Induction of differentiation in rat C6 glioma cells with Saikosaponins

Pharmacology, medical uses, and clinical translational challenges of Saikosaponin A: A review

Saikosaponin A (SSA), the primary active monomer derived from the Radix bupleuri, demonstrates a diverse array of pharmacological activities, including anti-inflammatory, antitumor, analgesic, anti-fibrotic, antidepressant, and immune-modulating properties. Despite its potential therapeutic impact on various human diseases, comprehensive studies exploring SSA's efficacy in these contexts remain limited. This review synthesizes the current research landscape regarding SSA's therapeutic applications across different diseases, highlighting critical insights to overcome existing limitations and clinical challenges. The findings underscore the importance of further investigations into SSA's mechanisms of action, facilitating the development of targeted therapeutic strategies and their translation into clinical practice.

A Network Pharmacology Prediction and Molecular Docking-Based Strategy to Explore the Potential Pharmacological Mechanism of Astragalus membranaceus for Glioma

Glioma treatment in traditional Chinese medicine has a lengthy history. Astragalus membranaceus, a traditional Chinese herb that is frequently utilized in therapeutic practice, is a component of many Traditional Chinese Medicine formulas that have been documented to have anti-glioma properties. Uncertainty persists regarding the molecular mechanism behind the therapeutic effects. Based on results from network pharmacology and molecular docking, we thoroughly identified the molecular pathways of Astragalus membranaceus' anti-glioma activities in this study. According to the findings of the enrichment analysis, 14 active compounds and 343 targets were eliminated from the screening process. These targets were mainly found in the pathways in cancer, neuroactive ligand-receptor interaction, protein phosphorylation, inflammatory response, positive regulation of phosphorylation, and inflammatory mediator regulation of Transient Receptor Potential (TRP) channels. The results of molecular docking showed that the active substances isoflavanone and 1,7-Dihydroxy-3,9-dimethoxy pterocarpene have strong binding affinities for the respective targets ESR2 and PTGS2. In accordance with the findings of our investigation, Astragalus membranaceus active compounds exhibit a multicomponent and multitarget synergistic therapeutic impact on glioma by actively targeting several targets in various pathways. Additionally, we propose that 1,7-Dihydroxy-3,9-dimethoxy pterocarpene and isoflavanone may be the main active ingredients in the therapy of glioma.

Antitumor mechanism of Saikosaponin A in the Xiaoying Sanjie Decoction for treatment of anaplastic thyroid cancer by network pharmacology analysis and experiments in vitro and in vivo

Effective therapies for anaplastic thyroid cancer (ATC) are still limited due to its dedifferentiated phenotype and high invasiveness. Xiaoying Sanjie Decoction (XYSJD), a clinically empirical Chinese medicine compound, has shown positive effects for ATC treatment and recovery. However, the pharmacological mechanisms of effective active compound in XYSJD remain unclear. In this study, we aimed at elucidating the antitumor mechanism of the active compound and identifying the kernel molecular mechanisms of XYSJD against ATC. Firstly, the main chemical constituents of XYSJD were identified by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS). Then we used network pharmacology and ClusterONE algorithm to analyze the possible targets and pathways of the prescription and active compound Saikosaponin A (SSA). Seven core targets, including P2RY12, PDK1, PPP1CC, PPP2CA, TBK1, ITGB1 and ITGB6, which may be involved in the anti-tumor activity of XYSJD were screened. Finally, using cell biology, molecular biology and experimental zoology techniques, we investigated the mechanism of active compound SSA in the treatment of ATC. The results of qRT-PCR indicated that these seven nuclear targets might play an important role in SSA, the active compound of XYSJD. The combined data provide preliminary study of the pharmacological mechanisms of SSA in XYSJD. SSA may be a promising potential therapeutic and chemopreventive candidate for ATC.

Chemotherapeutic Potential of Saikosaponin D: Experimental Evidence

Saikosaponin D (SSD), an active compound derived from the traditional plant Radix bupleuri, showcases potential in disease management owing to its antioxidant, antipyretic, and anti-inflammatory properties. The toxicological effects of SSD mainly include hepatotoxicity, neurotoxicity, hemolysis, and cardiotoxicity. SSD exhibits antitumor effects on multiple targets and has been witnessed in diverse cancer types by articulating various cell signaling pathways. As a result, carcinogenic processes such as proliferation, invasion, metastasis, and angiogenesis are inhibited, whereas apoptosis, autophagy, and differentiation are induced in several cancer cells. Since it reduces side effects and strengthens anti-cancerous benefits, SSD has been shown to have an additive or synergistic impact with chemo-preventive medicines. Regardless of its efficacy and benefits, the considerations of SSD in cancer prevention are absolutely under-researched due to its penurious bioavailability. Diverse studies have overcome the impediments of inadequate bioavailability using nanotechnology-based methods such as nanoparticle encapsulation, liposomes, and several other formulations. In this review, we emphasize the association of SSD in cancer therapeutics and the discussion of the mechanisms of action with the significance of experimental evidence.

Systematic transcriptome analysis reveals molecular mechanisms and indications of bupleuri radix

Pharmacogenomic analysis based on drug transcriptomic signatures is widely used to identify mechanisms of action and pharmacological indications. Despite accumulating reports on the efficacy of medicinal herbs, related transcriptome-level analyses are lacking. The aim of the present study was to elucidate the underlying molecular mechanisms of action of Bupleuri Radix (BR), a widely used herbal medicine, through a systematic transcriptomic analysis. We analyzed the drug-responsive transcriptome profiling of A549 lung cancer cell line after treating them with multiple doses of BR water (W-BR) and ethanol (E-BR) extracts and their phytochemicals. In vitro validation experiments were performed using both A549 and the immortalized human keratinocyte line HaCaT. Pathway enrichment analysis revealed the anti-cancer effects of BR treatment via inhibition of cell proliferation and induction of apoptosis. Enhanced cell adhesion and migration were observed with the W-BR but not with the E-BR. Comparison with a disease signature database validated an indication of the W-BR for skin disorders. Moreover, W-BR treatment showed the wound-healing effect in skin and lung cells. The main active ingredients of BR showed only the anti-cancer effect of the E-BR and not the wound healing effect of the W-BR, suggesting the need for research on minor ingredients of BR.

Saikosaponin A Inhibits Growth of Human Bladder Carcinoma T24 and 5637 Cells Both in Vitro and in Vivo

Saikosaponin A (SSA)-a natural compound extracted from Radix bupleuri-possesses antitumor properties in several types of carcinomas. However, the role of SSA on bladder cancer and the mechanisms remain unclear. In this study, we have described the effect of SSA on human bladder cancer cell lines T24 and 5637 in the context of the regulation of mitochondrial pathways of apoptosis. In vitro, the Cell Counting Kit-8 (CCK-8) assay and cell wound healing assays were used to determine the proliferative effect of SSA treatment. Flow cytometry and Western blotting were performed to evaluate the apoptosis and related mechanisms. To further confirm that apoptosis is mediated through Caspase activation, Hoechst 33258 fluorescence staining assay was done after cells were treated with SSA and caspase inhibitor-Z-VAD-FMK. In vivo, an orthotopic xenograft mice model was adopted to evaluate the effect of SSA. The tumors were analyzed by hematoxylin-eosin (H&E) staining, immunohistochemical analysis, and Western blotting. In vitro, the results with CCK-8 assay showed obvious SSA-induced suppression in cell growth in a dose- and time-dependent manner. Flow cytometry analysis, Hoechst 33258 fluorescence staining assay and the assessment of the changes in the B-cell lymphoma 2 (Bcl-2) family protein expression level revealed that SSA could significantly induce cell apoptosis, which was associated with apoptosis via the mitochondrial pathways. In vivo, the results revealed a reduction in cell proliferation. In conclusion, our data suggest that SSA inhibits the growth of bladder cancer cells by activating the mitochondrial apoptosis pathway and inducing cell apoptosis.

Saikosaponin D: review on the antitumour effects, toxicity and pharmacokinetics

CONTEXT

Bupleuri Radix, the dried root of Bupleurum chinense DC and Bupleurum scorzonerifolium Willd (Apiaceae), is an important medicinal herb widely used to treat cancers for hundreds of years in Asian countries. As the most antitumour component but also the main toxic component in Bupleuri Radix, saikosaponin D (SSD) has attracted extensive attention. However, no summary studies have been reported on the antitumour effects, toxicity and pharmacokinetics of this potential natural anticancer substance.

OBJECTIVE

To analyse and summarise the existing findings regarding to the antitumour effects, toxicity and pharmacokinetics of SSD.

MATERIALS AND METHODS

We collected relevant information published before April 2021 by conducting a search of literature available in various online databases including PubMed, Science Direct, CNKI, Wanfang database and the Chinese Biological Medicine Database. Bupleurum, Bupleuri Radix, saikosaponin, saikosaponin D, tumour, toxicity, and pharmacokinetics were used as the keywords.

RESULTS

The antitumour effects of SSD were multi-targeted and can be realised through various mechanisms, including inhibition of proliferation, invasion, metastasis and angiogenesis, as well as induction of cell apoptosis, autophagy, and differentiation. The toxicological effects of SSD mainly included hepatotoxicity, neurotoxicity, haemolysis and cardiotoxicity. Pharmacokinetic studies demonstrated that SSD had the potential to alter the pharmacokinetics of some drugs for its influence on CYPs and P-gp, and the oral bioavailability and actual pharmacodynamic substances in vivo of SSD are still controversial.

CONCLUSIONS

SSD is a potentially effective and relatively safe natural antitumour substance, but more research is needed, especially in vivo antitumour effects and pharmacokinetics of the compound.

Protective effect of dietary supplementation of Bupleurum falcatum L saikosaponins on ammonia exposure-induced ileum injury in broilers

Ammonia (NH3) at a high concentration has been recognized as a highly poisonous pollutant affecting both air and water quality. NH3, as a stimulus, exerts negative impact on broiler growth and production, but the molecular mechanisms are not clear yet. This study was designed to evaluate the effects of dietary supplementation of Bupleurum falcatum L saikosaponins (SP) on the growth and ileum health status in broilers exposed to NH3. Day-old Arbor Acers broilers (n = 480) were randomly allocated into 1 of 4 treatments. The main factors were dietary SP supplementation (0 or 80 mg/kg of diet) and NH3 challenge (with or without 70 ± 5 ppm NH3). The data of growth, intestinal morphology, and mRNA expression related to ileal function were collected from broilers exposed to NH3 for 7 d. Results showed that NH3 remarkably suppressed growth performance and intestinal development as well as induced biological injuries in the ileum of broilers, resulting from oxidative stress, mucous barrier damage, and immune dysfunction as well as upregulated apoptosis. These negative effects of NH3 were alleviated by the SP supplement. In conclusion, dietary supplementation of SP may be helpful in alleviating the detrimental effects of NH3 on the ileum development in broilers.

Inhibition of TGF-β Signaling in Gliomas by the Flavonoid Diosmetin Isolated from Dracocephalum peregrinum L

Background: Dracocephalum peregrinum L., a traditional Kazakh medicine, has good expectorant, anti-cough, and to some degree, anti-asthmatic effects. Diosmetin (3',5,7-trihydroxy-4'-methoxyflavone), a natural flavonoid found in traditional Chinese herbs, is the main flavonoid in D. peregrinum L. and has been used in various medicinal products because of its anticancer, antimicrobial, antioxidant, estrogenic, and anti-inflammatory effects. The present study aimed to investigate the effects of diosmetin on the proliferation, invasion, and migration of glioma cells, as well as the possible underlying mechanisms. Methods: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), scratch wound, and Transwell assays were used to demonstrate the effects of diosmetin in glioma. Protein levels of Bcl-2, Bax, cleaved caspase-3, transforming growth factor-β (TGF-β), E-cadherin, and phosphorylated and unphosphorylated smad2 and smad3 were determined by Western blots. U251 glioma cell development and progression were measured in vivo in a mouse model. Results: Diosmetin inhibited U251 cell proliferation, migration, and invasion in vitro, the TGF-β signaling pathway, and Bcl-2 expression. In contrast, there was a significant increase in E-cadherin, Bax, and cleaved caspase-3 expression. Furthermore, it effectively reduced the tumorigenicity of glioma cells and promoted apoptosis in vivo. Conclusion: The results of this study suggest that diosmetin suppresses the growth of glioma cells in vitro and in vivo, possibly by activating E-cadherin expression and inhibiting the TGF-β signaling pathway.

The Role of Saikosaponins in Therapeutic Strategies for Age-Related Diseases

As life expectancy increases, elderly populations tend to spend an increasing number of years in poor health, with chronic age-related diseases and disability. Therefore, the development of therapeutic strategies to treat or prevent multiple pathophysiological conditions in the elderly may improve health-adjusted life expectancy and alleviate the potential economic and social burdens arising from age-related diseases. Bioactive natural products might represent promising new drug candidates for the treatment of many chronic age-related diseases, including cancer, Alzheimer's disease, cardiovascular disease, obesity, and liver disease. Here, we discuss a therapeutic option using saikosaponins, which are triterpene saponins isolated from Bupleurum, against a variety of age-related diseases. Understanding the underlying mechanisms of natural products like saikosaponins in the treatment of age-related diseases may help in the development of diverse natural product-derived compounds that may be effective against a number of chronic health problems.

Ultrasound-assisted Extraction of Polysaccharide from Radix Bupleuri using Response Surface Methodology and Antioxidant Research of the Polysaccharide

This report used Response Surface Methodology (RSM) to analyze the conditions that extracting polysaccharide compound from Radix Bupleuri using ultrasonic wave. For determining the optimal extraction conditions, four independent variables, temperature (°C), ultrasonic intensity (UI, W/cm2), dilution rate (water-material ratio, mL/g) and time (min), were investigated using Box-Behnken design. In the results, the best condition after optimization was dilution rate of 35.0:1, UI of 24.5 W/cm2, temperature of 69.5°C and time of 14.6 min. Extraction efficiency was 7.67% and the purity reached 44.14%. It illustrates that the ultrasound-assisted extraction (UAE) was efficient and suitable for extracting polysaccharide from Radix Bupleuri. This paper also investigated the antioxidant activity of Radix Bupleuri polysaccharide (RBP) on superoxide anion radical, hydroxyl radical, and 2,2-diphenyl-1-picry-hydrazyl (DPPH), in vitro experiment. The result indicated that RBP could remarkably sweep away the hydroxyl radical, and had the capacity for clearing away superoxide radical and DPPH.

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

CONTEXT

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

OBJECTIVE

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

METHODS

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

RESULTS AND CONCLUSION

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

Rhein induces apoptosis and autophagy in human and rat glioma cells and mediates cell differentiation by ERK inhibition

In this study, we investigated the anticancer potentials of Rhein, an anthraquinone derivative of most commonly used Chinese rhubarb on the rat F98 glioma cells. The experimental studies revealed that Rhein induced cell cycle arrest, caspase mediated apoptosis. It results in the formation of intracellular acidic vesicles in cytoplasm, leading to autophagy. Differentiation of viable cells towards elongation of matured astrocytes was proved by monitoring dramatic changes in morphological characteristics as well as identified from the elevation of glial fibrillary acidic protein (GFAP) expression. Rhein treatment did not alter the phosphorylated MAPKs activation including p-38, JNK and NF-κB, transcription unit whereas rhein significantly inhibited ERK1/2 activation in F98 glioma cells. PD98059, a specific inhibitor for ERK activation imitates rhein effects on morphology and expressions of GFAP but did not help to induce any apoptosis or autophagy. Collective data exhibited that potentials of rhein in anti-cancer property in ERK-independent apoptosis and autophagy in association with downregulated ERK-dependent differentiation process of glioma cell lines.

Angelica polysaccharides inhibit the growth and promote the apoptosis of U251 glioma cells in vitro and in vivo

BACKGROUND

Angelica sinensis (Oliv) Diels (Apiaceae) is a traditional medicine that has been used for more than 2000 years in China. It exhibits various therapeutic effects including neuroprotective, anti-oxidant, anti-inflammatory, and immunomodulatory activities. Angelica polysaccharides (APs), bioactive constituents of Angelica have been shown to be responsible for these effects; however, the utility of APs for the treatment of glioma and their mechanism of action remain to be elucidated.

PURPOSE

In this study, we investigated the inhibitory effects of APs on a glioma cell line and their molecular mechanism of action.

STUDY DESIGN

U251 cells were utilized to confirm the effects of APs on glioma.

METHODS

The human glioblastoma cell line U251 was utilized for both in vitro and in vivo models, in which we tested the effects of APs. Flow cytometry, gene expression analysis, western blotting, and MTT assays were used to elucidate the effects of APs on cell proliferation, cell cycle, and apoptosis.

RESULTS

The results demonstrated that APs significantly inhibited the growth and proliferation of U251 cells and induced their apoptosis. Furthermore, APs effectively reduced the expression of several cell cycle regulators: cyclins D1, B, and E. The apoptosis suppressor protein Bcl-2 was also downregulated, and the expression of pro-apoptotic proteins Bax and cleaved-caspase-3 increased. Additionally, APs inhibited the transforming growth factor (TGF)-β signaling pathway and stimulated the expression of E-cadherin, thus prohibiting cell growth.

CONCLUSION

In conclusion, the results indicate that APs attenuate the tumorigenicity of glioma cells and promote their apoptosis by suppressing the TGF-β signaling pathway. The present study therefore provides evidence of the inhibitory effects of APs against glioma progression, and proposes their potential application as alternative therapeutic agents for glioma.

Saponins from Chinese Medicines as Anticancer Agents

Saponins are glycosides with triterpenoid or spirostane aglycones that demonstrate various pharmacological effects against mammalian diseases. To promote the research and development of anticancer agents from saponins, this review focuses on the anticancer properties of several typical naturally derived triterpenoid saponins (ginsenosides and saikosaponins) and steroid saponins (dioscin, polyphyllin, and timosaponin) isolated from Chinese medicines. These saponins exhibit in vitro and in vivo anticancer effects, such as anti-proliferation, anti-metastasis, anti-angiogenesis, anti-multidrug resistance, and autophagy regulation actions. In addition, related signaling pathways and target proteins involved in the anticancer effects of saponins are also summarized in this work.

Saikosaponin A, an active glycoside from Radix bupleuri, reverses P-glycoprotein-mediated multidrug resistance in MCF-7/ADR cells and HepG2/ADM cells

1. The expression and function of P-glycoprotein (P-gp) is associated with the phenotype of multidrug resistance (MDR). Saikosaponin A (SSA) is a triterpenoid saponin isolated from Radix Bupleuri. This study was mainly designed to understand effects of SSA on MDR in MCF-7/ADR and HepG2/ADM cells. 2. MDR reversal was examined as the alteration of cytotoxic drugs IC50 in resistant cells in the presence of SSA by MTT assay, and was compared with the non-resistant cells. Apoptosis and uptake of P-gp substrates in the tumor cells were detected by flow cytometry. Western blot was performed to assay the expression of P-gp. 3. Our results demonstrate SSA could increase the chemosensitivity of P-gp overexpressing HepG2/ADM and MCF-7/ADR cells to doxorubicin (DOX), vincristine (VCR) and paclitaxel. SSA promoted apoptosis of MCF-7/ADR cells in the presence of DOX. Moreover, it could also increase the retention of P-gp substrates DOX and rhodamine 123 in MCF-7/ADR cells, and decrease digoxin efflux ratio in Caco-2 cell monolayer. Finally, a mechanistic study showed that SSA reduced P-gp expression without affecting hydrolytic activity of P-gp. 4. In conclusion, our findings suggest that SSA could be further developed for sensitizing resistant cancer cells and used as an adjuvant therapy together with anticancer drugs to improve their therapeutic efficacies.

Investigation of the anti-glioma activity of Oviductus ranae protein hydrolysate

Oviductus Ranae is the dry oviducts of Rana temporaria chensinensis, and it has been reported to have a range of biological activities. This study aimed to investigate the effects of Oviductus Ranae protein hydrolysate (ORPH) on human glioma C6 cell proliferation and apoptosis in vitro and in vivo. Following in vitro treatment, cell viability and colony formation assays showed that ORPH inhibited C6 cell proliferation. In addition, the results of western blotting also demonstrated that ORPH effectively regulated the expression of the apoptosis related proteins, cleaved caspase-3, Bax and Bcl-2, DNA staining and flow cytometry analysis demonstrated that ORPH significantly promoted apoptosis in this cell line, a finding that was confirmed in vivo using terminal deoxynucleotidyl transferase dUTP nick end labeling. Further investigation demonstrated that ORPH increased apoptosis by modulating the release of inflammatory cytokines and the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway; this was demonstrated using a PI3K/AKT inhibitor (NVP-BEZ235). In summary, the present study suggested that ORPH promoted apoptosis and inhibited glioma cell proliferation by influencing the PI3K/AKT signaling pathway.

Ultrasensitive Time-Resolved Fluoroimmunoassay for Saikosaponin a in Chaihu (Bupleuri Radix)

The aim of this study is to establish a time-resolved fluoroimmunoassay (TRFIA) system for quantitative analysis of saikosaponin a (SSa) in the crude drug of Chaihu (Bupleuri Radix). A 96-well microplate coated with rabbit anti-mouse IgG was incubated with the methanol extracts of Chaihu samples and a mouse anti-SSa monoclonal antibody, and a Eu3+-labeled SSa-human serum albumin conjugate was used as the tracer. The established competitive TRFIA showed a good fourth order polynomial fitting from 0.01 to 10.0 μg/mL for standard SSa sample with a detection limit of 0.006 μg/mL. The intra- and inter-assay coefficients of variation of the assay were 7.3% and 8.9%, respectively, and the average SSa recovery was 119.2%. For samples of Chaihu extract, the results of this assay showed a good correlation with those by enzyme-linked immunosorbent assay established previously. This TRFIA system is ultrasensitive for detecting SSa with a wide detection range and a good stability and represents the first attempt of using TRFIA for quality evaluation of the crude drug of Chaihu.

Vinegar-baked Radix Bupleuri modulates the cell membrane constituents and inhibits the P-gp activity in rat hepatocytes

Background

Vinegar-baked Radix Bupleuri (VBRB) enhances the effects of other drugs on the liver by increasing drug distribution to the liver, but the mechanism of action remains unclear. The present study was designed to determine the effects of VBRB on the membrane permeability, constituents, and P-glycoprotein (P-gp) activity of hepatocyte BRL cells, in order to interpret the liver targeting enhancing effects of VBRB.

Methods

The membrane permeability and P-gp expression were analyzed by flow cytometry. The membrane constituents were determined by an automatic biochemistry analyzer and thin-layer chromatography.

Results

The results showed that, compared with the control, VBRB enhanced the membrane permeability by 41-67% (P < 0.05), which occurred in the absence of any cytotoxicity. VBRB had marginal effects on the cholesterol content, but significantly affected the total protein contents and the lipid constituents of the cell membrane in a dose- and time-dependent manner. VBRB inhibited P-gp expression in the cell membrane by 59-86% (P < 0.01).

Conclusion

VBRB affects the constituents of BRL cells and increases its permeability, which may help explain its liver-targeting effects.

Saikosaponin‑d suppresses the expression of cyclooxygenase‑2 through the phospho‑signal transducer and activator of transcription 3/hypoxia‑inducible factor‑1α pathway in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the most common malignancies and accounts for ~6% of all types of human cancer worldwide, particularly in Asia. The incidence and mortality rates in the USA have also rapidly increased. Saikosaponin‑d (SSD), a saponin derivative extracted from several species of Bupleurum (Umbelliferae), possesses unique biological activities, including anti‑inflammatory, antihepatitic and immunomodulatory effects. Our previous studies have demonstrated that SSD inhibits the proliferation and induces the apoptosis of HCC SMMC‑7721 cells by downregulating the expression of cyclooxygenase (COX)‑2 and decreasing the production of prostaglandin E2. However, the specific mechanism underlying how SSD controls the expression of COX‑2 remains to be elucidated. In the present study, it was demonstrated that hypoxia inducible factor‑1α (HIF‑1α) was responsible for the expression of COX‑2 under hypoxic conditions in HCC cells, and the activation of signal transducer and activator of transcription 3 (STAT3) was required for the expression of HIF‑1α. SSD treatment inhibited STAT3 activation [phosphorylation of STAT3 (p‑STAT3)], reduced the protein level of HIF‑1α and decreased the expression of COX‑2. These results suggested that SSD may target HCC cells by suppressing the expression of COX‑2 through the p‑STAT3/HIF‑1α pathway.

Glutamine synthetase functions as a negative growth regulator in glioma

Our recent study demonstrated that glutamine synthetase (GS) may not only serve as a glutamate-converting enzyme in glial cells, but may also function as a regulator of astrocyte migration after injury. In this report, we showed that GS expression increased in cultured rat C6 glioma cells that underwent long-term serially propagation. The stable overexpression of GS in C6 glioma cells resulted in growth arrest and motility suppression; however the stable knockdown of GS resulted in motility enhancement. In correlation with cell aggregation, N-cadherin levels increased at sites of cell-cell contact in C6 cells overexpressing GS, and decreased in C6 cells with stable GS knockdown; total N-cadherin expression levels remained unchanged in these cells. In addition, levels of p21, a potent cyclin-dependent kinase inhibitor, increased, while cyclin D1 levels decreased in C6 cells overexpressing GS. Our additional studies showed that N-cadherin-mediated cell-cell contacts were implicated in GS-induced cell growth arrest and impairment of cell migration, as evidenced by the inhibition of GS on cell growth and motility by the neutralizing anti-N-cadherin monoclonal antibody (GC-4 mAb). Collectively, these observations suggest a novel mechanism of growth regulation by GS that involves N-cadherin mediated cell-cell contact.

Metabolism of saikosaponin a in rats: diverse oxidations on the aglycone moiety in liver and intestine in addition to hydrolysis of glycosidic bonds

The main objective of the present study was to completely characterize the metabolites of the triterpenoid saikosaponin a (SSa) in rats. To this aim, we compared the metabolites in plasma, bile, urine, and feces samples following oral and i.v. routes of administration using liquid chromatography-diode array detector coupled with hybrid ion trap-time-of-flight mass spectrometry. As a result, besides 2 known metabolites, prosaikogenin f and saikogenin f, 15 new metabolites were detected in all. It was found that SSa is metabolized mainly in phase I manner, i.e., hydration and monooxidation on the aglycone moiety and hydrolysis of the β-glucosidic bond in the liver, and sequential hydrolysis of β-glucosidic and β-fucosidic bonds followed by dehydrogenation, hydroxylation, carboxylation, and combinations of these steps on the aglycone moiety in the intestinal tract. Both the renal and biliary routes were observed for the excretion of SSa and its metabolites. Further, a clear metabolic profile in rats was proposed in detail according to the results from the in vivo animal experiment after different routes of administration. Our results update the preclinical metabolism and disposition data on SSa, which is not only helpful for the future human metabolic study of this compound but also provides basic information for better understanding of the efficacy and safety of prescriptions containing saikosaponins.

Identification and determination of the saikosaponins in Radix bupleuri by accelerated solvent extraction combined with rapid-resolution LC-MS

A method based on accelerated solvent extraction combined with rapid-resolution LC-MS for efficient extraction, rapid separation, online identification and accurate determination of the saikosaponins (SSs) in Radix bupleuri (RB) was developed. The RB samples were extracted by accelerated solvent extraction using 70% aqueous ethanol v/v as solvent, at a temperature of 120 degrees C and pressure of 100 bar, with 10 min of static extraction time and three extraction cycles. Rapid-resolution LC separation was performed by using a C(18) column at gradient elution of water (containing 0.5% formic acid) and acetonitrile, and the major constituents were well separated within 20 min. A TOF-MS and an IT-MS were used for online identification of the major constituents, and 27 SSs were identified or tentatively identified. Five major bioactive SSs (SSa, SSc, SSd, 6''-O-acetyl-SSa and 6''-O-acetyl-SSd) with obvious peak areas and good resolution were chosen as benchmark substances, and a triple quadrupole MS operating in multiple-reaction monitoring mode was used for their quantitative analysis. A total of 16 RB samples from different regions of China were analyzed. The results indicated that the method was rapid, efficient, accurate and suitable for use in the quality control of RB.

Fast determination of saikosaponins in Bupleurum by rapid resolution liquid chromatography with evaporative light scattering detection

A rapid resolution liquid chromatography coupled with evaporative light scattering detection method was established for simultaneous determination of six saikosaponins, namely saikosaponin a, saikosaponin c, saikosaponin d, 6''-O-acetylsaikosaponin a, 3''-O-acetylsaikosaponin d and 6''-O-acetylsaikosaponin d in Bupleurum. The analysis was performed by using an Agilent Zorbax SB-C18 column (1.8 microm, 3.0 mm x 50 mm i.d.) at gradient elution of water and acetonitrile, and the saikosaponins were well separated within 12 min, which provided about a fourfold reduction in analysis time by comparing a conventional high performance liquid chromatography method. Owing to their low ultraviolet absorption, the saikosaponins were detected by evaporative light scattering. The standard curves to quantify the saikosaponins were constructed by the log-log plot, which showed good linearity with the correlation coefficients exceeding 0.9954. The detection limits and quantification limits ranged in 8.38-25.00 microg/mL and 25.13-45.00 microg/mL, respectively. Satisfactory intra-day and inter-day precisions were achieved with the relative standard deviation (R.S.D.) less than 6.58%, and the average recoveries obtained were in the range of 96.9-100.4%. In addition, MeOH-1.0% (v/v) pyridine was found to be the best the extraction solvent when compared to MeOH and MeOH-1.0% (v/v) ammonia water. A total of 23 samples of roots of Bupleurum from different species or locations were examined with this analytical method, and their chemical profiles provided information for the chemotaxonomic investigation. The results demonstrated that the analytical method is highly effective for the quality evaluation of Bupleurum species.

Effects of Bupleurum scorzoneraefolium, Bupleurum falcatum, and saponins on nephrotoxic serum nephritis in mice

ETHNOPHARMACOLOGICAL SIGNIFICANCE

Bupleuri radix is a commonly prescribed Oriental herbal medicine containing extracts of different Bupleuri species. We wished to determine whether two of these species, Bupleurum scorzoneraefolium and Bupleurum falcatum, or their active ingredients, saikosaponins a, c, and d, could prevent the development of immune-complex nephritis in nephrotoxic serum treated mice.

MATERIALS AND METHODS

Immune-complex nephritis was created in C57BL/6 mice by administration of nephrotoxic serum containing anti-basement membrane antibodies. Mice were next given one of five treatments: Bupleurum scorzoneraefolium, Bupleurum falcatum, saikosaponin a, saikosaponin c, or saikosaponin d. Proteinuria, blood urea nitrogen, creatinine, and renal histological changes were then examined.

RESULTS

Saikosaponin c almost completely prevented the development of nephritis, although immune-complex deposition was not affected. Bupleurum falcatum and saikosaponin d had a significant, although lesser effect, and Bupleurum falcatum and saikosaponin a showed no effect.

CONCLUSIONS

The mechanism of action of saikosaponin c and the reasons for the difference between the two bupleuri species should be investigated further in order to find the best way to utilize the therapeutic effect of Bupleuri radix on nephritis.

Mechanism of saikosaponin-d in the regulation of rat mesangial cell proliferation and synthesis of extracellular matrix proteins

Glomerulosclerosis is a common disorder in many types of chronic kidney diseases. Previous studies have shown that glomerular mesangial cells (MCs) play an important role in the pathogenesis of glomerulosclerosis. The ability of saikosaponin-d (SSd) to reduce the damage of kidney in progressive glomerulosclerosis has been demonstrated. In this study, the effects of saikosaponin-d on MC proliferation and synthesis of extracellular matrix proteins were investigated. Rat MCs were isolated from Wistar rats and cultured in Dulbecco's modified Eagle's medium. MCs were challenged with lipopolysacchorides and incubated with different concentrations of SSd. Cell proliferation and cytotoxicity were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, and lactate dehydrogenase assays. Type IV collagen, fibronectin, and TGF-beta1 in the conditioned medium were measured. The expression of cyclin-dependent kinase 4, c-Jun, and c-Fos was determined by immunohistochemistry. At a concentration of 4 microg/mL or lower, SSd inhibited MC proliferation but did not cause cell death. SSd also inhibited lipopolysaccharide-induced secretion of type IV collagen, fibronectin, and TGF-beta1 in MCs. Additionally, SSd reduced the expression of CDK4, c-Jun, and c-Fos in MCs. We conclude that SSd inhibited MC proliferation and synthesis of extracullular matrix proteins through the downregulation of the CDK4, c-Jun, and c-Fos genes.

Anticancer effects of Chinese herbal medicine, science or myth?

Currently there is considerable interest among oncologists to find anticancer drugs in Chinese herbal medicine (CHM). In the past, clinical data showed that some herbs possessed anticancer properties, but western scientists have doubted the scientific validity of CHM due to the lack of scientific evidence from their perspective. Recently there have been encouraging results, from a western perspective, in the cancer research field regarding the anticancer effects of CHM. Experiments showed that CHM played its anticancer role by inducing apoptosis and differentiation, enhancing the immune system, inhibiting angiogenesis, reversing multidrug resistance (MDR), etc. Clinical trials demonstrated that CHM could improve survival, increase tumor response, improve quality of life, or reduce chemotherapy toxicity, although much remained to be determined regarding the objective effects of CHM in human in the context of clinical trials. Interestingly, both laboratory experiments and clinical trials have demonstrated that when combined with chemotherapy, CHM could raise the efficacy level and lower toxic reactions. These facts raised the feasibility of the combination of herbal medicines and chemotherapy, although much remained to be investigated in this area.

Visual detection of saikosaponins by on-membrane immunoassay and estimation of traditional Chinese medicines containing Bupleuri radix

The purpose of this study was to describe the simple, rapid, and environmental-cost effective determination method for saikosaponins in complicated samples like Bupleuri radix and traditional Chinese medicines (TCM). Saikosaponin standards, extracts of Bupleuri radix and TCM, were applied to a polyethersulphone (PES) membrane and developed by acetonitrile-water (1:4, by volume). Saikosaponin a (SSa), SSc, and SSd were visually detected by an immunostaining method (called Eastern blotting technique) using a monoclonal antibody (MAb) against SSa. At least 62.5 ng of SSa, SSc, and SSd were clearly detectable individually. These coloring spot areas of saikosaponins on PES membrane were calculated by using the NIH Imaging software and three saikosaponins can be analyzed quantitatively between 62.5 ng and 1.0 microg. Saikosaponins in Bupleuri radix and TCM were determined and these results of SSa and total saikosaponin concentrations were in good agreement with those from the ELISA analysis.

A novel analytical ELISA-based methodology for pharmacologically active saikosaponins

A competitive enzyme-linked immunosorbent assay (ELISA) for saikosaponins was established using monoclonal antibody (MAb) 3G10. Hybridoma 3G10 prepared by fusing splenocytes immunized with saikosaponin a-BSA (SSa-BSA) conjugate and a hypoxanthine-aminopterin-thymidine (HAT)-sensitive mouse myeloma cell line, P3-X63-Ag8-U1, secreted monoclonal antibodies with wide cross-reactivity to saikosaponins including saikosaponin b(2) (SSb(2)), c (SSc) and d (SSd), which are stereo and/or regio isomers of SSa. The method, at an effective measuring range of 0.6 mug /ml to 2.3 mug/ml of SSa, successfully detected total saikosaponins in Bupleuri radix and Kampo medicines prescribed with Bupleuri radix. Good correlation between ELISA and HPLC analyses of total saikosaponin in a crude extract of Bupleuri radix was obtained after hydrolysis of acyl saikosaponins by treatment with a mild alkaline solution.

Saikosaponin C induces endothelial cells growth, migration and capillary tube formation

Saikosaponin C is one of the saikosaponins that are consisted in a Chinese herb, Radix Bupleuri. Recently, saikosaponins have been reported to have properties of cell growth inhibition, inducing cancer cells differentiation and apoptosis. However, saikosaponin C had no correlation with cell growth inhibition. In this study, we investigated the role of saikosaponin C on the growth of endothelial cells and angiogenesis. We found that saikosaponin C yielded a potent effect on inducing human umbilical vein endothelial cells (HUVECs) viability and growth. In addition to inducing endothelial cells growth, saikosaponin C also induced endothelial cells migration and capillary tube formation. The gene expression or activation of matrix metalloproteinase-2 (MMP-2), vascular endothelial growth factor (VEGF) and the p42/p44 mitogen-activated protein kinase (MAPK, ERK) that correlated with endothelial cells growth, migration and angiogenesis were also induced by saikosaponin C. From these results, we suggest that saikosaponin C may have the potential for therapeutic angiogenesis but is not suitable for cancer therapy.

Involvement of p53, nuclear factor kappaB and Fas/Fas ligand in induction of apoptosis and cell cycle arrest by saikosaponin d in human hepatoma cell lines

In this study, we report the proapoptotic effect of saikosaponin d in two liver cancer cell lines, Hep G2 and Hep 3B cells. Treatment with saikosaponin d decreased the cell proliferation of Hep G2 and Hep 3B cells in a dose dependent manner. In Hep G2, saikosaponin d blocked the progression of cell cycle at G1 phase by inducing p53 expression and further up-regulating p21/WAF1 expression. In addition, an enhancement in Fas/APO-1 and its two form ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), as well as Bax protein, was responsible for the apoptotic effect induced by saikosaponin d. Furthermore, saikosaponin d also inhibited the cell survival signaling by enhancing the amount of IkappaBalpha in cytoplasm and reducing the level and activity of NF-kappaB in the nucleus, and subsequently attenuated the expression of Bcl-XL in Hep G2 and Hep 3B cells. Saikosaponin d therefore decreased the cell proliferation and inducted apoptosis both in p53-positive Hep G2 and p53-negative Hep 3B cells.

The proliferative inhibition and apoptotic mechanism of Saikosaponin D in human non-small cell lung cancer A549 cells

Saikosaponin D is a saponin extract derived from several species of Bupleurum (Umbelliferae), which is used for the treatment of various liver diseases in traditional Chinese medicine. In this study, we report that Saikosaponin D inhibits the cell growth of human lung cancer cell line A549 and provide a molecular understanding of this effect. The results showed that Saikosaponin D inhibited the proliferation of A549 by inducing apoptosis and blocking cell cycle progression in the G1 phase. ELISA assay showed that Saikosaponin D significantly increased the expression of p53 and p21/WAF1 protein, contributing to cell cycle arrest. An enhancement in Fas/APO-1 and its two form ligands, membrane-bound Fas ligand (mFasL) and soluble Fas ligand (sFasL), as well as Bax protein, was responsible for the apoptotic effect induced by Saikosaponin D. Taken together, our study suggests that the induction of p53 and activity of the Fas/FasL apoptotic system may participate in the antiproliferative activity of Saikosaponin D in A549 cells.