by any extracts against L. innocua. An analysis of molar mass distribution of A. esculenta extracts showed high heterogeneity, with high-molecular-weight areas possibly indicating the presence of fucoidan. The FTIR spectra also indicated the presence of fucoidan as well as alginate, both of which are commonly found in brown seaweeds. These results indicate the potential of antimicrobials from seaweeds extracted using green technologies. Full article

Large quantities of brewer’s spent grains are not fully utilized even as cattle feed. These feedstocks can be used to produce highly functional biomaterials, carbonaceous materials, and additives. In this investigation, four major fractions were isolated and characterized: Hemicellulose A, Hemicellulose B, cellulosic-rich fraction (CRF), and oligosaccharides. Overall, 21.4% Hemicellulose A, 18.5% Hemicellulose B, 17.4% cellulosic rich fraction, and 5.5% pure oligosaccharides were obtained from the hexane-extracted brewery’s spent grains. Detailed physio-chemical analyses of each fraction showed that these fractions can be used to produce useful products such as emulsifiers, carbonaceous materials, modified cellulosic fibers, additives, as well as N-doped chars. Component analyses revealed that, Hemi. A contains high fixed carbon (20 wt.%), followed by hexane extracted material (17.1 wt.%), CRF (14.6 wt.%), and Hemi. B (14.5%). Standard proximate analyses showed that Hemi. A has the highest protein (66 wt.%), which can be utilized as a renewable solid-state N-precursor as dopants during the thermochemical conversion process. The sugar composition revealed that BSG has a typical arabinoxylan structure with a high percentage of arabinose and xylose. It also contains a high percentage of glucose, which may come from the residual β-glucan present in the BSG. FTIR analyses revealed changes in the structure of each fraction. Hence, BSG and extracted fractions exhibit significant potential for waste valorization, contributing significantly to the full utilization of products from the brewing industry. Full article

The purpose of this research was to investigate the prebiotic effects of different fractions of pectin-derived oligosaccharides (POSs) from apple pomace (AP) in relation to their molecular weight (MW), structure, and composition. Enzymatic treatment of the apple pomace resulted in high-molecular-weight arabinans and rhamnogalacturonans (MW 30–100 kDa, MW 10–30 kDa), as well as oligomeric fractions with molecular weights of less than 10 kDa, consisting mainly of homogalacturonan. The biological potential of the POSs against various lactobacilli and bifidobacteria was evaluated. The oligosaccharides with the highest molecular weights (MW 30–100 kDa, MW 10–30 kDa) showed better prebiotic effect to lactobacilli. The oligosaccharides with MW 3–10 kDa and MW 10–30 kDa caused an increase in the bifidogenic effect. Inhibition of Escherichia coli, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes was also observed. The preparations with MW 3–10 kDa and MW 10–30 kDa demonstrated the strongest biological activity, supporting the adhesion of beneficial microorganisms to mucin and collagen surfaces. Therefore, oligosaccharides with MW 10–30 kDa were considered to be the most promising prebiotic candidates. This study confirms that the biological effects of pectic oligosaccharides vary significantly based on their structural differences. Therefore, the conditions of enzymatic hydrolysis of apple pectin should be optimized to obtain oligosaccharides within a specific molecular mass range. Full article

Yeasts have emerged as an important resource of bioactive compounds, proteins and peptides, polysaccharides and oligosaccharides, vitamin B, and polyphenols. Hundreds of thousands of tons of spent brewer’s yeast with great biological value are produced globally by breweries every year. Hence, streamlining the practical application processes of the bioactive compounds recovered could close a loop in an important bioeconomy value-chain. Cell lysis is a crucial step in the recovery of bioactive compounds such as (glyco)proteins, vitamins, and polysaccharides from yeasts. Besides the soluble intracellular content rich in bioactive molecules, which is released by cell lysis, the yeast cell walls β-glucan, chitin, and mannoproteins present properties that make them good candidates for various applications such as functional food ingredients, dietary supplements, or plant biostimulants. This literature study provides an overview of the lysis methods used to valorize spent brewer’s yeast. The content of yeast extracts and yeast cell walls resulting from cellular disruption of spent brewer’s yeast are discussed in correlation with the biological activities of these fractions and resulting applications. This review highlights the need for a deeper investigation of molecular mechanisms to unleash the potential of spent brewer’s yeast extracts and cell walls to become an important source for a variety of bioactive compounds. Full article

Relatively little is known about enzymes with broad substrate spectra, leading to limited applications and progress. Herein, we elucidate Aly16-1 of Streptomyces sp. strain CB16 as a novel multifunctional member of the eighth polysaccharide lyase (PL8) family, although it shared few sequence identities with the characterized enzymes. The recombinant enzyme rAly16-1 showed lyase activities against several acidic polysaccharides, including many glycosaminoglycan types, xanthan, and alginate. It was mannuronate (M)-preferred, endolytic, and optimal at 50 °C and pH 6.0. The smallest substrate was an ∆M-terminal (∆: unsaturated monosaccharide) trisaccharide, and the minimal product was ∆. In the final alginate digestions by rAly16-1, the fractions larger than disaccharides were ∆G-terminal (G: guluronate), while the disaccharides were mainly ∆M, showing an oligosaccharide-yielding property under the succession law. However, when degrading various oligosaccharides, rAly16-1 continued producing ∆M from the non-reducing end even when the substrates increased their sizes, quite different from the elucidated alginate lyases with variable alginate-degrading modes. Thus, co-determined by its M-preference, Aly16-1 is novel for its ∆M-yielding property in oligosaccharide preparations. Additionally, rAly16-1 can be applied in sequencing unsaturated trisaccharides, whether ∆M- or ∆G-terminal. This study provides novel insights into the characteristics and applications of a multifunctional enzyme within the PL8 family for resource explorations. Full article

The current study evaluated the effect of combining mannan oligosaccharide (MOS) and onion peel (OP) on ruminal in vitro total gas (GP), greenhouse gas emissions, dry matter and fiber fraction digestibility, partitioning factor (PF₂₄; mg degradable DM per mL gas), microbial mass, and volatile fatty acids using two dietary substrates: high forage (HF) and high concentrate (HC) diets. The study was arranged as a 2 × 2 × 6 factorial design with two dietary substrates, two time points (6 and 24 h), and six treatments. The treatments included a control group with no MOS or OP administration and groups administered with 2% of a mixture containing MOS and OP in the following ratios: 1:0 (MOS), 0:1 (OP), 1:1 (MOS:OP), 1:2 (MOS:2OP), and 1:3 (MOS:3OP). No significant diet × treatment interactions were observed for any of the measured parameters. However, treatments decreased (p < 0.05) the undegraded portion of HC, and treatment × substrate interactions were significant (p < 0.05) for PF₂₄ and microbial mass. The treatments in the HC diet produced higher GP (p < 0.001) at 6 h compared to the treatments in the HF diet. Administration of MOS:2OP to the HC diet increased GP at 24 h of incubation, while the lowest GP was observed with the OP in the HF diet. The administration of MOS, OP, and MOS:2OP to the HC diet decreased methane production at 24 h of incubation. Additionally, MOS:2OP and MOS:3OP increased (p < 0.001) degradable acid detergent fiber (dADF) in the HC diet at 6 h of incubation. Both OP and MOS:3OP decreased the degradability of acid detergent lignin in the HC diet (p < 0.001). The OP also resulted in the lowest DM disappearance (p < 0.001) at 24 h of incubation in the HF diet, while the MOS:3OP had the highest dADF. At the end of incubation, the highest productions of total volatile fatty acids and acetate were observed (p = 0.002) with the MOS:OP administration in the HC diet, whereas the lowest values were observed with MOS and OP administration to the HF diet. The inclusion of mannan oligosaccharide and onion peel combinations as additives improved substrate (HC and HF) fermentation, leading to higher GP and volatile fatty production, and modulated fiber degradability by improving the breakdown of acid detergent fiber and acid detergent lignin. Full article

Background (1): The use of fungal chitosan as an antiseptic in wine appears as a promising alternative to sulfur dioxide for the elimination of Brettanomyces bruxellensis sensitive strains. Nevertheless, its utilization raises the question, “how are the treated wines different from the untreated ones?” Methods (2): Chitosan treatment residues were sought in the oligosaccharide and polysaccharide fractions and among 224 low MW ions (<1800 g·mol⁻¹) in several wines by using liquid chromatography (size exclusion HPLC or LC-MS) and GC-MS. Standard oenological parameters were also examined as well as possible sensory modifications by a panel of tasters composed of experts and non-experts. Results (3): None of these methods enabled the reproducible and reliable identification of a treated wine without comparing it to its untreated control. The fingerprints of treatment are not reliably detectable by the analytical methods used in this study. However, the treated wines seem permanently protected against the development of chitosan-sensitive strains of B. bruxellensis. Conclusions (4): If chitosan treatment modifies the wine, the associated changes were not identified by the liquid chromatography method mentioned above and they were not perceived by most people in our taster panel. However, the expected antimicrobial action of chitosan was observed on B. bruxellensis sensitive strains and persisted at least one year. Tolerant strains were less affected by these persistent effects. Full article