Animal lectins: potential receptors for ginseng polysaccharides

Ginseng polysaccharide components attenuate obesity and liver lipid accumulation by regulating fecal microbiota and hepatic lysine degradation

The increasing incidence of obesity has led to widespread attention in the exploration of natural ingredients. Ginseng polysaccharides (PGP), the main components from Panax ginseng, have been reported potential effect to attenuate obesity and regulate lipid metabolism. In this study, we found that PGP inhibited the high-fat diet (HFD)-induced weight gain, fat ratio and fat tissue weight after 8-week administration. Serum and liver lipid analysis showed that PGP decreased the levels of triglyceride and total cholesterol, which was mediated by the inhibition of key genes for fatty acid and cholesterol metabolisms. Metabolomics studies showed that the inhibitory effect of PGP on liver lipid accumulation was significantly correlated with its regulation of citric acid cycle and lysine degradation. PGP regulated the expression of genes related to lysine degradation in both liver tissue and hepatocytes. In addition, PGP reshaped the composition of fecal microbiota at the genus and species levels in obese mice. Spearman's correlation analysis demonstrated that Staphylococcus sciuri, Staphylococcus lentus, and Pseudoflavonifractor sp. An85 may be the potential targets that PGP maintains the abundance of l-lysine against obesity. It concluded that PGP can attenuate obesity and liver lipid accumulation by regulating fecal microbiota and hepatic lysine degradation.

UPLC-QTOF-MS based metabolomics unravels the modulatory effect of ginseng water extracts on rats with Qi-deficiency

Ginseng is commonly used as a nutritional supplement and daily wellness product due to its ability to invigorate qi. As a result, individuals with Qi-deficiency often use ginseng as a health supplement. Ginsenosides and polysaccharides are the primary components of ginseng. However, the therapeutic effects and mechanisms of action of these components in Qi-deficiency remain unclear. This study aimed to determine the modulatory effects and mechanisms of ginseng water extract, ginsenosides, and ginseng polysaccharides in a rat model of Qi-deficiency using metabolomics and network analysis. The rat model of Qi-deficiency was established via swimming fatigue and a restricted diet. Oral administration of different ginseng water extracts for 30 days primarily alleviated oxidative stress and disrupted energy metabolism and immune response dysfunction caused by Qi-deficiency in rats. Ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was used for untargeted serum metabolomic analysis. Based on the analysis results, the active constituents of ginseng significantly reversed the changes in serum biomarkers related to Qi-deficiency in rats, particularly energy, amino acid, and unsaturated fatty acid metabolism. Furthermore, analysis of the metabolite-gene network suggested that the anti-Qi-deficiency effects of the ginseng components were mainly associated with toll-like receptor (TLR) signaling and inflammatory response. Additional verification revealed that treatment with the ginseng components effectively reduced the inflammatory response and activation of the myocardial TLR4/NF-κB pathway induced by Qi-deficiency, especially the ginseng water extracts. Therefore, ginseng could be an effective preventive measure against the progression of Qi-deficiency by regulating metabolic and inflammatory responses.

Binding elucidation of azo dyes with human serum albumin via spectroscopic approaches and molecular docking techniques

The large number of synthesized azo dyes is widely applied in the food, pharmaceutical, cosmetic, textile, and leather industries. In this study, the binding mechanism of two synthesized dyes with human serum albumin (HSA); as the most abundant protein in plasma; was elucidated by fluorescence spectroscopy, Fourier-transform infrared spectroscopy and molecular modeling methods. The fluorescence quenching measurements showed that each dye can quench the intrinsic fluorescence of HSA via a dynamic quenching mechanism with an increase in concentration. From the thermodynamic data observations, revealed that the binding process is a spontaneous molecular force for each dye with HSA due to hydrophobic interactions and hydrogen bonding. FT-IR spectra showed that the secondary structure of the protein changes due to interaction of each dye with HSA. Furthermore, docking simulation demonstrated that the probable binding location of both dyes is subdomain IIA of HSA (Sudlow site I) and that complex formed is stabilized by hydrophobic interactions and hydrogen bonding.Communicated by Ramaswamy H. Sarma.

Back2Basics: animal lectins: an insight into a highly versatile recognition protein

The rapid advancement of molecular research has contributed to the discovery of 'Lectin', a carbohydrate-binding protein which specifically interacts with receptors on surface glycan moieties that regulate various critical cellular activities. The first animal lectin reported was 'the asialoglycoprotein receptor' in mammalian cells which helped analyze how animal lectins differ in glycoconjugate binding. Animal lectins are classified into several families, depending on their diverse cellular localization, and the binding specificities of their Carbohydrate-Recognition Domain (CRD) modules. Earlier characterization of animal lectins classified them into two structural families, the C-type (Ca²⁺-dependent binding) and S-type galectins (sulfhydryl-dependent binding) lectins. The C-type lectin includes the most significant animal lectins, such as endocytic receptors, mannose receptors, selectins, and collectins. The recent developments in research based on the complexity of the carbohydrate ligands, the metabolic processes they perform, their expression levels, and their reliance on divalent cations have identified more than 100 animal lectins and classified them into around 13 different families, such as Calnexin, F-lectin, Intelectin, Chitinase-like lectin, F-box lectin, etc. Understanding their structure and expression patterns have aided in defining their significant functions including cell adhesion, antimicrobial activity, innate immunity, disease diagnostic biomarkers, and drug delivery through specific carbohydrate-protein interactions. Such extensive potential roles of animal lectins made it equally important to plant lectins among researchers. Hence, the review focuses on providing an overview of animal lectins, their taxonomy, structural characteristics, and functions in diverse aspects interconnected to their specific carbohydrate and glycoconjugate binding.

Graphical abstract

Transcriptome reveals insights into biosynthesis of ginseng polysaccharides

BACKGROUND

Ginseng polysaccharides, have been used to treat various diseases as an important active ingredient. Nevertheless, the biosynthesis of ginseng polysaccharides is poorly understood. To elucidate the biosynthesis mechanism of ginseng polysaccharides, combined the transcriptome analysis and polysaccharides content determination were performed on the roots, stems, and leaves collected from four cultivars of ginseng.

RESULTS

The results indicated that the total contents of nine monosaccharides were highest in the roots. Moreover, the total content of nine monosaccharides in the roots of the four cultivars were different but similar in stems and leaves. Glucose (Glc) was the most component of all monosaccharides. In total, 19 potential enzymes synthesizing of ginseng polysaccharides were identified, and 17 enzymes were significantly associated with polysaccharides content. Among these genes, the expression of phosphoglucomutase (PGM), glucose-6-phosphate isomerase (GPI), UTP-glucose-1-phosphate uridylyltransferase (UGP2), fructokinase (scrK), mannose-1-phosphate guanylyltransferase (GMPP), phosphomannomutase (PMM), UDP-glucose 4-epimerase (GALE), beta-fructofuranosidase (sacA), and sucrose synthase (SUS) were correlated with that of MYB, AP2/ERF, bZIP, and NAC transcription factors (TFs). These TFs may regulate the expression of genes involved in ginseng polysaccharides synthesis.

CONCLUSION

Our findings could provide insight into a better understanding of the regulatory mechanism of polysaccharides biosynthesis, and would drive progress in genetic improvement and plantation development of ginseng.

Multi technique investigation on interaction between 5-(2-thiazolylazo)-2,4,6-triaminopyrimidine and HSA and BSA

In research laboratories and in various industries, azo compounds are among the most effective and commonly used organic dyes. The association between human (HSA) and bovine (BSA) serum albumins with 5-(2-thiazolylazo)-2,4,6-triaminopyrimidine (TTP) was investigated in this research using spectroscopy methods and molecular modeling study. The fluorescence quenching results showed that the quenching mechanisms were static and dynamic processes for HSA and BSA, respectively. From the thermodynamic observations, it is clear that the binding process is a spontaneous molecular interaction, in which van der Waals and hydrogen bonding interactions for HSA and hydrophobic interaction for BSA play the major roles. According to Förster energy transfer, non-radiative energy transferred from HSA and BSA to TTP, is provided by close distance (r₀) between TTP and Trp residues of HSA and BSA. The synchronous fluorescence spectroscopy, FT-IR findings and UV-Vis absorption data confirm that TTP can induce conformational and micro environmental changes in both the proteins. Furthermore, docking results predicted the probable binding site of TTP in subdomain IIA of HSA and BSA molecules where Trp residues are located. Types of amino acid residues surrounding the TTP molecule supported that van der Waals forces, hydrophobic forces and electrostatic forces play important roles in stabilization of drug-protein complexes formed.Communicated by Ramaswamy H. Sarma.

An Update of Lectins from Marine Organisms: Characterization, Extraction Methodology, and Potential Biofunctional Applications

Lectins are a unique group of nonimmune carbohydrate-binding proteins or glycoproteins that exhibit specific and reversible carbohydrate-binding activity in a non-catalytic manner. Lectins have diverse sources and are classified according to their origins, such as plant lectins, animal lectins, and fish lectins. Marine organisms including fish, crustaceans, and mollusks produce a myriad of lectins, including rhamnose binding lectins (RBL), fucose-binding lectins (FTL), mannose-binding lectin, galectins, galactose binding lectins, and C-type lectins. The widely used method of extracting lectins from marine samples is a simple two-step process employing a polar salt solution and purification by column chromatography. Lectins exert several immunomodulatory functions, including pathogen recognition, inflammatory reactions, participating in various hemocyte functions (e.g., agglutination), phagocytic reactions, among others. Lectins can also control cell proliferation, protein folding, RNA splicing, and trafficking of molecules. Due to their reported biological and pharmaceutical activities, lectins have attracted the attention of scientists and industries (i.e., food, biomedical, and pharmaceutical industries). Therefore, this review aims to update current information on lectins from marine organisms, their characterization, extraction, and biofunctionalities.

A review of the immunomodulatory activities of polysaccharides isolated from Panax species

Panax polysaccharides are biopolymers that are isolated and purified from the roots, stems, leaves, flowers, and fruits of Panax L. plants, which have attracted considerable attention because of their immunomodulatory activities. In this paper, the composition and structural characteristics of purified polysaccharides are reviewed. Moreover, the immunomodulatory activities of polysaccharides are described both in vivo and in vitro. In vitro, Panax polysaccharides exert immunomodulatory functions mainly by activating macrophages, dendritic cells, and the complement system. In vivo, Panax polysaccharides can increase the immune organ indices and stimulate lymphocytes. In addition, this paper also discusses the membrane receptors and various signalling pathways of immune cells. Panax polysaccharides have many beneficial therapeutic effects, including enhancing or activating the immune response, and may be helpful in treating cancer, sepsis, osteoporosis, and other conditions. Panax polysaccharides have the potential for use in the development of novel therapeutic agents or adjuvants with beneficial immunomodulatory properties.

Antibacterial and antitumor activities of a lectin-rich preparation from Microgramma vacciniifolia rhizome

The rhizome of Microgramma vacciniifolia contains a lectin (carbohydrate-binding protein) called MvRL. Studies demonstrated that a MvRL-rich fraction did not show in vivo genotoxicity and acute toxicity in mice. This study aimed to evaluate the MvRL-rich fraction from M. vacciniifolia rhizome for antibacterial activity in vitro and in vivo as well as antitumor effect in vivo using the Ehrlich carcinoma model in mice. The fraction showed antibacterial activity against Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus with minimal inhibitory concentrations ranging from 31.2 to 125.0 ​μg/mL and minimal bactericidal concentrations from 62.5 to 200 ​μg/mL. The fraction was also effective in vivo against infection caused by these bacteria on Tenebrio molitor larvae considering the parameters evaluated. In regard to the antitumor activity, the treatments of Ehrlich carcinoma-bearing mice with the fraction at 100 and 200 ​mg/kg per os resulted in 62.58% and 75.43% of tumor inhibition, respectively. In conclusion, the MvRL-rich fraction showed in vivo antibacterial and antitumor activities and thus can be considered as an alternative of natural origin for the development of candidates for therapy.

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The rhizome of Microgramma vacciniifolia contains a lectin called MvRL.

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MvRL-rich fraction showed antibacterial activity.

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The fraction was also effective in vivo against bacterial infection.

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MvRL-rich fraction causedn 62.58–75.43% inhibition of Erlich carcinoma.

The Galactose-Binding Lectin Isolated from Vatairea macrocarpa Seeds Enhances the Effect of Antibiotics Against Staphylococcus aureus-Resistant Strain

The use of natural products together with standard antimicrobial drugs has recently received more attention as a strategy to combat infectious diseases caused by multidrug-resistant (MDR) microorganisms. This study aimed to evaluate the capacity of a galactose-binding lectin from Vatairea macrocarpa seeds (VML) to modulate antibiotic activity against standard and MDR Staphylococcus aureus and Escherichia coli bacterial strains. The minimum inhibitory concentration (MIC) obtained for VML against all strains was not clinically relevant (MIC ≥ 1024 μg/mL). However, when VML was combined with the antibacterial drugs gentamicin, norfloxacin and penicillin, a significant increase in antibiotic activity was observed against S. aureus, whereas the combination of VML and norfloxacin presented decreased and, hence, antagonistic antibiotic activity against E. coli. By its inhibition of hemagglutinating activity, gentamicin (MIC = 50 mM) revealed its interaction with the carbohydrate-binding site (CBS) of VML. Using molecular docking, it was found that gentamicin interacts with residues that constitute the CBS of VML with a score of - 120.79 MDS. It is this interaction between the antibiotic and the lectin's CBS that may be responsible for the enhanced activity of gentamicin in S. aureus. Thus, our results suggest that the VML can be an effective modulating agent against S. aureus. This is the first study to report the effect of lectins as modulators of bacterial sensitivity, and as such, the outcome of this study could lay the groundwork for future research involving the use of lectins and conventional antibiotics against such infectious diseases such as community-acquired methicillin-resistant S. aureus (MRSA).

Activity of Mannose-Binding Lectin on Bacterial-Infected Chickens-A Review

Simple Summary

In the quest to combat bacterial-related diseases in chickens, different methods, of which some are less economical and less effective on the long-term, have been adapted. However, chickens possess mannose-binding lectin (MBL) which could be vital in managing pathogenic bacteria in chickens. MBL is one of the soluble proteins secreted by the chicken’s innate immune system which can be activated when chickens are exposed to chicken-related diseases. This review explains how mannose-binding lectin activation can help in fighting bacterial pathogens in chickens. This knowledge is believed to reduce incessant use of antibiotics and to assist in developing a profitable breeding program with less or no adverse effect on the chicken, human and the environment.

Abstract

In recent years, diseases caused by pathogenic bacteria have profoundly impacted chicken production by causing economic loss in chicken products and by-product revenues. MBL (mannose-binding lectin) is part of the innate immune system (IIS), which is the host’s first line defense against pathogens. The IIS functions centrally by identifying pathogen-specific microorganism-associated molecular patterns (MAMPs) with the help of pattern recognition receptors (PRRs). Studies have classified mannose-binding lectin (MBL) as one of the PRR molecules which belong to the C-type lectin family. The protective role of MBL lies in its ability to activate the complement system via the lectin pathway and there seems to be a direct link between the chicken’s health status and the MBL concentration in the serum. Several methods have been used to detect the presence, the level and the structure of MBL in chickens such as Enzyme-linked immunosorbent assay (ELISA), Polymerase Chain Reaction (PCR) among others. The concentration of MBL in the chicken ranges from 0.4 to 35 µg/mL and can be at peak levels at three to nine days at entry of pathogens. The variations observed are known to depend on the bacterial strains, breed and age of the chicken and possibly the feed manipulation strategies. However, when chicken MBL (cMBL) becomes deficient, it can result in malfunctioning of the innate immune system, which can predispose chickens to diseases. This article aimed to discuss the importance and components of mannose-binding lectin (MBL) in chickens, its mode of actions, and the different methods used to detect MBL. Therefore, more studies are recommended to explore the causes for low and high cMBL production in chicken breeds and the possible effect of feed manipulation strategies in enhancing cMBL production.

Therapeutic effects of non-saponin fraction with rich polysaccharide from Korean red ginseng on aging and Alzheimer's disease

Biological aging provokes morbidity and several functional declines, causing older adults more susceptible to a variety of diseases than younger adults. In particular, aging is a major risk factor contributing to non-communicable diseases, such as neurodegenerative disorders. Alzheimer's disease (AD) is an aging-related neurodegenerative disease that is characterized by cognitive deficits and the formation of amyloid plaques formed by the accumulation of amyloid-β (Aβ) peptides. Non-saponin fraction with rich polysaccharide (NFP) from red ginseng, the largest fraction of the components of red ginseng, perform many biological activities. However, it has not been clarified whether the NFP from Korean red ginseng (KRG) has beneficial effects in the aging and AD. First, proteomics analysis was performed in aged brain to identify the effect of NFP on protein changes, and we confirmed that NFP induced changes in proteins related to the neuroprotective- and neurogenic-effects. Next, we investigated (1) the effects of NFP on AD pathologies, such as Aβ deposition, neuroinflammation, neurodegeneration, mitochondrial dysfunction, and impaired adult hippocampal neurogenesis (AHN), in 5XFAD transgenic mouse model of AD using immunostaining; (2) the effect of NFP on Aβ-mediated mitochondrial respiration deficiency in HT22 mouse hippocampal neuronal cells (HT22) using Seahorse XFp analysis; (3) the effect of NFP on cell proliferation using WST-1 analysis; and (4) the effect of NFP on Aβ-induced cognitive dysfunction in 5XFAD mouse model of AD using Y-maze test. Histological analysis indicated that NFP significantly alleviated the accumulation of Aβ, neuroinflammation, neuronal loss, and mitochondrial dysfunction in the subiculum of 5XFAD mouse model of AD. In addition, NFP treatment ameliorated mitochondrial deficits in Aβ-treated HT22 cells. Moreover, NFP treatment significantly increased the AHN and neuritogenesis of neural stem cells in both healthy and AD brains. Furthermore, NFP significantly increased cell proliferation in the HT22 cells. Finally, NFP administration significantly enhanced and restored the cognitive function of healthy and AD mice, respectively. Taken together, NFP treatment demonstrated changes in proteins involved in central nervous system organization/maintenance in aged brain and ameliorates AD pathology. Collectively, our findings suggest that NFP from KRG could be a potential therapeutic candidate for aging and AD treatments.

Panax quinquefolius (North American Ginseng) Polysaccharides as Immunomodulators: Current Research Status and Future Directions

Panax quinquefolius (North American ginseng, NAG) is a popular medicinal plant used widely in traditional medicine. NAG products are currently available in various forms such as roots, extracts, nutraceuticals, dietary supplements, energy drinks, etc. NAG polysaccharides are recognized as one of the major bioactive ingredients. However, most NAG reviews are focused on ginsenosides with little information on polysaccharides. NAG polysaccharides have demonstrated a therapeutic activity in numerous studies, in which many of the bioactivities involve regulation of the immune response. The purpose of this review is to summarize the structural features and the immunomodulatory properties of crude, partially purified, and pure polysaccharides isolated from NAG. Receptors of the innate immune system that potentially bind to NAG polysaccharides and the respective signal transduction pathways initiated by these compounds are discussed. Major challenges, recent innovations, and future directions in NAG polysaccharide research are also summarized.

An acidic polysaccharide (AGC3) isolated from North American ginseng (Panax quinquefolius) suspension culture as a potential immunomodulatory nutraceutical

Polysaccharides isolated from Panax quinquefolius roots are widely used as nutraceuticals due to their immunomodulatory properties. Despite their popularity, several challenges exist in isolating ginseng root polysaccharides such as batch-to-batch structural inconsistencies and bacterial endotoxin contamination. A plant tissue culture-based platform offers a potential solution to isolate natural polysaccharide fractions with consistent chemical characteristics and reduced endotoxin content. In this study, an acidic polysaccharide fraction (AGC3) with immunomodulatory properties was isolated from Panax quinquefolius suspension cultures. The heterogeneous fraction (molecular weight: 4.81 and 32.14 kDa), purified by anion exchange chromatography, was predominantly composed of galactose (>60%) along with the presence of rhamnose, arabinose, glucose, glucuronic acid and galacturonic acid. The major glycosidic linkages were found to be t-Galp (47.7%), 4-Galp (15.6%), 2,4-Rhap (8.1%), 6-Galp (8.1%) and 4-GalAp (6.8%). Structural analyses indicated the presence of a pectic rhamnogalacturonan I polysaccharide in AGC3. AGC3 significantly (p < 0.05) stimulated RAW 264.7 murine macrophage cells and primary murine splenocytes by enhancing the production of several immunomodulatory mediators such as IL-6, TNF-α, GM-CSF and MCP-1. The results also indicated the putative roles of NF-κB (p65/RelA) and MAPK (p38) signaling pathways in the immunostimulatory response. Additionally, AGC3 induced murine splenocyte proliferation, another major indicator of immunostimulation. Overall, AGC3 has the potential to be used as an immunostimulatory nutraceutical.

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American ginseng suspension culture as source of natural bioactive polysaccharides.

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Acidic polysaccharide, AGC3 displayed potent immunostimulatory properties.

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Putative mechanism of action includes NF-κB (p65/RelA) and MAPK (p38) pathways.

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AGC3 predominantly composed of RGI-type pectins.

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Potential nutraceutical that can be used as an exogenous immunomodulator.

Biological Effects of Korean Red Ginseng Polysaccharides in Aged Rat Using Global Proteomic Approach

Much has been written on the physiological benefits of Korean Red Ginseng (KRG). Among its various components, ginsenosides have been widely investigated for their various pharmacological effects. However, polysaccharides are a major KRG component that has not received scrutiny similar to that of ginsenosides. The present study aims to fill that gap in the existing literature and to investigate the possible functions of polysaccharide in KRG. The researchers evaluated proteomic changes in non-saponin fractions with rich polysaccharides (NFP) in KRG. Based on the serum analysis, proteomics analysis of the liver and the spleen was additionally conducted to identify related functions. We validated the suggested functions of NFP with the galactosamine-induced liver injury model and the cyclophosphamide-induced immunosuppression model. Then, we evaluated the antimetastatic potential of NFP in the lungs. Further proteomics analysis of the spleen and liver after ingestion confirmed functions related to immunity, cancer, hepatoprotection, and others. Then, we validated the suggested corresponding functions of the NFP in vivo model. NFP showed immune-enhancing effects, inhibited melanoma cell metastasis in the lung, and decreased liver damage. The results show that using the proteomic approach uncovers the potential effects of polysaccharides in KRG, which include enhancing the immune system and protecting the liver.

Crystallographic and calorimetric analysis on Pleurotus ostreatus lectin and its sugar complexes - promiscuous binding driven by geometry

Carbohydrate recognition is established as a property of lectins and implicated in many functions including immunity and defense against pathogens. Many lectins are characterized and proposed for various applications owing to the above said recognition. The crystal structure of a lectin from Pleurotus ostreatus has been determined and shown to be calcium dependent. The overall structure is a tandem repeat of two β-jelly roll domains, a new fold for lectins. The calcium dependence of sugar binding is analyzed in-detail through isothermal titration calorimetry. The serendipitous observation of malonate and glycerol, the intentional N-Acetyl-D-galactosamine, D-Galactose and L-Rhamnose binding to Pleurotus ostreatus lectin by Ca²⁺ coordination revealed that the binding site is promiscuous. Among these sugars, Rhamnose binding found to be thermodynamically most favourable. In all these structures, a vicinal diol motif, one at axial and the other at equatorial positions could be established as a specific requirement for binding. Interestingly, when compared with other calcium mediated lectin structures; this geometric requirement is found conserved. This observation could lead to the conclusion that lectins are not 'molecule specific' but 'geometry specific' so that any molecule not necessarily a sugar may be recognized by this lectin if the geometry exists.

Animal Galectins and Plant Lectins as Tools for Studies in Neurosciences

Lectins are proteins or glycoproteins of non-immunological origin capable of reversibly and specifically binding to glycoconjugates. They exist in free form or associated with cells and are widely distributed in nature, being found in plants, microorganisms, and animals. Due to their characteristics and mainly due to the possibility of reversible binding to glycoconjugates, lectins have stood out as important tools in research involving Neurobiology. These proteins have the ability to modulate molecular targets in the central nervous system (CNS) which may be involved with neuroplasticity, neurobehavioral effects, and neuroprotection. The present report integrates existing information on the activity of animal and plant lectins in different areas of Neuroscience, presenting perspectives to direct new research on lectin function in the CNS, providing alternatives for understanding neurological diseases such as mental disorders, neurodegenerative, and neuro-oncological diseases, and for the development of new drugs, diagnoses and therapies in the field of Neuroscience.

Purification and Characterization of a New Lectin from Loach Skin Mucus

Lectin from loach skin mucus plays an important role in pathogen defense. However, hardly can any paper relevant to the character of lectin from loach skin mucus be found in recent years. In this study, a kind of new lectin (LML), with a high hemagglutination activity of 166.23 × 103 HU/mg, was successfully isolated and purified from loach skin mucus. LML was a kind of glycoprotein with a molecular weight of 245 kDa. Also, the monosaccharide composition suggested that its carbohydrate chain was composed of rhamnose, arabinose, xylose, mannose, glucose, and galactose with a molar ratio of 2.02 : 11.66 : 2.06 : 1.00 : 14.09 : 6.00. Besides, LML depended on Ca2+to induce hemagglutination and was strongly inhibited by D-lactose. The lectin exhibited powerful resistance to alkali and kept about 30% hemagglutination activity at pH 14.0, whereas its capacity of acid resistance was weak. The maximum hemagglutination activity of LML maintained at a temperature range from 20°C to 50°C. Moreover, the structure of LML was preliminarily studied, indicating it contained abundant glutamic acid, histidine, and serine, and its secondary structure containedα-helix (4.97%),β-sheet (27.55%), turns structure (49.78%), and unordered structure (17.70%).

Sources, Extraction and Biomedical Properties of Polysaccharides

In the recent era, bioactive compounds from plants have received great attention because of their vital health-related activities, such as antimicrobial activity, antioxidant activity, anticoagulant activity, anti-diabetic activity, UV protection, antiviral activity, hypoglycemia, etc. Previous studies have already shown that polysaccharides found in plants are not likely to be toxic. Based on these inspirational comments, most research focused on the isolation, identification, and bioactivities of polysaccharides. A large number of biologically active polysaccharides have been isolated with varying structural and biological activities. In this review, a comprehensive summary is provided of the recent developments in the physical and chemical properties as well as biological activities of polysaccharides from a number of important natural sources, such as wheat bran, orange peel, barely, fungi, algae, lichen, etc. This review also focused on biomedical applications of polysaccharides. The contents presented in this review will be useful as a reference for future research as well as for the extraction and application of these bioactive polysaccharides as a therapeutic agent.

Purification, structural elucidation and anti-inflammatory activity in vitro of polysaccharides from Smilax china L

Smilax china L. is a traditional Chinese medicine mainly used for the treatment of pelvic inflammation. Polysaccharide might be one of the anti-inflammatory components of Smilax china L. Based on this hypothesis, this work aimed at extraction, purification and structural elucidation of Smilax china L. polysaccharides and their preliminary anti-inflammatory effects were also studied. Two polysaccharides named SCLP1 (Smilax china L. polysaccharide 1, 42.1kDa) and SCLP3-2 (Smilax china L. polysaccharide 3-2, 16.8kDa) were for the first time purified from Smilax china L. The structures of SCLP1 and SCLP3-2 were elucidated by chemical and spectral analysis. The results revealed that SCLP1 was a neutral polysaccharide composed of glucose and mannose (54.5:1.0). Its backbone was 1,4‑linked α‑Glcp interspersed with 1,2‑linked α‑Glcp and Manp; the branches were 1,6‑linked α-Glcp and terminated with α‑Glcp. SCLP3-2 was composed of galacturonic acid, arabinose, galactose and rhamnose (23.3:2.1:1.7:1.0) and was a pectin-type polysaccharide with an α‑1,4‑linked homogalacturonan backbone which was partially methyl-esterified and slightly acetylated. The side chains consisted of α‑Rhap, β‑Galp and α‑Araf. SCLP1 and SCLP3-2 could inhibit the production of NO, IL-6 and TNF-α in LPS-stimulated RAW264.7 cells via NF-κB and MAPKs (ERK1/2, JNK) pathways, indicating that they possessed a potential anti-inflammatory activity.

Panax quinquefolius (North American ginseng) cell suspension culture as a source of bioactive polysaccharides: Immunostimulatory activity and characterization of a neutral polysaccharide AGC1

In this study, we propose the use of a plant tissue culture-based system for the production of polysaccharides with consistent chemical characteristics and reduced endotoxin content. Polysaccharides were isolated from suspension cultures of Panax quinquefolius (American ginseng), a widely used medicinal herb. A neutral fraction, AGC1, purified by anion exchange and size exclusion chromatography, displayed immunostimulatory activity in vitro and ex vivo. AGC1 (average molecular weight: 5.2kDa) was predominantly composed of galactose (>60%) along with the presence of several other neutral sugars such as arabinose, xylose, glucose, mannose and rhamnose in minor amounts. The major glycosidic linkages were found to be 3-Galp (48.5%), 3,6-Galp (10.2%), t-Galp (5.2%), 6-Galp (4.4%), 4-Glcp (5.7%), 4-Arap/5-Araf (4.0%) and t-Araf (4.5%). AGC1 significantly (p<0.05) stimulated the expression of a range of proinflammatory mediators in RAW 264.7 murine macrophages such as IL-6, TNF-α, MCP-1 and GM-CSF. Additionally, AGC1 treatment of RAW 264.7 cells stimulated NOS2 gene expression, leading to increased levels of iNOS and downstream NO. Consistent with this, AGC1 was able to act as an immunostimulant in primary murine splenocytes, enhancing cell proliferation, as well as NO and TNF-α production. Our results also indicate the partial role of NF-κB pathway in the immunostimulatory response.

Parkia platycephala lectin enhances the antibiotic activity against multi-resistant bacterial strains and inhibits the development of Haemonchus contortus

Lectins have been studied in the past few years as an alternative to inhibit the development of pathogenic bacteria and gastrointestinal nematodes of small ruminants. The development of new antibacterial and anthelmintic compounds is necessary owing to the increase in drug resistance among important pathogens. Therefore, this study aimed to evaluate the capacity of a glucose/mannose-binding lectin from Parkia platycephala seeds (PPL) to inhibit the development of Haemonchus contortus and to modulate antibiotic activity against multi-resistant bacterial strains, thereby confirming its efficacy when used in combination with gentamicin. PPL at the concentration of 1.2 mg/mL did not show inhibitory activity on H. contortus in the egg hatch test or the exsheathment assay. However, it did show significant inhibition of H. contortus larval development with an IC₅₀ of 0.31 mg/mL. The minimum inhibitory concentration (MIC) obtained for PPL against all tested bacterial strains was not clinically relevant (MIC ≥ 1024 μg/mL). However, when PPL was combined with gentamicin, a significant increase in antibiotic activity was observed against S. aureus and E.coli multi-resistant strains. The inhibition of hemagglutinating activity by gentamicin (MIC = 50 mM) revealed that it may be interacting with the carbohydrate-binding site of PPL. It is this interaction between the antibiotic and lectin carbohydrate-binding site that may be responsible for the enhanced activity of gentamicin against multi-resistant strains. It can be concluded that PPL showed selective anthelmintic effect, inhibiting the development of H. contortus larvae and that it increased the effect of the antibiotic gentamicin against multi-resistant bacterial strains, thus constituting a potential therapeutic resource against resistant bacterial strains and H. contortus.

Ginseng berry polysaccharides on inflammation-associated colon cancer: inhibiting T-cell differentiation, promoting apoptosis, and enhancing the effects of 5-fluorouracil

Background

Ginseng is a commonly used herbal medicine in treating various medical conditions. Chronic gut inflammation is a recognized factor for the development of colorectal cancer (CRC). In this project, Asian ginseng berry polysaccharide preparations were used to assess their effects on CRC and related immune regulation mechanisms.

Methods

Ginseng berry polysaccharide extract (GBPE) and purified ginseng berry polysaccharide portion (GBPP) were used to evaluate their activities on human HCT-116 and HT-29 CRC cell proliferation. Interleukin-8 secretion analysis was performed on HT-29 cells. Naive CD4 cell isolation and T-helper cell differentiation were performed and determined using flow cytometry for Th1 and Treg in addition to cell cycle and apoptotic investigation.

Results

GBPE and GBPP significantly inhibited interleukin-8 secretion and cancer cell proliferation, inhibited CD4⁺IFN-γ⁺ cell (Th1) differentiation, and decreased CD4⁺FoxP3⁺ cell (Treg) differentiation. Compared to the GBPE, GBPP showed more potent antiinflammatory activities on the malignant cells. This is consistent with the observation that GBPP can also inhibit Th1-cell differentiation better, suggesting that it has an important role in antiinflammation, whereas Treg cells hinder the body's immune response against malignancies. Supported by cell cycle and apoptosis data, GBPE and GBPP, at various degrees, remarkably enhanced the anticancer activities of 5-fluorouracil.

Conclusion

Data from this project suggested that Asian ginseng berry potentially has clinical utility in managing enteric inflammation and suppressing CRC through immunomodulation mechanisms.

Eupatilin inhibits angiogenesis-mediated human hepatocellular metastasis by reducing MMP-2 and VEGF signaling

Metastasis is responsible for the great majority of deaths in cancer patients. Matrix metalloproteinases (MMPs) have critical functions in cancer metastasis. Especially, MMP-2 and MMP-9 play a major role in tumor-cell migration and invasion. Therefore, to first find out the inhibitory effect of eupatilin on expression of MMPs in SNU182 cells, we used quantitative real-rime PCR to measure MMP-2 and MMP-9 mRNA levels. Eupatilin suppressed transcription of MMP-2 in SNU182 cells more than did the corresponding controls. Also, eupatilin significantly blocked tube formation when treated with a concentration of 3.125 or 6.25 μg/mL on human umbilical vein vascular endothelial cells (HUVECs). Eupatilin induced significant anti-angiogenic potential associated with down-regulation of hypoxia-inducible factor 1-alpha (HIF-1α), vascular endothelial growth factor (VEGF), and phosphorylated Akt expression. Thus, tube-formation inhibition and MMP-2-mediated migration are likely to be important therapeutic targets of eupatilin in hepatocellular carcinoma metastasis.

Bioactive lipids in gintonin-enriched fraction from ginseng

Background

Ginseng is a traditional herbal medicine for human health. Ginseng contains a bioactive ligand named gintonin. The active ingredient of gintonin is lysophosphatidic acid C18:2 (LPA C18:2). We previously developed a method for gintonin-enriched fraction (GEF) preparation to mass-produce gintonin from ginseng. However, previous studies did not show the presence of other bioactive lipids besides LPAs. The aim of this study was to quantify the fatty acids, lysophospholipids (LPLs), and phospholipids (PLs) besides LPAs in GEF.

Methods

We prepared GEF from white ginseng. We used gas chromatography-mass spectrometry for fatty acid analysis and liquid chromatography-tandem mass spectrometry for PL analysis, and quantified the fatty acids, LPLs, and PLs in GEF using respective standards. We examined the effect of GEF on insulin secretion in INS-1 cells.

Results

GEF contains about 7.5% linoleic (C18:2), 2.8% palmitic (C16:0), and 1.5% oleic acids (C18:1). GEF contains about 0.2% LPA C18:2, 0.06% LPA C16:0, and 0.02% LPA C18:1. GEF contains 0.08% lysophosphatidylcholine, 0.03% lysophosphatidylethanolamine, and 0.13% lysophosphatidylinositols. GEF also contains about 1% phosphatidic acid (PA) 16:0-18:2, 0.5% PA 18:2-18:2, and 0.2% PA 16:0-18:1. GEF-mediated insulin secretion was not blocked by LPA receptor antagonist.

Conclusion

We determined four characteristics of GEF through lipid analysis and insulin secretion. First, GEF contains a large amount of linoleic acid (C18:2), PA 16:0-18:2, and LPA C18:2 compared with other lipids. Second, the main fatty acid component of LPLs and PLs is linoleic acid (C18:2). Third, GEF stimulates insulin secretion not through LPA receptors. Finally, GEF contains bioactive lipids besides LPAs.

Cibotium barometz polysaccharides stimulate chondrocyte proliferation in vitro by promoting G1/S cell cycle transition

Cibotium barometz polysaccharides (CBPS) are one of the most important bioactive components extracted from the Cibotium barometz plant, which belongs to the Dicksoniaceae family. It has been widely used for the treatment of orthopedic diseases in traditional Chinese medicine. However, the molecular mechanisms behind the therapeutic effects of CBPS remain to be clarified. In the present study, the concentration of CBPS was detected by phenol-vitriol colorimetry. Furthermore, the effects stimulated by CBPS on the viability and G1/S cell cycle transition in primary chondrocytes from Sprague-Dawley rats were investigated. A cell viability assay demonstrated that chondrocyte proliferation may be enhanced by CBPS in a dose- and time-dependent manner. The mechanism underlying the promotion of chondrocyte cell cycle was suggested to involve the stimulation of G1 to S phase transition. To further confirm the results, reverse transcription-quantitative polymerase chain reaction and western blot analyses were used to detect the expression of mRNA and protein levels of cyclin D1, cyclin-dependent kinase 4 and retinoblastoma protein. The results suggested that CBPS may stimulate chondrocyte proliferation via promoting G1/S cell cycle transition. Since osteoarthritis is characterized by deficient proliferation in chondrocytes, the present study indicates that CBPS may potentially serve as a novel method for the treatment of osteoarthritis.