Enzymatic-fingerprinting workflow of polysaccharides in Hericium erinaceus fruiting bodies: From HILIC-ESI--MS screening to targeted MIM profiling

The Discovery of a Multidomain Mannanase Containing Dual-Catalytic Domain of the Same Activity: Biochemical Properties and Synergistic Effect

In recent years, the wide application of mannan has driven the demand for the exploration of mannanase. As one of the main components of hemicellulose, mannan is an important polysaccharide that ruminants need to degrade and utilize, making rumen a rich source of mannanases. In this study, gene mining of mannanases was performed using bioinformatics, and potential dual-catalytic domain mannanases were heterologously expressed to analyze their properties. The hydrolysis pattern and enzymatic products were identified by liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS). A dual-catalytic domain mannanase Man26/5 with the same function as the substrate was successfully mined from the genome of cattle rumen microbiota. Compared to the single-catalytic domain, its higher thermal stability (≤50 °C) and catalytic efficiency confirm the synergistic effect between the two catalytic domains. It exhibited a unique "crab-like" structure where the CBM located in the middle is responsible for binding, and the catalytic domains at both ends are responsible for cutting. The exploration of its multidomain structure and synergistic patterns could provide a reference for the artificial construction and molecular modification of enzymes.

Anti-aging activities of neutral and acidic polysaccharides from Polygonum multiflorum Thunb in Caenorhabditis elegans

Polygonum multiflorum Thunb (PM) is used to slow the aging process. Although polysaccharides are a major constituent of PM, their anti-aging properties have not been thoroughly investigated. Therefore, this study aimed to examine the anti-aging effects of polysaccharides extracted from PM using the Caenorhabditis elegans (C. elegans) model. Two types of water-soluble heteropolysaccharides, namely a neutral polysaccharide (RPMP-N) and an acidic polysaccharide (RPMP-A), were obtained from PM. Their structures were elucidated by various methods. The effects of these polysaccharides on the lifespan, levels of antioxidants, and activities of antioxidant-related enzymes in C. elegans were also evaluated. The results showed that RPMP-A had higher GalA content compared with RPMP-N. The average molecular weights of RPMP-N and RPMP-A were 245.30 and 28.45 kDa, respectively. RPMP-N is a α-1,4-linked dextran as the main chain, and contains a small amount of branched dextran with O-6 as the branched linkage site；RPMP-A may be a complex of α-1,4-linked dextran, HG and RG-I. Treatment with RPMP-N and RPMP-A increased the mean lifespan of C. elegans, and significantly regulated oxidative stress. RPMP-A exhibited stronger anti-aging effects compared with RPMP-N. These findings suggest that RPMP-A may be a potent antioxidant and anti-aging component that can be used for developing functional food products and effective dietary supplements.

Structure of a highly branched galacturonoglucan from fruits of Schisandra chinensis (Turcz.) Baill

A novel galacturonoglucan, named SCP-1, is isolated and purified from Schisandra chinensis fruits. The structure of SCP-1 is systematically investigated by a combination of monosaccharide compositions, absolute M_w, methylation analysis, partial acid hydrolysis, isoamylase degradations, and nuclear magnetic resonance spectroscopy. The structure of SCP-1 is theoretically described as follows: (i) Glc and GalA in a molar ratio of 17:3; (ii) → 4)-α-Glcp-(1→, →4,6)-α-Glcp-(1→, →3,4,6)-α-Glcp-(1→, α-Glcp-(1→, →4)-α-GalAp-6-OMe-(1→, α-GalAp-6-OMe-(1→, β-Glcp-(1→, →6-)-β-Glcp-(1 → and →3,4)-β-Glcp-(1 → in a molar ratio of 48:5:3:3:10:5:12:5:9; (iii) a repeating unit of →4)-α-Glcp-(1 → as a backbone with branched points at C-3 and C-6, substituted by different types of acidic and neutral side chains to form multiple branches; and (iv) a rigid rod configuration deduced from α value of 1.26 in Mark-Houwink equation ([η] = kM^α). Anti-tumor assay investigated the effects of SCP-1 on human HepG2 cancer cell lines in vitro. This is for the first time to report a galacturonoglucan in S. chinensis fruits.

Comparison of Lycium barbarum fruits polysaccharide from different regions of China by acidic hydrolysate fingerprinting-based HILIC-ELSD-ESI-TOF-MS combined with chemometrics analysis

INTRODUCTION

Lycium barbarum is an edible fruit widely used in herbal medicines and as a functional food. Polysaccharide is one of the most important active ingredients. Only L. barbarum grown in the Ningxia region of China are officially recognised as suitable for use in traditional Chinese medicine, but the systematic comparison of L. barbarum polysaccharide between Ningxia and the other growing regions of China has been rarely reported.

OBJECTIVE

To compare the difference of L. barbarum polysaccharide from different grown regions of China.

METHODS

A chemical fingerprint of L. barbarum polysaccharide hydrolysates was established based on controlled acidolysis combined with hydrophilic interaction liquid chromatography-evaporative light scattering detection-electrospray ionisation-time-of-flight-mass spectrometry (HILIC-ELSD-ESI-TOF-MS). Then, it was employed for the comparison of L. barbarum samples from different geographical origins of China combined with chemometrics analysis.

RESULTS

Six monosaccharides [rhamnose (Rha), xylose (Xyl), arabinose (Ara), mannose (Man), glucose (Glu), galactose (Gal)] were qualitatively and quantitatively determined and four glycoconjugates were preliminarily identified from the hydrolysates. Content determination for the polysaccharide and monosaccharide indicated obvious geographical features. The HILIC-ELSD fingerprint combined with partial least squares-discriminant analysis (PLS-DA) was able to differentiate L. barbarum samples from Ningxia, Xinjiang, Gansu and Qinghai regions with 89.19% classification accuracy. Orthogonal projection to latent structure discriminant analysis (OPLS-DA) was able to differentiate between samples from Ningxia and those from the other three growing regions, polysaccharide and Ara were the potential chemical markers.

CONCLUSIONS

These findings form the basis of a reliable method to trace the region of origin of L. barbarum sample and thereby, improve the quality control of L. barbarum therapeutic polysaccharides.