Characterization of acidic polysaccharides from the mollusks through acid hydrolysis

Bioactive terpenoids and sterols from the fruiting bodies of Fomitopsis pinicola

A chemical investigation of the fruiting bodies of Fomitopsis pinicola was conducted, resulting in the isolation of 51 compounds, which included 16 previously undescribed lanostane triterpenes (1-14, 16-17), 30 known analogs (15, 18-46) as well as two sterols (47-48) and three diterpenes (49-51). Comprehensive analyses utilizing 1D, 2D NMR, MS and IR spectroscopy and DFT calculations of 13C NMR chemical shifts have elucidated the structures of the compounds in question. Two undescribed compounds in addition to fomitosides F, G and K showed cytotoxicity against MCF-7 cell line with IC50 values ranging from 11.01 to 31.92 μM. Meanwhile, these isolates showed α-glucosidase inhibitory activity, and compound 7 showed the IC50 value of 9.22 μM.

Composition-dependent MRM transitions and structure-indicative elution segments (CMTSES)-based LC-MS strategy for disaccharide profiling and isomer differentiation

BACKGROUND

Carbohydrates exhibit diverse functions and extensive biological activities and are notable in the field of life sciences. However, their inherent diversity and complexity-steaming from variations in isomeric monomers, glycosidic bonds, configurations, etc.-present considerable challenges in structural analysis. Considering these challenges, the disaccharide building blocks with simpler structures could provide more structural information. Although various approaches have been explored, sufficient standards or specialized equipment are required to differentiate and characterize isomers. Therefore, a strategy that addresses these challenges is urgently needed.

RESULTS

A Composition-dependent MRM Transitions and Structure-indicative Elution Segments (CMTSES)-based liquid chromatography-triple quadrupole mass spectrometry (LC-QQQ-MS) strategy was developed to comprehensively profile disaccharide units and differentiate isomers. First, the composition-related precursor and structure-specific product ions of disaccharides were generated by QQQ-MS. Thereout, MRM transitions were proposed to enable the comprehensive profiling of disaccharides and rapid annotation of their compositions and saccharide types at both termini. Next, the linkage, composition, and configuration isomers of disaccharides were effectively differentiated and presented characteristic LC elution. Furthermore, low-cost and available "location references" (mannose, galactose, and isomaltose) were sought to define structure-indicative elution segments for the identification of isomeric hexose disaccharides. Building on this foundation, the novel CMTSES-based LC-MS strategy was designed, and its feasibility was further verified by successfully differentiating and identifying mixed homogenous and/or heterogenous disaccharide isomers in real samples. Sufficient structural information was obtained even for those consisting of diversified monomer types.

SIGNIFICANCE AND NOVELTY

This strategy comprehensively profiles both major and minor disaccharides and effectively differentiates multiple types of isomers. The use of readily available "location references" facilitated the identification of isomeric hexose disaccharide with reduced dependence on standards, thereby broadening the applicability of this strategy. However, the characterization of disaccharides with other compositions is challenging. Further in-depth investigations into intramolecular hydrogen bond simulation should provide solutions. Additionally, CMTSES-based LC-MS strategy is promising to analyze complex structures and samples.

Exploring the partial degradation of polysaccharides: Structure, mechanism, bioactivities, and perspectives

Polysaccharides are promising biomolecules with lowtoxicity and diverse bioactivities in food processing and clinical drug development. However, an essential prerequisite for their applications is the fine structure characterization. Due to the complexity of polysaccharide structure, partial degradation is a powerful tool for fine structure analysis, which can effectively provide valid information on the structure of backbone and branching glycosidic fragments of complex polysaccharides. This review aims to conclude current methods of partial degradation employed for polysaccharide structural characterization, discuss the molecular mechanisms, and describe the molecular structure and solution properties of degraded polysaccharides. In addition, the effects of polysaccharide degradation on the conformational relationships between the molecular structure and bioactivities, such as antioxidant, antitumor, and immunomodulatory activities, are also discussed. Finally, we summarize the prospects and current challenges for the partial degradation of polysaccharides. This review will be of great value for the scientific elucidation of polysaccharide fine structures and potential applications.

Tamarind Seed Polysaccharide Hydrolysate Ameliorates Dextran Sulfate Sodium-Induced Ulcerative Colitis via Regulating the Gut Microbiota

(1) Background: Ulcerative colitis (UC) is a disease caused by noninfectious chronic inflammation characterized by varying degrees of inflammation affecting the colon or its entire mucosal surface. Current therapeutic strategies rely on the suppression of the immune response, which is effective, but can have detrimental effects. Recently, different plant polysaccharides and their degradation products have received increasing attention due to their prominent biological activities. The aim of this research was to evaluate the mitigation of inflammation exhibited by tamarind seed polysaccharide hydrolysate (TSPH) ingestion in colitis mice. (2) Methods: TSPH was obtained from the hydrolysis of tamarind seed polysaccharide (TSP) by trifluoroacetic acid (TFA). The structure and physical properties of TSPH were characterized by ultraviolet spectroscopy (UV), thin-layer chromatography (TLC), fourier transform infrared spectroscopy (FT-IR), and High-Performance Liquid Chromatography and Electrospray Ionization Mass Spectrometry (HPLC-ESI/MS) analysis. Then, the alleviative effects of the action of TSPH on 2.5% dextran sodium sulfate (DSS)-induced colitis mice were investigated. (3) Results: TSPH restored pathological lesions in the colon and inhibited the over-secretion of pro-inflammatory cytokines in UC mice. The relative expression level of mRNA for colonic tight junction proteins was increased. These findings suggested that TSPH could reduce inflammation in the colon. Additionally, the structure of the gut microbiota was also altered, with beneficial bacteria, including Prevotella and Blautia, significantly enriched by TSPH. Moreover, the richness of Blautia was positively correlated with acetic acid. (4) Conclusions: In conclusion, TSPH suppressed colonic inflammation, alleviated imbalances in the intestinal flora and regulated bacterial metabolites. Thus, this also implies that TSPH has the potential to be a functional food against colitis.

New function of polysaccharide from Rubus chingii Hu: protective effect against ethyl carbamate induced cytotoxicity

BACKGROUND

Rubus chingii Hu is a widely cultivated fruit in China and has declared multiple bioactivities including antioxidative activity. Ethyl carbamate (EC), mostly found in fermented food and alcoholic beverages, is a recognized human carcinogen, and researchers have proposed the correlation between oxidative stress and its toxicity. This study acquired the polysaccharide from R. chingii (RP) and explored its effect on EC-induced cytotoxicity using Caco-2 cells as the cell model.

RESULTS

Results showed that RP exhibited protection against EC-induced toxicity by repairing redox imbalance as indicative of mitigated mitochondrial membrane potential collapse, attenuated reactive oxygen species overproduction, and impeded glutathione depletion. Moreover, the structural features of RP were characterized and revealed that it was mainly constituted by galacturonic acid and arabinose, with an average molecular weight of 7.039 × 10⁵  g mol^-1 .

CONCLUSION

Overall, our results provided a new approach dealing with the toxicity caused by EC from the perspective of oxidative stress and described a new potential healthy value of R. chingii Hu, which could contribute to the development of a promising dietary supplement and functional food. © 2020 Society of Chemical Industry.

Development and application of a HPLC-MS/MS method for quantitation of fucosylated chondroitin sulfate and fucoidan in sea cucumbers

Fucosylated chondroitin sulfate (FCS) and fucoidan (FUC) are two main bioactive polysaccharides in sea cucumbers. A novel method for quantitation of FCS and FUC was developed by detecting chondroitin disaccharide and fucose produced through acid hydrolysis using HPLC-MS/MS. The present method showed satisfactory performance for both saccharides. It was applied to assay sea cucumbers (Stichopus japonicus) reared in pond grow-out or bottom sowing, and the results were compared with those obtained by traditional HPLC method and 1,9-dimethylmethylene blue test, which could only provide the total sea cucumber polysaccharide (SCP) contents. No difference of total SCP content was observed between sea cucumbers reared through different ways, while a higher ratio of FCS to FUC of sea cucumbers of pond grow-out was revealed by the present method. Thus, this novel method is potential to quantify the two polysaccharides and could be a powerful tool for quality evaluation of sea cucumbers.

Effect of superheated steam roasting with hot smoking treatment on improving physicochemical properties of the adductor muscle of pen shell (Atrina pectinate)

The adductor muscle of the pen shell Atrina pectinata (AMPS) is a popular protein-enriched food item in Asian Pacific countries, and has only been marketed in the frozen condition, as a result browning and decreased sensory attributes occur. To overcome these problems, superheated steam roasting (at 270°C for 4 min) combined with the hot smoke (10 min) using a selective Oak sawdust was employed to develop a new AMPS product yielding high physicochemical properties during storage periods (0-13 days) especially at 10°C. The processed AMPS showed high sensory preferences because of good odor, color, and textural properties. It also significantly inhibited bacterial growth, volatile basic nitrogen, thiobarbituric acid-reactive species, and pH changes, and eventually possessed higher nutritional composition with low trimethylamine N-oxide level. Results indicate that saturated steam allows AMPS at good physicochemical conditions, whereas hot smoke-derived aroma compounds prolong its shelf life through antioxidant and antimicrobial activities.

Preparation and structural characterization of regioselective 4-O/6-O-desulfated chondroitin sulfate

The sulfation pattern plays a crucial role in chondroitin sulfate (CS) biological activity, and preparation of CS with defined structure is essential for accurate pharmacological study. In this study, we focused on the preparation of regioselective 4-O/6-O-desulfated CS derived from porcine, employing a dimethyl sulfoxide-methanol (DMSO-MeOH) method and an N-methyl-N-(trimethylsilyl) -trifluoroacetamide (MTSTFA) method CS, respectively. Results showed that the sulfate at C4 position (4-O-S) of N-acetylgalactosamine (GalNAc) was selectively removed by the DMSO-MeOH method, and the sulfate at C6 position (6-O-S) of GalNAc was selectively removed by the MTSTFA method. Structures of desulfated CS were characterized by means of FT-IR, NMR and disaccharide composition analysis. The preparations of regioselective 4-O/6-O-desulfated CS are powerful for the study of structure-activity relationship of CS.

Comprehensive analysis of glycosaminoglycans from the edible shellfish

We have previously reported that the keratan sulfate (KS) disaccharide was branched to the C-3 position of glucuronate in chondroitin sulfate (CS)-E derived from the Mactra chinensis. We carried out the comprehensive disaccharide analysis of GAGs from 10 shellfish, Ruditapes philippinarum, Scapharca broughtonii, Mizuhopecten yessoensis, Turbo cornutus, Crassostrea nippona, Corbicula japonica, Mytilus galloprovincialis, Neptunea intersculpta, Pseudocardium sachalinense and Crassostrea gigas, to better understand the glycan structures in marine organisms. The contents of CS, heparan sulfate and hyaluronic acid and their compositions depend on the species of shellfish. Interestingly, a peak corresponding to a pentasaccharide containing KS disaccharide was observed when GAGs from T. cornutus was treated with chondroitinase (Chase) ACII but not Chase ABC. In addition, unidentified peaks were also observed when CS derived from R. philippinarum, S. broughtonii were treated with Chase ACII. These results suggest the presence of additional unidentified structure of CS in these shellfish.