Relationship between haemolytic and adjuvant activity and structure of protopanaxadiol-type saponins from the roots of Panax notoginseng

Development of semisynthetic saponin immunostimulants

Many natural saponins demonstrate immunostimulatory adjuvant activities, but they also have some inherent drawbacks that limit their clinical use. To overcome these limitations, extensive structure-activity-relationship (SAR) studies have been conducted. The SAR studies of QS-21 and related saponins reveal that their respective fatty side chains are crucial for potentiating a strong cellular immune response. Replacing the hydrolytically unstable ester side chain in the C28 oligosaccharide domain with an amide side chain in the same domain or in the C3 branched trisaccharide domain is a viable approach for generating robust semisynthetic saponin immunostimulants. Given the striking resemblance of natural momordica saponins (MS) I and II to the deacylated Quillaja Saponaria (QS) saponins (e.g., QS-17, QS-18, and QS-21), incorporating an amide side chain into the more sustainable MS, instead of deacylated QS saponins, led to the discovery of MS-derived semisynthetic immunostimulatory adjuvants VSA-1 and VSA-2. This review focuses on the authors' previous work on SAR studies of QS and MS saponins.

Elucidating the anti-inflammatory activity of platycodins in lung inflammation through pulmonary distribution dynamics and grey relational analysis of cytokines

ETHNOPHARMACOLOGICAL RELEVANCE

Platycodonis Radix (PR) is a traditional herbal remedy used to prevent and treat lung inflammation, and platycodins are speculated to be the major active constituents. However, concrete experimental verification for this assertion remains absent thus far.

AIM OF THE STUDY

This study aims to compare the pulmonary distribution dynamics of five platycodins and analyze their effects on cytokines. Through the grey relational analysis (GRA) between pulmonary active components and cytokines, the study ascertains platycodins as the potential effective component against lung inflammation.

MATERIALS AND METHODS

A rat lung inflammation model was created using lipopolysaccharides (LPS). Pulmonary distribution dynamics were analyzed via LC-MS/MS. Cytokine changes and distribution patterns in lung tissues were studied by multi-factor reagent kit. GRA was applied to determine correlations between pulmonary components and cytokines. Finally, the anti-inflammatory properties of platycodins were further studied using LPS-induced BEAS-2B cells in vitro.

RESULTS

The results showed that five platycodins (Platycodin D, Platycodin D3, Deapio Platycodin D, 3-O-β-D-Glucopyranosyl Platycodigenin, and Platycodigenin) featured fast absorption rate, short time to peak, and slow metabolism rate. The pulmonary distribution dynamics were significantly affected within 2 h after LPS modeling. At the same time, PR altered the relationships among different cytokines induced by LPS stimulation, particularly inflammatory cytokines IL-6 and IFN-γ. The GRA results indicated good correlation between the pulmonary distribution dynamics of the five platycodins components and the changing patterns of cytokine levels, with Platycodin D3 contributing the most. Additionally, Platycodin D3 exhibited a protective role against LPS-induced inflammation by reducing the production of pro-inflammatory mediators such as IL-1β, IL-8, and ROS, as well as increasing the expression of the anti-inflammatory mediator IL-10.

CONCLUSIONS

Platycodins are the main anti-inflammatory agents in PR and there is a good correlation with cytokines. This contributes to the anti-pneumonia effect of PR.

Quantitative comparison and rapid discrimination of Panax notoginseng powder and Caulis clematidis armandii using NMR combined with pattern recognition

BACKGROUND

The market demand for Panax notoginseng (P. notoginseng) is growing rapidly because of its useful properties in food and medicine. However, the frequent adulteration of P. notoginseng seriously affects the health of consumers and is a great challenge to food safety. In this study, low- and high-field nuclear magnetic resonance (LF/HF-NMR) were applied to detect the transverse relaxation distribution of P. notoginseng contaminated with different ratios of Caulis clematidis armandii (CCA) and the components in P. notoginseng and CCA, respectively.

RESULTS

Fifty-seven kinds of major and minor components in P. notoginseng and CCA were identified and quantified from their high-resolution NMR spectra, and there were significant differences in ginsenosides, sucrose, and glucose between P. notoginseng and CCA. Furthermore, the partial least squares regression analysis results indicated that LF-NMR parameters (T₂₁ and S₂₁ ) changed linearly as the ratio of CCA increased, and these changes were attributed to the variations in polysaccharide and sucrose in adulterated P. notoginseng.

CONCLUSION

In the relaxation time-based pattern recognition models, the authentic P. notoginseng powder could be classified with 100% accuracy from adulterated P. notoginseng when the adulteration ratio was greater than 30%, demonstrating the possibility of LF-NMR, in combination with pattern recognition, for rapid discrimination of food authenticity. © 2022 Society of Chemical Industry.

A review: structure-activity relationship between saponins and cellular immunity

Saponins, which exhibit many different biological and pharmacological activities, are present in a wide range of plant species and in some marine organisms. Notably, the researchers have found that saponins can activate the immune system in mammals. The strength of this function is closely related to the chemical structure of saponins. The present study of the structure-activity relationship suggests that aglycones, glycochains on aglycones and special functional groups of saponins affect the immune activity of saponins. This paper reviews the effects of different saponins on cellular immunity. As well as the structure-activity relationship of saponins. It is hoped that the information integrated in this paper will provide readers with information on the effects of saponins on cellular immunity and promote the further study of these compounds.

Machine Learning-Assisted Screening of Herbal Medicine Extracts as Vaccine Adjuvants

Adjuvants are important vaccine components, composed of a variety of chemical and biological materials that enhance the vaccine antigen-specific immune responses by stimulating the innate immune cells in both direct and indirect manners to produce a variety cytokines, chemokines, and growth factors. It has been developed by empirical methods for decades and considered difficult to choose a single screening method for an ideal vaccine adjuvant, due to their diverse biochemical characteristics, complex mechanisms of, and species specificity for their adjuvanticity. We therefore established a robust adjuvant screening strategy by combining multiparametric analysis of adjuvanticity in vivo and immunological profiles in vitro (such as cytokines, chemokines, and growth factor secretion) of various library compounds derived from hot-water extracts of herbal medicines, together with their diverse distribution of nano-sized physical particle properties with a machine learning algorithm. By combining multiparametric analysis with a machine learning algorithm such as rCCA, sparse-PLS, and DIABLO, we identified that human G-CSF and mouse RANTES, produced upon adjuvant stimulation in vitro, are the most robust biological parameters that can predict the adjuvanticity of various library compounds. Notably, we revealed a certain nano-sized particle population that functioned as an independent negative parameter to adjuvanticity. Finally, we proved that the two-step strategy pairing the negative and positive parameters significantly improved the efficacy of screening and a screening strategy applying principal component analysis using the identified parameters. These novel parameters we identified for adjuvant screening by machine learning with multiple biological and physical parameters may provide new insights into the future development of effective and safe adjuvants for human use.

Ultrafiltration Process Yield Study on Aqueous Solution of Total Ginsenosides

Ultrafiltration membrane separation is a technology used to separate large and small molecules in solution by using the principle of membrane screening. This technology can retain the effective components of traditional Chinese medicine extract, remove macromolecular impurities and endotoxin, and meet the requirements of high quality, high efficiency, and low pollution in the modern production of traditional Chinese medicine. The study investigated the impact of 100 KDa molecular weight prepared from different ultrafiltration membrane on the ginsenosides ingredient composition of ginsenosides Rg1, ginsenoside Re, ginsenoside Rf, ginsenoside Rb1, ginsenoside Rg2, ginsenoside Rc, ginsenoside Rb2, ginsenoside Rb3, ginsenoside Rd and ginsenoside Rg3. Changes in retention rates were compared by the component changes in high-performance liquid chromatography in the volume concentrates, par volume of water constant volume diafiltration and 50% ethanol constant volume diafiltration ultrafiltration process. The results demonstrate that the 100 K cellulose ultrafiltration membrane was used for ginsenosides ultrafiltration. The yield and retention were superior to those of the polyethersulfone ultrafiltration membrane with the same molecular weight cutoffs.

Combining combretastatin A4 phosphate with ginsenoside Rd synergistically inhibited hepatocellular carcinoma by reducing HIF-1α via PI3K/AKT/mTOR signalling pathway

OBJECTIVES

Combretastatin A4 phosphate (CA4P), a vascular disrupting agent (VDA), can cause rapid tumour vessel occlusion. Subsequently, extensive necrosis is discovered in the tumour center, which induces widespread hypoxia and the rise of the α subunit of hypoxia-inducible factor-1 (HIF-1α). The aim of this study was to evaluate the inhibition of hepatocellular carcinoma growth by combining CA4P with HIF-1 α inhibitor and investigate the mechanism of this combination.

METHODS

Ginsenoside Rd (Rd) was used in combination with CA4P to estimate the inhibition effect in HepG2 cells and HepG2 xenograft mouse model. The efficacy of anti-tumour was evaluated by tumour growth curve. The protein expression of HIF-1α and PI3K/AKT/mTOR signalling pathway were analysed by western blot.

KEY FINDINGS

Combination of CA4P and Rd inhibited HepG2 cell proliferation and induced apoptosis in vivo and in vitro. It also increased the necrotic area of the tumour and delayed the tumour growth. Moreover, Rd down-regulated HIF-1α protein expression by inhibiting PI3K/AKT/mTOR signalling pathway.

CONCLUSIONS

Combination of CA4P and Rd had synergistic anti-tumour effects. The mechanism may be related to the inhibition of HIF-1α by PI3K/AKT/mTOR signalling pathway. This strategy provides a new thought for the combinative therapy of VDAs.

Inhibitory mechanism of 6-Pentyl-2H-pyran-2-one secreted by Trichoderma atroviride T2 against Cylindrocarpon destructans

Root rot caused by Cylindrocarpon destructans is one of the most devastating diseases of Panax notoginseng, and Trichoderma species are potential agents for the biocontrol of fungal diseases. Thus, we screened a total of 10 Trichoderma isolates against C. destructans and selected Trichoderma atroviride T2 as an antagonistic strain for further research. 6-Pentyl-2H-pyran-2-one (6PP) was identified as an important active metabolite in the fermentation broth of the strain and exhibited antifungal activity against C. destructans. Transcriptome and metabolome analyses showed that 6PP significantly disturbed the metabolic homeostasis of C. destructans, particularly the metabolism of amino acids. By constructing a gene coexpression network, ECHS1 was identified as the hub gene correlated with 6PP stress. 6PP significantly downregulated the expression of ECHS1 at the transcriptional level and combined with the ECHS1 protein. Autophagy occurred in C. destructans cells under 6PP stress. In conclusion, 6PP may induce autophagy in C. destructans by downregulating ECHS1 at the transcriptional level and inhibiting ECHS1 protein activity. 6PP is a potential candidate for the development of new fungicides against C. destructans.

Lipid Membranes as Key Targets for the Pharmacological Actions of Ginsenosides

In this review, we will focus on the activity of ginsenosides on membranes and their related effects, from physicochemical, biophysical, and pharmacological viewpoints. Ginsenosides are a class of saponins with a large structural diversity and a wide range of pharmacological effects. These effects can at least partly be related to their activity on membranes which results from their amphiphilic character. Some ginsenosides are able to interact with membrane lipids and associate into nanostructures, making them possible adjuvants for vaccines. They are able to modulate membrane biophysical properties such as membrane fluidity, permeability or the formation of lateral domains with some degree of specificity towards certain cell types such as bacteria, fungi, or cancer cells. In addition, they have shown antioxidant properties which protect membranes from lipid oxidation. They further displayed some activity on membrane proteins either through direct or indirect interaction. We investigate the structure activity relationship of ginsenosides on membranes and discuss the implications and potential use as anticancer, antibacterial, and antifungal agents.

Composition and function of rhizosphere microbiome of Panax notoginseng with discrepant yields

Background

Panax notoginseng is a highly valuable medicinal plant. Reduced P. notoginseng yield is a common and serious problem that arises in a continuous cropping system. Variation in the composition and function of soil microbial community is considered the primary cause of yield reduction.

Methods

This study used shotgun metagenomic sequencing approaches to describe the taxonomic and functional features of P. notoginseng rhizosphere microbiome and screen microbial taxa and functional traits related to yields.

Results

At the family and genus level, a total of 43 families and 45 genera (relative abundance > 0.1%) were obtained, and the correlation with the yield of P. notoginseng was further analyzed. Nitrosomonadaceae, Xanthomonadaceae, Mycobacterium and Arthrobacter that were enriched in soils with higher yields were positively correlated with P. notoginseng yields, thereby suggesting that they might increase yields. Negative correlation coefficients indicated that Xanthobacteraceae, Caulobacteraceae, Oxalobacteraceae, Chitinophagaceae, Sphingomonas, Hyphomicrobium, Variovorax and Phenylobacterium might be detrimental to P. notoginseng growth. A total of 85 functional traits were significantly (P < 0.05) correlated with P. notoginseng yields. Functional traits, likely steroid biosynthesis and MAPK signaling pathway were positively correlated with P. notoginseng yields. In contrast, functional traits, such as bacterial secretion system, ABC transporters, metabolism of xenobiotics by cytochrome P450 and drug metabolism–cytochrome P450, were negatively associated with yields.

Conclusions

This study describes an overview of the rhizosphere microbiome of P. notoginseng with discrepant yields and identifies the taxa and functional traits related to yields. Our results provide valuable information to guide the isolation and culture of potentially beneficial microorganisms and to utilize the power of the microbiome to increase plant yields in a continuous cropping system.

Identification of unhealthy Panax notoginseng from different geographical origins by means of multi-label classification

Root-knot nematode is a common plant-parasitic pest with a highly destructive that infects more than 2000 plant species. Panax notoginseng (P. notoginseng) is one of the most susceptible traditional medicine. More importantly, it is difficult to distinguish the powders of P. notoginseng infected with root-knot nematode from those of healthy P. notoginseng due to the color and shape are same after being ground into powder. In this paper, Attenuated Total Reflection-Fourier Transform Infrared (ATR-FTIR) was used to identify P. notoginseng samples. Multiplicative scatter correction (MSC) was applied to preprocess the spectral data. Competitive adaptive reweighted sampling (CARS) and successive projection algorithm (SPA) were employed to select feature variables. Density-based spatial clustering of application with noise (DBSCAN) was adopted to discover groups within the data. Also, we found that the geographical origin is a pivotal factor to consider when identifying unhealthy P. notoginseng. Therefore, we introduced a novel multi-label classification (MLC) method to identify healthy and unhealthy P. notoginseng powders from three different geographical origins. In addition, binary relevance method (BR), classifier chain (CC), ensembles of classifier chains (ECC), and multilayer perceptron classifier (MLPC) were applied to create classification models, ECC exhibits superior performance in particular.

Impact of continuous Panax notoginseng plantation on soil microbial and biochemical properties

Panax notoginseng is a highly regarded medicinal plant that has been cultivated for more than 400 years in Southwest China. The obstacles associated with the continuous cropping of P. notoginseng are the greatest issues for the development this plant. In the present study, the micro-ecologies of soils differing in the duration of P. notoginseng planting were compared, the results of which could provide important information to aid in solving the problems associated with the continuous cropping of P. notoginseng. Soils in which P. notoginseng had grown for 1, 3 or 5 years, as well as unplanted or fallow soil, which had a P. notoginseng planting interval of 1, 3, 6 or 9 years, were collected in Yunnan Province, China. The numbers and physiological groups of microorganisms, soil enzyme activities and nutrients present in the soil were analyzed to identify the effects of continuous cropping and determine the influence of crop rotation on the soil. After P. notoginseng was planted, the ecological structure of the soil and the balance of soil nutrients changed. These changes in the soil ecosystem prevented the soil from adapting to the continuous cropping of P. notoginseng, which eventually limited the growth of P. notoginseng and increased the incidence of diseases. After rotation of P. notoginseng, some soil indicators were restored, and some indicators with irregular changes may have been caused by crop rotation and field fertilization management practices. Thus, the selection of suitable crop rotations will facilitate the use of continuous cropping for P. notoginseng.

Therapeutic Potential and Cellular Mechanisms of Panax Notoginseng on Prevention of Aging and Cell Senescence-Associated Diseases

Owing to a dramatic increase in average life expectancy, most countries in the world are rapidly entering an aging society. Therefore, extending health span with pharmacological agents targeting aging-related pathological changes, are now in the spotlight of gerosciences. Panax notoginseng (Burk.) F. H. Chen, a species of the genus Panax, has been called the "Miracle Root for the Preservation of Life," and has long been used as a Chinese herb with magical medicinal value. Panax notoginseng has been extensively employed in China to treat microcirculatory disturbances, inflammation, trauma, internal and external bleeding due to injury, and as a tonic. In recent years, with the deepening of the research pharmacologically, many new functions have been discovered. This review will introduce its pharmacological function on lifespan extension, anti-vascular aging, anti-brain aging, and anti-cancer properties, aiming to lay the ground for fully elucidating the potential mechanisms of Panax notoginseng's anti-aging effect to promote its clinical application.

Rhizospheric soil and root endogenous fungal diversity and composition in response to continuous Panax notoginseng cropping practices

Rhizosphere and endophytic fungal communities are considered critically important for plant health and soil fertility. In response to continuous cropping, Panax notoginseng becomes vulnerable to attack by fungal pathogens. In the present study, culture-independent Illumina MiSeq was used to investigate the rhizospheric and root endophytic fungi in response to continuous Panax notoginseng cropping practices. The results demonstrated that fungal diversity is increased inside the roots and in rhizospheric. Ascomycota, Zygomycota, Basidiomycota and Chytridiomycota were the dominant phyla detected during the continuous cropping of Panax notoginseng. The fungal diversity in the rhizospheric soil and roots of root-rot P. notoginseng plants are less than that of healthy plants in the same cultivating year, thus showing that root-rot disease also affects the community structure and diversity of rhizospheric and root endophytic fungi. Similarities in the major fungal components show that endophytic fungal communities are similar to rhizospheric soil fungal community based on a specialized subset of organisms. Canonical correspondence analysis on the fungal communities in root-rot rhizospheric from both healthy plants and rotation soils reveals that the soil pH and organic matter have the greatest impact upon the microbial community composition during continuous cropping, whereas soil nutrition status does not significantly affect the fungal community composition in response to continuous cropping practices. In addition, the results suggest that the unclassified genera Leotiomycetes, Cylindrocarpon, Fusarium and Mycocentrospora are shown as the potential pathogens which are responsible for the obstacles in continuous cropping of P. notoginseng. Further exploration of these potential pathogens might be useful for the biological control of continuous cropping of P. notoginseng.

Traditional uses, botany, phytochemistry, pharmacology and toxicology of Panax notoginseng (Burk.) F.H. Chen: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Panax notoginseng (Burk.) F.H. Chen is a widely used traditional Chinese medicine known as Sanqi or Tianqi in China. This plant, which is distributed primarily in the southwest of China, has wide-ranging pharmacological effects and can be used to treat cardiovascular diseases, pain, inflammation and trauma as well as internal and external bleeding due to injury.

AIMS OF THE REVIEW

This paper provides up-to-date information on investigations of this plant, including its botany, ethnopharmacology, phytochemistry, pharmacology and toxicology. The possible uses and perspectives for future investigation of this plant are also discussed.

MATERIALS AND METHODS

The relevant information on Panax notoginseng (Burk.) F.H. Chen was collected from numerous resources, including classic books about Chinese herbal medicine, and scientific databases, including Pubmed, SciFinder, ACS, Ebsco, Elsevier, Taylor, Wiley and CNKI.

RESULTS

More than 200 chemical compounds have been isolated from Panax notoginseng (Burk.) F.H. Chen, including saponins, flavonoids and cyclopeptides. The plant has pharmacological effects on the cardiovascular system, immune system as well as anti-inflammatory, anti-atherosclerotic, haemostatic and anti-tumour activities, etc.

CONCLUSIONS

Panax notoginseng is a valuable traditional Chinese medical herb with multiple pharmacological effects. This review summarizes the botany, ethnopharmacology, phytochemistry, pharmacology and toxicology of P. notoginseng, and presents the constituents and their corresponding chemical structures found in P. notoginseng comprehensively for the first time. Future research into its phytochemistry of bio-active components should be performed by using bioactivity-guided isolation strategies. Further work on elucidation of the structure-function relationship among saponins, understanding of multi-target network pharmacology of P. notoginseng, as well as developing its new clinical usage and comprehensive utilize will enhance the therapeutic potentials of P. notoginseng.

Molecular characterization of microbial communities in the rhizosphere soils and roots of diseased and healthy Panax notoginseng

Rhizosphere and root-associated microbial communities are known to be related to soil-borne disease and plant health. In the present study, the microbial communities in rhizosphere soils and roots of both healthy and diseased Panax notoginseng were analyzed by high-throughput sequencing of 16S rRNA for bacteria and 18S rRNA internal transcribed spacer for fungi, to reveal the relationship of microbial community structure with plant health status. In total, 5593 bacterial operational taxonomic units (OTUs) and 963 fungal OTUs were identified in rhizosphere soils, while 1794 bacterial and 314 fungal OTUs were identified from root samples respectively. Principal coordinate analysis separated the microbial communities both in the rhizosphere soils and roots of diseased P. notoginseng from healthy plants. Compared to those of healthy P. notoginseng, microbial communities in rhizosphere soils and roots of diseased plants showed a decrease in alpha diversity. By contrast, bacterial community dissimilarity increased and fungal community dissimilarity decreased in rhizosphere soils of diseased plants, while both bacterial and fungal community dissimilarity in roots showed no significant difference between healthy and diseased plants. Redundancy analysis at the phylum level showed that mycorrhizal colonization and soil texture significantly affected microbial community composition in rhizosphere soils, whereas shoot nutrition status had a significant effect on microbial community composition in root samples. Our study provided strong evidence for the hypothesis that microbial diversity could potentially serve as an indicator for disease outbreak of medicinal plants, and supported the ecological significance of microbial communities in maintaining plant healthy and soil fertility.

The nematicidal effect of camellia seed cake on root-knot nematode Meloidogyne javanica of banana

Suppression of root-knot nematodes is crucially important for maintaining the worldwide development of the banana industry. Growing concerns about human and environmental safety have led to the withdrawal of commonly used nematicides and soil fumigants, thus motivating the development of alternative nematode management strategies. In this study, Meloidogyne javanica was isolated, and the nematicidal effect of Camellia seed cake on this pest was investigated. The results showed that in dish experiments, Camellia seed cake extracts under low concentration (2 g/L) showed a strong nematicidal effect. After treatment for 72 h, the eggs of M. javanica were gradually dissolved, and the intestine of the juveniles gradually became indistinct. Nematicidal compounds, including saponins identified by HPLC-ESI-MS and 8 types of volatile compounds identified by GC-MS, exhibited effective nematicidal activities, especially 4-methylphenol. The pot experiments demonstrated that the application of Camellia seed cake suppressed M. javanica, and promoted the banana plant growth. This study explored an effective nematicidal agent for application in soil and revealed its potential mechanism of nematode suppression.

A novel 12, 23-epoxy dammarane saponin from Panax notoginseng

The present study investigated the chemical constituents of the roots and rhizomes of Panax notoginseng. Compounds were isolated by various column chromatographic methods, and their structures were elucidated by the extensive analysis of spectroscopic data and chemical evidences. A novel 12, 23-epoxy dammarane-type saponin, named epoxynotoginsenoside A (1), together with four known compounds (2-5), was isolated and characterized.

Tenuifolin, a secondary saponin from hydrolysates of polygalasaponins, counteracts the neurotoxicity induced by Aβ25-35 peptides in vitro and in vivo

Alzheimer's disease (AD) is associated with damage to hippocampal neurons and declines in cognitive functions. The accumulation of amyloid peptides is regarded as a crucial event in the initiation of AD. The neurotoxicity induced by Aβ25-35 peptides was used to screen for cytoprotective factors in vitro, and the cognitive deficits induced by the injection of Aβ25-35 into the hippocampus were used to evaluate effect on learning and memory. Our previous study revealed that hydrolysate of polygalasaponins (HPS) clearly improve the cognitive deficits induced by the injection of Aβ25-35 in mice, but the potential active constituent of HPS remains unclear. The purposes of this study were to separate and purify the secondary saponins of HPS, screen for neuroprotective effects of the constituents in vitro, and to evaluate the effect of cognition in vivo. Various chromatographic methods were used to separate and purify the HPS. The neuroprotective effects were examined in Aβ25-35-damage-induced PC12 cells. The protective effect of tenuifolin on the cognitive impairments induced by Aβ25-35 injection was assessed using the Morris water maze and step-through passive avoidance tests. Tenuifolin and fallaxsaponin A were isolated from the HPS. Tenuifolin possessed neuroprotective effects against Aβ25-35-induced apoptosis in PC12 cells and significantly improved the cognitive deficits induced by the intrahippocampal injection of Aβ25-35 in mice. Thus, tenuifolin is one of the active constituents of HPS against the neurotoxicity induced by Aβ25-35 peptides in vitro and in vivo.

Ginsenoside-Rb2 inhibits dexamethasone-induced apoptosis through promotion of GPR120 induction in bone marrow-derived mesenchymal stem cells

Apoptosis of bone marrow-derived mesenchymal stem cells (BMMSCs) is an essential pathogenic factor of osteoporosis. Ginsenoside-Rb2 (Rb2), a 20(S)-protopanaxadiol glycoside extracted from ginseng, is a potent treatment for bone loss, which raises interest regarding the bone metabolism area. In the present study, we found that dose-response Rb2 inhibited high dosage of dexamethasone (Dex)-induced apoptosis in primary murine BMMSCs. Interestingly, Rb2 promoted GPR120 induction, which is the unsaturated long-chain fatty acid receptor. We further confirmed that GPR120-specific ShRNA reversed the inhibition of Rb2 on Dex-induced apoptosis by activating caspase-3 and reducing cell viability. In addition, Rb2 notably increased phosphorylated ERK1/2 levels and Ras kinase activity dependently through the GPR120. The ERK1/2 activity-specific inhibitor U0126 remarkably blocked the Rb2-induced antiapoptotic effect in response to Dex-induced apoptosis. Together, dose-response Rb2 protected BMMSCs against Dex-induced apoptosis dependently by inducing GPR120 promoted Ras-ERK1/2 signaling pathway. Therefore, in the prevalence of the abuse of Dex in the clinic, our findings suggest for the first time that Rb2 is not only a key to understand the link between Chinese medicine and the pathology of osteoporosis but also an underlying target for the treatment of bone complications in the foreseeable future.

Metabolic and functional diversity of saponins, biosynthetic intermediates and semi-synthetic derivatives

Saponins are widely distributed plant natural products with vast structural and functional diversity. They are typically composed of a hydrophobic aglycone, which is extensively decorated with functional groups prior to the addition of hydrophilic sugar moieties, to result in surface-active amphipathic compounds. The saponins are broadly classified as triterpenoids, steroids or steroidal glycoalkaloids, based on the aglycone structure from which they are derived. The saponins and their biosynthetic intermediates display a variety of biological activities of interest to the pharmaceutical, cosmetic and food sectors. Although their relevance in industrial applications has long been recognized, their role in plants is underexplored. Recent research on modulating native pathway flux in saponin biosynthesis has demonstrated the roles of saponins and their biosynthetic intermediates in plant growth and development. Here, we review the literature on the effects of these molecules on plant physiology, which collectively implicate them in plant primary processes. The industrial uses and potential of saponins are discussed with respect to structure and activity, highlighting the undoubted value of these molecules as therapeutics.

Vaccine delivery system for tuberculosis based on nano-sized hepatitis B virus core protein particles

Nano-sized hepatitis B virus core virus-like particles (HBc-VLP) are suitable for uptake by antigen-presenting cells. Mycobacterium tuberculosis antigen culture filtrate protein 10 (CFP-10) is an important vaccine candidate against tuberculosis. The purified antigen shows low immune response without adjuvant and tends to have low protective efficacy. The present study is based on the assumption that expression of these proteins on HBc nanoparticles would provide higher protection when compared to the native antigen alone. The cfp-10 gene was expressed as a fusion on the major immunodominant region of HBc-VLP, and the immune response in Balb/c mice was studied and compared to pure proteins, a mixture of antigens, and fusion protein-VLP, all without using any adjuvant. The humoral, cytokine, and splenocyte cell proliferation responses suggested that the HBc-VLP bearing CFP-10 generated an antigen-specific immune response in a Th1-dependent manner. By virtue of its self-adjuvant nature and ability to form nano-sized particles, HBc-VLPs are an excellent vaccine delivery system for use with subunit protein antigens identified in the course of recent vaccine research.

Macrophage activating activity of pyrrole alkaloids from Morus alba fruits

ETHNOPHARMACOLOGICAL RELEVANCE

The fruits of Morus alba have been traditionally used as a tonic to enhance immune responses.

MATERIALS AND METHODS

The macrophage activating constituents of Morus alba fruits were purified using various column chromatography techniques. The structures of isolated compounds were determined on the basis of spectroscopic data interpretation such as 1D and 2D NMR analysis. The macrophage activating activities of isolated compounds were evaluated by measuring the production of nitric oxide, TNF-α and IL-12 in RAW 264.7 cells. The phagocytic activity was also evaluated.

RESULTS

Five pyrrole alkaloids, 5-(hydroxymethyl)-1H-pyrrole-2-carboxaldehyde (1), 2-formyl-1H-pyrrole-1-butanoic acid (2), 2-formyl-5-(hydroxymethyl)-1H-pyrrole-1-butanoic acid (3), 2-formyl-5-(methoxymethyl)-1H-pyrrole-1-butanoic acid (4) and Morrole A (5) were isolated from the fruits of Morus alba. Morrole A (5) is first reported in nature and other pyrrole alkaloids (1-4) are first reported from Morus species. Among the isolated compounds, compounds 3 and 4 significantly activated macrophage activity by the enhancement of nitric oxide, TNF-α and IL-12 production, and the stimulation of phagocytic activity in RAW 264.7 cells.

CONCLUSION

Pyrrole alkaloids, including a new compound, were isolated from Morus alba fruits. These compounds activated macrophage activity in RAW 264.7 cells.

Comparative studies of saponins in 1-3-year-old main roots, fibrous roots, and rhizomes of Panax notoginseng, and identification of different parts and growth-year samples

Notoginsenosides R1, R4, Fa, and K (N-R1, N-R4, N-Fa, and N-K), as well as ginsenosides Rg1, Rb1, Rd, Re, Rf, Rg2 and Rh1 (G-Rg1, G-Rb1, G-Rd, G-Re, G-Rf, G-Rg2 and G-Rh1) in 47 Notoginseng samples including 1-, 2- and 3-year-old main roots, rhizomes and fibrous roots of Panax notoginseng were determined by high-performance liquid chromatography-diode array detection method. Total contents (%) of the 11 saponins were 9.82-14.57 for 2-year old and 14.20-16.00 for 3-year-old rhizomes; 2.72-4.50 for 2-year-old and 1.98-4.92 for 3-year-old fibrous roots; 1.75-3.05 for 1-year-old whole roots; and 3.71-8.98 for 2-year-old and 7.03-11.23 for 3-year-old main roots. Contents of most saponins and total content of 11 saponins were in the order 3- >2- >1-year-old main root samples. G-Rf content, sum of G-Rf and G-Rh1 were, respectively, 0.08-0.18 and 0.14-0.32 for 2- or 3-year-old rhizomes, and 0.01-0.07 and 0.03-0.10 for 2- or 3-year-old main roots. Combined contents of N-R1, G-Rg1 and G-Rb1 were 5.78-9.37 in 3-year-old main roots, and 2.99-7.13 in 2-year-old main roots, of which nearly one-third of samples were lower than the limit (5 %) in the Chinese Pharmacopoeia. Those of 2- or 3-year-old fibrous roots (1.47-3.83) and 1-year-old whole roots (1.41-2.44) were much lower than the limit, and were considered not suitable for use as Notoginseng. Two-year-old main roots are not appropriate for collection as Notoginseng. Different parts and growth years of P. notoginseng can be identified from each another according to differences in saponin content.

Inhibitory effect of ginsenoside-Rd on carrageenan-induced inflammation in rats

A previous study reported that ginsenoside-Rd reduced the production of tumor necrosis factor-α by inhibiting nuclear factor-κB in lipopolysaccharide-activated N9 microglia in vitro. The aim of the present study was to confirm the anti-inflammatory effects and mechanisms of ginsenoside-Rd in animal experiments involving acute inflammation. The results indicated that ginsenoside-Rd at doses ranging from 12.5 to 50 mg/kg i.m. significantly inhibited the swelling of hind paws in rats for 1-6 h after the carrageenan injection. The levels of proinflammatory cytokines and proinflammatory mediators were markedly reduced by ginsenoside-Rd. Ginsenoside-Rd, when administered intramuscularly at 12.5, 25, and 50 mg/kg doses, showed signicant inhibition of carrageenan-induced production of interleukin-1β (6.91%, 45.75%, and 55.18%, respectively), tumor necrosis factor-α (37.99%, 56.39%, and 47.38%, respectively), prostaglandin E(2) (22.92%, 30.12%, and 36.36%, respectively), and nitric oxide (28.27%, 44.53%, and 53.42%, respectively). In addition, ginsenoside-Rd (12.5, 25, and 50 mg/kg i.m.) effectively decreased the levels of nuclear factor-κB (6.77%, 20.28%, and 41.03%, respectively) and phosphorylation of IκBα (13.23%, 26.92%, and 41.80%, respectively) in the carrageenan-inflamed paw tissues. These results suggest that ginsenoside-Rd has significant anti-inflammatory effects in vivo, which might be due to its blocking of the nuclear factor-κB signaling pathway. Thus, it may be possible to develop ginsenoside-Rd as a useful agent for inflammatory diseases.

Mycobacterial cell-wall skeleton as a universal vaccine vehicle for antigen conjugation

Mycobacterial cell-wall skeleton (CWS) is an immunoactive and biodegradable particulate adjuvant and has been used for immunotherapy in patients with cancer. The CWS of Mycobacterium bovis bacillus Calmette-Guérin (BCG-CWS) was studied as a universal vaccine vehicle for antigen conjugation, to develop potentially effective and safe vaccines. Here, we describe experiments in which protein antigens, such as keyhole limpet haemocyanin (KLH), ovalbumin (OVA) and bovine serum albumin (BSA) were highly efficiently coupled to 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide (EDC/NHS)-activated carboxyl groups of BCG-CWS, and tested the immunogenicity of OVA-conjugated BCG-CWS vaccine. We found that a strong immune response was induced in mice immunised with OVA-conjugated BCG-CWS, which was similar to the enhancement of the immune responses in mice immunised with OVA and complete Freund's adjuvant. Covalent conjugation of OVA to BCG-CWS was essential for Th1-skewed immune responses, with prominent expression of IFN-γ. Furthermore, antigen-conjugated BCG-CWS vaccine is simple to manufacture, safe, and easy to use. Our results suggest that mycobacterial CWS as a universal vaccine vehicle for conjugation of a wide variety of antigens constitutes a breakthrough for development of the most promising vaccines for infections, allergic diseases, and cancer.

Adjuvant activities of saponins from traditional Chinese medicinal herbs

New generation vaccines such as recombinant, antigen purified and DNA vaccines are poorly immunogenic due to the lack of an innate immune stimulus. Therefore, search of new adjuvants for these vaccines has become a topic of interesting. In new adjuvant development, saponins are outstanding candidates. Recently, increased attention has been received on plant-derived saponins in search of new adjuvant candidates from traditional Chinese medicinal herbs such as Panax ginseng, Astragalus species, Panax notoginseng,Cochinchina momordica, Glycyrrhiza uralensis and Achyranthes bidentata. Many of the saponins have been found to have adjuvant effects on purified protein antigens. The chemical structures of the saponins are related to their adjuvant activities, and influence the nature of the immune responses. Saponin adjuvants have been reported to stimulate secretion of a broad range of cytokines, suggesting that saponins may act by triggering innate immunity. As these plant-originated adjuvants may promote different branches of the immune system, they have the potential to be used in design of new vaccines so as to induce a desired immune response.

Advances in saponin-based adjuvants

Saponins are natural glycosides of steroid or triterpene which exhibited many different biological and pharmacological activities. Notably, saponins can also activate the mammalian immune system, which have led to significant interest in their potential as vaccine adjuvants. The most widely used saponin-based adjuvants are Quil A and its derivatives QS-21, isolated from the bark of Quillaja saponaria Molina, which have been evaluated in numerous clinical trials. Their unique capacity to stimulate both the Th1 immune response and the production of cytotoxic T-lymphocytes (CTLs) against exogenous antigens makes them ideal for use in subunit vaccines and vaccines directed against intracellular pathogens as well as for therapeutic cancer vaccines. However, Quillaja saponins have serious drawbacks such as high toxicity, undesirable haemolytic effect and instability in aqueous phase, which limits their use as adjuvant in vaccination. It has driven much research for saponin-based adjuvant from other kinds of natural products. This review will summarize the current advances concerning adjuvant effects of different kinds of saponins. The structure-activity relationship of saponin adjuvants will also be discussed in the light of recent findings. It is hoped that the information collated here will provide the reader with information regarding the adjuvant potential applications of saponins and stimulate further research into these compounds.

Evaluation of widely consumed botanicals as immunological adjuvants

BACKGROUND

Many widely used botanical medicines are claimed to be immune enhancers. Clear evidence of augmentation of immune responses in vivo is lacking in most cases. To select botanicals for further study based on immune enhancing activity, we study them here mixed with antigen and injected subcutaneously (s.c.). Globo H and GD3 are cell surface carbohydrates expressed on glycolipids or glycoproteins on the cell surface of many cancers. When conjugated to keyhole limpet hemocyanin (KLH), mixed with an immunological adjuvant and administered s.c. the magnitude of the antibody responses against globo H, GD3 and KLH depend largely on the potency of the adjuvant. We describe here the results obtained using this s.c. immunization model with seven botanicals purported to have immune stimulant effects.

METHODS

Groups of 5-10 mice were immunized with globo H-KLH or GD3-KLH mixed with botanical, saline or positive control immunological adjuvant, s.c. three times at 1 week intervals. Antibody responses were measured 1 and 2 weeks after the 3rd immunization. The following seven botanicals and fractions were tested: (1) H-48 (Honso USA Co.), (2) Coriolus versicolor raw water extract, purified polysaccharide-K (PSK) or purified polysaccharide-peptide (PSP) (Institute of Chinese Medicine (ICM)), (3) Maitake extract (Yukiguni Maitake Co. Ltd. and Tradeworks Group), (4) Echinacea lipophilic, neutral and acidic extracts (Gaia Herbs), (5) Astragalus water, 50% or 95% ethanol extracts (ICM), (6) Turmeric supercritical (SC) or hydro-ethanolic (HE) extracts (New Chapter) or 60% ethanol extract (ICM) and (7) yeast beta-glucan (Biotec Pharmacon). Purified saponin extract QS-21 (Antigenics) and semisynthetic saponin GPI-0100 (Advanced BioTherapies) were used as positive control adjuvants. Sera were analyzed by ELISA against synthetic globo H ceramide or GD3 and KLH.

RESULTS

Consistent significant adjuvant activity was observed after s.c. vaccination with the Coriolus extracts (especially PSK), a 95% ethanol extract of Astragalus and yeast beta-glucan, and (to a lesser extent) Maitake. Antibodies against KLH in all cases and against globo H in most cases were induced by these botanicals. Little or no adjuvant activity was demonstrated with H-48 or Echinacea extracts or the Astragalus water extract. Experiments with GD3-KLH as immunogen confirmed the adjuvant activity of the Coriolus, yeast beta-glucan and Astragalus extracts. While extraction with ethanol concentrated the active ingredients in Astragalus, it had no impact on Coriolus where the 90% ethanol precipitate and solute were equally active.

CONCLUSIONS

Some, but not all, botanicals purported to be immune stimulants had adjuvant activity in our model. PSK and Astragalus were surprisingly active and are being further fractionated to identify the most active adjuvant components.

Inhibitory effects of ginsenosides and their hydrolyzed metabolites on daunorubicin transport in KB-C2 cells

We studied the effects of ginsenosides and their metabolites on daunorubicin transport in multidrug-resistant P-glycoprotein (P-gp)-overexpressing KB-C2 cells. Ginsenoside Rg1, which is a protopanaxatriol-type ginseng saponin, did not have any effects on the accumulation of P-gp substrate daunorubicin. On the other hand, its metabolite M4, which has no sugar moiety, increased the accumulation 3.6-fold at 5 microM. Metabolites of protoanaxadiol-type saponin M1 and M12 also increased accumulation, but the effects were less than that of M4. The findings showed larger effects of metabolites without glucose moieties. Analysis of verapamil-stimulated ATPase activity in membrane vesicles expressing human P-gp suggested that the increased daunorubicin accumulation by M4 was at least partly due to ATPase inhibition of P-gp.

Ginsenoside Rd from Panax notoginseng is cytotoxic towards HeLa cancer cells and induces apoptosis

The saponin ginsenoside Rd (1), isolated from Panax notoginseng, is used for the treatment of cardiovascular diseases, inflammation, different body pains, trauma, and internal and external bleeding due to injury. In this study, we report that 1 inhibits the cell growth of human cervical cancer (HeLa) cells in a concentration- and time-dependent manner, with an IC(50) value of 150.5+/-0.8 mcirog/ml after 48 h of incubation. The drug-treated cells displayed features of apoptosis, including typical morphological characteristics and formation of DNA ladders, as evident from agarose-gel electrophoresis. Flow-cytometric analysis showed that the cell-cycle distribution of HeLa cells exposed to 1 is characterized by a decrease of the G(0)/G(1)-phase and an increase of the S-phase cells, respectively, in a dose-dependent manner. The apoptotic rate of HeLa cells treated for 48 h with 210 microg/ml of 1 was 35.8%. Further, 1 was found to increase the expression of Bax and to decrease the expression of Bcl-2 proteins, respectively, and to lower the mitochondrial transmembrane potential of HeLa cells. The caspase-3 inhibitor DEVD-CHO (at 2 microM) increased the viability of HeLa cells treated with 1. Taken together, our study suggests that ginsenoside Rd (1) significantly inhibits HeLa cell proliferation, and induces cell apoptosis through down-regulating Bcl-2 expression, up-regulating Bax expression, lowering the mitochondrial transmembrane potential, and activating the caspase-3 pathway. Thus, 1 could serve as a lead to develop novel chemotherapeutic or chemopreventive agents against human cervical cancer.

Immunological Adjuvant Effect of Ginsenoside Rh4 from the Roots ofPanax notoginseng on Specific Antibody and Cellular Response to Ovalbumin in Mice

Ginsenoside Rh(4) (1), a saponin isolated from the roots of Panax notoginseng (Burk.) F. H. Chen, was evaluated for its haemolytic activity and adjuvant potential on specific antibody and cellular response to ovalbumin (OVA) in mice. Compound 1 showed a slight haemolytic effect, its concentration inducing 50% of the maximum haemolysis (HD(50) value) being 407+/-12 microg/ml using a 0.5% suspension of red blood cells. Compound 1 significantly increased the concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and OVA-induced splenocyte proliferation in OVA-immunized mice especially at a dose of 25 microg (P<0.05, P<0.01, or P<0.001). The OVA-specific serum IgG, IgG1, and IgG2b antibody levels were also significantly enhanced by 1 at a dose of 25 microg compared to the OVA control group (P<0.05 or P<0.01). Moreover, the enhancing effect of 1 on the OVA-specific IgG2b antibody responses to OVA in mice was more significant than that of Alum (Al(OH)(3) gel; P<0.01). These results suggest that 1 could be safely used as adjuvant with low or non-haemolytic effect.

Ginsenoside Rd elicits Th1 and Th2 immune responses to ovalbumin in mice

Ginsenoside Rd (Rd), a saponin isolated from the roots of panax notoginseng, was evaluated for inducing Th1 or Th2 immune responses in mice against ovalbumin (OVA). ICR mice were immunized subcutaneously with OVA 100 microg alone or with OVA 100 microg dissolved in saline containing alum (200 microg), or Rd (10, 25 or 50 microg) on days 1 and 15. Two weeks later (day 28), concanavalin A (Con A)-, lipopolysaccharide (LPS)- and OVA-stimulated splenocyte proliferation was determined using MTT assay, and OVA-specific antibody titers and levels of cytokines in serum were measured by ELISA and microparticle-based flow cytometric immunoassay, as well as peripheral blood T-lymphocyte subsets analyzed using flow cytometer. Rd significantly enhanced the Con A-, LPS-, and OVA-induced splenocyte proliferation in the OVA-immunized mice. OVA-specific IgG, IgG1, and IgG2b antibody titers in serum were significantly enhanced by Rd compared with OVA control group. Meanwhile, Rd also significantly promoted the production of the Th1 and Th2 cytokines in OVA-immunized mice. Further, the effects of Rd on expression of cytokine mRNA in Con A-stimulated mice splenocytes were evaluated by RT-PCR analysis. Rd significantly enhanced the interleukin-2 (IL-2), interferon-gamma (IFN-gamma), IL-4, and IL-10 mRNA expression in mice splenocyte induced by Con A. These results suggested that Rd had immunological adjuvant activity, and elicited a Th1 and Th2 immune response by regulating production and gene expression of Th1 cytokines and Th2 cytokines.

Immunological adjuvant effect of Glycyrrhiza uralensis saponins on the immune responses to ovalbumin in mice

In this study, the haemolytic activities of Glycyrrhiza uralensis saponins (GLS) and its adjuvant potentials on the cellular and humoral immune responses of ICR mice against ovalbumin (OVA) were evaluated. We determined the haemolytic activity of GLS using 0.5% rabbit red blood cell. Haemolytic percents of GLS-treated red blood cell were 11.20 and 5.54% at the concentrations of 500 and 250 microg/ml, respectively. ICR mice were immunized subcutaneously with OVA 100 microg alone or with OVA 100 microg dissolved in saline containing Alum (200 microg), QuilA (10 and 20 microg), or GLS (50, 100, or 200 microg) on Days 1 and 15. Two weeks later (Day 28), concanavalin A (Con A)-, lipopolysaccharide (LPS)-, and OVA-stimulated splenocyte proliferation and OVA-specific serum antibodies were measured. GLS significantly enhanced the Con A-, LPS-, and OVA-induced splenocyte proliferation in the OVA-immunized mice at a dose of 100 microg (P<0.025). OVA-specific IgG, IgG1, and IgG2b antibody titers in serum were also significantly enhanced by GLS compared with OVA control group (P<0.025). Moreover, no significant differences (P>0.05) were observed between enhancing effect of GLS and QuilA on the OVA-specific IgG, IgG1, and IgG2b antibody responses to OVA in mice. The results suggest that GLS showed a slight haemolytic effect and enhanced significantly a specific antibody and cellular response against OVA in mice, and deserved further researches to be developed as immunological adjuvant.