Current trends in marine algae polysaccharides: The digestive tract, microbial catabolism, and prebiotic potential

A review of NMR analysis in polysaccharide structure and conformation: Progress, challenge and perspective.

Human gut microbiota plays an important role in several metabolic processes and human diseases. Various dietary factors, including complex carbohydrates, such as polysaccharides, provide abundant nutrients and substrates for microbial metabolism in the gut, affecting the members and their functionality. Nowadays, the main sources of complex carbohydrates destined for human consumption are terrestrial plants. However, fresh water is an increasingly scarce commodity and world agricultural productivity is in a persistent decline, thus demanding the exploration of other sources of complex carbohydrates. As an interesting option, marine seaweeds show rapid growth and do not require arable land, fresh water or fertilizers. The present review offers an objective perspective of the current knowledge surrounding the impacts of seaweeds and their derived polysaccharides on the human microbiome and the profound need for more in-depth investigations into this topic. Animal experiments and in vitro colonic-simulating trials investigating the effects of seaweed ingestion on human gut microbiota are discussed.

https://www.mdpi.com/1420-3049/25/4/1004/pdf

Potential Use of Marine Seaweeds as Prebiotics: A Review.

Rhamnogalacturonan-I (RG-I)-enriched pectin (WRP) was recovered from citrus processing water by sequential acid and alkaline treatments in a previous study. RG-I-enriched pectin was proposed as a potential supplement for functional food and pharmaceutical development. However, previous studies illustrated that favorable modulations of gut microbiota by RG-I-enriched pectin were based on in vitro changes in the overall microbial structure and the question of whether there is a structure-dependent modulation of gut microbiota remains largely enigmatic. In the present study, modulations of gut microbiota by commercial pectin (CP), WRP and its depolymerized fraction (DWRP) with different RG-I contents and Mw were compared in vivo. It was revealed by 16s rRNA high-throughput sequencing that WRP and DWRP mainly composed of RG-I modulated the gut microbiota in a positive way. DWRP significantly increased the abundance of prebiotic such as Bifidobacterium spp., Lactobacillus spp., while WRP increased SCFAs producers including species in Ruminococcaceae family. By maintaining a more balanced gut microbiota composition and enriching some SCFA producers, dietary WRP and DWRP also elevated the SCFA content in the colon. Collectively, our findings offer new insights into the structure–activity correlation of citrus pectin and provide impetus towards the development of RG-I-enriched pectin with small molecular weight for specific use in health-promoting prebiotic ingredients and therapeutic products.

Depolymerized RG-I-enriched pectin from citrus segment membranes modulates gut microbiota, increases SCFA production, and promotes the growth of Bifidobacterium spp., Lactobacillus spp. and Faecalibaculum spp.

The human gut microbiota has been revealed in recent years as a factor that plays a decisive role in the maintenance of human health, as well as in the development of many non-communicable diseases. This microbiota can be modulated by various dietary factors, among which complex carbohydrates have a great influence. Although most complex carbohydrates included in the human diet come from vegetables, there are also options to include complex carbohydrates from non-vegetable sources, such as chitin and its derivatives. Chitin, and its derivatives such as chitosan can be obtained from non-vegetable sources, the best being insects, crustacean exoskeletons and fungi. The present review offers a broad perspective of the current knowledge surrounding the impacts of chitin and its derived polysaccharides on the human gut microbiota and the profound need for more in-depth investigations into this topic. Overall, the effects of whole insects or meal on the gut microbiota have contradictory results, possibly due to their high protein content. Better results are obtained for the case of chitin derivatives, regarding both metabolic effects and effects on the gut microbiota composition.

https://www.mdpi.com/2304-8158/9/6/782/pdf

Animal-Origin Prebiotics Based on Chitin: An Alternative for the Future? A Critical Review

Recently, accumulating evidence has suggested that Enteromorpha clathrata polysaccharide (ECP) could contribute to the treatment of diseases. However, as a promising candidate for marine drug development, although ECP has been extensively studied, less consideration has been given to exploring its effect on gut microbiota. In this light, given the critical role of gut microbiota in health and disease, we investigated here the effect of ECP on gut microbiota using 16S rRNA high-throughput sequencing. As revealed by bioinformatic analyses, ECP considerably changed the structure of the gut microbiota and significantly promoted the growth of probiotic bacteria in C57BL/6J mice. However, interestingly, ECP exerted different effects on male and female microbiota. In females, ECP increased the abundances of Bifidobacterium spp. and Akkermansia muciniphila, a next-generation probiotic bacterium, whereas in males, ECP increased the population of Lactobacillus spp. Moreover, by shaping a more balanced structure of the microbiota, ECP remarkably reduced the antigen load from the gut in females. Altogether, our study demonstrates for the first time a prebiotic effect of ECP on gut microbiota and forms the basis for the development of ECP as a novel gut microbiota modulator for health promotion and disease management.

Dietary Polysaccharide from Enteromorpha Clathrata Modulates Gut Microbiota and Promotes the Growth of Akkermansia muciniphila, Bifidobacterium spp. and Lactobacillus spp.

Fucoidan from sea cucumber Holothuria polii: Structural elucidation and stimulation of hematopoietic activity.

Two different fucosylated chondroitin sulfates: Structural elucidation, stimulating hematopoiesis and immune-enhancing effects.

Carbohydrate microarrays provide a powerful tool for high-throughput analysis of carbohydrate-mediated interactions. In this work, they were fabricated on poly(2-hydroxyethyl methacrylate) (pHEMA)-cyanuric chloride (CC)-modified substrates for the analysis of carbohydrate–lectin interactions. The pHEMA polymer provides an anti-fouling surface and the CC linker allows the covalent immobilization of intact carbohydrates. Carbohydrates of different sizes (mannose, glucose, galactose, maltose, and dextran) were successfully immobilized on the proposed substrates and their recognition specificity with concanavalin A (ConA) was highly conserved. Compared with a 4-hydroxyphenylacetic acid (HPA)-CC-based microarray, the proposed pHEMA-CC-based microarray exhibits better anti-nonspecific adsorption ability, higher carbohydrate loading capability, stronger multivalent recognition and a lower limit of detection for carbohydrate and lectin without any further signal amplification. The application of the proposed microarray was validated by studying carbohydrate-influenza A virus H1N1 hemagglutinin interactions and fabricating microarrays containing carbohydrates with different properties. It is possible to extend it to study interactions of more carbohydrates and different lectins, and it will meet the wider needs in bioanalytical and biomedical application.

Fabrication of carbohydrate microarrays on poly(2-hydroxyethyl methacrylate)-cyanuric chloride-modified substrates for the analysis of carbohydrate–lectin interactions

The invention discloses a novel sea cucumber fucoidan and a preparation method and application thereof. The average molecular weight of the novel sea cucumber fucoidan is 150-200kDa, the mass ratio ofsulfate radicals is 30-45%, and the novel sea cucumber fucoidan is provided with a tetrasaccharide repeating unit which consists of fucoidan and is connected by alpha-1->3. The repeating unit is [->3-alpha-l-Fucp-1->3-alpha-l-Fucp2 (OSO3 ) -1->3-alpha-l-Fucp2 (OSO3 ) -1->3-alpha-l-Fucp2,4 (OSO3 ) -1->]. The sea cucumber fucoidan is a fucoidan with a novel structure which is separated from sea cucumber Hollothuria polii in the Aegean sea for the first time. Meanwhile, the sea cucumber fucoidan in the invention can recover the reduction of leukocytes and neutrophils induced by cyclophosphamide, which indicates that the fucoidan in the invention has the function of stimulating hematopoiesis. In addition, the sea cucumber fucoidan also has good endogenous anticoagulant activity.

Chao Li

Papers

Dietary Polysaccharide from Enteromorpha Clathrata Modulates Gut Microbiota and Promotes the Growth of Akkermansia muciniphila, Bifidobacterium spp. and Lactobacillus spp.

Fucoidan from sea cucumber Holothuria polii: Structural elucidation and stimulation of hematopoietic activity.

Two different fucosylated chondroitin sulfates: Structural elucidation, stimulating hematopoiesis and immune-enhancing effects.

Fabrication of carbohydrate microarrays on poly(2-hydroxyethyl methacrylate)-cyanuric chloride-modified substrates for the analysis of carbohydrate–lectin interactions

Novel sea cucumber fucoidan and preparation method and application thereof