A regular Chlorella mannogalactan and its sulfated derivative as a promising anticoagulant: Structural characterization and anticoagulant activity

Chemical structure and anti-inflammatory effects on intestinal epithelial cells of a novel mannogalactan purified from Typhonium giganteum Engl

Inflammatory bowel disease (IBD) remains a pressing global health challenge due to its complex pathogenesis and limited treatment efficacy. Mannogalactans, abundant in certain algae and edible fungi, are recognized for their diverse biological functions, particularly their potent anti-inflammatory effects. Motivated by these findings, we hypothesized that Typhonium giganteum Engl. may contain structurally analogous mannogalactans with therapeutic potential against enteritis. To investigate, we isolated and purified a homogeneous polysaccharide, BFZ213, using hot water extraction, ethanol precipitation, and chromatographic techniques. Comprehensive structural analysis, employing methylation analysis, partial acid hydrolysis, 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization, infrared spectroscopy, HPLC, GC-MS, and NMR spectroscopy, identified BFZ213 as a novel mannogalactan (160 kDa). The backbone comprises 1, 3-linked mannose, 1, 2, 3-linked mannose, 1, 4-linked glucuronic acid, and 1, 2, 4, 6-linked galactose, with branching at the C-4 and C-6 positions of 1, 2, 4, 6-linked galactose, including 1, 4-linked galactose, 1, 6-linked galactose, terminal galactose, and arabinose. Bioactivity studies demonstrated that BFZ213 significantly suppressed TNF-α and IL-1β secretion in LPS-stimulated NCM460 cells and attenuated MAPK and NF-κB signaling by inhibiting the phosphorylation of p38, JNK, p65, and IκBα. These results highlight BFZ213 as a promising lead compound for IBD therapy, underscoring the therapeutic relevance of mannogalactans.

Photosynthetic microorganisms as an alternative source of thrombolytic compounds: a systematic review

Current conventional thrombolytic drugs have some limitations, including a short half-life, several adverse effects, low fibrin specificity, and high cost. Therefore, new thrombolytic sources have been widely investigated worldwide. In this sense, this work aims to evaluate the state of the art of the thrombolytic potential of different bioactive compounds produced from microalgae and cyanobacteria. Then, a systematic literature search was conducted using ScienceDirect, Medline (PubMed), Springer Link, Wiley Online Library, Scielo, MDPI, and BVS electronic databases to select original studies about thrombolytic agents obtained from microalgae and cyanobacteria. After the selection process, 20 studies met the inclusion criteria and were included in the final analysis. Most studies showed promising thrombolytic activity of polysaccharides or proteins produced by cyanobacteria and obtained through homogenization methods. Moreover, the majority of the studies used methods such as activated partial thromboplastin time, prothrombin time, thrombin time, or platelet aggregation tests as parameters to determine the thrombolytic activity. In conclusion, various bioactive compounds from microalgae and cyanobacteria showed high potential to act as alternative thrombolytic therapy, but some characteristics such as mechanism of action, cytotoxicity, immunogenicity and stability parameters need to be more exploited to make the application of these agents feasible in the future.

Structural Characterization and Anticoagulant Potential of Colochirus quadrangularis Fucosylated Glycosaminoglycan 5-12 Oligomers with Unusual Branches

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-Fuc2S4S, α-l-Fuc3S, α-l-Fuc4S, α-l-Fuc2S3S4S, and α-l-Fuc2S) and a disaccharide D-Gal3S4S-α1,3-l-Fuc2S4S 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-Fuc3S was the main FucS branch; no α-l-Fuc3S4S branch was found, and α-l-Fuc2S3S4S and α-l-Fuc2S 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.

Exploring the therapeutic potential of polysaccharide from Portulaca oleracea L.: A review of phytochemistry and immunomodulatory effect

Portulaca oleracea L., a plant with both edible and medicinal properties, is traditionally valued for its diuretic, antipyretic, antiseptic, antispasmodic, and anthelmintic functions in folk medicine. P. oleracea polysaccharide (POP), a pivotal bioactive component, has various biological activities. Notably, their immunomodulatory capabilities have emerged as a significant area of research. The extraction, purification, monosaccharide composition, structure characterization, and biological activity of POP have been extensively investigated to identify the active components and to clarify their pharmacological actions and underlying molecular mechanisms. It aims to delineate the pharmacological mechanisms and molecular pathways associated with these polysaccharides, thereby underscoring their therapeutic promise and nutritional significance. Furthermore, the review critically examines the current research landscape of POP, identifying gaps and proposing innovative perspectives to enrich the scientific discourse surrounding these bioactive compounds.

Structural analysis and in vitro fermentation characteristics of an Avicennia marina fruit RG-I pectin as a potential prebiotic

Avicennia marina (Forssk.) Vierh. is a highly salt-tolerant mangrove, and its fruit has been traditionally used for treating constipation and dysentery. In this study, a pectin (AMFPs-0-1) was extracted and isolated from this fruit for the first time, its structure was analyzed, and the effects on the human gut microbiota were investigated. The results indicated that AMFPs-0-1 with a molecular weight of 798 kDa had a backbone consisting of alternating →2)-α-L-Rhap-(1→ and →4)-α-D-GalpA-(1→ residues and side chains composed of →3-α-L-Araf-(1→-linked arabinan with a terminal β-L-Araf, →5-α-L-Araf-(1→-linked arabinan, and →4)-β-D-Galp-(1→-linked galactan that linked to the C-4 positions of all α-L-Rhap residues in the backbone. It belongs to a type I rhamnogalacturonan (RG-I) pectin but has no arabinogalactosyl chains. AMFPs-0-1 could be consumed by human gut microbiota and increase the abundance of some beneficial bacteria, such as Bifidobacterium, Mitsuokella, and Megasphaera, which could help fight digestive disorders. These findings provide a structural basis for the potential application of A. marina fruit RG-I pectic polysaccharides in improving human intestinal health.

Structural characterization of a Chlorella heteropolysaccharide by analyzing its depolymerized product and finding an inducer of human dendritic cell maturation

Chlorella polysaccharides have been gaining increasing attention because of their high yield from dried Chlorella powder and their remarkable immunomodulatory activity. In this study, the major polysaccharide fraction, CPP-3a, in Chlorella pyrenoidosa, was isolated, and its detailed structure was investigated by analyzing the low-molecular-weight product prepared via free radical depolymerization. The results indicated that CPP-3a with a molecular weight of 195.2 kDa was formed by →2)-α-L-Araf-(1→, →2)-α-D-Rhap-(1→, →5)-α-L-Araf-(1→, →3)-β-D-Glcp-(1→, →4)-α-D-Glcp-(1→, →4)-α-D-GlcpA-(1→, →2,3)-α-D-Manp-(1→, →3,4)-α-D-Manp-(1→, →3,4)-β-D-Galp-(1→, →3,6)-β-D-Galp-(1→, and →2,3,6)-α-D-Galp-(1→ residues, branched at C2, C3, C4, or C6 of α/β-D-Galp and α-D-Manp, and terminated by α/β-L-Araf, α-L-Arap, α-D-Galp, and β-D-Glcp. Biological assays showed that CPP-3a significantly altered the dendritic morphology of immature dendritic cells (DCs). Enhanced CD80, CD86, and MHC I expression on the cell surface and decreased phagocytic ability indicated that CPP-3a could induce the maturation of DCs. Furthermore, CPP-3a-stimulated DCs not only stimulated the proliferation of allogeneic naïve CD4+ T cells and the secretion of IFN-γ, but also directly stimulated the activation and proliferation of CD8+ T cells through cross-antigen presentation. These findings indicate that CPP-3a can promote human DC maturation and T-cell stimulation and may be a novel DC maturation inducer with potential developmental value in DC immunotherapy.

RN0D, a galactoglucan from Panax notoginseng flower induces cancer cell death via PINK1/Parkin mitophagy

Metabolic alterations within mitochondria, encompassing processes such as autophagy and energy metabolism, play a pivotal role in facilitating the swift proliferation, invasion, and metastasis of cancer cells. Despite this, there is a scarcity of currently available medications with proven anticancer efficacy through the modulation of mitochondrial dysfunction in a clinical setting. Here, we introduce the structural characteristics of RN0D, a galactoglucan isolated and purified from Panax notoginseng flowers, mainly composed of β-1,4-galactan and β-1,3/1,6-glucan. RN0D demonstrates the capacity to induce mitochondrial impairment in cancer cells, leading to the accumulation of reactive oxygen species, initiation of mitophagy, and reduction in both mitochondrial number and size. This sequence of events ultimately results in the inhibition of mitochondrial and glycolytic bioenergetics, culminating in the demise of cancer cells due to adenosine triphosphate (ATP) deprivation. Notably, the observed bioactivity is attributed to RN0D's direct targeting of Galectin-3, as affirmed by surface plasmon resonance studies. Furthermore, RN0D is identified as an activator of the PTEN-induced kinase 1 (PINK1)/Parkin pathway, ultimately instigating cytotoxic mitophagy in tumor cells. This comprehensive study substantiates the rationale for advancing RN0D as a potentially efficacious anticancer therapeutic.

A sulfated exopolysaccharide derived from Chlorella sp. exhibiting in vitro anti-α-D-Glucosidase activity

There is a great scientific curiosity to discover all environments sheltering microalgae, especially those with exceptional characteristics from coldest to hottest ones, the purpose remains to explore the potential of the native microalgae flora and the research for new bioactive compounds. This study aimed to isolate a polysaccharide-producing microalga from an extreme ecosystem and to evaluate its capacity to inhibit the α-D-glucosidase enzyme. Chlorella strain is isolated from hypersaline Lake in the Algerian desert. The exopolysaccharide extraction was performed by the concentration of free-cell supernatant in a rotary evaporator. The infrared analysis showed a characteristic footprint of carbohydrates with particular functional groups, such as sulfate. Gas chromatography-mass spectrometry has revealed a hetero-exopolysaccharide composed of galactose 35.75%, glucose 21.13%, xylose 16.81%, fructose 6.96%, arabinose 5.10%, and glucuronic acid 2.68%. The evaluation of the anti-hyperglycemic activity demonstrated a significant α-D-glucosidase inhibition of 80.94 ± 0.01% at 10 mg mL-1 with IC50 equal to 4.31 ± 0.20 mg mL-1. This study opens a vast prospect to use exopolysaccharides as natural nutraceutical or food additive.

Skin healthcare protection with antioxidant and anti-melanogenesis activity of polysaccharide purification from Bletilla striata

In this study, we investigated the structural characterization and biological activities of Bletilla striata polysaccharides (BSPs) for their role as antioxidants and anti-melanogenesis agents in skin healthcare protection. Three neutral polysaccharides (BSP-1, BSP-2, and BSP-3) with molecular weights of 269.121 kDa, 57.389 kDa, and 28.153 kDa were extracted and purified. Their structural characteristics were analyzed by ion chromatography, GC-MS, and 1D/2D NMR. The results showed that BSP-1, which constitutes the major part of BSPs, was composed of α-D-Glcp, β-D-Glcp, β-D-Manp, and 2-O-acetyl-β-D-Manp, with the branched-chain accompanied by β-D-Galp and α-D-Glcp. BSP-1, BSP-2, and BSP-3 can enhance the total antioxidant capacity of skin fibroblasts with non-toxicity. Meanwhile, BSP-1, BSP-2, and BSP-3 could significantly inhibit the proliferative activity of melanoma cells. Among them, BSP-1 and BSP-2 showed more significance in anti-melanogenesis, tyrosinase inhibition activity, and cell migration inhibition. BSPs have effective antioxidant capacity and anti-melanogenesis effects, which should be further emphasized and developed as skin protection components.