Isolation and evaluation of immunological adjuvant activities of saponins from the roots of Pulsatilla chinensis with less adverse reactions

Qualitative and quantitative analysis of triterpenoids in different tissues of Pulsatilla chinensis

Pulsatilla chinensis (P.chinensis) is a traditional Chinese medicine used for the treatment of intestinal amebiasis diseases, vaginal trichomoniasis and bacterial infections. Tritepenoid saponins were important components of P.chinensis. Therefore, we asssessmented expression profiling of triterpenoids in different fresh tissues of P.chinensis by ultra high performance liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) and ultra high performance liquid chromatography coupled to triple quadrupole mass spectrometry (UHPLC-QQQ-MS). Firstly, we identified 132 triterpenoids, including 119 triterpenoid saponins, 13 triterpenoid acids and forty seven of them were first determined in Pulsatilla genus, including new aglycones and new ways of rhamnose linking to the aglycone. Secondly, we established the analytical method to analysis triterpenoids content of P.chinensis and comprehensively verified the analytical method by linearity, precision, repeatability, stability and recovery. At last, we quantified 119 triterpenoids simultaneously based on UHPLC-QQQ-MS. The results show that the types and contents of triterpenoids had obvious tissue distribution. New components like rhamnose directly linked to the aglycone mainely distributed in aboveground tissues. Additionally, We identified 15 chemical ingredients as differential components between the aboveground and underground tissues of P.chinensis. This study provides an efficient analysis strategy for the qualitative and quantitative analysis of triterpenoids in P.chinensis even in other traditional Chinese medicines. At the same time, it provides important informations to explain the biosynthetic pathway of triterpenoid saponins in P.chinensis.

Evaluation of immunological adjuvant activities of saponin rich fraction from the fruits of Asparagus adscendens Roxb. with less adverse reactions

The hemolytic activity, in vitro as well as in vivo toxicity, and immunomodulatory potential of saponins-rich fraction of Asparagus adscendens Roxb. fruit (AA-SRF) have been assessed in this study in order to explore AA-SRF as an alternative safer adjuvant to standard Quil-A saponin. The AA-SRF showed lower hemolytic activity (HD₅₀ = 301.01 ± 1.63 µg/ml) than Quil-A (HD₅₀ = 17.15 ± 2.12 µg/ml). The sulforhodamine B assay also revealed that AA-SRF was less toxic to VERO cells (IC₅₀≥200 ± 4.32 µg/ml) than Quil-A (IC₅₀ = 60 ± 2.78 µg/ml). The AA-SRF did not lead to mortality in mice up to 1.6 mg and was much safer than Quil-A for in vivo use. Conversely, mice were subcutaneously immunized with OVA 100 μg alone or along with Alum (200 μg) or Quil-A (10 μg) or AA-SRF (50 μg/100 μg/200 μg) on days 0 and 14. The AA-SRF at 100 μg dose best supported the LPS/Con A primed splenocyte proliferation activity, elevated the serum OVA-specific total IgG antibody, IL-12, CD4 titer and upsurged CD3/CD19 expression in spleen as well as lymph node sections which in turn advocated its adjuvant potential. Thus, AA-SRF can be further studied for use as a safe alternative adjuvant in vaccines.

Potentials of saponins-based adjuvants for nasal vaccines

Respiratory infections are a major public health concern caused by pathogens that colonize and invade the respiratory mucosal surface. Nasal vaccines have the advantage of providing protection at the primary site of pathogen infection, as they induce higher levels of mucosal secretory IgA antibodies and antigen-specific T and B cell responses. Adjuvants are crucial components of vaccine formulation that enhance the immunogenicity of the antigen to confer long-term and effective protection. Saponins, natural glycosides derived from plants, shown potential as vaccine adjuvants, as they can activate the mammalian immune system. Several licensed human vaccines containing saponins-based adjuvants administrated through intramuscular injection have demonstrated good efficacy and safety. Increasing evidence suggests that saponins can also be used as adjuvants for nasal vaccines, owing to their safety profile and potential to augment immune response. In this review, we will discuss the structure-activity-relationship of saponins, their important role in nasal vaccines, and future prospects for improving their efficacy and application in nasal vaccine for respiratory infection.

Computational method for rapid screening of the metabolites of Pulsatilla chinensis in rats using UHPLC-Q-TOF/MS combined with mass spectrum-based orthogonal projection

Screening metabolites in vivo can be challenging due to the complexity of traditional Chinese medicine (TCM) and the ambiguous intracorporal process. To resolve this problem, we established the mass spectrum-based orthogonal projection (MSOP) method to differentiate prototype compounds from metabolites in vivo and applied it to the study of metabolites of Pulsatilla chinensis (PC). Initially, the validity and feasibility of the MSOP method were verified by using the ultra- high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-Q-TOF-MS) data of reference solution. Then, the MSOP method was applied to screen the metabolites of PC. A total of 63 metabolites were identified in vivo (urine, feces, bile, and plasma samples) and in vitro (intestinal bacteria biological sample). The results indicated that the main metabolic pathways of pentacyclic triterpenoids were demethylation, oxidation, dehydration, sulfation, and glucuronidation reactions. This study contributes to developing an integrated strategy based on chemometrics to characterize and classify the metabolism feature of pentacyclic triterpenoids of PC. This will support the scientific and rational application of PC in the clinic. The MSOP method based on the orthogonality of MS signals was used to differentiate the prototype compounds from metabolites in vivo. The method provides scientific and reliable support for fully understanding the metabolic fate of TCM.

Cooperative Interaction of Phenolic Acids and Flavonoids Contained in Activated Charcoal with Herb Extracts, Involving Cholesterol, Bile Acid, and FXR/PXR Activation in Broilers Fed with Mycotoxin-Containing Diets

The charcoal-herb extract complex (CHC) is a product of activated charcoal sorption of herb extracts that contain phenolic acids and flavonoids. The effective dose of CHC to promote animal growth is about one tenth of effective dosage of activated charcoal. The purpose of this study was to evaluate potential cooperative interactions between activated charcoal and herb extracts. Two feeding experiments were conducted. In Experiment 1, a responsive dose of CHC to broiler growth was determined to be 250 mg/kg of the diet. In Experiment 2, CHC increased growth performance and improved meat quality, but decreased indices of oxidative stress and inflammation as compared with similar doses of activated charcoal or herb extracts. CHC also increased concentrations of serum cholesterol, bile acid in the gallbladder, and bile acid in feces. The herb extracts present in CHC were largely represented by phenolic acids (PAs, caffeic acid, and vanillin) and flavonoids (FVs, daidzein, and quercetin-D-glucoside) in the detoxification activity of CHC in a mouse rescue test when the mice were gavaged with T-2 mycotoxin. PAs and FVs significantly increased the expression of CYP7A1, PXR, CYP3A37, Slco1B3, and Bsep in chicken primary hepatocytes. In conclusion, CHC integrated the cooperative interactions of activated charcoal and herb extracts via the FXR/RXR-PXR pathway to detoxify mycotoxins.

Effect of anemoside B4 on milk whey in clinical mastitis-affected cows elucidated using tandem mass tag (TMT)-based quantitative proteomics

Intramuscular injection of anemoside B4 (AB4) has a superior therapeutic effect on clinical mastitis in lactating cows. Here, we explored AB4's effect on milk whey in clinical mastitis-affected cows using proteomics. Among fifty clinical mastitis cows received AB4 administration (0.05 ml/kg/day, for 7 days), twelve healed cows were selected and marked as group T. Twelve clinically heathy cows received the same dose of saline for 7 days, marked as group C. Collected milk whey of group T before and after AB4 administration marked as T1 and T2, respectively. The milk whey of group C after saline injection marked as C1. Milk whey protein changes were detected using tandem mass tag-based quantitative proteomic. We identified 872 quantifiable proteins in the samples. Among them, 511 proteins between T1 and C1, and 361 proteins between T2 and T1 were significantly altered. T1 than C1 had significantly more proteins associated with inflammatory damage and trans-endothelial migration of leukocytes, whereas these proteins were reduced in T2 treated with AB4. Compared with C, proteins associated with fibrin clot degradation and complement system activation were downregulated in T1 but upregulated in T2. In summary, AB4 can exert its therapeutic effect on clinical mastitis in cows mainly by reducing inflammatory damage, activating the complement system, inhibiting trans-endothelial migration of leukocytes, and promoting degradation of milk fibrin clots.

Pharmacological activities and molecular mechanisms of Pulsatilla saponins

Saponins are found in a variety of higher plants and display a wide range of pharmacological activities, including expectorant, anti-inflammatory, vasoprotective and antimicrobial properties. Pulsatilla chinensis (P. chinensis, Bai Tou Weng, ) has been used medically in China for thousands of years for the treatment of diseases caused by bacteria, and it is rich in triterpenoid saponins. In recent decades, anemoside B4 (Pulchinenoside C) is well studied since it has been used as a quality control marker for P. chinensis. At the same time, more and more other active compounds were found in the genus of Pulsatilla. In this review, we summarize the pharmacological activities of Pulsatilla saponins (PS) and discuss the cellular or molecular mechanisms that mediate their multiple activities, such as inducing cancer cell apoptosis, inhibiting tumor angiogenesis, and protecting organs via anti-inflammatory and antioxidant measures. We aim to provide comprehensive analysis and summary of research progress and future prospects in this field to facilitate further study and drug discovery of PS.

Anemoside B4 inhibits enterovirus 71 propagation in mice through upregulating 14-3-3 expression and type I interferon responses

Enterovirus 71 (EV71) is the major pathogens of human hand, foot, and mouth disease (HFMD). EV71 efficiently escapes innate immunity responses of the host to cause infection. At present, no effective antiviral drugs for EV71 are available. Anemoside B4 (B4) is a natural saponin isolated from the roots of Pulsatilla chinensis (Bunge) Regel. P. chinensis extracts that shows a wide variety of biological activities. In this study, we investigated the antiviral activities of B4 against EV71 both in cell culture and in suckling mice. We showed that B4 (12.5-200 μM) dose dependently increased the viability of EV71-infected RD cells with an IC₅₀ value of 24.95 ± 0.05 μM against EV71. The antiviral activity of B4 was associated with enhanced interferon (IFN)-β response, since knockdown of IFN-β abolished its antiviral activity. We also confirmed that the enhanced IFN response was mediated via activation of retinoic acid-inducible gene I (RIG-I) like receptors (RLRs) pathway, and it was executed by upregulation of 14-3-3 protein, which disrupted the interaction between yes-associated protein (YAP) and interferon regulatory factor 3 (IRF3). By using amino acids in cell culture (SILAC)-based proteomics profiling, we identified the Hippo pathway as the top-ranking functional cluster in B4-treated EV71-infected cells. In vivo experiments were conducted in suckling mice (2-day-old) infected with EV71 and subsequently B4 (200 mg · kg^-1 · d^-1, i.p.) was administered for 16 days. We showed that B4 administration effectively suppressed EV71 replication and improved muscle inflammation and limb activity. Meanwhile, B4 administration regulated the expressions of HFMD biomarkers IL-10 and IFN-γ, attenuating complications of EV71 infection. Collectively, our results suggest that B4 could enhance the antiviral effect of IFN-β by orchestrating Hippo and RLRs pathway, and B4 would be a potential lead compound for developing an anti-EV71 drug.

Quality Evaluation of Pulsatilla chinensis Total Saponin Extracts via Quantitative Analysis of Multicomponents by Single Marker Method Combined with Systematic Quantified Fingerprint Method

Chinese medicine extracts are complex in composition. The combination of the quantitative analysis of multicomponents by single marker (QAMS) and the systematic quantified fingerprint method (SQFM) can be used for better quantitative analysis. The contents of Pulsatilla saponin D, Pulsatilla saponin A, Pulsatilla saponin F, and oleanolic acid 3-o-β-d-pyranoglucosyl-(1⟶4)-β-d-pyranoglucosyl-(1⟶3)-α-l-pyridine rhamnosyl-(1⟶2)-α-l-pyranosine arabinoside (B9) were determined by HPLC and QAMS. The methodological verification was carried out. The relative correction factor (RCF) was calculated, and the reproducibility of the RCF was investigated. The experimental results of the external standard method (ESM) and the QAMS were compared. Meanwhile, the fingerprint of the extract of Pulsatilla chinensis total saponins was established and the quality of the extract was evaluated by SQFM and hierarchical cluster analysis (HCA). The results showed that there was no significant difference between the QAMS and ESM. QAMS could be used for the rapid determination of various saponins in the extract of Pulsatilla chinensis. SQFM and HCA could objectively and comprehensively reflect the overall quality difference of total saponin extract of Pulsatilla chinensis. Therefore, QAMS and SQFM could provide a more convenient and effective selection for the quality evaluation of total saponin extract from this plant.

Ulmoidol, an unusual nortriterpenoid from Eucommia ulmoides Oliv. Leaves prevents neuroinflammation by targeting the PU.1 transcriptional signaling pathway

Chronic neuroinflammation is closely associated with the development of neurodegenerative diseases, including Alzheimer's disease (AD). In the current study, 13 anti-neuroinflammatory compounds were isolated from Eucommia ulmoides Oliv. leaves. Among these compounds, trans-sinapaldehyde (6), 3',4',5,7-tetrahydroxy-3-methylflavone (7), and amarusine A (13) were isolated from E. ulmoides leaves for the first time. The ursane-type C₂₉-triterpenoid, ulmoidol (ULM, 9), significantly inhibited the production of proinflammatory mediators and reduced the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). Moreover, ULM inhibited the cluster of differentiation 14 (CD14)/Toll-like receptor 4 (TLR4) signaling pathway and consequently limited the activation of nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways. Notably, electrophoretic mobility shift assay (EMSA) and molecular docking analyses indicated that ULM could prevent PU box binding-1 (PU.1) from binding to DNA, suggesting that PU.1 might be a potential ULM target. In conclusion, ULM alleviates neuroinflammatory responses in microglia, which could be partly explained by its targeting of PU.1 and the resulting suppression of the TLR4/MAPK/NF-κB signaling pathways. These results suggested that ULM may have therapeutic potential as an agent for treating neuroinflammation-related neurodegenerative diseases.

Therapeutic potential of triterpenoid saponin anemoside B4 from Pulsatilla chinensis

Pulsatilla Decoction (Bai-Tou-Weng-Tang) has been used medically in China for thousands of years for the treatment of diseases caused by bacteria. In recent decades, Pulsatilla Decoction is becoming a well-known formula prescription used for the treatment of ulcerative colitis in traditional Chinese medicine. Pulsatilla chinensis is the chief herbal source of Pulsatilla Decoction, and it is rich in triterpenoid saponins, such as anemoside B4, anemoside A3, and 23-hydroxybetulinic acid. Anemoside B4 is the most abundant of that group and has been used as a quality control marker for Pulsatilla chinensis. As the major active component of Pulsatilla chinensis, anemoside B4 has also received attention as a pure compound for its therapeutic potential. In this review, we systematically analyze the findings on triterpenoid saponins, especially anemoside B4, anemoside A3 and 23-hydroxybetulinic acid, included in Pulsatilla chinensis and Pulsatilla Decoction. We discuss the pharmacokinetics and tissue distribution of these triterpenoid saponins as well as their biological activities. We also summarize the pharmacological effects of anemoside B4 and its two possible metabolites, anemoside A3 and 23-hydroxybetulinic acid, as pure compounds. In summary, this review sketches a profile of the state of existing knowledge with regard to the pharmacological effects of anemoside B4, especially its anti-inflammatory and immunomodulatory effects. These findings point to the possibility that anemoside B4 has potential to be studied further as a natural compound-originated immunomodulatory agent for the treatment of inflammatory diseases such as ulcerative colitis and thus, may represent one of the most important active components of Pulsatilla Decoction responsible for its anti-ulcerative colitis efficacy.

Promising Plant-Derived Adjuvants in the Development of Coccidial Vaccines

Coccidial parasites cause medical and veterinary diseases worldwide, frequently leading to severe illness and important economic losses. At present, drugs, chemotherapeutics and prophylactic vaccines are still missing for most of the coccidial infections. Moreover, the development and administration of drugs and chemotherapeutics against these diseases would not be adequate in livestock, since they may generate unacceptable residues in milk and meat that would avoid their commercialization. In this scenario, prophylactic vaccines emerge as the most suitable approach. Subunit vaccines have proven to be biologically safe and economically viable, allowing researchers to choose among the best antigens against each pathogen. However, they are generally poorly immunogenic and require the addition of adjuvant compounds to the vaccine formulation. During the last decades, research involving plant immunomodulatory compounds has become an important field of study based on their potential pharmaceutical applications. Some plant molecules such as saponins, polysaccharides, lectins and heat shock proteins are being explored as candidates for adjuvant/carriers formulations. Moreover, plant-derived immune stimulatory compounds open the possibility to attain the main goal in adjuvant research: a safe and non-toxic adjuvant capable of strongly boosting and directing immune responses that could be incorporated into different vaccine formulations, including mucosal vaccines. Here, we review the immunomodulatory properties of several plant molecules and discuss their application and future perspective as adjuvants in the development of vaccines against coccidial infections.

UPLC-Q-TOF-MS/MS-guided dereplication of Pulsatilla chinensis to identify triterpenoid saponins

INTRODUCTION

Triterpenoid saponins are the major bioactive constituents of Pulsatilla chinensis, playing an important role in various biological activities such as anti-tumour, cognition-enhancing, anti-biosis, anti-inflammatory, hypoglycemic and immunological adjuvant.

OBJECTIVE

To establish a systematic strategy based on ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS/MS) for the efficient characterisation and identification of triterpenoid saponins in crude extracts from Pulsatilla chinensis.

METHODOLOGY

In this work, the strategy includes two aspects: (1) positive mode: by target screening, we can deduce the aglycone type and the composition of sugar moiety according to the fragment ions; untargeted screening includes four steps, find unknown, formula finder, ChemSpider search and MS/MS identification; (2) negative mode: according to the MS/MS spectra, the composition of sugar chain bonded to C-28 is inferred reasonably. The extract of Pulsatilla chinensis was separated within 60 min on a C₁₈ column and eluted with methanol and water both containing 0.1% formic acid.

RESULTS

As a result, a total of 22 triterpenoid saponins (11 pairs of isomers) with four aglycone skeletons were tentatively identified or elucidated in crude extracts from Pulsatilla chinensis based on their retention times, the mass spectrometric fragmentation patterns, and MS and MS/MS data.

CONCLUSION

This study provides an efficient analysis strategy to rapidly identify the triterpenoid saponins in Pulsatilla species even in traditional Chinese medicines.

Low-molecular-weight polysaccharides from Agaricus blazei Murrill modulate the Th1 response in cancer immunity

To assess the effect of low-molecular-weight polysaccharides from Agaricus blazei Murrill (ABP-AW1) as an immunoadjuvant therapy for type 1 T-helper (Th1) responses in tumorigenesis, C57BL/6 mice were inoculated subcutaneously with ovalbumin (E.G7-OVA). After 3, 10 and 17 days, the mice were immunized with PBS, OVA alone, or OVA and ABP-AW1, at low (50 µg), intermediate (100 µg) or high (200 µg) doses. Tumor growth was examined and compared among the groups, as were the following parameters: Splenocyte viability/proliferation, peripheral blood CD4⁺/CD8⁺ T cell ratio, serum OVA-specific IgG1 and IgG2b, secretion of interleukin (IL)-2 and interferon (IFN)-γ, and IFN-γ production on a single cell level from cultured splenocytes. Tumor growth in mice treated with OVA and ABP-AW1 (100 or 200 µg) was significantly slower, compared with in the other groups at the same time-points. OVA with 100 or 200 µg ABP-AW1 was associated with a higher number of total splenocytes, a higher ratio of peripheral blood CD4⁺/CD8⁺ T-lymphocytes, higher serum levels of OVA-specific Th1-type antibody IgG2b and greater secretion of the Th1 cytokines IL-1 and IFN-γ from splenocytes. ABP-AW1 is a promising immunoadjuvant therapy candidate, due to its ability to boost the Th1 immune response when co-administered with a cancer vaccine intended to inhibit cancer progression.

The enhancing effect of Klebsiella pneumoniae lysate on cellular immunity

Cellular immunity plays important roles in clearing intracellular pathogens or tumor cells. It is of significance to develop an adjuvant able to efficaciously induce cellular immunity, but such an approved adjuvant is not currently available. Klebsiella pneumoniae ( K. pneumoniae) possesses lipopolysaccharide and capsular polysaccharide, both of which have been demonstrated to be able to induce humoral immunity. In this study, we investigated the effect of K. pneumoniae on epidermal cellular immunity, in vitro. The effects of K. pneumoniae on the maturation of Langerhans cells (LCs), the capacity to induce T-cell proliferation, and the secretion of interferon gamma (IFN-γ) by T cells were examined. The results showed that K. pneumoniae induced significant upregulation of CD86 and human leukocyte antigen-deterodimer (HLA-DR) levels on LCs, but not CD40 and CD80. K. pneumoniae-loaded LCs induced significant CD4+ and CD8+ T-cell proliferation. Significant increases in extracellular IFN-γ secretion by CD4+ and CD8+ T cells stimulated with K. pneumoniae-pulsed LCs using enzyme-linked immunospot assay (ELISPOT) were demonstrated, while only a part of the subjects showed increases in intracellular secretion of IFN-γ using intracellular staining assay. In sum, K. pneumoniae has the potential to enhance epidermal cellular immunity and may act as a potential adjuvant in intradermal vaccines designed to enhance cellular immunity.

A sensitive HPLC-MS/MS method for the simultaneous determination of anemoside B4, anemoside A3 and 23-hydroxybetulinic acid: Application to the pharmacokinetics and liver distribution of Pulsatilla chinensis saponins

Pulsatilla chinensis saponins, the major active components in the herb, have drawn great attention as potential hepatitis B virus infection and hepatoma treatments. Here, a sensitive and accurate HPLC-MS/MS method was established for simultaneous determination of three saponins - anemoside B4, anemoside A3 and 23-hydroxybetulinic acid - in rat plasma and liver, and fully validated. The method was successfully applied to a pharmacokinetics and liver distribution study of P. chinensis saponins. Consequently, 23-hydroxybetulinic acid, with an extremely low content in the P. chinensis saponins, exhibited the highest exposure in the liver and in sites before and after hepatic disposition, namely, in the portal vein plasma and systemic plasma, followed by anemoside B4, which showed the highest content in the herb, whereas anemoside A3 displayed quite limited exposure. The hepatic first-pass effects were 71% for 23-hydroxybetulinic acid, 27% for anemoside B4 and 37% for anemoside A3, corresponding to their different extents of liver distribution. To our knowledge, this is the first investigation on the liver first-pass effect and distribution of P. chinensis saponins to date. These results also provide valuable information for the understanding of the pharmacological effect of P. chinensis saponins on liver diseases.

Biotransformation and metabolic profile of anemoside B4 with rat small and large intestine microflora by ultra-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry

Pulsatilla chinensis (Bunge) Regel is commonly used in Asia, and anemoside B4 (AB4) is its major saponin, with diverse pharmaceutical effects. Previous studies showed that intestinal flora plays an important role in the metabolism of herbs administered orally. In this study, the metabolic profile of AB4 with microflora in rat small and large intestines in vitro was investigated. Gut microflora was collected from different intestinal segments and anaerobically incubated with AB4 at 37°C for 24, 48, 72 and 96 h, respectively. A total of 10 metabolites were detected and identified by ultra- performance liquid chromatography/quadrupole time-of-flight mass spectrometry, involving the products of oxygenation and deglycosylation reactions. Gut microflora in the large intestine generated more comprehensive metabolic pathways, which appears to be attributable to the wider range of bacterial types and numbers of bacteria. Human cancer cell lines SMMC-7721, Hela and MCF-7 were treated with metabolite pools by MTT assay, together with M6 as the greatest deglycosylation product. As a result, M6 exhibited a reduction in cell viability of SMMC-7721 with an IC₅₀ value of 22.28 ± 1.26 μg/mL. The present study provided scientific evidence for AB4 metabolism in small and large intestines, which is helpful to reveal the active forms of AB4 in vivo.

EPSAH, an exopolysaccharide from Aphanothece halophytica GR02, improves both cellular and humoral immunity as a novel polysaccharide adjuvant

EPSAH is an exopolysaccharide from Aphanothece halophytica GR02. The present study was designed to evaluate its toxicity and adjuvant potential in the specific cellular and humoral immune responses in ovalbumin (OVA) in mice. EPSAH did not cause any mortality and side effects when the mice were administered subcutaneously twice at the dose of 50 mg·kg(-1). Hemolytic activity in vitro indicated that EPSAH was non-hemolytic. Splenocyte proliferation in vitro was assayed with different concentrations of EPSAH. The mice were immunized subcutaneously with OVA 0.1 mg alone or with OVA 0.1 mg dissolved in saline containing Alum (0.2 mg) or EPSAH (0.2, 0.4, or 0.8 mg) on Day 1 and 15. Two weeks later, splenocyte proliferation, natural killer (NK) cell activity, production of cytokines IL-2 from splenocytes, and serum OVA-specific antibody titers were measured. Phagocytic activity, production of pro-inflammatory cytokines IL-1 and IL-12 in mice peritoneal macrophages were also determined. EPSAH showed a dose-dependent stimulating effect on mitogen-induced proliferation. The Con A-, LPS-, and OVA-induced splenocyte proliferation and the serum OVA-specific IgG, IgG1, and IgG2a antibody titers in the immunized mice were significantly enhanced. EPSAH also significantly promoted the production of Th1 cytokine IL-2. Besides, EPSAH remarkably increased the killing activities of NK cells from splenocytes in the immunized mice. In addition, EPSAH enhanced phagocytic activity and the generation of pro-inflammatory cytokines IL-1 and IL-12 in macrophages. These results indicated that EPSAH had a strong potential to increase both cellular and humoral immune responses, particularly promoting the development of Th1 polarization.

Chinese herb medicine against Sortase A catalyzed transformations, a key role in gram-positive bacterial infection progress

Many Gram-positive bacteria can anchor their surface proteins to the cell wall peptidoglycan covalently by a common mechanism with Sortase A (SrtA), thus escaping from the host's identification of immune cells. SrtA can complete this anchoring process by cleaving LPXTG motif conserved among these surface proteins and thus these proteins anchor on the cell wall. Moreover, those SrtA mutants lose this capability to anchor these relative proteins, with these bacteria no longer infectious. Therefore, SrtA inhibitors can be promising anti-infective agents to cure bacterial infections. Chinese herb medicines (CHMs) (chosen from Science Citation Index) have exhibited inhibition on SrtA of Gram-positive pathogens irreversibly or reversibly. In general, CHMs are likely to have important long-term impact as new antibacterial compounds and sought after by academia and the pharmaceutical industry. This review mainly focuses on SrtA inhibitors from CHMs and the potential inhibiting mechanism related to chemical structures of compounds in CHMs.

Rapid Detection and Characterisation of Triterpene Saponins from the Root of Pulsatilla chinensis (Bunge) Regel by HPLC-ESI-QTOF-MS/MS

INTRODUCTION

Triterpene saponins are the major bioactive components in the root of Pulsatilla chinensis (Bunge) Regel (RPC), and have been reported to possess antitumor and immunological adjuvant activities. However, the isolation, purification and elucidation procedures of triterpene saponins from RPC are difficult and time consuming due to high polarity and structural similarity.

OBJECTIVES

To develop an analytical strategy for discovering and elucidating triterpene saponins in RPC.

METHODS

Methanolic extract of RPC is analysed by high-performance liquid chromatography coupled to electrospray ionisation and quadrupole time-of-flight-mass spectrometry (HPLC-ESI-QTOF-MS/MS). The MS and MS/MS experiments are conducted using the negative-ionisation mode, in order to provide molecular-mass information and production spectra for the structural elucidation of compounds.

RESULTS

Based on retention times, accurate mass and mass spectrometric fragmentation, 24 triterpene saponins are identified or tentatively elucidated from RPC, of which nine triterpene saponins were not reported previously.

CONCLUSION

The HPLC-ESI-QTOF-MS/MS could be employed as a rapid, effective technique to screen and identify triterpene saponins in RPC without tedious and time-consuming isolation of pure constituents. Copyright © 2016 John Wiley & Sons, Ltd.

Novel ISCOMs from Quillaja brasiliensis saponins induce mucosal and systemic antibody production, T-cell responses and improved antigen uptake

In the last decades, significant efforts have been dedicated to the search for novel vaccine adjuvants. In this regard, saponins and its formulations as "immunostimulating complexes" (ISCOMs) have shown to be capable of stimulating potent humoral and cellular immune responses, enhanced cytokine production and activation of cytotoxic T cells. The immunological activity of ISCOMs formulated with a saponin fraction extracted from Quillaja brasiliensis (QB-90 fraction) as an alternative to classical ISCOMs based on Quil A(®) (IQA) is presented here. The ISCOMs prepared with QB-90, named IQB-90, typically consist of 40-50 nm, spherical, cage-like particles, built up by QB-90, cholesterol, phospholipids and antigen (ovalbumin, OVA). These nanoparticles were efficiently uptaken in vitro by murine bone marrow-derived dendritic cells. Subcutaneously inoculated IQB-90 induced strong serum antibody responses encompassing specific IgG1 and IgG2a, robust DTH reactions, significant T cell proliferation and increases in Th1 (IFN-γ and IL-2) cytokine responses. Intranasally delivered IQB-90 elicited serum IgG and IgG1, and mucosal IgA responses at distal systemic sites (nasal passages, large intestine and vaginal lumen). These results indicate that IQB-90 is a promising alternative to classic ISCOMs as vaccine adjuvants, capable of enhancing humoral and cellular immunity to levels comparable to those induced by ISCOMs manufactured with Quillaja saponaria saponins.

A polysaccharide isolated from Agaricus blazei Murill (ABP-AW1) as a potential Th1 immunity-stimulating adjuvant

In the present study, a low molecular weight polysaccharide, ABP-AW1, isolated from Agaricus blazei Murill was assessed for its potential adjuvant activity. ABP-AW1 is considered to create a ‘depot’ of antigen at a subcutaneous injection site. ICR mice were immunized with 100 μg ovalbumin (OVA) alone or with 100 μg OVA formulated in 0.9% saline containing 200 μg aluminum (alum) or ABP-AW1 (50, 100 and 200 μg) on days 1 and 15. Two weeks after the secondary immunization, splenocyte proliferation, the expression of surface markers, cytokine production and the OVA-specific antibody levels in the serum were determined. The OVA/ABP-AW1 vaccine, in comparison with OVA alone, markedly increased the proliferation of splenic lymphocytes and elicited greater antigen-specific CD4⁺ T cell activation, as determined by splenic CD4⁺CD69⁺ T cells and Th1 cytokine interferon (IFN)-γ release. The combination of ABP-AW1 and OVA also enhanced IgG2b antibody responses to OVA. In conclusion, these data indicated that ABP-AW1 significantly enhanced the humoral and cellular immune responses against OVA in the mice, suggesting that ABP-AW1 stimulated Th1-type immunity. We suggest that ABP-AW1 may serve as a new adjuvant.

Toxicity and dose determination of quillaja saponin, aluminum hydroxide and squalene in olive flounder (Paralichthys olivaceus)

Adjuvants are substances added to vaccines to enhance the immune response of a given antigen. Most of the adjuvants are toxic at certain doses, and toxicity varies in different species. Moreover, there are no standard dosage limits set for adjuvant use in fish vaccines. We evaluated the acute toxicity, serum enzymes (AST/ALT) indicating hepatic injury and histopathological changes due to intra-peritoneal administration of different concentrations of a panel of adjuvants including quillaja saponin, aluminum hydroxide, squalene emulsion and Freund's incomplete adjuvant (FIA) with a dose ranging study of saponin (500, 160, 50, 16 and 5μgfish(-1)), aluminum hydroxide (5000, 1600, 500, 160 and 50μgfish(-1)), squalene emulsion (20, 10 and 5%), and FIA to determine the acceptable dosage for vaccination in olive flounder (Paralichthys olivaceus) fingerlings measuring 4.66±0.41g, 8.47±0.42cm. Saponin was highly toxic with a LD50 of approximately 105μgfish(-1) (22.4mgkg(-1)) causing severe histological damage and AST level was high at dose above 16μgfish(-1) and ALT, specific for liver damage was high only at 160μgfish(-1) (11U/L) and was safe at 5μgfish(-1). Aluminum hydroxide was toxic at 5000μgfish(-1) and was acceptable at dose below 1600μgfish(-1) with moderate histology and AST/ALT levels similar with control. Squalene emulsion showed increased inflammation at 20% and 10% emulsions and the inflammatory response was mild at a concentration of 5% oil emulsion and AST/ALT levels being similar to control in 10% and 5% emulsions and elevated in 20% on both sampling days. FIA was not lethal, but induced severe inflammation at injection site and around blood vessels. In comparison to FIA, saponin found to be safe at dose of 5μgfish(-1), aluminum hydroxide below 1600μgfish(-1), and squalene at 5% emulsion and could be accepted for vaccination studies. These results provide an insight for the selection of safer dose of adjuvants for intra-peritoneal vaccination of olive flounder.

Immunopontentiating and antitumor activities of a polysaccharide from Pulsatilla chinensis (Bunge) Regel

One water-soluble polysaccharide (PCPw) was isolated and purified from the roots of Pulsatilla chinensis by DEAE cellulose-52 and Sephadex G-100 column chromatography, and its antitumor activity was evaluated on 4T1 tumor-bearing mice through transplantable animal tumor. After 10 days of PCPw (50, 100 and 200 mg/kg) treatment once daily in tumor-bearing mice, PCPw oral administration could not only significantly inhibit the growth of transplantable 4T1 tumor in mice but also promote concanavalin A (Con A), lipopolysaccharide (LPS)-stimulated splenocytes proliferation, the serum lysozyme level and 2,4-dinitrofluorobenzene (DNFB)-induced delayed-type hypersensitivity (DTH) reactions, especially at the dose of 100 mg/kg. Meanwhile, significant improvements in peripheral blood abnormality and anemia were observed in PCPw-treated group. These results suggested that PCPw could improve both cellular and humoral immune response and might be explored as a potential natural antitumor drug.

Nanopatch targeted delivery of both antigen and adjuvant to skin synergistically drives enhanced antibody responses

Many vaccines make use of an adjuvant to achieve stronger immune responses. Alternatively, potent immune responses have also been generated by replacing the standard needle and syringe (which places vaccine into muscle) with devices that deliver vaccine antigen to the skin's abundant immune cell population. However it is not known if the co-delivery of antigen plus adjuvant directly to thousands of skin immune cells generates a synergistic improvement of immune responses. In this paper, we investigate this idea, by testing if Nanopatch delivery of vaccine - both the antigen and the adjuvant - enhances immunogenicity, compared to intramuscular injection. As a test-case, we selected a commercial influenza vaccine as the antigen (Fluvax 2008®) and the saponin Quil-A as the adjuvant. We found, after vaccinating mice, that anti-influenza IgG antibody and haemagglutinin inhibition assay titre response induced by the Nanopatch (with delivered dose of 6.5ng of vaccine and 1.4μg of Quil-A) were equivalent to that of the conventional intramuscular injection using needle and syringe (6000ng of vaccine injected without adjuvant). Furthermore, a similar level of antigen dose sparing (up to 900 fold) - with equivalent haemagglutinin inhibition assay titre responses - was also achieved by delivering both antigen and adjuvant (1.4μg of Quil-A) to skin (using Nanopatches) instead of muscle (intramuscular injection). Collectively, the unprecedented 900 fold antigen dose sparing demonstrates the synergistic improvement to vaccines by co-delivery of both antigen and adjuvant directly to skin immune cells. Successfully extending these findings to humans with a practical delivery device - like the Nanopatch - could have a huge impact on improving vaccines.