Analysis of saikosaponins in rat plasma by anionic adducts-based liquid chromatography tandem mass spectrometry method

Saikosaponin D inhibits nasal inflammation by regulating the transcription factors T-box protein expressed in T cells/GATA-3 and retinoic acid-related orphan nuclear receptor γt in a murine model of allergic rhinitis

Context

Saikosaponin D (SSD) is a commonly prescribed agent against inflammatory diseases in Asian countries. However, the anti-allergic inflammatory effect of SSD in allergic rhinitis (AR) model is not well known.

Objective

We investigated the anti-allergic and anti-inflammatory effects of SSD on the ovalbumin (OVA)-induced AR model.

Materials and method

BALB/c mice were divided into the control, OVA, OVA + SSD, and OVA + dexamethasone (Dex) groups. AR was established by intraperitoneal injection with OVA adsorbed to aluminum hydroxide, and intranasal challenge with OVA. Thereafter, the mice were treated with 10 mg/kg BW (Body weight) of OVA + SSD and 2.5 mg/kg BW of Dex orally for 11 days before being challenged. Subsequently, the mice were challenged with OVA 1 h after SSD or Dex treatment. The Control group was treated with saline only.

Results

The addition of 10 mg/kg BW of OVA + SSD significantly ameliorated the nasal symptoms including sneezing and rubbing from 30 ± 5.2 times in OVA group to 20 ± 5.8 times. Moreover, OVA + SSD group decreased the production of TNF-α, IL-4, IL-5, IL-17, GATA-3 and RORγ about 1.2-1.4-fold compared to the OVA-induced AR mice near to 2.5 mg/kg BW of Dex levels. Meanwhile OVA + SSD group slightly increased the levels of INF-γ, IL-12 and T-bet about 1.8-2.0-fold compared to the OVA group near to control group. Notably, OVA + SSD group also reduced the levels of OVA-specific IgE and IgG1 about 0.5-2.5-fold compared OVA group but increased the levels of IgG2a in serum. The results were analyzed using Graph Pad Prism software (v5.0, La Jolla, CA, USA).

Conclusion

SSD may represent an alternative therapeutic approach for the treatment of patients with AR through the regulation of transcription factors T-bet, GATA-3, and RORγ in inflammatory cells.

Recent Advances in Separation and Analysis of Saponins in Natural Products

To better control the quality of saponins, ensure their biological activity and clinical therapeutic effect, and expand the development and application of saponins, this paper systematically and comprehensively reviews the separation and analytical methods of saponins in the past decade. Since 2010, the electronic databases of PubMed, Google Scholar, ISI Web of Science, Science Direct, Wiley, Springer, CNKI (National Knowledge Infrastructure, CNKI), Wanfang Med online, and other databases have been searched systematically. As a result, it is found that ionic liquids and high-performance countercurrent chromatography are the most popular extraction and separation techniques for saponins, and the combined chromatography technique is the most widely used method for the analysis of saponins. Liquid chromatography can be used in combination with different detectors to achieve qualitative or quantitative analysis and quality control of saponin compounds in medicinal materials and their preparations. This paper provides the latest valuable insights and references for the analytical methods and continued development and application of saponins.

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.

Quality Assessment of Insamyangpye Decoction by Liquid Chromatography Tandem Mass Spectrometry Multiple Reaction Monitoring

Insamyangpye decoction (ISYPD) is an oriental herbal prescription used in Korea to treat lung-related diseases such as chronic obstructive pulmonary disease. ISYPD is a complex prescription consisting of 13 herbal medicines, and ISYPD sample was obtained by adding 50 L of distilled water to a mixture (5 kg) of 13 herbal medicines, extracting at 100 °C for 2 h using an electric extractor, and freeze-drying. In this study, an accurate and sensitive liquid chromatography tandem mass spectrometry (LC–MS/MS) method based on multiple reaction monitoring (MRM) was developed and verified for quality assessment of ISYPD using 10 marker components: mulberroside A (1), amygdalin (2), liquiritin apioside (3), naringin (4), poncirin (5), platycodin D (6), ginsenoside Rb1 (7), glycyrrhizin (8), saikosaponin A (9), and schizandrin (10). These marker compounds were separated using an Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 μm) maintained at 30 °C with a mobile phase elution gradient of acetonitrile in distilled water, both containing 0.1% (v/v) trifluoroacetic acid. Marker components were quantified using the LC–MS/MS MRM method developed and validated, and found at 0.09–7.47 mg/g.

Studies on the Changes of Pharmacokinetics Behaviors of Phytochemicals and the Influence on Endogenous Metabolites After the Combination of Radix Bupleuri and Radix Paeoniae Alba Based on Multi-Component Pharmacokinetics and Metabolomics

Radix Bupleuri-Radix Paeoniae Alba (RB-RPA) is a classic herb pair, which is commonly used to treat depression by soothing "liver qi stagnation" in the clinic. However, little is yet known concerning the combination mechanism of Radix Bupleuri (RB) and Radix Paeoniae Alba (RPA), their bioactive forms in vivo and the regulatory effects on the organism. The present study aimed to elucidate the changes in multi-component pharmacokinetics (PK) behavior after the combination of RB and RPA by a high-resolution full-scan mode of UPLC-HRMS method (a total of 38 components PK profiles were obtained, of which 23 components come from RB and 15 components come from RPA). Moreover, the metabolomics approach was used to analyze the dynamic response of endogenous metabolites intervened by RB-RPA, and the correlation between concentration-time curves of 38 components from RB-RPA and the dynamic response profiles of endogenous metabolites was characterized by Pearson correlation analysis. The results demonstrated that the combination of RB and RPA could significantly improve the bioavailability of five components in RB, and six components in RPA. Besides, metabolomics results indicated that a total of 21 endogenous metabolites exhibited time-dependent changes in response to the RB-RPA administration, of which 12 endogenous metabolites were significantly increased, and nine endogenous metabolites were significantly decreased. Furthermore, correlation analysis results indicated that the components with significantly improved bioavailability after combination such as saikogenin F, saikogenin G, albiflorin, methyl gallate, paeonimetabolin II were significantly positively correlated with picolinic acid, a metabolite with neuroprotective effect; saikogenin F, saikogenin G were significantly positively correlated with itaconic acid, a endogenous metabolite with anti-inflammatory activity; and albiflorin, paeonimetabolin II were significantly positively correlated with α-linolenic acid, a metabolite with strong protective actions on brain functions. These results indicated that the combination of RB and RPA can enhance each other's neuroprotective and anti-inflammatory activities. In this study, A novel and efficient strategy has been developed to analyze the influence of the combination of RB and RPA in vivo behaviors by combining multi-component pharmacokinetics with metabolomics, which was contributed to clarifying the scientific connotation of herb-herb compatibility.

The permeability characteristics and interaction of main components from Si-Ni-San in a MDCK epithelial cell monolayer model

1. Si-Ni-San (SNS) possesses extensive therapeutic effects, however, the extent to which main components are absorbed and the mechanisms involved are controversial. 2. In this study, MDCK cell model was used to determine the permeability characteristics and interaction between the major components of Si-Ni-San, including saikosaponin a, paeoniflorin, naringin and glycyrrhizic acid. 3. The transport of the major components was concentration-dependent in both directions. Moreover, the transport of paeoniflorin, naringin and glycyrrhizic acid was significantly reduced at 4 °C or in the presence of NaN3. Additionally, the efflux of paeoniflorin and naringin were apparently reduced in the presence of P-gp inhibitor verapamil. The transport of glycyrrhizic acid was clearly inhibited by the inhibitors of MRP2, indicating that MRP2 may be involved in the transport of glycyrrhizic acid. However, the results indicated that saikosaponin a was absorbed mainly by passive diffusion. Furthermore, the combined incubation of four major components had a powerful sorbefacient effect than a single drug used alone which may be regulated by tight junctions. 4. Taken together, our study provides useful information for pharmacological applications of Si-Ni-San and offers new insights into this ancient decoction for further researches, especially in drug synergism.

Efficient and clean preparation of rare prosaikogenin D by enzymatic hydrolysis of saikosaponin B2 and response surface methodology optimization

Prosaikogenin D, a rare secondary saponin in Radix Bupleuri, has much higher in vivo bioactivities than its original glycoside saikosaponin B₂. Its preparation methods, such as conventional acid hydrolysis and column chromatograph, are unfriendly to environment with serious pollution and undesired products. The aim of this study was to establish an efficient and clean approach for convenient preparation of this rare steroid saponin based on the enzymatic hydrolysis. Cellulase was selected from four commercial enzymes due to its higher hydrolysis performance. Then the hydrolysis conditions were optimized by response surface methodology after preliminary investigation on affecting factors by single-factor experiments. The reaction system was constructed by 100 μg/mL of saikosaponin B₂ and 8.00 mg/mL of cellulase, which was incubated in HAc-NaAc buffer (pH 4.7) at 60 °C for 33 h. Consequently, a high conversion ratio of the substrate has been achieved at 95.04 %. The newly developed strategy is an efficient and clean approach for the preparation of prosaikogenin D and it is a promising technology in industrial application.

Botany, traditional uses, phytochemistry, analytical methods, processing, pharmacology and pharmacokinetics of Bupleuri Radix: A systematic review

Bupleuri Radix (BR) is the dry root of Bupleurum chinense DC. and Bupleurum scorzonerifolium Willd. It has the functions of evacuation and antipyretic, soothing liver and relieving depression and often used to treat cold fever, chest and rib swelling pain, irregular menstruation, uterine prolapse, rectocele and other diseases. In this paper, the botany, traditional application, phytochemistry, pharmacology and toxicity of BR were reviewed. On the basis of limited literature, the analytical method, quality control, processing method, processing effect and pharmacokinetics of BR were summarized and analyzed for the first time. This review makes an in-depth discussion on the shortcomings of the current research on BR, and puts forward its own views and solutions. This has never been summarized in the previous review of BR. It is of great practical significance for future scholars to find a breakthrough point in the study of BR. So far, its mechanism has not been satisfactorily explained. Moreover, the comprehensive quality evaluation and multi-target network pharmacology of BR need to be further studied. In the future, more in vitro and in vivo experiments are needed to give full play to the therapeutic potential of BR.

The biotransformation of Bupleuri Radix by human gut microbiota

1. Bupleuri Radix (BR) is a herbal medicine traditionally used orally in oriental countries, which inevitably comes into contact with the intestinal microbiota. However, whether gut microbiota contribute to the biotransformation of BR, and/or the formation of pharmacologically active compounds remains unknown.2. In this study, the main saikosaponins (SAPs) of Bupleurum (including saikosaponin a, b1, b2, c, d, f, h) and BR extract (BRE) were individually incubated with human fecal suspensions (HFS), and metabolic time courses of SAPs and their metabolites by human gut bacteria were systematically characterized.3. Deglycosylation and dehydration were the main metabolic pathways identified for SAPs including newly investigated saikosaponin f (SSf) and saikosaponin h (SSh); dehydration had not been reported previously. A total of 19 dehydrated and deglycosylated metabolites of SAPs were detected and characterized, and 10 of them were newly identified. Moreover, SAPs of BRE were found to be deglycosylated to prosaikogenins. In addition, 13 metabolic pathways related to human gut microbiota were identified for phytochemicals of BRE except for SAPs. Gut microbiota may play a significant role in the biotransformation of BR in humans.

Identification and characterization of saikosaponins as antagonists of transient receptor potential A1 channel

Neuropathic pain is associated with an increased sensitivity to painful stimuli or abnormal sensitivity to otherwise innocuous stimuli. However, in addition to adverse effects, currently available drugs have shown limited response in patients with neuropathic pain, which provides a rationale to explore new drug classes acting on novel targets and with better efficacy and safety profiles. Here, we found that saikosaponins potently inhibit agonist-induced activation of the transient receptor potential A1 (TRPA1) channel, which has been reported to mediate neuropathic pain by sensing a variety of chemical irritants. Molecular docking and site-directed mutagenesis analyses suggested that saikosaponins bind to the hydrophobic pocket in TRPA1 near the Asn855 residue, which, when mutated to Ser, was previously associated with enhanced pain perception in humans. In support of these findings, saikosaponin D significantly attenuated agonist-induced nociceptive responses and vincristine-induced mechanical hypersensitivity in mice. These results indicate that saikosaponins are TRPA1 antagonists and provide a basis for further elaboration of saikosaponin derivatives for the development of new therapeutics for neuropathic pain.

Localization of malonyl and acetyl on substituted saikosaponins according to the full-scan mass spectra and the fragmentation of sodium-adduct ions in the positive mode

RATIONALE

Discriminating between aglycone-substituted and saccharide-substituted saikosaponins by liquid chromatography/tandem mass spectrometry (LC/MSⁿ ) is a long-standing issue that is still to be resolved. It is necessary to characterize the two types of substituted saikosaponins taking into consideration the potential significant difference in their bioactivity.

METHODS

Taking the substituents malonyl and acetyl as examples, we developed a MS strategy to discriminate between the aglycone-substituted and saccharide-substituted saikosaponins through comparing their Y₀  - nH₂ O (n = 1-2) ions from the protonated molecules in the full-scan mass spectra and their B ions in the MS² spectra of sodium-adduct molecules in the positive mode.

RESULTS

The deprotonated molecules of the aglycone-substituted saikosaponins presented similar fragmentation patterns to those of saccharide-substituted ones in the negative mode, which could not discriminate whether the substitutes were located on the aglycone or the saccharide. In contrast, the Y₀  - nH₂ O (n = 1-2) ions containing or no substituent were observed respectively in the mass fragmentation of the protonated molecules of aglycone-substituted or saccharide-substituted saikosaponins in the positive mode. In addition, the B ions containing or no substituent were observed respectively in the mass fragmentation of the sodium-adduct molecules of the saccharide-substituted or aglycone-substituted saikosaponins in the positive mode. Two aglycone-malonylated saikosaponins were reported for the first time.

CONCLUSIONS

Whether the substituents were located on the aglycone or the saccharide could be determined according to the Y₀  - nH₂ O (n = 1-2) ions from the protonated molecules in the full-scan mass spectra and the B ions in the MS² spectra of sodium-adduct molecules in the positive mode. Our results have updated the mass fragmentation patterns of substituted saikosaponins, which is helpful for the quality control of pharmaceutical preparations containing saikosaponins. More importantly, this MS strategy should be able to be extended to characterize other substituted saponins of bioactive significance in future studies.

A comprehensive review and perspectives on pharmacology and toxicology of saikosaponins

BACKGROUND

Radix Bupleuri (RB) has been widely used in Chinese Traditional Medicine for over 2000 years and is currently marketed in China as Chai-Hu-Shu-Gan tablets and Xiao-Yao-Wan tablets. Saikosaponins (SSs, especially SSa, SSc and SSd), as the major bioactive compounds in RB, represent anti-inflammatory, anti-tumor, anti-oxidant, anti-viral and hepatoprotective effects.

PURPOSE

To summarize recent findings regarding to the extraction, detection, biosynthesis, metabolism, pharmacological/toxicological effects of SSs.

METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Saikosaponin", "Radix Bupleuri", "Bupleurum" and combinations to include published studies of SSs primarily from 2003 to 2018. Several critical previous studies beyond this period were also included.

RESULTS

354 papers were found and 165 papers were reviewed. SSs have drawn great attention for their anti-inflammation, anti-viral and anti-cancer effects and contradictory roles in the regulation of cell apoptosis, oxidative stress and liver fibrosis. Meanwhile, increased risks of overdose-induced acute or accumulation-related chronic hepatotoxicity of SSs and RB have also been reported. However, underlying mechanisms of SSs bioactivities, the metabolism of SSs and bioactivities of SSs metabolites are largely unknown.

CONCLUSION

This comprehensive review of SSs provides novel insights and perspectives on the limitations of current studies and the importance of metabolism study and the dose-pharmacological/toxic relationship of SSs for the future discovery of SSs-based therapeutic strategies and clinical safe practice.

A comprehensive review and perspectives on pharmacology and toxicology of saikosaponins

BACKGROUND

Radix Bupleuri (RB) has been widely used in Chinese Traditional Medicine for over 2000 years and is currently marketed in China as Chai-Hu-Shu-Gan tablets and Xiao-Yao-Wan tablets. Saikosaponins (SSs, especially SSa, SSc and SSd), as the major bioactive compounds in RB, represent anti-inflammatory, anti-tumor, anti-oxidant, anti-viral and hepatoprotective effects.

PURPOSE

To summarize recent findings regarding to the extraction, detection, biosynthesis, metabolism, pharmacological/toxicological effects of SSs.

METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Saikosaponin", "Radix Bupleuri", "Bupleurum" and combinations to include published studies of SSs primarily from 2003 to 2018. Several critical previous studies beyond this period were also included.

RESULTS

354 papers were found and 165 papers were reviewed. SSs have drawn great attention for their anti-inflammation, anti-viral and anti-cancer effects and contradictory roles in the regulation of cell apoptosis, oxidative stress and liver fibrosis. Meanwhile, increased risks of overdose-induced acute or accumulation-related chronic hepatotoxicity of SSs and RB have also been reported. However, underlying mechanisms of SSs bioactivities, the metabolism of SSs and bioactivities of SSs metabolites are largely unknown.

CONCLUSION

This comprehensive review of SSs provides novel insights and perspectives on the limitations of current studies and the importance of metabolism study and the dose-pharmacological/toxic relationship of SSs for the future discovery of SSs-based therapeutic strategies and clinical safe practice.

A comprehensive review and perspectives on pharmacology and toxicology of saikosaponins

BACKGROUND

Radix Bupleuri (RB) has been widely used in Chinese Traditional Medicine for over 2000 years and is currently marketed in China as Chai-Hu-Shu-Gan tablets and Xiao-Yao-Wan tablets. Saikosaponins (SSs, especially SSa, SSc and SSd), as the major bioactive compounds in RB, represent anti-inflammatory, anti-tumor, anti-oxidant, anti-viral and hepatoprotective effects.

PURPOSE

To summarize recent findings regarding to the extraction, detection, biosynthesis, metabolism, pharmacological/toxicological effects of SSs.

METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Saikosaponin", "Radix Bupleuri", "Bupleurum" and combinations to include published studies of SSs primarily from 2003 to 2018. Several critical previous studies beyond this period were also included.

RESULTS

354 papers were found and 165 papers were reviewed. SSs have drawn great attention for their anti-inflammation, anti-viral and anti-cancer effects and contradictory roles in the regulation of cell apoptosis, oxidative stress and liver fibrosis. Meanwhile, increased risks of overdose-induced acute or accumulation-related chronic hepatotoxicity of SSs and RB have also been reported. However, underlying mechanisms of SSs bioactivities, the metabolism of SSs and bioactivities of SSs metabolites are largely unknown.

CONCLUSION

This comprehensive review of SSs provides novel insights and perspectives on the limitations of current studies and the importance of metabolism study and the dose-pharmacological/toxic relationship of SSs for the future discovery of SSs-based therapeutic strategies and clinical safe practice.

A comprehensive review and perspectives on pharmacology and toxicology of saikosaponins

BACKGROUND

Radix Bupleuri (RB) has been widely used in Chinese Traditional Medicine for over 2000 years and is currently marketed in China as Chai-Hu-Shu-Gan tablets and Xiao-Yao-Wan tablets. Saikosaponins (SSs, especially SSa, SSc and SSd), as the major bioactive compounds in RB, represent anti-inflammatory, anti-tumor, anti-oxidant, anti-viral and hepatoprotective effects.

PURPOSE

To summarize recent findings regarding to the extraction, detection, biosynthesis, metabolism, pharmacological/toxicological effects of SSs.

METHODS

Online academic databases (including PubMed, Google Scholar, Web of Science and CNKI) were searched using search terms of "Saikosaponin", "Radix Bupleuri", "Bupleurum" and combinations to include published studies of SSs primarily from 2003 to 2018. Several critical previous studies beyond this period were also included.

RESULTS

354 papers were found and 165 papers were reviewed. SSs have drawn great attention for their anti-inflammation, anti-viral and anti-cancer effects and contradictory roles in the regulation of cell apoptosis, oxidative stress and liver fibrosis. Meanwhile, increased risks of overdose-induced acute or accumulation-related chronic hepatotoxicity of SSs and RB have also been reported. However, underlying mechanisms of SSs bioactivities, the metabolism of SSs and bioactivities of SSs metabolites are largely unknown.

CONCLUSION

This comprehensive review of SSs provides novel insights and perspectives on the limitations of current studies and the importance of metabolism study and the dose-pharmacological/toxic relationship of SSs for the future discovery of SSs-based therapeutic strategies and clinical safe practice.

Pharmacokinetics and Brain Distribution of the Active Components of DA-9805, Saikosaponin A, Paeonol, and Imperatorin in Rats

DA-9805 is a botanical anti-Parkinson’s drug candidate formulated from ethanol extracts of the root of Bupleurum falcatum, the root cortex of Paeonia suffruticosa, and the root of Angelica dahurica. The pharmacokinetics (PKs) and brain distribution of active/representative ingredients of DA-9805, Saikosaponin a (SSa; 1.1–4.6 mg/kg), Paeonol (PA; 14.8–59.2 mg/kg), and Imperatorin (IMP; 1.4–11.5 mg/kg) were evaluated following the intravenous or oral administration of each pure component and the equivalent dose of DA-9805 in rats. All three components had greater dose-normalized areas under the plasma concentration-time curve (AUC) and slower clearance with higher doses, following intravenous administration. By contrast, dose-proportional AUC values of SSa, PA, and IMP were observed following the oral administration of each pure component (with the exception of IMP at the highest dose) or DA-9805. Compared to oral administration of each pure compound, DA-9805 administration showed an increase in the AUC of SSa (by 96.1–163%) and PA (by 155–164%), possibly due to inhibition of their metabolism by IMP or other component(s) in DA-9805. A delay in the absorption of PA and IMP was observed when they were administered as DA-9805. All three components of DA-9805 showed greater binding values in brain homogenates than in plasma, possibly explaining why the brain-to-plasma ratios were greater than unity following multiple oral administrations of DA-9805. By contrast, their levels in cerebrospinal fluid were negligible. Our results further our understanding of the comprehensive PK characteristics of SSa, PA, and IMP in rats and the comparative PKs between each pure component and DA-9805.

A feasibility study of the toxic responses of human induced pluripotent stem cell-derived hepatocytes to phytochemicals

Herbal medicines have been increasingly used in the last three decades. Despite their popularity, safety issues with herbal products need to be addressed. We performed a feasibility study of the toxic responses of human induced pluripotent stem cell-derived hepatocytes (iHep cells) to phytochemicals in comparison with hepatoblasoma-derived HepG2 cells and long-term human hepatocytes (LTHHs). The iHep cells expressed typical hepatocyte markers cytochrome P450 3A4 (CYP3A4), hepatocyte nuclear factor 4α, and albumin despite the expression of immature markers α-fetoprotein and cytokeratin 19. We studied the responses of iHep cells to phytochemicals saikosaponin D, triptolide, deoxycalyciphylline B, and monocrotaline with different mode of toxicity employing MTS and lactate dehydrogenase (LDH) assays. Saikosaponin D and triptolide caused dose-dependent cytotoxicity in the iHep cells, which were more sensitive than LTHHs and HepG2 cells. Saikosaponin D-induced cytotoxicity tightly correlated with increased LDH leakage in the iHep cells. Although deoxycalyciphylline B did not exhibit toxic effect on the iHep and HepG2 cells when compared with LTHHs, it decreased CYP3A7 expression in the iHep cells and increased CYP1A2 expression in HepG2 cells. We hereby show the feasibility of using iHep cells to detect toxic effects of phytochemicals.

Content decline of SERCA inhibitors saikosaponin a and d attenuates cardiotoxicity and hepatotoxicity of vinegar-baked Radix bupleuri

Improper usage of unprocessed Radix bupleuri root (chaihu) may cause cardiotoxicity and liver injury. Baking herb with vinegar is believed to attenuate the adverse responses. However, the chemical and molecular basis involved remained unclear. To this end, we investigated the in vitro toxicity of saikosaponin a, c, d, and their hydrolysates saikosaponin b1 and b2. Results showed that SSa and SSd possessed higher affinity with sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA) by molecular docking, and exhibited stronger toxic responses on cardiomyocytes and hepatocytes than the other three saikosaponins in equivalent concentrations. Further, SSa and SSd induced LC3 puncta formation in U2OS-mCherry-EGFP-LC3 cells. Blockage of autophagy by 3-methyladenine did not abrogate the cytotoxicities induced by SSa and SSd. In parallel, none of SSc, SSb1, or SSb2 caused cell injury. Our study reveals how changes in chemical ingredients are connected to the toxicity of Chaihu during vinegar baking process and also provides a guidance for structure optimization to reduce drug induced toxicity.

Radix Bupleuri: A Review of Traditional Uses, Botany, Phytochemistry, Pharmacology, and Toxicology

Radix Bupleuri (Chaihu) has been used as a traditional medicine for more than 2000 years in China, Japan, Korea, and other Asian countries. Phytochemical studies demonstrated that this plant contains essential oils, triterpenoid saponins, polyacetylenes, flavonoids, lignans, fatty acids, and sterols. Crude extracts and pure compounds isolated from Radix Bupleuri exhibited various biological activities, such as anti-inflammatory, anticancer, antipyretic, antimicrobial, antiviral, hepatoprotective, neuroprotective, and immunomodulatory effects. However, Radix Bupleuri could also lead to hepatotoxicity, particularly in high doses and with long-term use. Pharmacokinetic studies have demonstrated that the major bioactive compounds (saikosaponins a, b₂, c, and d) were absorbed rapidly in rats after oral administration of the extract of Radix Bupleuri. This review aims to comprehensively summarize the traditional uses, botany, phytochemistry, pharmacology, toxicology, and pharmacokinetics of Radix Bupleuri reported to date with an emphasis on its biological properties and mechanisms of action.

Saikosaponin d protects against acetaminophen-induced hepatotoxicity by inhibiting NF-κB and STAT3 signaling

Overdose of acetaminophen (APAP) can cause acute liver injury that is sometimes fatal, requiring efficient pharmacological intervention. The traditional Chinese herb Bupleurum falcatum has been widely used for the treatment of several liver diseases in eastern Asian countries, and saikosaponin d (SSd) is one of its major pharmacologically-active components. However, the efficacy of Bupleurum falcatum or SSd on APAP toxicity remains unclear. C57/BL6 mice were administered SSd intraperitoneally once daily for 5days, followed by APAP challenge. Biochemical and pathological analysis revealed that mice treated with SSd were protected against APAP-induced hepatotoxicity. SSd markedly suppressed phosphorylation of nuclear factor kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) and reversed the APAP-induced increases in the target genes of NF-κB, such as pro-inflammatory cytokine Il6 and Ccl2, and those of STAT3, such as Socs3, Fga, Fgb and Fgg. SSd also enhanced the expression of the anti-inflammatory cytokine Il10 mRNA. Collectively, these results demonstrate that SSd protects mice from APAP-induced hepatotoxicity mainly through down-regulating NF-κB- and STAT3-mediated inflammatory signaling. This study unveils one of the possible mechanisms of hepatoprotection caused by Bupleurum falcatum and/or SSd.

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.