Cytotoxic triterpenoid glycosides (saikosaponins) from the roots of Bupleurum chinense

Advances in the anti-tumor mechanisms of saikosaponin D

Saikosaponin D, a saponin compound, is extracted from Bupleurum and is a principal active component of the plant. It boasts a variety of pharmacologic effects including anti-inflammatory, antioxidant, immunomodulatory, metabolic, and anti-tumor properties, drawing significant attention in anti-tumor research in recent years. Research indicates that saikosaponin D inhibits the proliferation of numerous tumor cells, curbing the progression of cancers such as liver, pancreatic, lung, glioma, ovarian, thyroid, stomach, and breast cancer. Its anti-tumor mechanisms largely involve inhibiting tumor cell proliferation, promoting tumor cell apoptosis, thwarting tumor-cell invasion, and modulating tumor cell autophagy. Moreover, saikosaponin D enhances the sensitivity to anti-tumor drugs and augments body immunity. Given its multi-faceted anti-tumor roles, saikosaponin D offers promising potential in anti-tumor therapy. This paper reviews recent studies on its anti-tumor effects, aiming to furnish new theoretical insights for clinical cancer treatments.

A new triterpenoid saponin and a new natural saponin from the roots of Bupleurum scorzonerifolium willd

Sixteen triterpenoid saponins were isolated from the roots of Bupleurum scorzonerifolium Willd., including a new triterpenoid saponin and new natural saponin that was characterised by NMR for the first time, along with 14 known triterpenoid saponins. The structures of the compounds were established by 1D and 2D NMR spectroscopy, HR-ESI-MS, and comparison with the literature. The cytotoxic activity of the compounds against 4T1 cells was determined using the CCK8 method. Compounds 9 and 6 showed the strongest cytotoxic activity with IC50 values of 2.75 ± 0.86 and 3.78 ± 0.50 μM, respectively. Compounds 2-5 and 8 showed potent cytotoxic activity. Compounds 14 and 16 showed moderate cytotoxicity.

Two new triterpenoid saponins from Bupleurum marginatum Wall. ex DC

Two new triterpenoid saponins (1 and 2), together with two known saponins (3 and 4) were isolated from Bupleurum marginatum Wall. ex DC. Their structures were elucidated by the comprehensive spectroscopic analysis. Compounds 1 and 2 represented the rare example of an oleanane-type triterpenoid with two sugar moieties at C-3 and C-28. The cytotoxic activity of four compounds was evaluated against normal heptocell BRL-3A in vitro.

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.

Tubeimoside-1: A review of its antitumor effects, pharmacokinetics, toxicity, and targeting preparations

Tubeimoside-1 (TBMS-1), a natural triterpenoid saponin found in traditional Chinese herbal medicine Bolbostemmatis Rhizoma, is present in numerous Chinese medicine preparations. This review aims to comprehensively describe the pharmacology, pharmacokinetics, toxicity and targeting preparations of TBMS-1, as well the therapeutic potential for cancer treatement. Information concerning TBMS-1 was systematically collected from the authoritative internet database of PubMed, Web of Science, and China National Knowledge Infrastructure applying a combination of keywords involving “tumor,” “pharmacokinetics,” “toxicology,” and targeting preparations. New evidence shows that TBMS-1 possesses a remarkable inhibitory effect on the tumors of the respiratory system, digestive system, nervous system, genital system as well as other systems in vivo and in vitro. Pharmacokinetic studies reveal that TBMS-1 is extensively distributed in various tissues and prone to degradation by the gastrointestinal tract after oral administration, causing a decrease in bioavailability. Meanwhile, several lines of evidence have shown that TBMS-1 may cause adverse and toxic effects at high doses. The development of liver-targeting and lung-targeting preparations can reduce the toxic effect of TBMS-1 and increase its efficacy. In summary, TBMS-1 can effectively control tumor treatment. However, additional research is necessary to investigate in vivo antitumor effects and the pharmacokinetics of TBMS-1. In addition, to reduce the toxicity of TBMS-1, future research should aim to modify its structure, formulate targeting preparations or combinations with other drugs.

Saikosaponins: A Review of Structures and Pharmacological Activities

Radix Bupleuri is a traditional medicine widely used in China and other Asian countries. Phytochemistry and pharmacology study reveal that saikosaponins(SSs) are the main bioactive compounds in Radix Bupleuri. SSs are complex compounds composed of triterpene aglycone and carbohydrate part containing 1-13 monosaccharides, which can be divided into seven types based on their structural characteristics. Many different kinds of SSs have been isolated from plants of Bupleurum L. SSs show a variety of biological activities, such as central nervous system protection, liver protection, antivirus, anti-tumor, anti-inflammation, hormone-like effects, and immune regulation functions. Due to their broad activity and favorable safety profile, SSs attract an increasing amount of attention in recent years. In this review, the structures of 86 SSs are summarized based on the different aglycones due to the diverse structures of saikosaponin(SS). The pharmacological effects and related mechanism of SSs are thoroughly reviewed, and perspectives for future research are further discussed.

Chemical synthesis of saponins: An update

Saponins, as secondary metabolites in terrestrial plants and marine invertebrate, constitute one of the largest families of natural products. The long history of folk medicinal applications of saponins makes them attractive candidates for innovative drug design and development. Chemical synthesis has become a practical alternative to the availability of the natural saponins and their modified analogs, so as to facilitate SAR studies and the discovery of optimal structures for clinical applications. The recent achievements in the synthesis of these complex saponins reflect the advancements of both steroid/triterpene chemistry and carbohydrate chemistry. This chapter provides an updated review on the chemical synthesis of natural saponins, covering the literature from 2014 to 2020.

Characterization of a Highly Selective 2″-O-Galactosyltransferase from Trollius chinensis and Structure-Guided Engineering for Improving UDP-Glucose Selectivity

A novel 2″-O-galactosyltransferase TcOGT4 was discovered from Trollius chinensis. TcOGT4 could regio-specifically catalyze 2″-O-galactosylation of 17 flavone 8-C-β-d-glucosides and shows high preference for UDP-Gal. Molecular docking indicated that Pro361 may play a key role in sugar donor selectivity, and the P361W mutant exhibited significantly enhanced selectivity toward UDP-Glc. A total of 21 products including 17 new compounds were obtained, and 5 of them showed potent COX-2 inhibitory activities. TcOGT4 is the first reported 2″-O-galactosyltransferase for flavone C-glycosides, and could be a powerful biocatalyst to synthesize bioactive flavone glycosides.

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.

UV-guided isolation of enantiomeric polyacetylenes from Bupleurum scorzonerifolium Willd. with inhibitory effects against LPS-induced NO release in BV-2 microglial cells

UV-guided fractionation led to the isolation of thirteen new polyacetylenes (1-13) from the roots of Bupleurum scorzonerifolium Willd. All polyacetylenes were analyzed as racemates since the lack of optical activity and Cotton effects in the ECD spectra. The sequent chiral-phase HPLC resolution successfully gave twelve pairs of enantiomers 1a/1b and 3a/3b-13a/13b. Their structures were elucidated based on the HRESIMS and NMR data analyses. The absolute configurations were determined by the combination of Snatzke's method, electronic circular dichroism calculations, and single-crystal X-ray diffraction. Using Griess methods and MTT assays, polyacetylenes 1a, 3a, 4a/4b-12a/12b, and 13a displayed inhibitory activities against LPS-induced NO release in BV-2 microglial cells.

Systematic Characterization and Identification of Saikosaponins in Extracts From Bupleurum marginatum var. stenophyllum Using UPLC-PDA-Q/TOF-MS

Saikosaponins comprise a large group of chemical components present in the Bupleurum species that have attracted attention in the field of medicine because of their significant biological activities. Due to the high polarity, structural similarity, and the presence of several isomers of this class of components, their structural identification is extremely challenging. In this study, the mass spectrometric fragmentation pathways, UV spectral features, and chromatographic behavior of different types of saikosaponins were investigated using 24 standard substances. Saikosaponins containing carbonyl groups (C=O) in the aglycone produced fragment ions by loss of 30 Da, and in addition, type IV saikosaponins could produce [aglycone−CH₂OH−OH−H]⁻ and [aglycone−H₂O−H]⁻ fragment ions through neutral losses at positions C₁₆ and C₁₇. The above characteristic ions can be used to identify saikosaponins. More notably, the identification process of saikosaponins was systematically summarized, and using this method, 109 saikosaponins were identified or tentatively characterized from the saikosaponins extract of Bupleurum marginatum var. stenophyllum (BMS) using UPLC-PDA-Q/TOF-MS with both data-dependent acquisition (DDA) and data-independent acquisition (DIA) modes, of which 25 were new compounds and 60 were first discovered from BMS. Further studies revealed that the saikosaponins profiles of BMS, Bupleurum chinense DC (BC), and Bupleurum marginatum Wall. ex DC (BMW) were very similar. This work is of great significance for the basic research of the Bupleurum species and provides strong technical support to solve the resource problems associated with Radix Bupleuri.

Malconenoside A, a New Phenolic Glycoside from Bupleurum malconense

A new phenolic glycoside, 7-(4- O- β-D-glucopyranosyl, 3-methoxyphenyl)-6,8-dihydrofuro[3′,4′:7,8]naphtho[1,2-d][1,3]dioxol-10(7H)-one, named malconenoside A (1), was isolated from Bupleurum malconense Shan et Y. Li . The structure, including absolute configurations, was assigned by using spectroscopic methods and ECD calculation. Biological activities of compound 1 towards human cancer cells (HepG2, BGC-823, and A549) were evaluated. The most sensitive two cell lines were HepG2 and BGC823, in which the IC50 values of compound 1 were 8.70 and 16.94 μM, respectively.

Facile Synthesis of Saikosaponins

Saikosaponin A (SSa) and D (SSd) are typical oleanane-type saponins featuring a unique 13,28-epoxy-ether moiety at D ring of the aglycones, which exhibit a wide range of biological and pharmacological activities. Herein, we report the first synthesis of saikosaponin A/D (1-2) and their natural congeners, including prosaikosaponin F (3), G (4), saikosaponin Y (5), prosaikogenin (6), and clinoposaponin I (7). The present synthesis features ready preparation of the aglycones of high oxidation state from oleanolic acid, regioselective glycosylation to construct the β-(1→3)-linked disaccharide fragment, and efficient gold(I)-catalyzed glycosylation to install the glycans on to the aglycones.

Site-selective C-H hydroxylation of pentacyclic triterpenoids directed by transient chiral pyridine-imino groups

Pentacyclic triterpenoids (PTs) constitute one of the biggest families of natural products, many with higher oxidation state at the D/E rings possess a wide spectrum of biological activties but are poorly accessible. Here we report a site-selective C-H hydroxylation at the D/E rings of PTs paving a way toward these important natural products. We find that Schönecker and Baran's Cu-mediated aerobic oxidation can be applied and become site-selective on PT skeletons, as being effected unexpectedly by the chirality of the transient pyridine-imino directing groups. To prove the applicability, starting from the most abundant triterpenoid feedstock oleanane, three representative saponins bearing hydroxyl groups at C16 or C22 are expeditiously synthesized, and barringtogenol C which bears hydroxyl groups at C16, C21, and C22 is synthesized via a sequential hydroxylation as the key steps.

A New Alkaloid from the Aerial Parts of Bupleurum chinense DC

A new isoalloxazine alkaloid, named bupleurine A (1), along with five known compounds (2-6), were isolated from the aerial parts of Bupleurum chinense DC. The structure elucidation of the new alkaloid (1) was employed by combining NMR and HR-MS data with comparison of reference in the literature. Five known compounds (2-6) were isolated from Bupleurum genus for the first time. Additionally, their antiproliferative activities on HeLa cells were evaluated by MTT assay and IC₅₀ of compounds 1 and 4-6 were below 10 μm after treatment for 24 h.

Triterpenoids

This review covers newly isolated triterpenoids that have been reported during 2015.

Triterpenoid Saponins from Ardisia gigantifolia and Mechanism on Inhibiting Proliferation of MDA-MB-231 Cells

Seventeen 13,28-epoxy triterpenoid saponins obtained from Ardisia gigantifolia STAPF. were evaluated their anti-proliferative activities on MCF-7 cells. The structure-activity relationship analysis indicated that CH₃ group at C-30, four saccharide units with L-rhamnose at R6 in the sugar units are crucial for the cytotoxic activity on MCF-7. Compounds 1, 2, 6, 7, 12, and 14 were selected to identify the anti-proliferative activity on the other three breast cancer cell lines (T47D, MDA-MB-231 and SK-BR-3). Compounds 2, 6, and 7 with good activity on MCF-7 also showed activity on T47D, MDA-MB-231, and SK-BR-3. Compounds 12 and 14 without cytotoxic activity on MCF-7 almost showed no activities on the other three cell lines. For the triple-negative breast cancer MDA-MB-231, Saponins 7 and 14 showed selective cytotoxic activity, 7 showed much more activity than 14, suggesting the six saccharide units in sugar units and CH₃ on C-30 were the key moieties for the anti-proliferative activities. Further molecular mechanism of saponin 7 was studied on inhibiting cell proliferation of MDA-MB-231 cells. Saponin 7 could enhance apoptosis, arrest cell cycles, decrease mitochondrial membrane potentials (MMPs), and considered the involvement of reactive oxygen species (ROS) may explain this conundrum.

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.

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.

Cytotoxic lignans from the barks of Juglans mandshurica

Phytochemical investigation of the barks of Juglans mandshurica Maxim led to the isolation, purification, and identification of one new lignan named Juglansol A (1), along with nine known compounds (2-10). Their structures were determined by the results of UV, IR, CD, HRESIMS, 1D, and 2D NMR spectroscopic analysis. Compounds 1-10 were evaluated for their cytotoxicities against A549, HepG2, Hep3B, Bcap-37, and MCF-7 cell lines. The results showed that compound 2 possessed stronger cytotoxicities against the tested tumor cell lines compared with positive control 5-fluorouracil.

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.

Multitarget botanical pharmacotherapy in major depression: a toxic brain hypothesis

A significant number of patients with major depression do not respond optimally to current antidepressant drugs. As depression is likely to be a heterogeneous disorder, it is possible that existing neurotransmitter-based antidepressant drugs do not fully address other pathologies that may exist in certain cases. Biological pathologies related to depression that have been proposed and studied extensively include inflammation and immunology, hypercortisolemia, oxidative stress, and impaired angiogenesis. Such pathologies may induce neurodegeneration, which in turn causes cognitive impairment, a symptom increasingly being recognized in depression. A neurotoxic brain hypothesis unifying all these factors may explain the heterogeneity of depression as well as cognitive decline and antidepressant drug resistance in some patients. Compared with neurotransmitter-based antidepressant drugs, many botanical compounds in traditional medicine used for the treatment of depression and its related symptoms have been discovered to be anti-inflammatory, immunoregulatory, anti-infection, antioxidative, and proangiogenic. Some botanical compounds also exert actions on neurotransmission. This multitarget nature of botanical medicine may act through the amelioration of the neurotoxic brain environment in some patients resistant to neurotransmitter-based antidepressant drugs. A multitarget multidimensional approach may be a reasonable solution for patients resistant to neurotransmitter-based antidepressant drugs.

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.

Triterpenoid glycosides from Ladenbergia hexandra Klotzsch

From the bark of Ladenbergia hexandra Klotzsch, ten triterpenoid glycosides were isolated along with five known compounds, and their structures were determined based on extensive NMR and mass spectroscopic, GC and HPLC analyses. Some triterpenoid glycosides contained 6-deoxy-D-allose or D-allose as a sugar moiety. The absolute stereochemical assignment of the sugars was determined by comparison with synthetic samples, as well as by GC and HPLC analysis.

Anti-influenza triterpenoid saponins (saikosaponins) from the roots of Bupleurum marginatum var. stenophyllum

This study to investigate antiviral components from the roots of Bupleurum marginatum var. stenophyllum led to the isolation of five novel saikosaponins, namely 6″-O-crotonyl-saikosaponin a (1), tibesaikosaponin I (2), tibesaikosaponin II (3), tibesaikosaponin III (4), tibesaikosaponin IV (5), along with 9 known analogues (6-14). Their structures were established by spectral data analyses (IR, MS, 1D and 2D NMR) and by comparison of spectral data with those of the related known compounds. Antiviral testing of all compounds against influenza A virus A/WSN/33 (H1N1) in 293TGluc cells showed that nepasaikosaponin k (12), saikosaponin n (13) and saikosaponin h (14) behaved more potent inhibitory activity and selectivity than the positive control, Ribavirin. The preliminary structure-activity relationship studies suggest that the 13, 28-epoxy group, the type of sugar chain and the type of olefinic bonds are significant for antiviral activity and selectivity.

Design and synthesis of a new series of 3,5-disubstituted isoxazoles active against Trypanosoma cruzi and Leishmania amazonensis

Chagas disease and leishmaniasis are neglected tropical diseases (NTDs) endemic in developing countries. Although there are drugs available for their treatment, efforts on finding new efficacious therapies are continuous. The natural lignans grandisin (1) and veraguensin (2) show activity against trypomastigote T. cruzi and their scaffold has been used as inspiration to design new derivatives with improved potency and chemical properties. We describe here the planning and microwave-irradiated synthesis of 26 isoxazole derivatives based on the structure of the lignans 1 and 2. In addition, the in vitro evaluation against culture trypomastigotes and intracellular amastigotes of T. cruzi and intracellular amastigotes of L. amazonensis and L. infantum is reported. Among the synthesized derivatives, compounds 17 (IC₅₀ = 5.26 μM for T. cruzi), 29 (IC₅₀ = 1.74 μM for T. cruzi) and 31 (IC₅₀ = 1.13 μM for T. cruzi and IC₅₀ = 5.08 μM for L. amazonensis) were the most active and were also evaluated against recombinant trypanothione reductase of T. cruzi in a preliminary study of their mechanism of action.

Microbial hydroxylation and glycosylation of pentacyclic triterpenes as inhibitors on tissue factor procoagulant activity

To discover new inhibitors on tissue factor procoagulant activity, 20 pentacyclic triterpenes were semi-synthetized through microbial transformation and assayed on the model of human THP-1 cells stimulated by lipopolysaccharide. In the biotransformation two types of reactions were observed, regio-selective hydroxylation and glycosylation. The bioassay results showed that most of tested compounds were significant effective on this model and two of the biotransformation products 23-hydroxy-28-O-β-d-glucopyranosyl betulinic acid (3d) and 28-O-β-d-glucopyranosyl oleanic acid (1a) exhibited most potential activities with the IC₅₀ values of 0.028, 0.035nM respectively. The preliminary structure and activity relationship analysis revealed that the aglycones with single free hydroxyl group on the skeleton (1, 1j) were less effective than that with more free hydroxyl groups (1d, 1f, 2), mono-glycosylation can significantly enhance their inhibitory effects. Our findings also provide some potential leading compounds for tissue factor-related diseases, such as cancer and cardiovascular diseases.

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.

Steroids from the rhizome of Anemarrhena asphodeloides and their cytotoxic activities

Cancer remains a major killer worldwide. To search for novel naturally occurring compounds that are cytotoxic to cancer cells to be used as lead structures for drug development, five new steroids (1-5) along with seven known ones (6-12) were isolated from the rhizome of Anemarrhena asphodeloides Bge. Their structures were established by detailed spectral studies, including 1D-NMR, 2D-NMR, HR-ESI-MS and by comparison with literature data. These compounds exhibited different levels of growth inhibition against A549, HepG2, Hep3B, Bcap37 and MCF7 cell lines in vitro. Compounds 9, 10 and 11 showed potent inhibitory against all the tested cell lines with IC50 values ranging from 0.35±0.15 to 25.53±0.31μM. The three compounds displayed stronger inhibitory activities against A549, HepG2 and Hep3B cell lines compared with the positive control 5-fluorouracil. The experimental data obtained permit us to identify the roles of the sugar moieties, hydroxyl group, double bond and F-ring with regard to their cytotoxic activities.

Neuroprotective oleanane triterpenes from the roots of Bupleurum chinense

The discovery of new natural compounds with pharmacological properties is an increasingly important field, and a continuous phytochemical investigation of the roots of Bupleurum chinense D.C. has led to the isolation of 17 triterpenoids, including three new oleanane triterpenes (1-3) together with 14 known ones. Their structures were determined on the basis of 1D and 2D NMR spectra as well as HR-ESI-MS data. The cytotoxicities of all compounds against five selected human cancer cell lines were assayed. Only compounds 9 and 14 exhibited moderate activities. Recently, a number of investigations have focused on the neuroprotective properties of triterpenoids in B. chinense. In order to expand our knowledge about this herb, the neuroprotective effects of compounds 1-17 against hydrogen peroxide (H2O2)-induced neuronal cell damage in human neuroblastoma SH-SY5Y cells were evaluated. Compounds 1-3, 6-7 showed significant neuroprotective effects against H2O2-induced SH-SY5Y cell death. Preliminary structure-activity relationships (SARs) between neuroprotective effects and the isolates were also discussed.