Polysaccharides from Bupleurum chinense impact the recruitment and migration of neutrophils by blocking fMLP chemoattractant receptor-mediated functions

Study on characterization of Bupleurum chinense polysaccharides with antioxidant mechanisms focus on ROS relative signaling pathways and anti-aging evaluation in vivo model

This study explored the structures of three polysaccharides from Bupleurum chinense DC. (BCPRs), and evaluated their antioxidant and anti-aging properties. The HPGPC and ion chromatography analyses revealed that the molecular weights of the BCPRs ranged from 12.05 to 21.20 kDa, and were primarily composed of rhamnose, arabinose, xylose, galactose, glucose and galacturonic acid. Methylation and NMR studies identified 10 PMAAs, establishing the various backbones of BCPRs 1-3. BCPR-3 demonstrated potent antioxidant activities, including DPPH, ABTS, hydroxy, and superoxide radicals scavenging in vitro. At concentrations between 125 and 500 μg/mL, BCPR-3 increased T-AOC, SOD and GSH-Px activities, while decreasing MDA levels in H2O2-induced SH-SY5Y cells. In addition, RNA-seq results indicated that BCPR-3 considerably downregulated the expression of 49 genes and upregulated five genes compared with the control group. KEGG analysis suggested that these differentially expressed genes (DEGs) were predominantly involved in the TNF and PI3K/Akt signaling pathways. Furthermore, in vivo experiment with Drosophila melanogaster showed that BCPR-3 could extend the average lifespan of flies. In conclusion, polysaccharides from B. chinense exhibited potential antioxidant and anti-aging activities, which could be developed as new ingredients to combat oxidative stress damage and slow the aging process.

Comparative Study on Anti-Inflammatory Effect of Polysaccharides from Vinegar-Baked Radix Bupleuri Using Different Methods

The impact of the extraction method on the physiochemical characteristics and anti-inflammatory effect of polysaccharides from vinegar-baked Radix Bupleuri (VBCPs) was studied. Five extraction methods were employed to obtain the VBCPs: hot water extraction (HW), ultrasound-assisted extraction (UA), enzyme-assisted extraction (EA), citric acid-assisted extraction (CA), and ammonia-assisted extraction (KA). The results showed that the extraction method affects the yield, characteristics, and anti-inflammatory effect of the polysaccharides significantly. KA produced the highest yield, Ara content, and the strongest effect of enhancing IL-10 secretion. VBCP-EA exhibited the largest molecular weight (Mw), the highest Man content, and the poorest effect on inhibiting NO, VBCP-UA possessed more Gal than other VBCPs, the lowest Mw, and a comparable effect on inhibiting NO and TNF-α with VBCP-KA and VBCP-CA. All VBCP self-assembled into nanoparticles in solutions, and VBCP-KA presented the lowest particle size. The structure-activity analysis showed that Mw and Man content are negatively correlated and Ara content is positively correlated with the NO inhibition and IL-10 secretion effects; Rha and Gal A content are positively correlated and Glu is negatively correlated with the TNF-α inhibiting effect. The above results indicated that KA is an efficient method for obtaining anti-inflammatory VBCP, which provides new insight into the extraction of VBCP.

A comprehensive review on traditional and modern research of the genus Bupleurum (Bupleurum L., Apiaceae) in recent 10 years

ETHNOPHARMACOLOGICAL RELEVANCE

The genus Bupleurum (family Apiaceae), comprising approximately 248 accepted species, is widely distributed and used in China, Japan, India, Central Asia, North Africa and some European countries as traditional herbal medicines. Certain species have been reported to have significant therapeutic effects in fever, inflammatory disorders, cancer, gastric ulcer, virus infection and other diseases.

AIM OF THE REVIEW

we performed a comprehensive review of the ten-year research progress in phytochemistry, pharmacology, toxicity, along with bibliometrics research of the genus Bupleurum, aiming to identify knowledge gaps for future research.

MATERIALS AND METHODS

All the literatures are retrieved from library and electronic sources including Web of Science, PubMed, Elsevier, Google Scholar, CNKI and Baidu Scholar. These papers cover studies of the traditional use, phytochemistry, pharmacology, and toxicology of the genus Bupleurum.

RESULTS

There is a long history of using the genus Bupleurum in traditional herbal medicine that dated back to over 2000 years ago. Twenty-five species and 8 varieties with 3 variants within this genus have been reported to be effective to treat fever, pain, liver disease, inflammation, thoracolumbar pain, irregular menstruation and rectal prolapse. The main phytochemicals found in these plants are triterpene saponins, volatile oil, flavonoid, lignans, and polysaccharides. Many of these compounds have also been shown to have anti-inflammatory, anti-tumor, antimicrobial, immunoregulation, neuroregulation, hepatoprotective and antidiabetic activities. Meanwhile, improper usage of Bupleurum may induce cytotoxic effects, and polyacetylenes may be the main poisonous compounds.

CONCLUSIONS

This article summarized recent findings about Bupleurum research from many different aspects. While a small number of Bupleurum species have been investigated through modern pharmacology methods, there are still major knowledge gaps due to inadequate studies and ambiguous findings. Future research could focus on more specific phytochemistry studies combined with mechanistic analysis to provide better guidance to utilize Bupleurum as medicinal resources.

Extraction, purification, structure characteristics, biological activities and pharmaceutical application of Bupleuri Radix Polysaccharide: A review

Bupleuri Radix (BR), as a well-known plant medicine of relieving exterior syndrome, has a long history of usage in China. Bupleuri Radix Polysaccharide (BRP), as the main component and an important bioactive substance of BR, has a variety of pharmacological activities, including immunoregulation, antioxidant, antitumor, anti-diabetic and anti-aging, etc. In this review, the advancements on extraction, purification, structure characteristics, biological activities and pharmaceutical application of BRP from different sources (Bupleurum chinense DC., Bupleurum scorzonerifolium Willd., Bupleurum falcatum L. and Bupleurum smithii Woiff. var. Parvifolium Shan et Y. Li.) are summarized. Meanwhile, this review makes an in-depth discussion on the shortcomings of the research on BRP, and new valuable insights for the future researches of BRP are proposed.

Clarification of the structural features of Rhamnogalacturonan-I type polysaccharide purified from radish leaves

Determining the structure of REPI, an immunostimulatory polysaccharide fraction from radish leaves, is an important health objective. Herein, we show that REP-I contains nine different monosaccharides, including GalA (22.2%), Gal (32.6%), Ara (27.5%), and Rha (10.2%) as main sugars. REP-I was also reacted with β-glucosyl Yariv reagent (29.8%), suggesting the presence of the arabino-β-3,6-galactan. Furthermore, methylated-product analysis revealed that REP-I contains 13 different glycosyl linkages, including 4-linked GalpA (21.0%), 2,4-linked Rhap (7.0%), 4-linked Galp (5.8%), 5-linked Araf (10.1%), and 3,6-linked Galp (7.9%), which are characteristic of RG-I. Microstructural information was obtained by sequential degradation using four linkage-specific glycosylases and β-elimination, with fragments analyzed on the basis of sugar composition, methylation, and MS/MS spectra. The results show that the immunostimulatory activity of REP-I is possibly due to the structure of RG-I, which is composed of a main chain with repeating [→2)-Rhap-(1 → 4)-GalpA-(1→] linkage units and three side-chains: a branched α(1 → 5)arabinan, a β(1 → 4)galactan, and arabino-β-3,6-galactan, which are branched at the C(O)4 position of each Rha residue in the REP-I main chain.

Physicochemical characterization of Sargassum fusiforme fucoidan fractions and their antagonistic effect against P-selectin-mediated cell adhesion

P-selectin, mediated adhesion between endothelium and neutrophils, is a promising target for the therapeutics of acute inflammatory-related diseases. It is reported that brown algal fucoidans can antagonize P-selectin function. However, the fractionation and physicochemical characterization of Sargassum fusiforme fucoidan, and the screening of fucoidan fractions with P-selectin antagonistic capability have not been investigated. In this study, we isolated and fractionated systematically the S. fusiforme fucoidan by ion-exchange chromatography and size exclusion chromatography to obtain eight fucoidan fractions. Their physicochemical characterization was determined by chemical methods, HPLC and FT-IR. The inhibitory capacity of the fucoidan fractions in P-selectin-mediated leukocyte adhesion was evaluated by static adhesion assay and parallel-plate flow chamber. Results showed that fucoidan fractions possessed distinct physicochemical properties, including total carbohydrate, uronic acid and sulfate contents, molecular weight, and monosaccharide compositions. Among all the fucoidan fractions, SFF-32 and SFF-42 showed better blocking ability against P-selectin-mediated cell adhesion.

Polysaccharides from Bupleurum Induce Immune Reversal in Late Sepsis

BACKGROUND

Bupleurum chinense, a well-known Traditional Chinese Medicine, has been used for thousands of years in China. In this study, we would suggest that Bupleurum polysaccharides (BPS) could improve the prognosis of sepsis through its impact on redistribution of BMCs, which triggers immune reversal in late sepsis.

METHODS

BALB/c mice were divided into five groups: sham burn group, burn plus P aeruginosa group, burn plus P aeruginosa with BPS (40 mg/kg, 100 mg/kg, and 250 mg/kg) treatment group, and they were sacrificed at post-burn day (PBD) 0, 3, 5, and 7. BMCs, liver cells, and dendritic cells (DCs) were harvested. Flow cytometry was used to determine the change of phenotypes of DCs and isolate these cells. Cytometric beads array was utilized to analyze the level of inflammatory factors. Cell therapy of BMCs, liver cells, and DCs was administrated to explore the protective role of regional organ immunity.

RESULTS

BPS could decrease the lethality of burn sepsis in a dose-dependent fashion and increase both the percentage of CD11cCD45RB DCs in bone marrow (BM) and liver and the number of BMCs and liver cells significantly. Cell therapy of BMCs, liver cells, and CD11cCD45RB DCs at PBD7 could protect septic mice from sepsis.

CONCLUSION

BPS has shown its potential in promoting the prognosis of post-burn sepsis through its effect on immune redistribution of BMCs, especially via differentiation of CD11cCD45RB DC cells in BM and nonimmune organs to induce immune reversal in late sepsis.

A systematic review of the active saikosaponins and extracts isolated from Radix Bupleuri and their applications

CONTEXT

Radix Bupleuri has been used in traditional Chinese medicine for over 2000 years with functions of relieving exterior syndrome, clearing heat, regulating liver-qi, and lifting yang-qi. More natural active compounds, especially saikosaponins, have been isolated from Radix Bupleuri, which possess various valuable pharmacological activities.

OBJECTIVE

To summarize the current knowledge on pharmacological activities, mechanisms and applications of extracts and saikosaponins isolated from Radix Bupleuri, and obtain new insights for further research and development of Radix Bupleuri.

METHODS

PubMed, Web of Science, Science Direct, Research Gate, Academic Journals and Google Scholar were used as information sources through the inclusion of the search terms 'Radix Bupleuri', 'Bupleurum', 'saikosaponins', 'Radix Bupleuri preparation', and their combinations, mainly from the year 2008 to 2016 without language restriction. Clinical preparations containing Radix Bupleuri were collected from official website of China Food and Drug Administration (CFDA).

RESULTS AND CONCLUSION

296 papers were searched and 128 papers were reviewed. A broad spectrum of in vitro and in vivo research has proved that Radix Bupleuri extracts, saikosaponin a, saikosaponin d, saikosaponin c, and saikosaponin b₂, exhibit evident anti-inflammatory, antitumor, antiviral, anti-allergic, immunoregulation, and neuroregulation activities mainly through NF-κB, MAPK or other pathways. 15 clinical preparations approved by CFDA remarkably broaden the application of Radix Bupleuri. The main side effect of Radix Bupleuri is liver damage when the dosage is excess, which indicates that the maximum tolerated dose is critical for clinical use of Radix Bupleuri extract and purified compounds.

c-Abl tyrosine kinase regulates neutrophil crawling behavior under fluid shear stress via Rac/PAK/LIMK/cofilin signaling axis

The excessive recruitment and improper activation of polymorphonuclear neutrophils (PMNs) often induces serious injury of host tissues, leading to inflammatory disorders. Therefore, to understand the molecular mechanism on neutrophil recruitment possesses essential pathological and physiological importance. In this study, we found that physiological shear stress induces c-Abl kinase activation in neutrophils, and c-Abl kinase inhibitor impaired neutrophil crawling behavior on ICAM-1. We further identified Vav1 was a downstream effector phosphorylated at Y174 and Y267. Once activated, c-Abl kinase regulated the activity of Vav1, which further affected Rac1/PAK1/LIMK1/cofilin signaling pathway. Here, we demonstrate a novel signaling function and critical role of c-Abl kinase during neutrophil crawling under physiological shear by regulating Vav1. These findings provide a promising treatment strategy for inflammation-related disease by inactivation of c-Abl kinase to restrict neutrophil recruitment.

Advances on Bioactive Polysaccharides from Medicinal Plants

In recent decades, the polysaccharides from the medicinal plants have attracted a lot of attention due to their significant bioactivities, such as anti-tumor activity, antioxidant activity, anticoagulant activity, antidiabetic activity, radioprotection effect, anti-viral activity, hypolipidemic and immunomodulatory activities, which make them suitable for medicinal applications. Previous studies have also shown that medicinal plant polysaccharides are non-toxic and show no side effects. Based on these encouraging observations, most researches have been focusing on the isolation and identification of polysaccharides, as well as their bioactivities. A large number of bioactive polysaccharides with different structural features and biological effects from medicinal plants have been purified and characterized. This review provides a comprehensive summary of the most recent developments in physiochemical, structural features and biological activities of bioactive polysaccharides from a number of important medicinal plants, such as polysaccharides from Astragalus membranaceus, Dendrobium plants, Bupleurum, Cactus fruits, Acanthopanax senticosus, Angelica sinensis (Oliv.) Diels, Aloe barbadensis Miller, and Dimocarpus longan Lour. Moreover, the paper has also been focused on the applications of bioactive polysaccharides for medicinal applications. Recent studies have provided evidence that polysaccharides from medicinal plants can play a vital role in bioactivities. The contents and data will serve as a useful reference material for further investigation, production, and application of these polysaccharides in functional foods and therapeutic agents.

Anvillea garcinii extract inhibits the oxidative burst of primary human neutrophils

BACKGROUND

Anvillea garcinii Coss. & Durieu (Anv) plant is used as a traditional North African medicine against several diseases associated with inflammation. At inflammatory sites, reactive oxygen species (ROS) produced in excess by activated phagocyte NADPH oxidase (NOX2) can accentuate inflammatory responses. Thus, we investigated if Anv-water soluble polysaccharides could modulate primary human neutrophil oxidative burst in vitro.

METHODS

Human neutrophils were isolated from fresh whole blood and O₂^.- generation was measured by cytochrome c reduction assays. Western blots were used to analyse the translocation of PKC, p47^phox (a key component of NOX2 activity) to neutrophil plasma membrane. Also, myeloperoxidase (MPO) release in the extracellular medium was studied by western blots. Flow cytometric analysis was used to detect CD11b membrane expression.

RESULTS

Water soluble polysaccharides from Anv dose-dependently inhibited N-formyl-methionyl-leucyl-phenylalanine (fMLF)- and phorbol myristate acetate (PMA)-induced O₂^.- generation by human neutrophils. Moreover, Anv-polysaccharides strongly inhibited PMA-induced PKCβ and p47^phox translocation to membranes and p47^phox phosphorylation on Ser328, a main PKC target. In contrast, polysaccharides extract from Zygophyllum gaetulum plant, which is also used as a traditional North African medicine against inflammatory diseases, was ineffective on this PKCβ-p47phox pathway. Further, Anv inhibited important neutrophil degranulation markers corresponding to myeloperoxidase (MPO) release and CD11b membrane expression.

CONCLUSION

The process of down-regulating NADPH oxidase by polysaccharides extracts from Anv provides new insights into the mechanism of Anv's anti-inflammatory actions.

Characterization of a polysaccharide from Rosa davurica and inhibitory activity against neutrophil migration

The rapid recruitment of neutrophils from peripheral blood into infected sites is critical step for inflammatory responses; however, the excessive and improper recruitment can lead to serious tissue damages. Thus, it is a promising strategy to inhibit their excessive recruitment for treating inflammation-related disease. Here, we isolated a polysaccharide (RDPA1) from Rosa davurica, to evaluate its physicochemical property and inhibitory effects on neutrophil migration. RDPA1 was obtained by hot-water extraction, ethanol precipitation, and fractionated by DEAE-cellulose and Sepharose CL-6B columns. RDPA1 significantly inhibited in vitro migration of human neutrophils evaluated by transwell chamber and impacted the migratory behavior observed by time-lapsed microscopy, we found the migrated distance and average velocity of RDPA1-treated cells were greatly reduced. In addition, RDPA1 treatment impaired in vivo neutrophil infiltration in the peritonitis mice. RDPA1 exhibited significant blocking capacity of the interaction between β2 integrins and ICAM-1 evaluated by flow cytometry and in vitro protein binding assay. Together, these results suggest RDPA1 could be considered as a potential candidate for developing a novel anti-inflammatory agent.

Inhibitory function of P-selectin-mediated leukocyte adhesion by the polysaccharides from Sanguisorba officinalis

CONTEXT

P-selectin is a promising target for inflammatory-related diseases. Polysaccharides are the active ingredients of Sanguisorba officinalis L. (Rosaceae) responsible for its anti-inflammatory activities; however, the molecular mechanism is not clear yet.

OBJECTIVE

This study evaluates the effects of polysaccharides (SOPs) from Sanguisorba officinalis on their antagonistic function against P-selectin-mediated leukocyte adhesion.

MATERIALS AND METHODS

The antagonistic function of SOPs was investigated by flow cytometry and static adhesion assay at the concentrations of 25 and 100 μg/ml. The dynamic interaction between HL-60 cells and CHO-P cell monolayer treated with SOPs (25 and 100 μg/ml) was analyzed in a parallel plate flow chamber, and quantitatively calculated by ImageJ software (NIH, Bethesda, MD). In vitro protein binding assay was carried out to evaluate the blocking effects of SOPs (25 and 100 μg/ml) on the interaction between P-selectin and PSGL-1.

RESULTS

SOPs-treatment (100 μg/ml) significantly reduced the percentage of HL-60 cells binding to P-selectin (p < 0.01) determined by flow cytometry. In addition, SOPs (25 and 100 μg/ml) markedly blocked the adhesion between HL-60 cells and CHO-P cells under static condition, and the inhibitory rates reached 39.9% and 71.2%, respectively. Compared with the positive control group, SOPs-treatment (25 and 100 μg/ml) significantly reduced the percentage of HL-60 cells rolling on CHO-P cell monolayers by 43.5% and 75.2%, respectively. Protein binding assay showed the interaction between P-selectin and PSGL-1 was significantly blocked by SOPs.

DISCUSSION AND CONCLUSION

SOPs possess a significant antagonistic function against P-selectin-mediated leukocyte adhesion, and SOPs could be considered as a promising candidate for amelioration of inflammation-related diseases.

Comparison of root transcriptomes and expressions of genes involved in main medicinal secondary metabolites from Bupleurum chinense and Bupleurum scorzonerifolium, the two Chinese official Radix bupleuri source species

Radix bupleuri, roots of Bupleurum species, is a widely used traditional Chinese medicine. Here, we compared the root transcriptomes of both Bupleurum chinense DC. and Bupleurum scorzonerifolium Willd. A total of 313 483 and 342 263 high quality expressed sequence tags were obtained, respectively. In addition, 17 117 (59.2%) and 19 416 (62.8%) unigenes for B. chinense and B. scorzonerifolium had homologous genes in the opposite dataset. For B. chinense, Kyoto Encyclopedia of Genes and Genomes database (KEGG) annotation identified carbohydrate metabolism, energy metabolism and amino acid metabolism as the three highest groups in the metabolism category. For B. scorzonerifolium, the lipid metabolism group had the most unigenes. Genes that may participate in the biosynthesis of terpenoid, triterpenoid, sterol, lignan and flavonoids were identified according to their annotations. (Tri)terpenoid-related genes were predominantly found in B. chinense. The expressions of certain genes were analyzed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) in the roots of the two species. A total of 558 putative transcription factors (TFs) and 137 transcriptional regulators (TRs) among 1364 TFs and 327 TRs, and 610 TFs and 129 TRs among 1600 TFs and 323 TRs were specific for B. chinense and B. scorzonerifolium, respectively. Our transcriptome comparison reflects the different types and proportions of metabolites synthesized by the two species. The data, especially, those genes involved in the biosynthesis of particular types of metabolites, will provide the basis for further investigations of the secondary metabolite repertoire of the two Bupleurum species, as well as other species from the genus of Bupleurum.

Inhibition of inflammatory injure by polysaccharides from Bupleurum chinense through antagonizing P-selectin

P-selectin-mediated adhesion between endothelium and neutrophils is a crucial process leading to acute inflammatory injure. Thus, P-selectin has been considered as promising target for therapeutics of acute inflammatory-related diseases. In the present study, the water-soluble polysaccharides (BCPs) were isolated from Bupleurum chinense, and we evaluated their therapeutical effects on acute inflammatory injure and antagonistic function against P-selectin-mediated neutrophil adhesion. Our results showed that BCPs significantly impaired the leukocyte infiltration and relieve lung injury in LPS-induced acute pneumonia model. BCPs significantly blocked the binding of P-selectin to neutrophils and inhibited P-selectin-mediated neutrophils rolling along CHO-P cell monolayer. The result from in vitro protein binding assay showed a direct evidence indicating that BCPs-treatment significantly eliminated the interaction between rhP-Fc and its physiological ligand PSGL-1 at protein level. Together, these results provide a novel therapeutical strategy for amelioration of inflammation-related disease processes by polysaccharides from B. chinense.