Characterization and Evaluation of the Pro-Coagulant and Immunomodulatory Activities of Polysaccharides from Bletilla striata

Self-healing, antioxidant, and antibacterial Bletilla striata polysaccharide-tannic acid dual dynamic crosslinked hydrogels for tissue adhesion and rapid hemostasis

Biomaterials capable of achieving effective sealing and hemostasis at moist wounds are in high demand in the clinical management of acute hemorrhage. Bletilla striata polysaccharide (BSP), a natural polysaccharide renowned for its hemostatic properties, holds promising applications in biomedical fields. In this study, a dual-dynamic-bonds crosslinked hydrogel was synthesized via a facile one-pot method utilizing poly(vinyl alcohol) (PVA)-borax as a matrix system, followed by the incorporation of BSP and tannic acid (TA). Chemical borate ester bonds formed around borax, coupled with multiple physical hydrogen bonds between BSP and other components, enhanced the mechanical properties and rapid self-healing capabilities. The catechol moieties in TA endowed the hydrogel with excellent adhesive strength of 30.2 kPa on the surface of wet tissues and facilitated easy removal without residue. Benefiting from the synergistic effect of TA and the preservation of the intrinsic properties of BSP, the hydrogel exhibited outstanding biocompatibility, antibacterial, and antioxidant properties. Moreover, it effectively halted acute bleeding within 31.3 s, resulting in blood loss of 15.6 % of that of the untreated group. As a superior hemostatic adhesive, the hydrogel in this study is poised to offer a novel solution for addressing future acute hemorrhage, wound healing, and other biomedical applications.

Cytochemical localization and synthesis mechanism of the glucomannan in pseudobulbs of Bletilla striata Reichb. f

The dried pseudobulbs of Bletilla striata, an important traditional Chinese medicine named BaiJi, have an extraordinary polysaccharide content and excellent prospects for medicinal effects. However, the distribution and molecular mechanism underlying biosynthesis are poorly understood. In this study, chemical and immunologic analyses were performed in representative tissues of B. striata, and the results showed that what are conventionally termed Bletilla striata polysaccharides (BSPs) are water-soluble polysaccharides deposited only in pseudobulbs. The structural component of BSPs is glucomannan, with a mannose:glucose mass ratio of ~3:2. BSPs are present in the parenchyma of the pseudobulbs in cells known as glucomannan idioblasts and distributed in the cytoplasm within cellular membranes, but are not contained in the vacuole. Comparative transcriptomics and bioinformatics analyses mapped the pathway from sucrose to BSP and identified BsGPI, BsmanA, and BsCSLAs as the key genes of BSP biosynthesis, suggesting that the functional differentiation of the cellulose synthase-like family A (CSLA) may be critical for the flow of glucomannan to the BSP or cell wall. Subsequently, virus-mediated gene silencing showed that silencing of two CSLAs (Bs03G11846 and Bs03G11849) led to a decrease in BSP content, and yeast two-hybrid and luciferase complementation experiments confirmed that four CSLAs (Bs03G11846, Bs03G11847, Bs03G11848, and Bs03G11849) can form homo- or heterodimers, suggesting that multiple CSLAs may form a large complex that functions in BSP synthesis. Our results provide cytological evidence of BSP and describe the isolation and characterization of candidate genes involved in BSP synthesis, laying a solid foundation for further research on its regulation mechanisms and the genetic engineering breeding of B. striata.

Activities of polysaccharide fractions from corn silk: Hemostatic, immune, and anti-lung cancer potentials

Corn silk is the stigma and style of corn and is rich in polysaccharides. Despite the extensive research on its polysaccharides, the hemostatic characteristics of effective parts and the related activities remain insufficiently explored. Corn silk polysaccharide (CSP) was extracted with hot water and purified using a diethylaminoethyl cellulose membrane. Then, it was separated with sephadex G-150 to obtain five fractions. These fractions were investigated for their potential in hemostasis, antioxidant, immune response, and anti-lung cancer activities. CSP-2, CSP-3, and CSP-4 significantly affected the coagulation indicators activated partial thromboplastin time (APTT) and thrombin time (TT) at 125-500 μg/mL. Corn silk flavonoids and saponins at 32.25 μg/mL significantly prolonged APTT, TT, and prothrombin time (PT). CSP-2, with potent antioxidant ability, approaches Vitamin C. At 25 μg/mL, CSPs nearly reached the phagocytosis of neutral red of lipopolysaccharides. The five fractions promoted the proliferation of RAW264.7 cells at 25-800 μg/mL and stimulated NO secretion at 25-100 μg/mL. CSP-2 also showed an 86 % inhibition rate effect on A549 at 200 μg/mL. These results indicate that CSP not only has hemostatic effects but also has immune and anti-lung cancer activities. Thus, it is a potential candidate compound with immune activity for managing bleeding in cancer.

Structural characterization and prebiotic activity of Bletilla striata polysaccharide prepared by one-step fermentation with Bacillus Licheniformis BJ2022

Bletilla striata polysaccharide (BP) is one of the main active ingredients in Orchidaceae plant Bletilla striata. BP has a high molecular weight, high viscosity, and complex diffusion, which is not conducive to the absorption and utilization of the human body. For the first time, we produced fermented Bletilla striata polysaccharide (FBP) with a low polymerization degree using Bacillus licheniformis BJ2022 one-step fermentation. FBP was a neutral polysaccharide with the molecular weight of 6790 Da. It was composed of glucose and mannose at a molar ratio of 1:2.7. The glycosidic bonds of FBP were composed of β-1,4-linked mannose, β-1,4-linked glucose and β-1,6-linked mannose according to methylation and NMR analysis. Compared with BP, FBP has a lower viscosity and higher solubility. The scanning electron microscopy results showed that the surface of FBP was porous and honeycomb-like. The rheology properties of FBP solution were close to non-Newtonian fluid. Using in vitro fermentation, we proved that FBP could regulate human gut microbiota and significantly increase the content of Bifidobacterium and Bacteroides. Our results suggested that Bacillus licheniformis fermentation significantly improved the physical and prebiotic properties of FBP. This study provides a new strategy for developing and utilizing Bletilla striata resources in China.

Kuijie decoction ameliorates ulcerative colitis by affecting intestinal barrier functions, gut microbiota, metabolic pathways and Treg/Th17 balance in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Currently, the clinical treatment is limited and difficult to achieve satisfactory results for ulcerative colitis (UC). The role of traditional Chinese medicine (TCM) in the treatment of UC is very complex. Kuijie decoction (KJD) as a classic TCM, is widely used in the clinical treatment of UC, but the mechanism of its action is still unclear.

AIM OF THE STUDY

This study is to investigate the protective effects of KJD on UC and the underlying mechanisms.

MATERIALS AND METHODS

The experimental model of UC was induced by DSS, and KJD was introduced into the model at the same time. Clinical symptoms, including the body weight, colon length and colon histopathological, were used to measure the severity of colitis. The expression of inflammatory cytokines and tight junction proteins was quantified. The effect of KJD on intestinal flora and intestinal metabolism was determined by 16S rRNA and untargeted metabolomics analysis, respectively. The proportion of Th17 cells and Tregs in the spleen was examined by flow cytometry.

RESULTS

Mice treated with KJD showed significantly alleviated clinical symptoms and histological damage, such as more body weight gain, lower disease activity index (DAI) score, and longer colon length. The administration of KJD also led to the down-regulation of inflammatory mediators, upregulation of the expression of ZO-1, occludin and decreased claudin-2, as well as altered microbiota composition against DSS challenges (especially an increase of Lachnospiraceae). KJD enhanced the percentage of Treg cells but decreased the proportion of Th17 cells to maintain intestinal homeostasis by improving gut microbiota metabolism.

CONCLUSIONS

In summary, KJD maintained intestinal epithelial homeostasis by regulating epithelial barrier function, intestinal flora, and restoring Th17/Treg balance. KJD has the potential to be a Chinese medicine treatment for UC.

Dual properties of pharmacological activities and preparation excipient: Bletilla striata polysaccharides

Bletilla striata has been used for thousands of years and shows the functions of stopping bleeding, reducing swelling, and promoting healing in traditional applications. For Bletilla striata, Bletilla striata polysaccharides (BSP) is the main active ingredient, exhibiting biological functions of anti-inflammatory, anti-oxidant, anti-fibrotic, immune modulation, anti-glycation, and so on. In addition, BSP has exhibited the characteristics of excipient such as bio-adhesion, bio-degradability, and bio-safety and has been prepared into a series of preparations such as nanoparticles, microspheres, microneedles, hydrogels, etc. BSP, as both a drug and an excipient, has already aroused more and more attention. In this review, publications in recent years related to the extraction and identification, biological activities, and excipient application of BSP are reviewed. Specifically, we focused on the advances in the application of BSP as a formulation excipient. We hold opinion that BSP not only needed more researches in the mechanisms, but also the development into hydrogels, nano-formulations, tissue engineering, and so on. And we believe that this paper provides a beneficial reference for further BSP innovation and in-depth research and promotes the use of these natural products in pharmaceutical applications.

Structural characterization of a water-soluble acidic polysaccharide CSP-IV with potential anticoagulant activity from fruit pulp of Clausena lansium (Lour.) Skeels Guifei

Four main water-soluble wampee fruit pulp polysaccharides, named CSP-I, CSP-II, CSP-III and CSP-IV, were isolated from Clausena lansium (Lour.) Skeels Guifei, therein CSP-IV content was higher than the others. All components possess certain anticoagulant activity demonstrated by prolonged activated partial thromboplastin time, especially CSP-IV, which suggests that CSP-IV plays anticoagulant effect through disturbing intrinsic coagulation pathway. The wampee polysaccharide CSP-IV with Mw of 510.1 kDa was mainly composed of Gal, Ara and GalA. Backbone of CSP-IV contains Gal, Ara and GalA, two kinds of side chains contain one monosaccharide Gal or Ara, both branch on Gal residue of backbone. CSP-IV has no the conformation of triple helix demonstrated by Congo red test. These results showed that CSP-IV is an acidic polysaccharide with potential anticoagulant activity via targeting intrinsic coagulation pathway.

Antimicrobial Activity of Stilbenes from Bletilla striata against Cutibacterium acnes and Its Effect on Cell Membrane

The abnormal proliferation of Cutibacterium acnes is the main cause of acne vulgaris. Natural antibacterial plant extracts have gained great interest due to the efficacy and safety of their use in skin care products. Bletilla striata is a common externally used traditional Chinese medicine, and several of its isolated stilbenes were reported to exhibit good antibacterial activity. In this study, the antimicrobial activity of stilbenes from B. striata (BSS) against C. acnes and its potential effect on cell membrane were elucidated by determining the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), bacterial growth curve, adenosine triphosphate (ATP) levels, membrane potential (MP), and the expression of genes related to fatty acid biosynthesis in the cell membrane. In addition, the morphological changes in C. acnes by BSS were observed using transmission electron microscopy (TEM). Experimentally, we verified that BSS possessed significant antibacterial activity against C. acnes, with an MIC and MBC of 15.62 μg/mL and 62.5 μg/mL, respectively. The growth curve indicated that BSS at 2 MIC, MIC, 1/2 MIC, and 1/4 MIC concentrations inhibited the growth of C. acnes. TEM images demonstrated that BSS at an MIC concentration disrupted the morphological structure and cell membrane in C. acnes. Furthermore, the BSS at the 2 MIC, MIC, and 1/2 MIC concentrations caused a decrease in the intracellular ATP levels and the depolarization of the cell membrane as well as BSS at an MIC concentration inhibited the expression of fatty acid biosynthesis-associated genes. In conclusion, BSS could exert good antimicrobial activity by interfering with cell membrane in C. acnes, which have the potential to be developed as a natural antiacne additive.

Polysaccharides from waste Zingiber mioga leaves: Ultrasonic-microwave-assisted extraction, characterization, antioxidant and anticoagulant potentials

Zingiber mioga is a highly economic crop that is used to produce vegetables, spices and herbal pharmaceuticals. Its edible flower bud contributes most to the economic value, but the big leaves were discarded as agricultural waste, which urgently needs to be exploited. In this work, polysaccharides from waste Z. mioga leaves (PWZMLs) were extracted using ultrasonic-microwave-assisted extraction (UMAE). After purification and characterization, the antioxidation and anticoagulation of PWZMLs were evaluated to appraise the potential in cardiovascular protection. Under the liquid-solid ratio of 26: 1 mL/g, after ultrasonication at 495 W for 10 min, followed by microwaving at 490 W for 5 min, the yield of PWZMLs achieved to 6.22 ± 0.14 %, notably higher (P < 0.01) than other methods, and ultrasound contributed more to the yield than microwave. Various analyses confirmed that PWZMLs were negatively charged polysaccharides with galacturonic acid the dominant uronic acid. PWZMLs exerted excellent antioxidant capacity, especially for scavenging 1, 1-diphenyl-2-picrylhydrazyl radical. PWZMLs also elicited promising anticoagulant property, particularly for prolonging activated partial thromboplastin time and lowering fibrinogen, which were almost equivalent to heparin at the same concentration. PWZMLs contained two polysaccharide fractions (199.53 and 275.42 kDa) that could synergistically contribute to the pronounced antioxidant and anticoagulant activities. The PWZMLs extracted with optimized UMAE have great potential in cardiovascular protection.

Extraction, structural-activity relationships, bioactivities, and application prospects of Bletilla striata polysaccharides as ingredients for functional products: A review

Bletilla striata is a well-known medicinal plant with high pharmaceutical and ornamental values. Polysaccharide is the most important bioactive ingredient in B. striata and has various health benefits. Recently, B. striata polysaccharides (BSPs) have attracted much attention from industries and researchers due to their remarkable immunomodulatory, antioxidant, anti-cancer, hemostatic, anti-inflammatory, anti-microbial, gastroprotective, and liver protective effects. Despite the successful isolation and characterization of B. striata polysaccharides (BSPs), there is still limited knowledge regarding their structure-activity relationships (SARs), safety concerns, and applications, which hinders their full utilization and development. Herein, we provided an overview of the extraction, purification, and structural features, as well as the effects of different influencing factors on the components and structures of BSPs. We also highlighted and summarized the diversity of chemistry and structure, specificity of biological activity, and SARs of BSP. The challenges and opportunities of BSPs in the food, pharmaceutical, and cosmeceutical fields are discussed, and the potential development and future study direction are scrutinized. This article provides comprehensive knowledge and underpinnings for further research and application of BSPs as therapeutic agents and multifunctional biomaterials.

In vitro digestion and human gut microbiota fermentation of Bletilla striata polysaccharides and oligosaccharides

Background

Bletilla striata is one of the commonly used traditional Chinese medicine. B. striata polysaccharides (BP) and oligosaccharides (BO) are one of the main components of B. striata, which have been proved to have a variety of biological activities. However, the digestion and fermentation characteristics of BP and BO are still unclear.

Methods

The study evaluated different prebiotic effects of BP and BO by in vitro simulating digestion and gut microbiota fermentation.

Results

The results show that the simulating saliva partly degraded BP, but had no effect on BO. The molecular weights of BP and BO remained basically unchanged in gastric and intestinal digestion. In addition, BP and BO could be rapidly degraded and utilized by gut microbiota. During in vitro fermentation, the growth rates of the BP and BO groups were higher than that of the Control group and the pH value and total carbohydrate content in BP group and BO group decreased significantly. Although the reducing sugar level in the BO group decreased rapidly, it remained at a low level in the BP group. Both BP and BO improved the composition and structure of gut microbiota, indicative of the upregulated abundances of Streptococcus and Veillonella, and the downregulated populations of Escherichia and Bacteroides. There were differences in the SCFA production by gut microbiota and antioxidant activities between the BP and BO groups. The fermentation broth of the BP group displayed a stronger suppression of O₂-, but a higher scavenging effect on DPPH for the BO group.

Conclusions

BP and BO displayed different digestion and fermentation characteristics in vitro due to their distinct polymerization degrees. The study point towards the potential of BP and BO as prebiotics in the application to human diseases by selectively regulating gut microbiota in the future.

Microwave-Assisted Enzymatic Extraction, Partial Characterization, and Antioxidant Potential of Polysaccharides from Sagittaria trifolia Tuber

Sagittaria trifolia tuber is an aquatic vegetable. In this work, microwave-assisted enzymatic extraction (MEE) was used to extract S. trifolia tuber polysaccharides (STTPs). Optimum conditions were complex enzyme of 2 %, liquid-to-solid ratio of 43 : 1 mL g^-1 , microwave power of 506 W, and time of 8 min, under which STTPs yield was 36.22±0.69 %, higher than those of other methods. STTPs were sulfated polysaccharides with sulfur valence of S⁶⁺ . STTPs comprised mannose, glucose, galactose, and arabinose at a mole ratio of 3.69 : 19.33 : 6.21 : 1.00, molecular weights of 3606 kDa and 149.6 kDa, particle size of 220 nm, and zeta potential of -5.02 mV. The surface of STTPs was full of bumps and holes, and abundant in O1s and non-functionalized C1s. STTPs would scavenge reactive oxygen species with advantage. It would provide an efficient MEE method to obtain antioxidant STTPs, also a clue for extracting polysaccharides from starch-rich crops.

A new polysaccharide platform constructs self-adjuvant nanovaccines to enhance immune responses

Background

Nanovaccines have shown the promising potential in controlling and eradicating the threat of infectious diseases worldwide. There has been a great need in developing a versatile strategy to conveniently construct diverse types of nanovaccines and induce potent immune responses. To that end, it is critical for obtaining a potent self-adjuvant platform to assemble with different types of antigens into nanovaccines.

Results

In this study, we identified a new natural polysaccharide from the rhizomes of Bletilla striata (PRBS), and used this polysaccharide as a platform to construct diverse types of nanovaccines with potent self-adjuvant property. In the construction process of SARS-CoV-2 nanovaccine, PRBS molecules and RBD protein antigens were assembled into ~ 300 nm nanoparticles by hydrogen bond. For HIV nanovaccine, hydrophobic effect dominantly drove the co-assembly between PRBS molecules and Env expression plasmid into ~ 350 nm nanospheres. Importantly, PRBS can potently activate the behaviors and functions of multiple immune cells such as macrophages, B cells and dendritic cells. Depending on PRBS-mediated immune activation, these self-adjuvant nanovaccines can elicit significantly stronger antigen-specific antibody and cellular responses in vivo, in comparison with their corresponding traditional vaccine forms. Moreover, we also revealed the construction models of PRBS-based nanovaccines by analyzing multiple assembly parameters such as bond energy, bond length and interaction sites.

Conclusions

PRBS, a newly-identified natural polysaccharide which can co-assemble with different types of antigens and activate multiple critical immune cells, has presented a great potential as a versatile platform to develop potent self-adjuvant nanovaccines.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01533-3.

Structural characterization and preventive effect on non-alcoholic fatty liver disease of oligosaccharides from Bletilla striata

In this study, Bletilla striata polysaccharides were degraded into oligosaccharides. The structural features were analyzed by HPLC, HPLC-MS, FT-IR, and NMR spectroscopy. The results indicated that Bletilla striata oligosaccharides (BOs) were composed of mannose and glucose with a molar ratio of 5.2 : 1, and the main backbones of BOs contained (1→4)-linked-α-D-Man, (1→2)-linked-α-D-Man, and (1→2)-linked-α-D-Glc. By using a high-fat diet (HFD)-induced mouse model, we demonstrated that BOs had an improving effect on non-alcoholic fatty liver disease (NAFLD). Using the metabolomics assay, we found that BOs significantly regulated the hepatic metabolism of fatty acids, arachidonic acid, and other related metabolites in HFD-fed mice, accompanied by the reduction of lipid accumulation and fibrosis in liver tissues. In summary, BOs displayed high potential for the treatment of NAFLD as a functional food.

Structural characterization of a pure polysaccharide from Bletilla striata tubers and its protective effect against H2O2-induced injury fibroblast cells

The present study investigated the structural characteristics and its protective effect against H₂O₂-induced injury fibroblast cells of Bletilla striata tuber polysaccharide. The polysaccharides were gently extracted by water and recovered using the method of alcohol precipitation, and after further purification by DEAE-Sepharose Fast Flow gel column, a pure polysaccharide (pBSP) was finally obtained. The structural characterization of pBSP were investigated by using periodate oxidation studies, Smith-degradation, FT-IR spectroscopy, 1D and 2D NMR spectroscopy. The antioxidant effect of pBSP was evaluated by inhibiting the production of reactive oxygen species (ROS) in human fibroblast model cells induced by H₂O₂. It was firstly reported that pBSP was composed of d-glucose and D-mannose in a molar ratio of 1.00:1.34 with a molecular weight of 327.6 kDa. The repeating units of pBSP contained (1 → 4)-linked-β-D-Manp, (1 → 4)-linked-α-D-Glcp and (1 → 3)-linked-β-D-Manp, and there was no branched chain. pBSP exhibited no toxic effect on fibroblasts cells and could protect them against H₂O₂-induced injuries. After pretreatment with pBSP for 24 h, the content of ROS in fibroblasts decreased significantly. These results not only confirm the availability B. striata, but also indicate that pBSP have potential antioxidant capacity. Our observations can provide foundation for further development of pBSP-based cosmetics.