Tetrandrine and fangchinoline, bisbenzylisoquinoline alkaloids from Stephania tetrandra can reverse multidrug resistance by inhibiting P-glycoprotein activity in multidrug resistant human cancer cells

Therapeutic effects of tetrandrine in inflammatory diseases: a comprehensive review

Inflammation can be triggered by any factor. The primary pathological manifestations can be summarized as the deterioration, exudation, and proliferation of local tissues, which can cause systemic damage in severe cases. Inflammatory lesions are primarily localized but may interact with body systems to cause provocative storms, parenchymal organ lesions, vascular and central nervous system necrosis, and other pathologic responses. Tetrandrine (TET) is a bisbenzylquinoline alkaloid extracted from the traditional Chinese herbal medicine Stephania tetrandra, which has been shown to have significant efficacy in inflammatory conditions such as rheumatoid arthritis, hepatitis, nephritis, etc., through NF-κB, MAPK, ERK, and STAT3 signaling pathways. TET can regulate the body's imbalanced metabolic pathways, reverse the inflammatory process, reduce other pathological damage caused by inflammation, and prevent the vicious cycle. More importantly, TET does not disrupt body's normal immune function while clearing the body's inflammatory state. Therefore, it is necessary to pay attention to its dosage and duration during treatment to avoid unexpected side effects caused by a long half-life. In summary, TET has a promising future in treating inflammatory diseases. The author reviews current therapeutic studies of TET in inflammatory conditions to provide some ideas for subsequent anti-inflammatory studies of TET.

Design and Synthesis of Cyclolipopeptide Mimics of Dysoxylactam A and Evaluation of the Reversing Potencies against P-Glycoprotein-Mediated Multidrug Resistance

Inspired by the structure of dysoxylactam A (DLA) that has been demonstrated to reverse P-glycoprotein (P-gp)-mediated multidrug resistance (MDR) effectively, 61 structurally simplified cyclolipopeptides were thus designed and synthesized via an effective method, and their reversing P-gp-mediated MDR potentials were evaluated, which provided a series of more potent analogues and allowed us to explore their structure-activity relationship (SAR). Among them, a well-simplified compound, 56, with only two chiral centers that all derived from amino acids dramatically reversed drug resistance in KBV200 cells at 10 μM in combination with vinorelbine (VNR), paclitaxel (PTX), and adriamycin (ADR), respectively, which is more promising than DLA. The mechanism study showed that 56 reversed the MDR of tumor cells by inhibiting the transport function of P-gp rather than reducing its expression. Notably, compound 56 effectively restored the sensitivity of MDR tumors to VNR in vivo at a dosage without obvious toxicity.

Natural medicinal compounds target signal transduction pathways to overcome ABC drug efflux transporter-mediated multidrug resistance in cancer

ATP-binding cassette (ABC) transporters such as ABCB1, ABCG2, and ABCC1 are the major players in drug efflux-mediated multidrug resistance (MDR), which severely affects the efficacy of chemotherapy. Several synthetic compounds block the drug transport by ABC transporters; however, they exhibit a narrow therapeutic window, and produce side effects in non-target normal tissues. Conversely, the downregulation of the expression of ABC drug transporters seems to be a promising strategy to reverse MDR in cancer cells. Several signaling pathways, such as NF-κB, STAT3, Gli, NICD, YAP/TAZ, and Nrf2 upregulate the expression of ABC drug transporters in drug-resistant cancers. Recently, natural medicinal compounds have gained importance to overcome the ABC drug-efflux pump-mediated MDR in cancer. These compounds target transcription factors and the associated signal transduction pathways, thereby downregulating the expression of ABC transporters in drug-resistant cancer cells. Several potent natural compounds have been identified as lead candidates to synergistically enhance chemotherapeutic efficacy, and a few of them are already in clinical trials. Therefore, modulation of signal transduction pathways using natural medicinal compounds for the reversal of ABC drug transporter-mediated MDR in cancer is a novel approach for improving the efficiency of the existing chemotherapeutics. In this review, we discuss the modulatory role of natural medicinal compounds on cellular signaling pathways that regulate the expression of ABC transporters in drug-resistant cancer cells.

Fangchinoline derivatives inhibits PI3K signaling in vitro and in vivo in non-small cell lung cancer

Fangchinoline (Fan) are extracted from the traditional Chinese medicine Stephania tetrandra S., which is a bis-benzyl isoquinoline alkaloids with anti-tumor activity. Therefore, 25 novel Fan derivatives have been synthesized and evaluated for their anti-cancer activity. In CCK-8 assay, these fangchinoline derivatives displayed higher proliferation inhibitory activity on six tumor cell lines than the parental compound. Compared to the parent Fan, compound 2h presented the anticancer activity against most cancer cells, especially A549 cells, with an IC50 value of 0.26 μM, which was 36.38-fold, and 10.61-fold more active than Fan and HCPT, respectively. Encouragingly, compound 2h showed low biotoxicity to the human normal epithelial cell BEAS-2b with an IC50 value of 27.05 μM. The results indicated compound 2h remarkably inhibited the cell migration by decreasing MMP-2 and MMP-9 expression and inhibited the proliferation of A549 cells by arresting the G2/M cell cycle. Meanwhile, compound 2h could also induce A549 cell apoptosis by promoting endogenous pathways of mitochondrial regulation. In nude mice presented that the growth of tumor tissues was markedly inhibited by the consumption of compound 2h in a dose-dependent manner, and it was found that compound 2h could inhibit the mTOR/PI3K/AKT pathway in vivo. In docking analysis, high affinity interaction between 2h and PI3K was responsible for drastic kinase inhibition by the compound. To conclude, this derivative compound may be useful as a potent anti-cancer agent for treatment of NSCLC.

Simplified Derivatives of Tetrandrine as Potent and Specific P-gp Inhibitors to Reverse Multidrug Resistance in Cancer Chemotherapy

Targeted inhibition of a drug efflux transporter P-glycoprotein (P-gp) is an important strategy to reverse multidrug resistance in cancer chemotherapy. In this study, a rationally structural simplification to natural tetrandrine was performed based on molecular dynamics simulation and fragment growth, leading to an easily prepared, novel, and simplified compound OY-101 with high reversal activity and low cytotoxicity. Its excellent synergistic anti-cancer effect with vincristine (VCR) against drug-resistant cells Eca109/VCR was confirmed by reversal activity assay, flow cytometry, plate clone formation assay, and drug synergism analysis (IC50 = 9.9 nM, RF = 690). Further mechanism study confirmed that the OY-101 was a specific and efficient P-gp inhibitor. Importantly, OY-101 increased VCR sensitization in vivo without obvious toxicity. Overall, our findings may provide an alternative strategy for the design of novel specific P-gp inhibitor as an anti-tumor chemotherapy sensitizer.

Ginsenoside Rb1 for overcoming cisplatin-insensitivity of A549/DDP cells in vitro and vivo through the dual-inhibition on two efflux pumps of ABCB1 and PTCH1

BACKGROUND

The multi-drug resistance is an inherent weakness in the chemotherapeutics of non-small cell lung cancer occurring frequently all over the world. Clinically, ginseng and Chinese medicinal prescriptions including ginseng usually used as anti-tumor adjuncts due to its characteristic of qi-invigorating, which could improve the curative effect of chemotherapy drugs and reduce their toxic side effects. Triterpenoid saponins are the crucial active ingredients in Panax ginseng, and Ginsenoside Rb₁ is of the highest quantities. However, the research on the tumor drug-resistance reversal effect and mechanism of ginsenoside Rb₁ is still not clear.

PURPOSE

This study aimed to systematically estimate the reversal activity of Ginsenoside Rb₁ on cisplatin-insensitivity of A549/DDP cells and to reveal its prospective molecular mechanism.

METHODS

MTT assay were conducted to evaluate the reversal activity on cisplatin-insensitivity of A549/DDP cells of Ginsenoside Rb₁in vitro, and the behavior was also studied by establishing a subcutaneous transplanted tumor model of A549/DDP in BALB/c-nu mice. In addition, P-gp ATPase activity assay, cisplatin accumulation assay, Annexin V-FITC apoptosis assay, real-time qPCR analysis and western blotting analysis were used to clarify the potential mechanism.

RESULTS

Ginsenoside Rb₁ could effectively reverse the cisplatin-resistance of A549/DDP in vitro and vivo. And after the co-treatment of Ginsenoside Rb₁ plus cisplatin, the accumulation of cisplatin increased in A549/DDP cells, which was accompanied with the down-regulation of the mRNA and protein expression levels of ABCB1, SHH, PTCH1 and GLI2. Besides, the apoptosis-inducing ability of cisplatin improved by the relative regulation on the protein expression level of Bax and Bcl-2. Far more importantly, the changes of CYP3A4 mRNA and protein levels were not significant.

CONCLUSION

Ginsenoside Rb₁ could increase the concentration of intracellular cisplatin and improve the insensitivity for cisplatin on A549/DDP cells. Even better, there was perhaps no unpredictable CYP3A4-mediated pharmacokinetic interactions after the combination of Ginsenoside Rb₁ plus cisplatin. Ginsenoside Rb₁ was a probable reversal agent for the cisplatin-insensitivity of A549/DDP cells, with a bifunction of inhibiting the efflux of two drug pumps (P-gp and PTCH1) by targeting ABCB1 and Hedgehog (Hh) pathway. In general, this research laid the groundwork for the development of a new reversal agent for the cisplatin-insensitivity of NSCLC.

Stephtetrandrine A-D, bisbenzylisoquinoline alkaloids from Stephania tetrandra

Four undescribed bisbenzylisoquinoline alkaloids, designated as Stephtetrandrine A-D, were isolated from the roots of Stephania tetrandra. Their structures were elucidated by IR, HRESIMS, ECD spectra, 1 D and 2 D NMR spectra and comparison with the literature data. Additional five known compounds (limacine, tetrandrine, N-trans-Feruloyltyramine, 2'-N-chloromethyltetrandrine, 2,2'-N-N-dichloromethyltetrandrine) were also isolated. N-trans-Feruloyltyramine was isolated from Stephania tetrandra for the first time. The isolated compounds were tested for monoamine oxidase, acetylcholinesterase, phosphoinositide 3-kinase α and human hepatoma cell HepG2 inhibitory activities. Stephtetrandrine C showed obvious inhibitory effect on human hepatoma HepG2, with IC₅₀ value of 16.2 μM. Limacine and 2'-N-chloromethyltetrandrine showed moderate monoamine oxidase inhibitory effect with the IC₅₀ values of 37.7 and 29.2 μM, respectively.

Progress on structural modification of Tetrandrine with wide range of pharmacological activities

Tetrandrine (Tet), derived from the traditional Chinese herb Fangji, is a class of natural alkaloids with the structure of bisbenzylisoquinoline, which has a wide range of physiological activities and significant pharmacfological effects. However, studies and clinical applications have revealed a series of drawbacks such as its poor water solubility, low bioavailability, and the fact that it can be toxic to humans. The results of many researchers have confirmed that chemical structural modifications and nanocarrier delivery can address the limited application of Tet and improve its efficacy. In this paper, we summarize the anti-tumor efficacy and mechanism of action, anti-inflammatory efficacy and mechanism of action, and clinical applications of Tet, and describe the progress of Tet based on chemical structure modification and nanocarrier delivery, aiming to explore more diverse structures to improve the pharmacological activity of Tet and provide ideas to meet clinical needs.

Alkaloids in genus stephania (Menispermaceae): A comprehensive review of its ethnopharmacology, phytochemistry, pharmacology and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Approximately 60 species of the genus Stephania (Menispermaceae) are distributed worldwide. Among these, 39 species are located in South and Southwest China; in particular, these plants are rich in alkaloids and were used in traditional Chinese medicine (TCM) against numerous ailments.

AIM OF THIS REVIEW

The purpose of this study was to provide organized information on the ethnopharmacological uses as well as the phytochemical, pharmacological, and toxicological evaluation of the alkaloids derived from plant species included in the genus Stephania. In addition, we aimed to provide comprehensive basic knowledge on the medicinal properties of these plants and establish meaningful guidelines for further research.

MATERIALS AND METHODS

Information related to the Stephania genus was collected from scientific databases, such as Web of Science, PubMed, Baidu Scholar, and China Academic Journals (CNKI), within the last 20 years on phytochemistry, pharmacology, and toxicology of the plants in genus Stephania. Furthermore, information was obtained from the Pharmacopoeia of the People's Republic of China. Chinese Pharmacopoeia and Flora of China.

RESULTS

Plant species belonging to the genus Stephania have been mentioned as traditional remedies and various alkaloidal compounds have been identified and isolated, including aporphine, proaporphine, morphinane, hasubanane, protoberberine, benzylisoquinoline, and bisbenzylisoquinoline and among others. The isolated alkaloidal compounds reportedly exhibited promising pharmacological properties, such as antimicrobial, antiviral, antitumor, antioxidant, antihyperglycemic, anti-inflammatory, antinociceptive, anti-multidrug resistance, neuroprotective, and cardioprotective activities.

CONCLUSIONS

The genus Stephania is widely used in TCM. The ethnopharmacological uses, phytochemistry, and pharmacology of the Stephania sp. Described in this review demonstrated that these plants contain numerous alkaloids and active constituents and display myriad pharmacological activities. Typically, research on the plants' pharmacological activity focuses on parts of the plants and the associated compounds. However, many Stephania species have rarely been studied, and the ethnomedicinal potential of those discovered has not been scientifically evaluated and needs to be further elucidated. Furthermore, quality control and toxicology studies are warranted in the future.

Roles of Medicinal Plants and Constituents in Gynecological Cancer Therapy: Current Literature and Future Directions

Gynecologic cancers, including cervical, primary peritoneal, ovarian, uterine/endometrial, vaginal and vulvar cancers and gestational trophoblastic disease, are characterized by abnormal cell proliferation in female reproductive cells. Due to the variable pathology of these cancers and the lack of appropriate screening tests in developing countries, cancer diagnosis can be reported in advanced stages in most women and this situation adversely affects prognosis and clinical outcomes of illness. For this reason, many researchers in the field of gynecological oncology have carried out many studies. The treatment of various gynecological problems, which cause physical, biological and psychosocial conditions such as fear, shame, blame and anger, has been important throughout the history. Treatment with herbs has become popular nowadays due to the serious side effects of the synthetic drugs used in treatment and the medical and economical problems caused by them. Many scientists have identified various active drug substances through in vivo and in vitro biological activity studies on medicinal plants from the past to the present. While the intrinsic complexity of natural product-based drug discoveries requires highly integrated interdisciplinary approaches, scientific and technological advances and research trends clearly show that natural products will be among the most important new drug sources in the future. In this review, an overview of the studies conducted for the discovery of multitargeted drug molecules in the rational treatment of gynecological cancers is presented.

An overview on the chemistry, pharmacology and anticancer properties of tetrandrine and fangchinoline (alkaloids) from Stephania tetrandra roots

Tetrandrine (TET) and fangchinoline (FAN) are dominant bisbenzylisoquinoline (BBIQ) alkaloids from the roots of Stephania tetrandra of the family Menispermaceae. BBIQ alkaloids comprise two benzylisoquinoline units linked by oxygen bridges. The molecular structures of TET and FAN are exactly the same, except that TET has a methoxy (-OCH₃) group, while FAN has a hydroxyl (-OH) group at C7. In this overview, the current knowledge on the chemistry, pharmacology and anticancer properties of TET and FAN have been updated. The focus is on colon and breast cancer cells, because they are most susceptible to TET and FAN, respectively. Against colon cancer cells, TET inhibits cell proliferation and tumor growth by inducing apoptosis and G1 cell cycle arrest, and suppresses adhesion, migration and invasion of cells. Against breast cancer cells, FAN inhibits cell proliferation by inducing apoptosis, G1-phase cell cycle arrest and inhibits cell migration. The processes involve various molecular mechanisms and signaling pathways. Some insights on the ability of TET and FAN to reverse multi-drug resistance in cancer cells and suggestions for future research are provided.

Design, synthesis and in vitro anticancer research of novel tetrandrine and fangchinoline derivatives

Cancer treatment is one of the major public health issues in the world. Tetrandrine (Tet) and fangchinoline (d-Tet) are two bis-benzyl isoquinoline alkaloids extracted from Stephania tetrandra S. Moore, and their antitumor activities have been confirmed. However, the effective dose of Tet and d-Tet were much higher than that of the positive control and failed to meet clinical standards. Therefore, in this study, as a continuation of our previous work to study and develop high-efficiency and low-toxic anti-tumor lead compounds, twenty new Tet and d-Tet derivatives were designed, synthesized and evaluated as antitumor agents against six cancer cell lines (H460, H520, HeLa, HepG-2, MCF-7, SW480 cell lines) and BEAS-2B normal cells by CCK-8 analysis. Ten derivatives showed better cytotoxic effects than the parent fangchinoline, of which 4g showed the strongest cell growth inhibitory activity with an IC₅₀ value of 0.59 μM against A549 cells. Subsequently, the antitumor mechanism of 4g was studied by flow cytometry, Hoechst 33258, JC-1 staining, cell scratch, transwell migration, and Western blotting assays. These results showed that compound 4g could inhibit A549 cell proliferation by arresting the G2/M cell cycle and inhibiting cell migration and invasion by reducing MMP-2 and MMP-9 expression. Meanwhile, 4g could induce apoptosis of A549 cells through the intrinsic pathway regulated by mitochondria. In addition, compound 4g inhibited the phosphorylation of PI3K, Akt and mTOR, suggesting a correlation between blocking the PI3K/Akt/mTOR pathway and the above antitumor activities. These results suggest that compound 4g may be a future drug for the development of new potential drug candidates against lung cancer.

Current Updates on Naturally Occurring Compounds Recognizing SARS-CoV-2 Druggable Targets

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been identified in China as the etiologic agent of the recent COVID-19 pandemic outbreak. Due to its high transmissibility, this virus quickly spread throughout the world, causing considerable health issues. The scientific community exerted noteworthy efforts to obtain therapeutic solutions for COVID-19, and new scientific networks were constituted. No certified drugs to efficiently inhibit the virus were identified, and the development of de-novo medicines requires approximately ten years of research. Therefore, the repurposing of natural products could be an effective strategy to handle SARS-CoV-2 infection. This review aims to update on current status of the natural occurring compounds recognizing SARS-CoV-2 druggable targets. Among the clinical trials actually recruited, some natural compounds are ongoing to examine their potential role to prevent and to treat the COVID-19 infection. Many natural scaffolds, including alkaloids, terpenes, flavonoids, and benzoquinones, were investigated by in-silico, in-vitro, and in-vivo approaches. Despite the large data set obtained by a computational approach, experimental evidences in most cases are not available. To fill this gap, further efforts to validate these results are required. We believe that an accurate investigation of naturally occurring compounds may provide insights for the potential treatment of COVID-19 patients.

Repurposing Approved Drugs for Guiding COVID-19 Prophylaxis: A Systematic Review

The SARS-CoV-2 outbreak originally appeared in China in December 2019 and became a global pandemic in March 2020. This infectious disease has directly affected public health and the world economy. Several palliative therapeutic treatments and prophylaxis strategies have been used to control the progress of this viral infection, including pre-(PrEP) and post-exposure prophylaxis. On the other hand, research groups around the world are still studying novel drug prophylaxis and treatment using repurposing approaches, as well as vaccination options, which are in different pre-clinical and clinical testing phases. This systematic review evaluated 1,228 articles from the PubMed and Scopus indexing databases, following the Kitchenham bibliographic searching protocol, with the aim to list drug candidates, potentially approved to be used as new options for SARS-CoV-2 prophylaxis clinical trials and medical protocols. In searching protocol, we used the following keywords: "Covid-19 or SARS-CoV-2" or "Coronavirus or 2019 nCoV," "prophylaxis," "prophylactic," "pre-exposure," "COVID-19 or SARS-CoV-2 Chemoprophylaxis," "repurposed," "strategies," "clinical," "trials," "anti-SARS-CoV-2," "anti-covid-19," "Antiviral," "Therapy prevention in vitro," in cells "and" human testing. After all protocol steps, we selected 60 articles that included: 15 studies with clinical data, 22 studies that used in vitro experiments, seven studies using animal models, and 18 studies performed with in silico experiments. Additionally, we included more 22 compounds between FDA approved drugs and drug-like like molecules, which were tested in large-scale screenings, as well as those repurposed approved drugs with new mechanism of actions. The drugs selected in this review can assist clinical studies and medical guidelines on the rational repurposing of known antiviral drugs for COVID-19 prophylaxis.

Biologically active isoquinoline alkaloids covering 2014-2018

Isoquinoline alkaloids, an important class of N-based heterocyclic compounds, have attracted considerable attention from researchers worldwide since the early 19th century. Over the past 200 years, many compounds from this class were isolated, and most of them and their analogs possess various bioactivities. In this review, we survey the updated literature on bioactive alkaloids and highlight research achievements of this alkaloid class during the period of 2014-2018. We reviewed over 400 molecules with a broad range of bioactivities, including antitumor, antidiabetic and its complications, antibacterial, antifungal, antiviral, antiparasitic, insecticidal, anti-inflammatory, antioxidant, neuroprotective, and other activities. This review should provide new indications or directions for the discovery of new and better drugs from the original naturally occurring isoquinoline alkaloids.

History of uses, phytochemistry, pharmacological activities, quality control and toxicity of the root of Stephania tetrandra S. Moore: A review

ETHNOPHARMACOLOGICAL RELEVANCE

the root of Stephania tetrandra S. Moore, known as Fangji in China (Chinese: ), is a traditional Chinese medicine (TCM) with a long history of use. Fangji is a type of medicine used to treat various diseases, including rheumatism, arthralgia, edema and beriberi, unfavorable urination, and eczema.

AIM OF THIS REVIEW

There are many newly published reports on the history of uses, phytochemistry, pharmacological activity, quality control and toxicity of Fangji; however, no comprehensive systematic review exists. Therefore, the purpose of this review is to compile the latest and most comprehensive information on Fangji and provide a scientific basis for future research.

MATERIALS AND METHODS

A systematic literature search was conducted using multiple electronic databases, including SciFinder, Web of Science, PubMed, Science Direct, ACS Publications, J-stage, SpringerLink, Thieme, Wiley, and CNKI. Information was also collected from journals and Chinese Pharmacopoeia.

RESULT

Thus far, there were uses of Fangji against 20 different diseases/disorders, such as relieving edema and rheumatism pain, treating cough and asthma, treating enuresis, astringent urine and beriberi edema, purging blood and damp heat, and dispelling wind evil and dampness, etc. 48 compounds have been isolated from Fangji, belonging to alkaloids, flavonoids, and steroids, other compounds. The crude extracts and isolated compound of Fangji have shown a wide range of pharmacological activities, such as anti-tumor, anti-inflammatory, and neuroprotective activities, as well as role in reoxygenation, and antimicrobial effect, etc. Moreover, qualitative and quantitative analyses of quality control are reviewed, including qualitative analyses for the identification of compounds, as well as fingerprint and quantitative analyses by high performance liquid chromatography (HPLC) and capillary electrochromatography (CE). In the toxicity study, the hepatotoxicity, hepatorenal toxicity, nephrotoxicity, subacute and acute toxicities of the alcohol extract and water extract of Fangji, and tetrandrine were studied in-vitro and in-vivo experiments.

CONCLUSION

In the history of uses, Fangji can be used to treat a variety of diseases, most of which are manifested in removing wind and dampness. In recent years, the phytochemistry of Fangji has rarely been reported. The pharmacological activities of Fangji mainly focus on the compounds, tetrandrine and fangchinoline, and there are a few reports on the pharmacological studies of other compounds in Fangji. Moreover, the quality control of Fangji lacks a standard fingerprint to distinguish Fangji from other easily-confused medicinal materials. In the toxicity study, there is no report on the mechanism of toxicity research. Therefore, further studies on such mechanisms are needed.

Synthesis, biological evaluation and toxicity of novel tetrandrine analogues

In this work, we present the design and synthesis of novel fully synthetic analogues of the bisbenzylisoquinoline tetrandrine, a molecule with numerous pharmacological properties and the potential to treat life-threatening diseases, such as viral infections and cancer. Its toxicity to liver and lungs and the underlying mechanisms, however, are controversially discussed. Along this line, novel tetrandrine analogues were synthesized and biologically evaluated for their hepatotoxicity, as well as their antiproliferative and chemoresistance reversing activity on cancer cells. Previous studies suggesting CYP-mediated toxification of tetrandrine prompted us to amend/replace the suspected metabolically instable 12-methoxy group. Of note, employing several in vitro models showed that the proposed CYP3A4-driven metabolism of tetrandrine and analogues is not the major cause of hepatotoxicity. Biological characterization revealed that some of the novel tetrandrine analogues sensitized drug-resistant leukemia cells by inhibition of the P-glycoprotein. Interestingly, direct anticancer effects improved in comparison to tetrandrine, as several compounds displayed a markedly enhanced ability to reduce proliferation of drug-resistant leukemia cells and to induce cell death of liver cancer cells. Those enhanced anticancer properties were linked to influences on activation of the kinase Akt and mitochondrial events. In sum, our study clarifies the role of CYP3A4-mediated toxicity of the bisbenzylisoquinoline alkaloid tetrandrine and provides the basis for the exploitation of novel synthetic analogues for their antitumoral potential.

Molecular mechanisms and therapeutic implications of tetrandrine and cepharanthine in T cell acute lymphoblastic leukemia and autoimmune diseases

Inappropriately activated T cells mediate autoimmune diseases and T cell acute lymphoblastic leukemia (T-ALL). Glucocorticoid and chemotherapeutic agents have largely extended lives of these patients. However, serious side effects and drug resistance often limit the prognosis of considerable number of the patients. The efficient treatment of autoimmune diseases or T-ALL with drug resistance remains an important unmet demand clinically. Bisbenzylisoquinoline alkaloids tetrandrine and cepharanthine have been applied for the treatment of certain types of autoimmune diseases and cancers, while studies on their action mechanisms and their further applications combined with glucocorticoids or chemotherapeutic agents remains to be expanded. This review introduced molecular mechanisms of tetrandrine and cepharanthine in T cells, including their therapeutic implications. Both tetrandrine and cepharnthine influence the growth of activated T cells via several kinds of signaling pathways, such as NF-κB, caspase cascades, cell cycle, MAPK, and PI3K/Akt/mTOR. According to recent preclinical and clinical studies, P-glycoprotein inhibitory effect of tetrandrine and cepharnthine could play a significant role on T cell-involved refractory diseases. Therefore, tetrandrine or cepharanthine combined with glucocorticoid or other anti-leukemia drugs would bring a new hope for patients with glucocorticoid-resistant autoimmune disease or refractory T-ALL accompanied with functional P-glycoprotein. In conclusion, bisbenzylisoquinoline alkaloids tetrandrine and cepharanthine can regulate several signaling pathways in abnormally activated T cells with low toxicity. Bisbenzylisoquinoline alkaloids deserve to be paid more attention as a lead compound to develop new drugs for the treatment of T cell-involved diseases in the future.

Tetrandrine partially reverses multidrug resistance of human laryngeal cancer cells

OBJECTIVE

Studies have demonstrated that tetrandrine reverses multidrug resistance (MDR) in animal models or cell lines derived from multiple cancer types. We examined the potential MDR reversal activity of tetrandrine in a multidrug-resistant variant of a human laryngeal cancer Hep-2 cell line and explored potential mechanisms involved.

METHODS

We developed the multidrug-resistant variant cell line (Hep-2/v) by exposing Hep-2 cells to stepwise increasing concentrations of vincristine (VCR). After Hep-2 or Hep-2/v cells were treated with tetrandrine (2.52 µg/mL), MDR was measured by MTT assay, rhodamine 123 retention was measured by flow cytometry, and mRNA and protein expression of multidrug resistance 1 (MDR1), regulator of G-protein signaling 10 (RGS10), high-temperature requirement protein A1 (HTRA1), and nuclear protein 1 (NUPR1) were detected by real-time reverse transcription-PCR and western blotting, respectively.

RESULTS

Tetrandrine significantly lowered the half-maximal inhibitory concentration (IC50) of VCR in Hep-2/v cells, resulting in a 2.22-fold reversal of MDR. Treatment with tetrandrine increased rhodamine 123 retention, downregulated the mRNA and protein expression of MDR1 and RGS10, and upregulated expression of HTRA1 in Hep-2/v cells.

CONCLUSION

We showed that tetrandrine exerts anti-MDR activity in Hep-2/v cells, possibly by inhibiting MDR1 overexpression-mediated drug efflux and by altering expression of HTRA1 and RGS10.

Tetrandrine: a review of its anticancer potentials, clinical settings, pharmacokinetics and drug delivery systems

OBJECTIVES

Tetrandrine, a natural bisbenzylisoquinoline alkaloid, possesses promising anticancer activities on diverse tumours. This review provides systematically organized information on cancers of tetrandrine in vivo and in vitro, discuss the related molecular mechanisms and put forward some new insights for the future investigations.

KEY FINDINGS

Anticancer activities of tetrandrine have been reported comprehensively, including lung cancer, colon cancer, bladder cancer, prostate cancer, ovarian cancer, gastric cancer, breast cancer, pancreatic cancer, cervical cancer and liver cancer. The potential molecular mechanisms corresponding to the anticancer activities of tetrandrine might be related to induce cancer cell apoptosis, autophagy and cell cycle arrest, inhibit cell proliferation, migration and invasion, ameliorate metastasis and suppress tumour cell growth. Pharmaceutical applications of tetrandrine combined with nanoparticle delivery system including liposomes, microspheres and nanoparticles with better therapeutic efficiency have been designed and applied encapsulate tetrandrine to enhance its stability and efficacy in cancer treatment.

SUMMARY

Tetrandrine was proven to have definite antitumour activities. However, the safety, bioavailability and pharmacokinetic parameter studies on tetrandrine are very limited in animal models, especially in clinical settings. Our present review on anticancer potentials of tetrandrine would be necessary and highly beneficial for providing guidelines and directions for further research of tetrandrine.

Phytochemicals: Potential Lead Molecules for MDR Reversal

Multidrug resistance (MDR) is one of the main impediments in the treatment of cancers. MDR cancer cells are resistant to multiple anticancer drugs. One of the major mechanisms of MDR is the efflux of anticancer drugs by ABC transporters. Increased activity and overexpression of these transporters are important causes of drug efflux and, therefore, resistance to cancer chemotherapy. Overcoming MDR is a fundamental prerequisite for developing an efficient treatment of cancer. To date, various types of ABC transporter inhibitors have been employed but no effective anticancer drug is available at present, which can completely overcome MDR. Phytochemicals can reverse MDR in cancer cells via affecting the expression or activity of ABC transporters, and also through exerting synergistic interactions with anticancer drugs by addressing additional molecular targets. We have listed numerous phytochemicals which can affect the expression and activity of ABC transporters in MDR cancer cell lines. Phytochemicals in the groups of flavonoids, alkaloids, terpenes, carotenoids, stilbenoids, lignans, polyketides, and curcuminoids have been examined for MDR-reversing activity. The use of MDR-reversing phytochemicals with low toxicity to human in combination with effective anticancer agents may result in successful treatment of chemotherapy-resistant cancer. In this review, we summarize and discuss published evidence for natural products with MDR modulation abilities.

Tetrandrine enhances glucocorticoid receptor translocation possibly via inhibition of P-glycoprotein in daunorubicin-resistant human T lymphoblastoid leukemia cells

Glucocorticoids are used as anticancer and immunosuppressive agents, whereas glucocorticoid resistance has been observed in a significant fraction of patients due to overexpression of P-glycoprotein encoded by multi-drug resistance-1 gene. Tetrandrine is a bisbenzylisoquinoline alkaloid isolated from traditional herb Fangji. According to our previous report, tetrandrine potentiated glucocorticoid pharmacodynamics partially via inhibiting P-glycoprotein function. In the present study, we investigated whether glucocorticoid receptor translocation was influenced indirectly by tetrandrine via P-glycoprotein inhibition, using human T lymphoblastoid leukemia MOLT-4 cell line with little P-glycoprotein expression and its multidrug resistant sub-line MOLT-4/DNR exhibiting a large amount of P-glycoprotein. Molecular mechanism investigation suggested that overexpressed P-glycoprotein weakened the glucocorticoid receptor translocation in MOLT-4/DNR cells comparing with the parent MOLT-4 cells. Our data also suggested that tetrandrine enhanced nuclear glucocorticoid receptor translocation in MOLT-4/DNR cells indirectly by dual influences on P-glycoprotein, inhibiting the efflux function and downregulating the protein expression. Therefore, tetrandrine potentiated the cytotoxic effect of methylprednisolone against MOLT-4/DNR cells with less effects on MOLT-4 cells. These effects of tetrandrine were suggested to be beneficial for the treatment of glucocorticoid resistant diseases induced by the overexpression of P-glycoprotein.

Bisbenzylisoquinoline alkaloids and P-glycoprotein function: A structure activity relationship study

Conflicts with the notion that specific substrate interactions were required in the control of reaction path in active transport systems, P-glycoprotein showed extraordinarily low specificity. Therefore, overexpression P-glycoprotein excluded a large number of anticancer agents from cancer cells, and multidrug resistance happened. Several kinds of bisbenzylisoqunoline alkaloids were reported to modulate P-glycoprotein function and reverse drug resistance. In order to provide more information for their structure activity relationship on P-glycoprotein function, the effects of tetrandrine, isotetrandrine, fangchinoline, berbamine, dauricine, cepharanthine and armepavine on the P-glycoprotein function were compared by using daunorubicin-resistant leukemia MOLT-4 cells in the present study. Among them, tetrandrine exhibited the strongest P-glycoprotein inhibitory effect, followed with fangchinoline and cepharanthine, and subsequently with berbamine or isotetrandrine. However, dauricine and armepavine showed little influence on the P-glycoprotein function. These data revealed that the 18-membered ring of the bisbenzylisoquinoline alkaloids maintained the P-glycoprotein inhibitory activity, suggesting that double isoquinoline units connected by two oxygen bridges were indispensable. Moreover, stereo-configuration of bisbenzylisoquinoline 3D structures determined their inhibitory activities, which provided a new viewpoint to recognize the specificity of binding pocket in P-glycoprotein. Our data also indicated that 3D chemical structure was more sensitive than 2D to predict the P-glycoprotein inhibitory-potencies of bisbenzylisoqunoline alkaloids.

Design, Synthesis of Novel Tetrandrine-14-l-Amino Acid and Tetrandrine-14-l-Amino Acid-Urea Derivatives as Potential Anti-Cancer Agents

Tetrandrine, a dibenzyltetrahydroisoquinoline alkaloid isolated from the root of the traditional Chinese medicinal plant Stephania tetrandra S. Moore, a member of the Menispermaceae, showed anti-cancer activity by inhibiting cell proliferation, preventing cell cycle progress and induction of cell death and autophagy. In this study, twelve tetrandrine-l-amino acid derivatives and twelve tetrandrine-14-l-amino acid-urea derivatives were designed and synthesized, using C14-aminotetrandrine as raw material. Then the preliminary in vitro anti-cancer activities of these derivatives against human breast cancer cell line MDA-MB-231, human leukemia cell lines HEL and K562 were evaluated. The in vitro cytotoxicity results showed that these derivatives exhibited potent inhibitory effects on cancer cell growth, and the primary structure-activity relationships were evaluated. Notably, compound 3f exhibited satisfactory anticancer activity against all three cancer cell lines, especially the HEL cell line, with the IC₅₀ value of 0.23 µM. Further research showed that 3f could induce G1/S cycle arrest and apoptosis in a dose- and time- dependent manner on the leukemia cell line HEL. The results suggested that 3f may be used as a potential anti-cancer agent for human leukemia.

Natural products for the prevention and treatment of cholestasis: A review

Cholestasis is a common manifestation of decreased bile flow in various liver diseases. It results in fibrosis and even cirrhosis without proper treatment. It is believed that a wide range of factors, including transporter dysfunction, oxidative stress, inflammatory damage, and immune disruption, can cause cholestasis. In recent years, natural products have drawn much attention for specific multiple-target activities in diseases. Many attempts have been made to investigate the anticholestatic effects of natural products with advanced technology. This review summarizes recent studies on the biological activities and mechanisms of recognized compounds for cholestasis treatment. Natural products, including various flavonoids, phenols, acids, quinones, saponins, alkaloids, glycosides, and so on, function as comprehensive regulators via ameliorating oxidative stress, inflammation, and apoptosis, restoring bile acid balance with hepatic transporters, and adjusting immune disruption. Moreover, in this progress, nuclear factor erythroid 2-related factor 2, reactive oxygen species production, heme oxygenase-1, NF-κB, cholesterol 7 alpha-hydroxylase, and farnesoid X receptors are thought as main targets for the activity of natural products. Therefore, this review presents the detailed mechanisms that include multiple targets and diverse signalling pathways. Natural products are the valuable when seeking novel therapeutic agents to treat cholestatic liver diseases.

A critical review: traditional uses, phytochemistry, pharmacology and toxicology of Stephania tetrandra S. Moore (Fen Fang Ji)

ABSTRACT

Stephania tetrandra S. Moore (S. tetrandra) is distributed widely in tropical and subtropical regions of Asia and Africa. The root of this plant is known in Chinese as "Fen Fang Ji". It is commonly used in traditional Chinese medicine to treat arthralgia caused by rheumatism, wet beriberi, dysuria, eczema and inflamed sores. Although promising reports have been published on the various chemical constituents and activities of S. tetrandra, no review comprehensively summarizes its traditional uses, phytochemistry, pharmacology and toxicology. Therefore, the review aims to provide a critical and comprehensive evaluation of the traditional use, phytochemistry, pharmacological properties, pharmacokinetics and toxicology of S. tetrandra in China, and meaningful guidelines for future investigations.

Synergistic Inhibition of Acetylcholinesterase by Alkaloids Derived from Stephaniae Tetrandrae Radix, Coptidis Rhizoma and Phellodendri Chinensis Cortex

Alkaloids having acetylcholinesterase (AChE) inhibitory activity are commonly found in traditional Chinese medicine (TCM); for example, berberine from Coptis chinensis, galantamine from Lycoris radiata, and huperzine A from Huperzia serrata. In practice of TCM, Stephaniae Tetrandrae Radix (STR) is often combined with Coptidis Rhizoma (CR) or Phellodendri Chinensis Cortex (PCC) as paired herbs during clinical application. Fangchinoline from STR and coptisine and/or berberine from CR and/or PCC are active alkaloids in inhibiting AChE. The traditional usage of paired herbs suggests the synergistic effect of fangchinoline–coptisine or fangchinoline–berberine pairing in AChE inhibition. HPLC was applied to identify the main components in herbal extracts of STR, CR, and PCC, and the AChE inhibition of their main components was determined by Ellman assay. The synergism of herb combination and active component combination was calculated by median-effect principle. Molecular docking was applied to investigate the underlying binding mechanisms of the active components with the AChE protein. It was found that fangchinoline showed AChE inhibitory potency; furthermore, fangchinoline–coptisine/berberine pairs (at ratios of 1:5, 1:2, 1:1, and 2:1) synergistically inhibited AChE; the combination index (CI) at different ratios was less than one when Fa = 0.5, suggesting synergistic inhibition of AChE. Furthermore, the molecular docking simulation supported this enzymatic inhibition. Therefore, fangchinoline–coptisine/berberine pairs, or their parental herbal mixtures, may potentially be developed as a possible therapeutic strategy for Alzheimer’s patients.

Antiplasmodial natural products: an update

Background

Malaria remains a significant public health challenge in regions of the world where it is endemic. An unprecedented decline in malaria incidences was recorded during the last decade due to the availability of effective control interventions, such as the deployment of artemisinin-based combination therapy and insecticide-treated nets. However, according to the World Health Organization, malaria is staging a comeback, in part due to the development of drug resistance. Therefore, there is an urgent need to discover new anti-malarial drugs. This article reviews the literature on natural products with antiplasmodial activity that was reported between 2010 and 2017.

Methods

Relevant literature was sourced by searching the major scientific databases, including Web of Science, ScienceDirect, Scopus, SciFinder, Pubmed, and Google Scholar, using appropriate keyword combinations.

Results and Discussion

A total of 1524 compounds from 397 relevant references, assayed against at least one strain of Plasmodium, were reported in the period under review. Out of these, 39% were described as new natural products, and 29% of the compounds had IC₅₀ ≤ 3.0 µM against at least one strain of Plasmodium. Several of these compounds have the potential to be developed into viable anti-malarial drugs. Also, some of these compounds could play a role in malaria eradication by targeting gametocytes. However, the research into natural products with potential for blocking the transmission of malaria is still in its infancy stage and needs to be vigorously pursued.

Tetrandrine Interaction with ABCB1 Reverses Multidrug Resistance in Cancer Cells Through Competition with Anti-Cancer Drugs Followed by Downregulation of ABCB1 Expression

The overexpression of ABC transporters induced by anticancer drugs has been found to be the main cause of multidrug resistance. It is actually also a strategy by which cancer cells escape being killed. Tetrandrine is a natural product extracted from the stem of Tinospora crispa. In this study, tetrandrine showed synergistic cytotoxic activity in combinational use with chemotherapeutic drugs, such as Doxorubicin, Vincristine, and Paclitaxel, in both drug-induced and MDR1 gene-transfected cancer cells that over-expressed ABCB1/P-glycoprotein. Tetrandrine stimulated P-glycoprotein ATPase activity, decreased the efflux of [³H]-Paclitaxel and increased the intracellular accumulation of [³H]-Paclitaxel in KB-C2 cells. Furthermore, SW620/Ad300 and KB-C2 cells pretreated with 1 μM tetrandrine for 72 h decreased P-glycoprotein expression without changing its cellular localization. This was demonstrated through Western blotting and immunofluorescence analysis. Interestingly, down-regulation of P-glycoprotein expression was not correlated with gene transcription, as the MDR1 mRNA level exhibited a slight fluctuation in SW620/Ad300 and KB-C2 cells at 0, 24, 48, and 72 h treatment time points. In addition, molecular docking analysis predicted that tetrandrine had inhibitory potential with the ABCB1 transporter. Our results suggested that tetrandrine can antagonize MDR in both drug-selected and MDR1 gene-transfected cancer cells by down regulating the expression of the ABCB1 transporter, followed by increasing the intracellular concentration of chemotherapeutic agents. The combinational therapy using tetrandrine and other anticancer drugs could promote the treatment efficiency of drugs that are substrates of ABCB1.

Natural compounds as potential adjuvants to cancer therapy: Preclinical evidence

Traditional chemotherapy is being considered due to hindrances caused by systemic toxicity. Currently, the administration of multiple chemotherapeutic drugs with different biochemical/molecular targets, known as combination chemotherapy, has attained numerous benefits like efficacy enhancement and amelioration of adverse effects that has been broadly applied to various cancer types. Additionally, seeking natural‐based alternatives with less toxicity has become more important. Experimental evidence suggests that herbal extracts such as Solanum nigrum and Claviceps purpurea and isolated herbal compounds (e.g., curcumin, resveratrol, and matairesinol) combined with antitumoral drugs have the potential to attenuate resistance against cancer therapy and to exert chemoprotective actions. Plant products are not free of risks: Herb adverse effects, including herb–drug interactions, should be carefully considered.

Linked Articles

This article is part of a themed section on The Pharmacology of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v177.6/issuetoc

Jatrorrhizine inhibits mammary carcinoma cells by targeting TNIK mediated Wnt/β-catenin signalling and epithelial-mesenchymal transition (EMT)

BACKGROUND

Traf2 and Nck interacting serine protein kinase (TNIK) is a tumour target protein which its high expression is closely related to the occurrence and development of mammary carcinoma cells. Molecular docking revealed that jatrorrhizine, a protoberberine alkaloid, exhibits good binding affinity and interaction with TNIK. However, the underlying mechanisms of jatrorrhizine targeting TNIK inhibits the proliferation and metastasis of breast cancer cells remain unclear.

METHODS

To figure out the mechanisms in vitro and in vivo, the CRISPR/Cas9 technology was used to knockout TNIK gene and detected qualitatively by immunofluorescence and immunoblotting assay. The MTT cell viability assay for cytotoxicity test, the apoptosis were detected by flow cytometry, the migration and invasion were evaluated by colony formation, wound healing assay and cell invasion assay, respectively. Anticancer effects were further corroborated by 4T1/Luc homograft tumour model.

RESULTS

The results showed that targeted knockout of TNIK that attenuated Wnt/β-catenin signalling and epithelial-mesenchymal transition (EMT) expression, the effects were potentiated by the addition of jatrorrhizine. Moreover, jatrorrhizine distinctly inhibited the proliferation of MDA-MB-231, MCF-7 and 4T1 cells with IC₅₀ values of 11.08 ± 1.19 μM, 17.11 ± 4.54 μM and 22.14 ± 2.87 μM, induced mitochondrial dysfunction and early apoptosis involving mitochondrial apoptotic pathway. These results were further corroborated by the 4T1 tumour-bearing mice, which showed that jatrorrhizine significantly suppressed the proliferation and metastasis of mammary carcinoma cells without obvious toxicity.

CONCLUSION

These findings provide an overall perspective that jatrorrhizine potentially restrains TNIK regulating Wnt/β-catenin signalling and EMT expression for mammary cancer targeted therapy.

Acid-breakable TPGS-functionalized and diallyl disulfide-crosslinked nanogels for enhanced inhibition of MCF-7/ADR solid tumours

Herein, the dual-functionalized nanogels were used for multidrug resistance (MDR) solid tumour therapy by combining ROS with inhibition of efflux.

Modulation of multidrug resistant in cancer cells by EGCG, tannic acid and curcumin

BACKGROUND

Cancer is one of the most common life-threatening diseases worldwide; many patients develop multidrug resistance after treatment with anticancer drugs. The main mechanism leading to multidrug resistance is the overexpression of ABC transporters in cancer cells. Chemosensitizers are needed to inhibit the activity of ABC transporters, resulting in higer intracellular concentration of anticancer drugs. Some secondary metabolites have been reported to be chemosensitizers by inhibiting ABC transporters. Epigallocatechin gallate (EGCG), tannic acid, and curcumin were employed in this study. Different assays were used to detect whether they have the ability to inhibit P-gp activity and overcome multidrug resistance in cancer cells overexpressing P-gp. Hypothesis/Purpose: CEM/ADR 5000 and Caco-2 cell lines, which overexpress P-gp, are multidrug resistant cell lines. We first detected whether the combination of polyphenols (EGCG, tannic acid, curcumin) and doxorubicin, an anticancer drug, is synergistic or not. To further understand the potential mechanism, EGCG, tannic acid, and curcumin were tested to check whether they have the ability to inhibit P-gp activity. When P-gp activity is inhibited, the intracellular concentration of doxorubicin is higher, resulting in enhanced cytotoxicity of doxorubicin.

STUDY DESIGN

The P-gp overexpressing human colon cancer cell line Caco-2 and human T-lymphoblastic leukemia cell line CEM/ADR 5000 were used in this study. Two-drug combinations (doxorubicin + polyphenol) and three-drug combinations (doxorubicin + polyphenol + digitonin) were tested to examine potential synergism. The potential mechanism leading to synergism would be the inhibition of P-gp activity. A Rhodamine 123 assay and Calcein-AM assay in Caco-2 and CEM/ADR 5000, respectively, were used to detect P-gp inhibition by EGCG, curcumin, and tannic acid.

METHODS

MTT assay was used to determine the cytotoxicity of doxorubicin, polyphenols and digitonin alone, and then their combinations. Furthermore, Rhodamine 123 and Calcein-AM were used to detect the effects of polyphenols on the activity of P-gp.

RESULTS

The results demonstrated that a combination of non-toxic concentrations of each polyphenol with doxorubicin synergistically sensitized Caco-2 and CEM/ADR 5000 cells. Furthermore, three-drug combinations (doxorubicin + polyphenol + digitonin) were much more effective. In addition, the activity of P-gp in Caco-2 and CEM/ADR 5000 cells was measured. Consistent with the combination results, tannic acid and curcumin decreased the activity of P-gp both in Caco-2 and CEM/ADR 5000. EGCG, which weakly affected the activity of P-gp in CEM/ADR 5000, only had an effect on P-gp under higher concentration in Caco-2 cells.

CONCLUSION

Our results show that EGCG, curcumin, and tannic acid, when combined with doxorubicin, can exert synergism, mediated by a reduced activity of P-gp. This study suggests that polyphenols, by modulating the activity of P-gp, may be used as chemosensitisers.

Effect of five novel 5-substituted tetrandrine derivatives on P-glycoprotein-mediated inhibition and transport in Caco-2 cells

Tetrandrine (Tet) is a potent inhibitor that reverses P-glycoprotein-mediated multidrug resistance (MDR). A number of novel 5-substituted tetrandrine derivatives were synthesized by the authors. The present study aimed at identifying potential P-gp inhibitor candidates, and intracellular uptake and efflux experiments and Caco-2 cell-based Transwell transport studies were performed. It was demonstrated that all five test compounds were able to inhibit efflux and increase intracellular uptake of the P-gp substrate, rhodamine-123 (Rho-123); the test compounds were P-gp inhibitors. The transepithelial transport experiment indicated that the secretory (basolateral-to-apical) of Rho-123 decreased, the absorption (apical-to-basolateral) increased and the transport efflux ratio (ER) reduced in the presence of the five compounds. Among the compounds, fluobenzene-Tet (TF) exhibited similar inhibitory effect as Tet. Although the other four test compounds exhibited weaker inhibitory effects than Tet and TF, the compounds exhibited stronger inhibitory effects compared with the reference compound verapamil. The study demonstrated that the five novel 5-substituted tetrandrine derivatives are able to act as inhibitors of P-gp to overcome P-gp-mediated drug resistance.

Synthesis of novel tetrandrine derivatives and their inhibition against NSCLC A549 cells

A series of novel tetrandrine (Tet) derivatives were synthesized through Suzuki -Miyaura reaction and evaluated for their cytotoxicity against human non-small cell lung carcinoma (NSCLC) A549 cells. Interestingly, most of derivatives showed similar cytotoxicity to Tet against NSCLC A549 cells, and particularly, compounds Y5, Y6, Y9 and Y11 showed the most significant cytotoxic effects with IC₅₀ values ranging from 3.87 to 4.66 mM. The present study is expected to contribute to the future design of more effective anticancer agents in lung cancer chemotherapy.

Application of alkaloids in reversing multidrug resistance in human cancers

Multidrug resistance (MDR) in human cancer is one of greatest challenges in cancer therapy. Natural products, especially the alkaloids, exert reversed effects on MDR with low toxicity, by interacting with various targets. In this review article, we summarize the recent progress made in the research of the main alkaloids, including classification, function, mechanism, research status, and application in reversing MDR.

Molecular Targets Modulated by Fangchinoline in Tumor Cells and Preclinical Models

Despite tremendous progress made during the last few decades in the treatment options for cancer, compounds isolated from Mother Nature remain the mainstay for therapy of various malignancies. Fangchinoline, initially isolated from the dried root of Stephaniae tetrandrine, has been found to exhibit diverse pharmacological effects including significant anticancer activities both in tumor cell lines and selected preclinical models. This alkaloid appears to act by modulating the activation of various important oncogenic molecules involved in tumorigenesis leading to a significant decrease in aberrant proliferation, survival and metastasis of tumor cells. This mini-review briefly describes the potential effects of fangchinoline on important hallmarks of cancer and highlights the molecular targets modulated by this alkaloid in various tumor cell lines and preclinical models.

Study on spectrum-effect correlation for screening the effective components in Fangji Huangqi Tang basing on ultra-high performance liquid chromatography-mass spectrometry

BACKGROUD

Fangji Huangqi Tang (FHT) is a traditional Chinese medicine formula. Our previous work found that FHT could improve glomerular filtration function. The research on the effective materials basis of FHT was rarely reported.

PURPOSE

The effect indicators of glomerular filtration function were determined. The components in serum of FHT was detected and identified. The relationships between chemical spectra of serum and effect indicators were elucidated.

STUDY DESIGN

The paper was to study the underlying correlations between the chemical spectra and the protective effect of FHT on glomerulus to reveal the potential effective compounds in FHT.

METHODS

For the serum pharmacochemistry study, the biological samples were collected according to a time schedule designed carefully in advance. The fingerprint chromatograms of rat serum after oral administration of FHT were established by UHPLC-ESI-Q-TOF-MS technique. Meanwhile, in the pharmacodynamics research, the protective effects of FHT on glomerulonephritis were evaluated by detecting the contents of cystatin C (Cys C), blood urea nitrogen (BUN) and serum creatinine (Scr). Then, the spectrum-effect relationships between UHPLC fingerprints and anti-adriamycin nephrosis activities were evaluated using canonical correlation analysis (CCA) statistical method.

RESULTS

As a result, 105 peaks were identified from rat serum samples, which turned out to be 26 original compounds of FHT as well as 79 metabolites. According to the CCA results, eleven components were finally found to be the main anti-adriamycin nephrosis components.

CONCLUSIONS

The model successfully discovered the spectrum-effect relationships of FHT, which showed a representative way to discover the primary active ingredients from the complex herbal medicine system.

Tetrandrine enhances the antifungal activity of fluconazole in a murine model of disseminated candidiasis

BACKGROUND

Tetrandrine (TET), a bis-benzylisoquinoline alkaloid isolated from the Chinese medicinal herb Stephaniae tetrandrae, has a long history in Chinese clinical applications as an anti-inflammatory or anti-arrhythmic agent in the treatment of diverse diseases. In our previous study, TET exhibited the synergisitic action on azoles against pathogenic fungi.

PURPOSE

In the current study, we examined whether TET can enhance the antifungal activity of FLC against disseminated candidiasis in mice.

METHODS

BALB/c mice were inoculated intravenously with FLC-sensitive or FLC-resistant strains of Candida albicans, randomized and treated intraperitoneally with different doses of TET and/or FLC daily for 7 days. The treatment effectiveness, fungal burdens and the levels of the IFN-γ, IL-10, TGF-β1 and IL-17A are determined in serum by ELISA and in the kidney by Real-time RT-PCR methods.

RESULTS

We found that treatment with 45, 30 and 15 mg/kg of TET, enhanced the antifungal activities of a sub-critical dose (0.4 or 5 mg/kg) and minimal dose (0.8 or 10 mg/kg) of FLC against FLC-sensitive and FLC-resistant (respectively) infected mice. In the resistant strains the resistance mechanisms included MDR1 overexpression-and CDR1/CDR2 overexpression. Furthermore, when animals were treated with a sub-high dose (1.6-3.2 and 20-30 mg/kg) of FLC in the presence of fixed amounts of TET at 45, 30 and 15 mg/kg, the therapeutic doses of FLC could be substantially reduced in all strains tested. The findings in infected animal are consistent with the conclusion that TET exerts a synergistic effect on FLC against C. albicans by fractional inhibitory concentration index (FICI) and time-killing test in vitro.

CONCLUSION

In summary, our data indicate that TET will enhance the antifungal activity of FLC against C. albicans infection in disseminated mice model.

Research Progress on Reversing Multidrug Resistance in Tumors by Using Chinese Medicine

Multidrug resistance (MDR) is a major cause of cancer chemotherapy failure, and it is important to develop suitable reversal agents to overcome MDR. A majority of chemical reversal agents have acceptable reversal effects. However, the toxicity and adverse reactions associated with these agents restricts their clinical use. Chinese medicines (CMs) have lower toxicities and adverse reactions and are associated with multiple components, multiple targets and reduced toxicity. CMs have several advantages and could reverse MDR, decrease drug dosage, enhance patient compliance and increase efficacy. This review summarizes the current progress of CM reversal agents..

Tetrandrine, a Chinese plant-derived alkaloid, is a potential candidate for cancer chemotherapy

Cancer is a disease caused by the abnormal proliferation and differentiation of cells governed by tumorigenic factors. Chemotherapy is one of the major cancer treatment strategies, and it functions by targeting the physiological capabilities of cancer cells, including sustained proliferation and angiogenesis, the evasion of programmed cell death, tissue invasion and metastasis. Remarkably, natural products have garnered increased attention in the chemotherapy drug discovery field because they are biologically friendly and have high therapeutic effects. Tetrandrine, isolated from the root of Stephania tetrandra S Moore, is a traditional Chinese clinical agent for silicosis, autoimmune disorders, inflammatory pulmonary diseases, cardiovascular diseases and hypertension. Recently, the novel anti-tumor effects of tetrandrine have been widely investigated. More impressive is that tetrandrine affects multiple biological activities of cancer cells, including the inhibition of proliferation, angiogenesis, migration, and invasion; the induction of apoptosis and autophagy; the reversal of multidrug resistance (MDR); and the enhancement of radiation sensitization. This review focuses on introducing the latest information about the anti-tumor effects of tetrandrine on various cancers and its underlying mechanism. Moreover, we discuss the nanoparticle delivery system being developed for tetrandrine and the anti-tumor effects of other bisbenzylisoquinoline alkaloid derivatives on cancer cells. All current evidence demonstrates that tetrandrine is a promising candidate as a cancer chemotherapeutic.

Biological characteristics, bioactive components and antineoplastic properties of sporoderm-broken spores from wild Cordyceps cicadae

BACKGROUND

Cordyceps cicadae, an entomogenous fungus has been used as a dietary therapeutic in traditional Chinese medicine for several millennia, in the form of powders and decoction. However, wild C. cicadae is notably scarce. To date, there is still a lack of comprehensive and deep studies on the biological characteristics, chemical profiles and antineoplastic mechanisms of C. cicadae, especially its spores.

AIM OF THE STUDY

This study aimed to identify wild C. cicadae using rDNA-ITS sequences. Active constituents and volatile ingredients of C. cicadae sporoderm-broken spore powders (CCBSP) were elucidated using UPLC-ESI-Q-TOF-MS and GC-MS, respectively. The underlying anti-neoplastic mechanisms of CCBSP were further investigated in A549 lung carcinoma cells.

RESULTS

Molecular phylogenetic analysis of nuclear rDNA sequences indicated that wild C. cicadae belonged to Paecilomyces cicadae. Eight primary compounds from CCBSP were identified by MS fragmentation ions including nucleosides, cordycepic acid, cordycepin, beauvericin and myriocin. In total, forty-nine volatile components representing 99.56% of CCBSP were clearly identified. CCBSP exhibited antiproliferative effects on A549 cells with IC₅₀ value of 125.54 ± 2.71 µg/ml, blocking the cell cycle in the G2/M phase. The nuclear morphology exhibited typical characteristics of apoptosis by Hoechst fluorescent stain. AnnexinV-FITC/PI staining revealed that the number of apoptotic cells increased after CCBSP treatment. Furthermore, immunofluorescence experiments indicated that CCBSP lowered the expressions of β-catenin and N-cadherin, which was accompanied by repressed Wnt/β-catenin signalling and activation of caspase-mediated apoptosis pathways.

CONCLUSIONS

rDNA-ITS sequencing enabled molecular identification of wild C. cicadae. Importantly, these findings provide the first evidence regarding the full-scale bioactive components and antineoplastic properties of CCBSP. These data highlight the significance of C. cicadae as a potential antineoplastic agent.