Search

Human gut Bacteroides and Parabacteroides species play crucial roles in human health and are known for their capacity to utilize diverse polysaccharides. Understanding how these bacteria utilize medicinal polysaccharides is foundational for developing polysaccharides-based prebiotics and drugs. Here, we systematically mapped the utilization profiles of 20 different medicinal polysaccharides by 28 human gut Bacteroides and Parabacteroides species. The growth profiles exhibited substantial variation across different bacterial species and medicinal polysaccharides. Ginseng polysaccharides promoted the growth of multiple Bacteroides and Parabacteroides species; in contrast, Dendrobium polysaccharides selectively promoted the growth of Bacteroides uniformis. This distinct utilization profile was associated with genomic variation in carbohydrate-active enzymes, rather than monosaccharides composition variation among medicinal polysaccharides. Through comparative transcriptomics and genetical manipulation, we validated that the polysaccharide utilization locus PUL34_Bu enabled Bacteroides uniformis to utilize Dendrobium polysaccharides (i.e. glucomannan). In addition, we found that the GH26 enzyme in PUL34_Bu allowed Bacteroides uniformis to utilize multiple plant-derived mannan. Overall, our results revealed the selective utilization of medicinal polysaccharide by Bacteroides and Parabacteroides species and provided insights into the use of polysaccharides in engineering the human gut microbiome. Here, the authors characterize the utilization of 20 medicinal polysaccharides by 28 human gut Bacteroides and Parabacteroides species, revealing substantial variability in bacterial growth responses, which they link to genomic differences in carbohydrate-active enzymes. [ABSTRACT FROM AUTHOR]

This study investigated the structural composition and antioxidant properties of pectic polysaccharides extracted from Rohdea japonica (Thunb.) Roth. Pectins, which belong to a complex category of acidic polysaccharides, possess a wide range of biological effects stemming from their distinctive structural domains. The polysaccharides were extracted using water, and were subsequently purified through ion exchange and gel permeation chromatography. In order to elucidate their structural features, Fourier Transform Infrared Spectroscopy and Nuclear Magnetic Resonance techniques were applied. Two specific polysaccharides, WRJP-A2a and WRJP-A3b, with molecular weights of 42.7 kDa and 64.1 kDa, respectively, were identified to contain varying proportions of homogalacturonan, rhamnogalacturonan I, and rhamnogalacturonan II domains. Regarding antioxidant capacity, WRJP-A3b exhibited superior scavenging capabilities against DPPH, ABTS, and hydroxyl radicals, potentially attributed to its higher galacturonic acid content and abundance of homogalacturonan domains. These results enhance our comprehension of the structure–activity interplay of pectic polysaccharides sourced from Rohdea japonica (Thunb.) Roth and their potential utility in the healthcare and functional food sectors. [ABSTRACT FROM AUTHOR]

An alkali-soluble β-glucan (AHEP-A-b, 20 kDa) purified from Hericium erinaceus fruiting bodies, was structurally characterized and examined for antioxidant activity. Methylation analysis and NMR spectroscopy show that the backbone of AHEP-A-b is composed of (1→6)-linked-D-β-glucopyran residues, branched at O-3 of glucopyranose (Glcp) residues with [→3)-β-D-Glcp-(1→] oligosaccharides or single unit of β-Glcp. Periodate oxidation analysis and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) indicate that the degree of polymerization (DP) of [→3)-β-D-Glcp-(1→] side chains is 2 to 8. Functionally, AHEP-A-b is a relatively strong antioxidant as demonstrated by using 2, 2′-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) free radical (ABTS·+), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and hydroxyl radicals scavenging assays. The present study lays the foundation for further studies into structure-activity relationships of polysaccharides from H. erinaceus. [ABSTRACT FROM AUTHOR]

Background: Centella Asiatica has been shown to have beneficial value for the treatment of tumors. However, its active ingredients and molecular mechanisms of action have not been fully elucidated. Pectic polysaccharides are the primary active components from medicinal plants. Moreover, these polysaccharides are regarded as potential inhibitors of galectins, such as galectin-1, -3, -7, that generally promote tumor growth. Nevertheless, detailed structural analysis of pectic polysaccharides from Centella Asiatica is sorely lacking, as is knowledge of their interactions with galectins. Methods: Water-soluble pectic polysaccharides (WCAP) isolated from Centella Asiatica were purified into two homogeneous fractions (WCAP-A2b and WCAP-A5b) by a combination of anion-exchange and gel-permeation chromatography. Monosaccharide composition, FT-IR, NMR and enzymatic analyses were used to characterize their structural features. Furthermore, the interactions between galectin-1, -3, -7 and a series of these polysaccharides, including two pectin fractions and their structural domains produced by enzymatic hydrolysis, were evaluated by using hemagglutination and biolayer interferometry. Results: WCAP-A2b and WCAP-A5b have weight averaged molecular weights of 30.0 kDa and 34.0 kDa, respectively, and both polysaccharides consist of rhamnogalacturonan I (RG-I), rhamnogalacturonan II (RG-II) and homogalacturonan (HG) domains, with mass ratios of 1.3: 1.0: 1.4 and 1.1: 1.0: 2.4, respectively. Their RG-I domains contain arabinan, galactan, and/or arabinogalactan, along with neutral sugar side chains that are more prevalent in WCAP-A2b than in WCAP-A5b. Hemagglutination and biolayer interferometry binding assays indicate that galectin-3 vis-à-vis galectin-1 and -7, binds strongly to the RG-I domain (likely via its neutral side chains) in WCAP-A5b, thereby inhibiting galectin-3-mediated cell–cell interactions. Conclusions: Our study provides structural information on pectin polysaccharides from Centella Asiatica. Results suggest that RG-I domains from WCAP-A5b and WCAP-A2b may be developed as potential inhibitors of galectin-3-mediated cell–cell adhesion and tumor growth. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Molecular Science is the property of Journal of Molecular Science Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)