Triptolide: progress on research in pharmacodynamics and toxicology

Detoxication mechanisms of Radix Tripterygium wilfordii via compatibility with Herba Lysimachia christinae in S180-bearing mice by involving Nrf2

The combined administration between Radix Tripterygium wilfordii Hook F (LGT) and Herba Lysimachia christinae Hance (JQC) belongs to mutual detoxication compatibility of seven emotions in traditional Chinese medicine (TCM) theory. However, until now, the compatibility detoxication mechanisms remain unknown. The present study was undertaken to observe detoxication mechanisms of LGT through compatibility with JQC in tumor-bearing mice by involving NF-E2-related factor 2 (Nrf2)-mediated antioxidant defenses. In addition, influence of compatibility on antitumor activity was also investigated here. Our results demonstrated that compatibility with JQC administration significantly reversed LGT-elevated serum alanine/aspartate transaminase (ALT/AST) levels and alleviated hepatocytes’ swelling or degeneration damage, and at the ratio 2/1 (LGT/JQC) produced the strongest detoxication effect. Besides, compatibility with JQC administration reversed not only LGT-elevated hepatic malondialdehyde (MDA) and tumor necrosis factor-α (TNF-α) but also the LGT lowered GSH, glutathione-s transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and interleukin (IL)-10 levels. Furthermore, compatibility with JQC administration significantly up-regulated protein expression of Nrf2 and mRNA expression of it regulated downstream antioxidant genes such as heme oxygenase-1 (HO-1), NAD(P)H: quinone oxidoreductase-1 (NQO1), and glutamate cysteine ligase catalytic subunit (GCLC). In addition, compatibility with JQC further decreased LGT-decreased tumor weight and at the ratio 2/1 (LGT/JQC) also exerted the strongest synergistic effect. Collectively, through compatibility with JQC exerted detoxication effect on LGT-induced hepatotoxicity and the mechanisms could be at least partly attributed to up-regulation of Nrf2 and its downstream signals, thereby enhancing antioxidant defenses, and inhibiting lipid peroxidation, oxidative stress, and inflammation. Additionally, at the ratio 2/1 (LGT/JQC) exerted the strongest effects on both detoxication and synergism.

Chinese Medicine in the Battle Against Obesity and Metabolic Diseases

Obesity is a multi-factor chronic disease caused by the mixed influence of genetics, environments and an imbalance of energy intake and expenditure. Due to lifestyle changes, modern society sees a rapid increase in obesity occurrence along with an aggravated risk of metabolic syndromes in the general population, including diabetes, hepatic steatosis, cardiovascular diseases and certain types of cancer. Although obesity has become a serious worldwide public health hazard, effective and safe drugs treating obesity are still missing. Traditional Chinese medicine (TCM) has been implicated in practical use in China for thousands of years and has accumulated substantial front line experience in treating various diseases. Compared to western medicine that features defined composition and clear molecular mechanisms, TCM is consisted with complex ingredients from plants and animals and prescribed based on overall symptoms and collective experience. Because of their fundamental differences, TCM and western medicine were once considered irreconcilable. However, nowadays, sophisticated isolation technologies and deepened molecular understanding of the active ingredients of TCM are gradually bridging the gap between the two, enabling the identification of active TCM components for drug development under the western-style paradigms. Thus, studies on TCM open a new therapeutic avenue and show great potential in the combat against obesity, though challenges exist. In this review, we highlight six key candidate substances derived from TCM, including artemisinin, curcumin, celastrol, capsaicin, berberine and ginsenosides, to review their recent discoveries in the metabolic field, with special focus on their therapeutic efficacy and molecular mechanisms in treating obesity and metabolic diseases. In addition, we discuss the translational challenges and perspectives in implementing modern Chinese medicine into the western pharmaceutical industry.

Biochemical and computational evaluation of Triptolide-induced cytotoxicity against NSCLC

Triptolide is the major bioactive component isolated from the Chinese Medicinal plant Tripterygium wilfordii. Despite the growing interest and the plethora of reports discussing the pharmacological activity of this diterpenoid, no clear consensus regarding its cellular targets and full mechanism of action has been reached. In the present work, a combined in vitro and in silico approach was used to evaluate the biological activity of Triptolide on Non-small cell lung cancer (NSCLC). In vitro, Triptolide treatment induced apoptosis in NSCLC cell lines and down-regulated the phosphorylation of AKT, mTOR, and p70S6K. Triptolide also impacted cellular glycolysis as well as the antioxidant response through the impairment of glucose utilization, HKII, glutathione, and NRF2 levels. Molecular docking results examined the possible interactions between Triptolide and AKT and predicted an allosteric binding to AKT-1 structure. Molecular dynamics simulations were further used to evaluate the stability of the complex formed by Triptolide's best conformer and AKT. These findings provide an insightful approach to the anticancer effect of Triptolide against NSCLC and highlight a possible new role for AKT/mTOR HKII inhibition.

Small Peptides Compound Isolated from Agkistrodon with Antiarthritic Effect in Collagen-Induced Arthritis Rats

Agkistrodon in Chinese medicine has long been used as an effective treatment against rheumatoid arthritis (RA). The present research further investigated the effects of peptides extracted from the crude Agkistrodon on the RA rat model. Extracted peptides were separated by parameter-optimized ion-exchange chromatography (IEC), peptide fractions were further analysed by MALDI-TOF/TOF MS, and nano-LC-MS/MS acquired mass spectra were further characterized using Mascot software, which ranks the best matches in the NCBI database. RT-PCR results in RAW264.7 cells indicated that Agkistrodon peptide components had inhibitory effects against inflammatory cytokines. The therapeutic efficacy of Agkistrodon peptides was evaluated on the Wistar rats with collagen-induced arthritis. Symptom relief and reduced cartilage destruction and bone erosion were observed, which can be explained by the direct suppression of inflammatory cytokines in the joints. Agkistrodon peptides downregulate the expression of TNF-α, IL-1β, and IL-6, which may alleviate cartilage destruction and bone erosion, thus relieving symptoms of RA.

Extrahepatic cytochrome P450s play an insignificant role in triptolide-induced toxicity

Background

Triptolide, an active ingredient of Chinese medicine plant Tripterygium wilfordii Hook.f., has been shown to exert anti-tumor, immunosuppressive, anti-inflammatory, and anti-fertility pharmacological effects. However, triptolide also causes severe side effects, which are manifested as toxicities in multiple organs. The aim of this study was to analyze the role of extrahepatic cytochrome P450 enzymes in triptolide-induced toxicity.

Methods

Xh-CL mouse model with normal liver, but low extrahepatic P450 expression levels was used in this study. Xh-CL mice and C57BL/6 (wildtype, WT) mice were treated with 200 μg/kg triptolide intraperitoneally every other day for 30 days. The serum levels of alanine aminotransferase (ALT), aspartate transaminase (AST), creatine (Cre), and blood urea nitrogen (BUN) were detected by kits. The changes of tissue were observed with H&E staining. Two groups of mice (Xh-CL and WT animals), were received a single dose of 1 mg/kg TP by oral gavage for pharmacokinetic analysis.

Results

Xh-CL mice displayed higher serum levels of ALT, AST, Cre, and BUN compared to untreated Xh-CL mice. The organ-to-body weight ratio for spleen was high, while that for testes was low. Histopathological changes were observed in multiple organs. However, compared with triptolide-treated WT mice, no significant differences in either blood chemistry or histopathology were recorded. Furthermore, pharmacokinetic studies showed no significant differences between triptolide-treated Xh-CL and WT mice.

Conclusions

Our findings suggest that sub-chronic triptolide treatment can induce toxicities in mouse kidney, spleen, and testis with or without normal local P450 functions. Therefore, extrahepatic P450s play an insignificant role in triptolide-induced toxicity.

Electronic supplementary material

The online version of this article (10.1186/s13020-018-0179-8) contains supplementary material, which is available to authorized users.

Triptolide-induced hepatotoxicity can be alleviated when combined with Panax notoginseng saponins and Catapol

ETHNOPHARMACOLOGICAL RELEVANCE

The hepatotoxicity of Tripterygium wilfordii Hook. f. (TW), due to the presence of triptolide (TP), limits its therapeutic potential. Based on the traditional Chinese medicine theory, the theory of "Yi lei xiang zhi" was proposed that Chinese herbs with different efficacy can restrict each other to achieve the least adverse reactions.

AIM OF THE STUDY

To observe the effects of Catapol (CAT) and Panax notoginseng saponins (PNS), active ingredients in Rehmannia glutinosa (RG) and Panax notoginseng (PN) respectively, on reducing TP-induced hepatotoxicity, and further to explore the mechanisms.

MATERIALS AND METHODS

The human hepatic cell line L-02 was cultured and treated with CAT, PNS or Combinations, and then treated with TP. The cytotoxic assay, the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH), apoptosis, mitochondrial membrane potential and the expressions of NF-E2-related factor 1 (Nrf1) and its downstream targets were detected. Rats were treated with TP, TP + CAT, TP + PNS, or the combinations for 4 weeks. The levels of ALT, AST and LDH in serum, apoptosis of liver cells, mitochondria injury and the protein expressions of Caspase 3 and Nrf1 were investigated.

RESULTS

CAT, PNS or CAT+PNS pre-treatment inhibited TP-induced toxicity in L-02 cells, distinctly decreased the apoptosis, alleviated the reduction of mitochondrial membrane potential, and modulated the expressions of Nrf1 and its downstream target, the mitochondrial transcription factor A (TFAM) and cytochrome C (Cyt-C). CAT, PNS or CAT+PNS inhibited the TP-induced hepatotoxicity in SD rats by reducing the mitochondria injury, decreasing the cells apoptosis and increasing the Nrf1 protein expression. Noticeably, TP + PNS + CAT combinations exhibited more effective than any single ingredient alone.

CONCLUSION

PNS and CAT were able to effectively attenuate TP-induced hepatotoxicity. The efficiency benefits from their modulating Nrf1 and its downstream genes TFAM and Cyt-C, and further influencing mitochondrial functions and cells apoptosis. The combination is more effective than single ingredient alone.

Mechanisms of Triptolide-Induced Hepatotoxicity and Protective Effect of Combined Use of Isoliquiritigenin: Possible Roles of Nrf2 and Hepatic Transporters

Triptolide (TP), the main bioactive component of Tripterygium wilfordii Hook F, can cause severe hepatotoxicity. Isoliquiritigenin (ISL) has been reported to be able to protect against TP-induced liver injury, but the mechanisms are not fully elucidated. This study aims to explore the role of nuclear transcription factor E2-related factor 2 (Nrf2) and hepatic transporters in TP-induced hepatotoxicity and the reversal protective effect of ISL. TP treatment caused both cytotoxicity in L02 hepatocytes and acute liver injury in mice. Particularly, TP led to the disorder of bile acid (BA) profiles in mice livers. Combined treatment of TP with ISL effectively alleviated TP-induced hepatotoxicity. Furthermore, ISL pretreatment enhanced Nrf2 expressions and nuclear accumulations and its downstream NAD(P)H: quinine oxidoreductase 1 (NQO1) expression. Expressions of hepatic P-gp, MRP2, MRP4, bile salt export pump, and OATP2 were also induced. In addition, in vitro transport assays identified that neither was TP exported by MRP2, OATP1B1, or OATP1B3, nor did TP influence the transport activities of P-gp or MRP2. All these results indicate that ISL may reduce the hepatic oxidative stress and hepatic accumulations of both endogenous BAs and exogenous TP as well as its metabolites by enhancing the expressions of Nrf2, NQO1, and hepatic influx and efflux transporters. Effects of TP on hepatic transporters are mainly at the transcriptional levels, and changes of hepatic BA profiles are very important in the mechanisms of TP-induced hepatotoxicity.

Triptolide suppresses the in vitro and in vivo growth of lung cancer cells by targeting hyaluronan-CD44/RHAMM signaling

Higher levels of hyaluronan (HA) and its receptors CD44 and RHAMM have been associated with poor prognosis and metastasis in NSCLC. In the current study, our goal was to define, using cellular and orthotopic lung tumor models, the role of HA-CD44/RHAMM signaling in lung carcinogenesis and to assess the potential of triptolide to block HA-CD44/RHAMM signaling and thereby suppress the development and progression of lung cancer. Triptolide reduced the viability of five non-small cell lung cancer (NSCLC) cells, the proliferation and self-renewal of pulmospheres, and levels of HA synthase 2 (HAS2), HAS3, HA, CD44, RHAMM, EGFR, Akt and ERK, but increased the cleavage of caspase 3 and PARP. Silencing of HAS2, CD44 or RHAMM induced similar effects. Addition of excess HA to the culture media completely abrogated the effects of triptolide and siRNAs targeting HAS2, CD44, or RHAMM. In an orthotopic lung cancer model in nude rats, intranasal administration of liposomal triptolide (400 μg/kg) for 8 weeks significantly reduced lung tumor growth as determined by bioluminescence imaging, lung weight measurements and gross and histopathological analysis of tumor burden. Also, triptolide suppressed expressions of Ki-67, a marker for cell proliferation, HAS2, HAS3, HA, CD44, and RHAMM in lung tumors. Overall, our results provide a strong rationale for mitigating lung cancer by targeting the HA-CD44/RHAMM signaling axis.

Paeoniflorin Inhibits Receptor Activator for Nuclear Factor κB (RANK) Ligand-Induced Osteoclast Differentiation In Vitro and Particle-Induced Osteolysis In Vivo

Background

Paeoniflorin (PF), a glucoside isolated from the dried root of Paeonia lactiflora Pall, has been reported to have a number of pharmacological properties, including immunity-regulation, anticancer activities, and neuroprotective effect. However, PF’s pharmacological role in bone disorder has been seldom reported. Hence, this study was designed to investigate the effects of PF on osteoclast differentiation and osteolysis diseases.

Material/Methods

The bone marrow macrophages were isolated from C57BL/6 mice and incubated with RANK ligand (RANKL) and various concentrations of PF. After 5 days of incubation, tartrate-resistant acid phosphatase (+) cells and bone resorption pits were counted. Effects of PF on expression of osteoclast-specific protein and gene were investigated via Western blot, q-PCR, and immunofluorescence assay. The osteoprotective effect of PF in vivo was evaluated in a calvarial osteolysis model via micro-CT scan and histological stain.

Results

In vitro, PF intervention inhibited osteoclast formation and resorption activity. PF also impaired RANKL-induced NF-κB phosphorylation and immigration to the nucleus. PF suppressed osteoclast-marker protein and gene expression. In vivo, PF inhibited cobalt-chromium-molybdenum alloy particle-induced osteolysis and reduced osteoclast number in tissue slice.

Conclusions

PF is a potential agent against osteolysis-related diseases caused by excessive osteoclast activity.

Further Study of Influence of Panax notoginseng on Intestinal Absorption Characteristics of Triptolide and Tripterine in Rats with Tripterygium wilfordii

Background:

Tripterygium wilfordii (TW) is widely employed to treat rheumatoid arthritis and autoimmune disorders clinically, which, however, accompany with disturbing hepatotoxicity and nephrotoxicity. The previous research showed that Panax notoginseng (PN) compatibly and significantly reduces the TW-induced hepatotoxicity.

Objective:

To explore the underlying mechanism, the present study was designed to reveal the influence of PN on the intestinal absorption process of TW-derived active components in rat.

Materials and Methods:

An in situ single-pass intestinal perfusion technique was established and preformed to obtain the perfusate samples of triptolide (TP), tripterine (TE), TW extract, and TW-PN extract. A rapid and sensitive ultra-performance liquid-chromatography tandem mass spectrometry method was subsequently developed and validated to determine the concentrations of TP and TE in the perfusate samples. Then, the absorption parameters, effective permeability, absorption rate constant, and percentage of 10 cm intestinal absorption were calculated strictly.

Results:

The final data indicated that both TP and TE have no special absorption site in the intestine and are primarily absorbed in a passive manner. Otherwise, the absorption of TP was decreased from compatibility of PN, but the absorption of TE was enhanced.

Conclusion:

The absorption reduction of TP and absorption elevation of TE from TW initiated by the combination of PN are contributed to attenuate the toxicity and reinforce the therapeutic efficacy of TW. It is practically reasonable of usage of TW compatibility with PN clinically.

SUMMARY

Panax notoginseng (PN) regulated the absorption process of Tripterygium wilfordii (TW) in intestine

Both triptolide (TP) and tripterine (TE), two typical components of TW, have no special absorption site in the intestine and are primarily absorbed in a passive manner

PN decreased the absorption of TP and enhanced the absorption of TE in the intestine.

Abbreviations used: 10 cm% ABS: percentage of 10 cm intestinal absorption, DMARDs: Disease-modifying antirheumatic drugs, GU: Glycyrrhiza uralensis, K_a: Absorption rate constant, NSAIDs: Nonsteroidal anti-inflammatory drugs, P_eff: Effective permeability, PN: Panax notoginseng, QC: Quality control, RA: Rheumatoid arthritis, RG: Rehmannia glutinosa, SPIP: Single-pass intestinal perfusion, TE: Tripterine, TP: Triptolide, TW: Tripterygium wilfordii, UPLC-MS/MS: Ultra-performance liquid-chromatography tandem mass spectrometry.

Triptolide induces autophagy and apoptosis through ERK activation in human breast cancer MCF-7 cells

To investigate the effects of triptolide (TPI) on proliferation, autophagy and death in human breast cancer MCF-7 cells, and to elucidate the associated molecular mechanisms, intracellular alterations were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometry assays. The results of the MTT assay revealed that TPI significantly reduced the MCF-7 cell survival rate when the concentration was >10 nmol/l. TPI activated a caspase cascade reaction by regulating Bcl-2-associated X protein (Bax), caspase-3 and B-cell lymphoma 2 expression, and promoted programmed cell death via the mitochondrial pathway. The results demonstrated that TPI significantly reduced the cell proliferation rate and viability in a time- and dose-dependent manner, which was confirmed by western blotting and immunofluorescent staining. TPI induced autophagy and influenced p38 mitogen-activated protein kinases, extracellular signal-regulated kinase (Erk)1/2, and mammalian target of rapamycin (mTOR) phosphorylation, which resulted in apoptosis. When cells were treated with a combination of TPI and the Erk1/2 inhibitor U0126, the downregulation of P62 and upregulation of Bax were inhibited, which demonstrated that the inhibition of Erk1/2 reversed the autophagy changes induced by TPI. The results indicated that Erk1/2 activation may be a novel mechanism by which TPI induces autophagy and apoptosis in MCF-7 breast cancer cells. In conclusion, TPI affects the proliferation and apoptosis of MCF-7 cells, potentially via autophagy and p38/Erk/mTOR phosphorylation. The present study offers a novel view of the mechanisms by which TPI regulates cell death.

Synthesis, Characterization, and Evaluation of Triptolide Cell-Penetrating Peptide Derivative for Transdermal Delivery of Triptolide

Triptolide (TP) has been used as one of the most common systemic treatments for various diseases since the 1960s. However, TP displays diverse side effects on various organs, which limits its clinical application. To overcome this issue, numerous C-14-hydroxyl group derivatives of TP have been synthesized. In this research, the C-14-hydroxyl group of TP is modified by a cell-penetrating peptide polyarginine (R₇). The derivative TP-disulfide-CR₇ (TP-S-S-CR₇) containing a disulfide linkage between TP and R₇ possesses less toxicity at various concentrations on the immortal human keratinocyte (HaCaT) cell line by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay compared with free TP. Treating HaCaT cells with TP (100 nM) could increase intracellular ROS (reactive oxygen species) and decrease the activity of SOD (superoxide dismutase). Meanwhile, treating HaCaT cells with equimolar concentration of TP-S-S-CR₇ did not cause both of the above TP-induced alterations. In addition, TP-S-S-CR₇ did not show significant dermal toxicity on guinea pigs and could efficiently overcome the barrier of corneum and then reach epidermis and dermis within 2 h of transdermal administration. In addition, there was a relatively lower concentration of TP in blood indicating less toxicity on organs. Such results suggest that topical therapy using polyarginine is possible by the transdermal delivery of TP.

The total terpenoids of Celastrus orbiculatus (TTC) inhibit NOX-dependent formation of PMA-induced neutrophil extracellular traps (NETs)

Previously, we identified that Celastrus orbiculatus, a traditional Chinese herbal medicine, exhibited prominent anti-inflammatory and anti-tumor activities. More recently, the formation of neutrophil extracellular traps (NETs) or NETosis has been recognized as a critical pathological event in the development of inflammatory and autoimmune diseases. The present study is aimed to explore the pharmacological effect of the total terpenoids from the stems of C. orbiculatus (TTC) on NETosis and underlying mechanisms, which may provide fundamental knowledge for future utilization of the Chinese medicine. Human neutrophils were isolated by density gradient centrifugation; lactase dehydrogenase (LDH) assay was used to detect cytotoxic effect of TTC on neutrophils. Moreover, we established phorbol-12-myristate-13-acetate (PMA)-induced NETosis. Quantitative and qualitative study of PMA-induced NET release was labeled by SYTOX™ Green. ROS production was determined by flow cytometry. The neutrophil NADPH oxidase (NOX) activity was assessed by lucigenin chemiluminescence assay, and the phosphorylation of NOX subunit was analyzed by immunoblot assay. TTC (5–80 μg.mL−1) had no predominant neutrophil cytotoxicity after 4 h exposure. PMA (200 ng.mL−1) significantly induced the formation of NETs after 4 h stimulus, whereas TTC dose-dependently (5–80 μg.mL−1) inhibited the process. TTC (40 μg.mL−1) blocked neutrophil elastase (NE) and myeloperoxidase (MPO) translocation from cytoplasm to nucleus and disrupted the formation of NET-associated deoxyribonucleic acid (DNA)–MPO and DNA–NE complexes. Moreover, TTC dose-dependently blocked PMA-mediated ROS production, and inhibited the NOX enzymatic activity of neutrophils upon PMA stimulus for 1 h. Finally, TTC suppressed PMA-induced phosphorylation of NOX subunit p40phox on Thr154 residue. TTC inhibited PMA-induced NOX phosphorylation, thereby suppressing NOX enzymatic activity and ROS generation in neutrophils undergoing NETosis. Consequently, TTC disrupted NETosis in the early stage of NOX-dependent NETs formation, which might serve as a promising anti-inflammatory agent by targeting suicidal NETosis.

A galactose-mediated targeting nanoprobe for intracellular hydroxyl radical imaging to predict drug-induced liver injury

Drug-induced liver injury (DILI) is a serious concern in modern medicine due to its unpredictability. Currently, biochemical serum markers are being used in DILI detection. However, these biomarker-based methods lack sensitivity and specificity. A high intracellular level of hydroxyl radicals (˙OH) has been regarded as an early indicator of DILI. Therefore, we proposed an ˙OH-responsive and hepatocyte-targeted nanoprobe via conjugation of carboxyfluorescein-labeled DNA and pegylated galactose on the surface of gold nanoparticles. The nanoprobe could bind to a hepatocyte-specific asialoglycoprotein receptor through galactose, and it could be internalized into liver cells. In the presence of high levels of ˙OH in DILI, the DNA could be cleaved to release carboxyfluorescein, leading to remarkable fluorescence enhancement for ˙OH detection. Confocal fluorescence imaging demonstrated that the nanoprobe could be successfully applied in monitoring high ˙OH levels resulting from acetaminophen or triptolide-induced liver injury, which may provide a simple but powerful protocol for the prediction of DILI.

A galactose-mediated targeting nanoprobe has been developed for the accurate imaging of ˙OH to predict drug-induced hepatotoxicity at an early stage.

Protective effects of silymarin on triptolide-induced acute hepatotoxicity in rats

Silymarin has been used in the treatment of a number of liver diseases for a long time, but its efficacy in preventing triptolide induced acute hepatotoxicity has not been reported previously. The present study aimed to assess the protective effect of silymarin against triptolide (TP)-induced hepatotoxicity in rats. Rats were orally administrated with silymarin (50, 100 and 200 mg/kg) for 7 days and received intraperitoneal TP (2 mg/kg) on the day 8. Hepatic injuries were comprehensively evaluated in terms of serum parameters, morphological changes, oxidative damage, inflammation and apoptosis. The results demonstrated that TP-induced increases in serum parameters, including alanine transaminase, aspartate aminotransferase, alkaline phosphatase, total cholesterol and γ-glutamyl transpeptidase, which were determined using a biochemical analyzer, and histopathological alterations and hepatocyte apoptosis as determined by hematoxylin and eosin and TUNEL staining, respectively, were prevented by silymarin pretreatment in a dose-dependent manner. TP-induced depletions in the activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase, glutathione S-transferase and catalase, and glutathione levels, were also significantly reversed by silymarin, as determined using specific kits. Additionally, silymarin dose-dependently exhibited inhibitory effects on malonaldehyde content in the liver. The production of proinflammatory cytokines was investigated using ELISA kits, and the results demonstrated that silymarin dose-dependently inhibited the production of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-10 and IL-1β in the liver. To determine the mechanism of silymarin, western blot analysis was performed to investigate the protein expression of phosphorylated (p)-p38 and p-c-Jun N-terminal kinase (JNK) of the TNF-α induced inflammatory response and apoptotic pathways. Silymarin significantly blocked p38 and JNK phosphorylation and activation. Additionally, the expression of the proapoptotic proteins cytochrome c, cleaved caspase-3 and Bcl-2-associated X was also reduced following treatment with silymarin, as determined by ELISA, western blotting and immunohistochemistry, respectively. In conclusion, silymarin was demonstrated to dose-dependently protect rat liver from TP-induced acute hepatotoxicity, with the high dose (200 mg/kg) achieving a superior effect. This protective effect may be associated with the improvement of antioxidant and anti-inflammatory status, as well as the prevention of hepatocyte apoptosis. Therefore, silymarin may have the potential to be applied clinically to prevent TP-induced acute hepatotoxicity.

The protective effects of triptolide on age-related bone loss in old male rats

BACKGROUND

Previous studies have showed that triptolide have a critical role in inhibiting osteoclast formation, bone resorption and attenuating regional osteoporosis. However, the protective role of triptolide on age-related bone loss has not been investigated. In the study, we assessed the effect of triptolide supplementation on bone microstructure and bone remolding in old male rat lumbars.

METHODS

Fifty-two 22-month-old male Sprague-Dawley rats were randomly assigned to either triptolide treatment group or control group. Triptolide (15 μg/kg/d) or normal saline was administered to the rats of assigned group for 8 weeks. Lumbar bone mineral density (BMD) and bone microstructure were analyzed by micro-CT. Fluorochrome labeling of the bones was performed to measure the mineral apposition rate (MAR) and bone formation rate (BFR). Osteoclast number was also measured by TRAP staining. Plasma level of osteocalcin and tartrate-resistant acid phosphatase 5b (Tracp 5b) was also analyzed.

RESULTS

Micro-CT results revealed that triptolide-treated rats had significant higher BMD, bone volume over total volume (BV/TV), trabecular thickness (Tb.Th), bone trabecular number (Tb.N), and lower trabecular separation (Tb.Sp) compared to the control group. Although fluorochrome labeling result showed no significant difference in MAR and BFR between the groups, triptolide decreased osteoclast number in vivo. In addition, a significant higher level of plasma Tracp 5b was observed in the triptolide-treated rats. Furthermore, triptolide also reduced the expression of receptor for activation of NF-κB ligand (RANKL) and increased osteoprotegerin (OPG) expression in the lumbars.

CONCLUSION

These results suggested that triptolide had a protective effect on age-related bone loss at least in part by reducing osteoclast number in elder rats. Therefore, triptolide might be a feasible therapeutic approach for senile osteoporosis.

Ontology-based systematic representation and analysis of traditional Chinese drugs against rheumatism

Background

Rheumatism represents any disease condition marked with inflammation and pain in the joints, muscles, or connective tissues. Many traditional Chinese drugs have been used for a long time to treat rheumatism. However, a comprehensive information source for these drugs is still missing, and their anti-rheumatism mechanisms remain unclear. An ontology for anti-rheumatism traditional Chinese drugs would strongly support the representation, analysis, and understanding of these drugs.

Results

In this study, we first systematically collected reported information about 26 traditional Chinese decoction pieces drugs, including their chemical ingredients and adverse events (AEs). By mostly reusing terms from existing ontologies (e.g., TCMDPO for traditional Chinese medicines, NCBITaxon for taxonomy, ChEBI for chemical elements, and OAE for adverse events) and making semantic axioms linking different entities, we developed the Ontology of Chinese Medicine for Rheumatism (OCMR) that includes over 3000 class terms. Our OCMR analysis found that these 26 traditional Chinese decoction pieces are made from anatomic entities (e.g., root and stem) from 3 Bilateria animals and 23 Mesangiospermae plants. Anti-inflammatory and antineoplastic roles are important for anti-rheumatism drugs. Using the total of 555 unique ChEBI chemical entities identified from these drugs, our ChEBI-based classification analysis identified 18 anti-inflammatory, 33 antineoplastic chemicals, and 9 chemicals (including 3 diterpenoids and 3 triterpenoids) having both anti-inflammatory and antineoplastic roles. Furthermore, our study detected 22 diterpenoids and 23 triterpenoids, including 16 pentacyclic triterpenoids that are likely bioactive against rheumatism. Six drugs were found to be associated with 184 unique AEs, including three AEs (i.e., dizziness, nausea and vomiting, and anorexia) each associated with 5 drugs. Several chemical entities are classified as neurotoxins (e.g., diethyl phthalate) and allergens (e.g., eugenol), which may explain the formation of some TCD AEs. The OCMR could be efficiently queried for useful information using SPARQL scripts.

Conclusions

The OCMR ontology was developed to systematically represent 26 traditional anti-rheumatism Chinese drugs and their related information. The OCMR analysis identified possible anti-rheumatism and AE mechanisms of these drugs. Our novel ontology-based approach can also be applied to systematic representation and analysis of other traditional Chinese drugs.

Electronic supplementary material

The online version of this article (10.1186/s12918-017-0510-5) contains supplementary material, which is available to authorized users.

Triptolide suppresses paraquat induced idiopathic pulmonary fibrosis by inhibiting TGFB1-dependent epithelial mesenchymal transition

Idiopathic pulmonary fibrosis (IPF) and tumor are highly similar to abnormal cell proliferation that damages the body. This malignant cell evolution in a stressful environment closely resembles that of epithelial-mesenchymal transition (EMT). As a popular EMT-inducing factor, TGFβ plays an important role in the progression of multiple diseases. However, the drugs that target TGFB1 are limited. In this study, we found that triptolide (TPL), a Chinese medicine extract, exerts an anti-lung fibrosis effect by inhibiting the EMT of lung epithelial cells. In addition, triptolide directly binds to TGFβ and subsequently increase E-cadherin expression and decrease vimentin expression. In in vivo studies, TPL improves the survival state and inhibits lung fibrosis in mice. In summary, this study revealed the potential therapeutic effect of paraquat induced TPL in lung fibrosis by regulating TGFβ-dependent EMT progression.

Efficacy and safety of Tripterygium wilfordii Hook F for CKD in Mainland China: A systematic review and meta-analysis

Tripterygium wilfordii Hook F (TwHF) is a promising Chinese traditional medicine used to significantly reduce proteinuria and improve renal function. However, its efficacy and safety in treatment of chronic kidney disease need to be further explored in order to promote its application in clinics. This review compared the efficacy and safety of TwHF with the placebo, conventional Western medicine and other immunosuppressive medicine in a range of kidney disorders. One hundred three randomized controlled trials were included. TwHF therapy decreased 24-hr proteinuria by 0.59 g/day (95% confidence interval [CI; -0.68, -0.50]), serum creatinine level by 1.93 μmol/L (95% CI [-3.69, -0.17]), and blood urea nitrogen level by 0.24 mmol/L (95% CI [-0.41, -0.07]); increased the total effective rate by 27% (95% CI [1.24, 1.30]); and decreased the incidence of adverse reactions by 19% (95% CI [0.68, 0.96]) overall. Meta regression results showed that the duration of therapy and mean age of participants were the major sources of high heterogeneity. Sensitivity analysis demonstrated that our statistic results were relatively stable and credible. The present findings suggested that TwHF possibly has nephroprotective effects by decreasing proteinuria, serum creatinine level, and blood urea nitrogen level and no more adverse reactions compared with control group in most kidney disorders. However, these findings still need to be further confirmed by high-quality trials.

The analgesic effects of triptolide in the bone cancer pain rats via inhibiting the upregulation of HDACs in spinal glial cells

Background

Bone cancer pain (BCP) severely compromises the quality of life, while current treatments are still unsatisfactory. Here, we tested the antinociceptive effects of triptolide (T10), a substance with considerable anti-tumor efficacies on BCP, and investigated the underlying mechanisms targeting the spinal dorsal horn (SDH).

Methods

Intratibial inoculation of Walker 256 mammary gland carcinoma cells was used to establish a BCP model in rats. T10 was intrathecally injected, and mechanical allodynia was tested by measuring the paw withdrawal thresholds (PWTs). In mechanism study, the activation of microglia, astrocytes, and the mitogen-activated protein kinase (MAPK) pathways in the SDH were evaluated by immunofluorescence staining or Western blot analysis of Iba-1, GFAP, p-ERK, p-p38, and p-JNK. The expression and cellular localization of histone deacetylases (HDACs) 1 and 2 were also detected to investigate molecular mechanism.

Results

Intrathecal injection of T10 inhibited the bone cancer-induced mechanical allodynia with an ED₅₀ of 5.874 μg/kg. This effect was still observed 6 days after drug withdrawal. Bone cancer caused significantly increased expression of HDAC1 in spinal microglia and neurons, with HDAC2 markedly increased in spinal astrocytes, which were accompanied by the upregulation of MAPK pathways and the activation of microglia and astrocytes in the SDH. T10 reversed the increase of HDACs, especially those in glial cells, and inhibited the glial activation.

Conclusions

Our results suggest that the upregulation of HDACs contributes to the pathological activation of spinal glial cells and the chronic pain caused by bone cancer, while T10 help to relieve BCP possibly via inhibiting the upregulation of HDACs in the glial cells in the SDH and then blocking the neuroinflammation induced by glial activation.

The Ethanol Extract of Licorice (Glycyrrhiza uralensis) Protects against Triptolide-Induced Oxidative Stress through Activation of Nrf2

To investigate the potential role of nuclear factor erythroid 2-related factor 2 (Nrf2) in licorice ethanol extract (LEE) against triptolide- (TP-) induced hepatotoxicity, HepG2 cells were exposed to LEE (30, 60, and 90 mg·L⁻¹) for 12 h and then treated with TP (50 nM) for 24 h. Besides, an acute liver injury model was established in ICR mice by a single dose of TP (1.0 mg·kg⁻¹, i.p.). Relevant oxidant and antioxidant mediators were analyzed. TP led to an obvious oxidative stress as evidenced by increasing levels of ROS and decreasing GSH contents in HepG2 cells. In vitro results were likely to hold true in in vivo experiments. LEE protected against TP-induced oxidative stress in both in vitro and in vivo conditions. Furthermore, the decreased level of Nrf2 in the TP-treated group was observed. The mRNA levels of downstream genes decreased as well in ICR mice liver, whereas they increased in HepG2 cells. In contrast, LEE pretreatment significantly increased the level of Nrf2 and its downstream genes. LEE protects against TP-induced oxidative stress partly via the activation of Nrf2 pathway.

WITHDRAWN: Toxicity of triptolide and the molecular mechanisms involved

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Triptolide suppresses growth and hormone secretion in murine pituitary corticotroph tumor cells via NF-kappaB signaling pathway

Triptolide is a principal diterpene triepoxide from the Chinese medical plant Tripterygium wilfordii Hook. f., whose extracts have been utilized in dealing with diverse diseases in traditional Chinese medicine for centuries. Recently, the antitumor effect of triptolide has been found in several pre-clinical neoplasm models, but its effect on pituitary corticotroph adenomas has not been investigated so far. In this study, we are aiming to figure out the antitumor effect of triptolide and address the underlying molecular mechanism in AtT20 murine corticotroph cell line. Our results demonstrated that triptolide inhibited cell viability and colony number of AtT20 cells in a dose- and time-dependent pattern. Triptolide also suppressed proopiomelanocortin (Pomc) mRNA expression and extracellular adrenocorticotropic hormone (ACTH) secretion in AtT20 cells. Flow cytometry prompted that triptolide leaded to G2/M phase arrest, apoptosis program and mitochondrial membrane depolarization in AtT20 cells. Moreover, dose-dependent activation of caspase-3 and decreased Bcl2/Bax proportion were observed after triptolide treatment. By western blot analysis we found that triptolide impeded phosphorylation of NF-κB p65 subunit and extracellular signal-regulated kinase (ERK), along with reduction of cyclin D1, without any impact on other NF-κB related protein expression like total p65, p50, IκB-α, p-IκB-α. Furthermore, the mouse xenograft model revealed the inhibition of tumor growth and hormone secretion after triptolide administration. Altogether this compound might be a potential pharmaceutical choice in managing Cushing's disease.

Effect of the Natural Product Triptolide on Pancreatic Cancer: A Systematic Review of Preclinical Studies

Objective: Triptolide (TL), a natural product isolated from Tripterygium wilfordii Hook F (TwHF), shows potent anticancer effects in vitro and in vivo. We aimed to summary the biochemical mechanisms through which TL has been shown to induce apoptosis, autophagy and inhibit angiogenesis in pancreatic cancer (PC).

Methods: We undertook a systematic review of preclinical evidence. We searched electronic databases. The potential mechanisms and the underlying signaling pathways have been accumulated as well.

Results: We screened 116 abstracts for eligibility and included 17 preclinical studies in the analysis. Details of the animals and cell lines were provided in 16 studies (94.1%). Six studies (75.0%) randomly assigned animals to treatment or control groups and only 1 study (12.5%) reported on blinding. The majority of the TL's research field has focused on its pro-apoptotic effects through downregulation of inhibitory pathways and upregulation of apoptotic pathways. The studies have shown that TL is effective both in vitro and in vivo against PC cells.

Conclusion: This study provides a systematic summary of TL's anti-pancreatic cancer profile and the underlying mechanisms of with special emphasis on the apoptosis, autophagy, angiogenesis and related molecular pathways. Improved study quality in terms of treatment allocation methods reporting, randomization and blinding will accelerate needed progress toward trials.

Renal-targeted delivery of triptolide by entrapment in pegylated TRX-20-modified liposomes

Previously, 3,5-dipentadecyloxybenzamidine hydrochloride (TRX-20)-modified liposomes were reported to specifically target mesangial cells (MCs) in glomeruli. To further gain a better understanding of the characteristics and potential application for glomerular diseases of TRX-20-modified liposomes, we synthesized TRX-20 and prepared TRX-20-modified liposomes (TRX-LPs) with different molar ratios - 6% (6%-TRX-LP), 11% (11%-TRX-LP), and 14% (14%-TRX-LP) - of TRX-20 to total lipid in the present study. All TRX-LPs exhibited concentration-dependent toxicity against the MCs at a lipid concentration ranging from 0.01 to 1.0 mg/mL with IC50 values of 3.45, 1.13, and 0.55 mg/mL, respectively. Comparison of the cell viability of TRX-LPs indicated that high levels of TRX-20 caused severe cell mortality, with 11%-TRX-LP showing the higher cytoplasmic accumulation in the MCs. Triptolide (TP) as a model drug was first loaded into 11%-TRX-LP and the liposomes were further modified with PEG5000 (PEG-TRX-TP-LP) in an attempt to prolong their circulation in blood and enhance TP-mediated immune suppression. Due to specific binding to MCs, PEG-TRX-TP-LP undoubtedly showed better anti-inflammatory action in vitro, evidenced by the inhibition of release of nitric oxide (NO) and tumor necrosis factor-α from lipopolysaccharide-stimulated MCs, compared with free TP at the same dose. In vivo, the PEG-TRX-TP-LP effectively attenuated the symptoms of membranous nephropathic (MN) rats and improved biochemical markers including proteinuria, serum cholesterol, and albumin. Therefore, it can be concluded that the TRX-modified liposome is an effective platform to target the delivery of TP to glomeruli for the treatment of MN.

The novel and potent anti-depressive action of triptolide and its influences on hippocampal neuroinflammation in a rat model of depression comorbidity of chronic pain

Chronic pain and depression frequently coexist in clinical setting, and current clinical treatments for this comorbidity have shown limited efficacy. Triptolide (T10), an active component of Tripterygium wilfordii Hook F., has been demonstrated to exert strong analgesic activities in experimental pain models, but whether it possesses anti-depressive actions remains unknown. Using a depression comorbidity of chronic pain rat model induced by spinal nerve ligation (SNL), we investigated the potency of T10 for the treatment of comorbid depression in comparison with a widely used antidepressant, fluoxetine (FLX). Concomitant neuroinflammation changes were also examined in the hippocampus. The results showed that prophylactic and reversal treatments with T10 dose-dependently (30, 100, 300μg/kg) inhibited the depression-like behaviors (DLB) assessed by the forced swim test, sucrose preference test and body weight measurement. The anti-depressive efficacy of T10 at 300μg/kg was significantly stronger than that of FLX at 18mg/kg. T10 at all three doses exhibited more efficient analgesic effects than FLX at 18mg/kg. The combined application of T10 with FLX markedly augmented the effects of T10 or FLX per se, with the facilitating effects of T10 at 30μg/kg being most prominent. In addition, nerve injury caused the activation of microglia and p38 MAPK, the upregulation of IL-1β and TNF-α as well as the downregulation of IL-10 in the hippocampus at postoperative week (POW) 3. These neuroinflammatory responses were reversed by subchronic treatment with T10. Taken together, these results demonstrate that T10 possesses potent anti-depressive function, which is correlated with its immunoregulation in the hippocampus. The combination of a low dose of T10 with FLX may become a more effective medication strategy for the treatment of comorbid depression and chronic pain.

Self-protection against triptolide-induced toxicity in human hepatic cells via Nrf2-ARE-NQO1 pathway

OBJECTIVE

To find the signaling pathway of triptolide (TP)-induced liver injury and to reveal whether NF-E2-related factor 2 (Nrf2) plays an important role in cellular self-protection.

METHODS

The L-02 and HepG2 cells were cultured and treated with various concentrations of TP. The cell viability was observed, and the cell medium was collected for detecting the aspartate aminotransferase (ALT), alanine aminotransferase (AST), lactate dehydrogenase (LDH), superoxide dismutase (SOD) and L-glutathione production (GSH) levels. Nrf2 and its downstream target NAD(P)H: quinine oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1) expression, the nuclear translocation of Nrf2, and the binding ability of Nrf2 and antioxidant response element (ARE) were also identified. Meanwhile, shRNA was used to silence Nrf2 in L-02 cells to find out whether Nrf2 plays a protective role.

RESULTS

The viability of the L-02 and HepG2 cells treated with TP decreased in a doseand time-dependent manner, and TP (20-80 μg/mL) markedly induced the release of ALT, AST and LDH (P<0.05 or P<0.01), reduced the levels of SOD and GSH (P<0.01), and increased the intracellular reactive oxygen species. Meanwhile, TP augmented the Nrf2 expression in L-02 and HepG2 cells (P<0.05 or P<0.01), induced Nrf2 nuclear translocation, increased the Nrf2 ARE binding activity, and increased HO-1 and NQO1 expressions. Nrf2 knockdown revealed a more severe toxic effect of TP (P<0.05 or P<0.01).

CONCLUSIONS

Human hepatic cells treated with TP induced oxidative stress, and led to cytotoxicity. Self-protection against TP-induced toxicity in human hepatic cells might be via Nrf2-ARE-NQO1 transcriptional pathway.

Protective Effect of 18β-Glycyrrhetinic Acid against Triptolide-Induced Hepatotoxicity in Rats

Triptolide (TP) is the major active component of Tripterygium wilfordii Hook F (TWHF) and possesses multiple pharmacological effects. However, hepatotoxicity of TP which is one of the toxic properties slows its progression in clinical application. 18β-Glycyrrhetinic acid (GA) is the main bioactive ingredient of Licorice (Glycyrrhiza glabra L.), a herbal medicine famous for its detoxification. This study aims to investigate whether GA possesses protective effect against TP-induced hepatotoxicity in rats. TP interference markedly elevated serum levels of ALT, AST, and ALP, caused evident liver histopathological changes, and elevated hepatic TNF-α, IL-6, IL-1β, and IFN-γ as well as nuclear translocation of NF-κB. TP also significantly elevated liver MDA and declined hepatic activities of SOD, CAT, and GSH-Px. Assay of TUNEL and apoptosis proteins (Bax, Bcl-2, and active caspase-3) showed that TP induced severe hepatocellular apoptosis. In contrast, low-dose GA (50 mg/kg) significantly reversed TP-induced changes above. However, high-dose GA (100 mg/kg) had no such effect. Overall, these findings indicated that low-dose GA but not high-dose GA exhibited a protective effect against TP-induced hepatotoxicity in rats by anti-inflammation, antioxidation, and antiapoptosis, which suggests that the doses of GA/Licorice should be carefully considered when used together with TWHF or TWHF preparations.

Activation of Sirt1/FXR Signaling Pathway Attenuates Triptolide-Induced Hepatotoxicity in Rats

Triptolide (TP), a diterpenoid isolated from Tripterygium wilfordii Hook F, has an excellent pharmacological profile of immunosuppression and anti-tumor activities, but its clinical applications are severely restricted due to its severe and cumulative toxicities. The farnesoid X receptor (FXR) is the master bile acid nuclear receptor and plays an important role in maintaining hepatic metabolism homeostasis. Hepatic Sirtuin (Sirt1) is a key regulator of the FXR signaling pathway and hepatic metabolism homeostasis. The aims of this study were to determine whether Sirt1/FXR signaling pathway plays a critical role in TP-induced hepatotoxicity. Our study revealed that the intragastric administration of TP (400 μg/kg body weight) for 28 consecutive days increased bile acid accumulation, suppressed hepatic gluconeogenesis in rats. The expression of bile acid transporter BSEP was significantly reduced and cholesterol 7α-hydroxylase (CYP7A1) was markedly increased in the TP-treated group, whereas the genes responsible for hepatic gluconeogenesis were suppressed in the TP-treated group. TP also modulated the FXR and Sirt1 by decreasing its expression both in vitro and in vivo. The Sirt1 agonist SRT1720 and the FXR agonist obeticholic acid (OCA) were used both in vivo and in vitro. The remarkable liver damage induced by TP was attenuated by treatment with either SRT1720 or OCA, as reflected by decreased levels of serum total bile acids and alkaline phosphatase and increased glucose levels. Meanwhile, SRT1720 significantly alleviated TP-induced FXR suppression and FXR-targets involved in hepatic lipid and glucose metabolism. Based on these results, we conclude that Sirt1/FXR inactivation plays a critical role in TP-induced hepatotoxicity. Moreover, Sirt1/FXR axis represents a novel therapeutic target that could potentially ameliorate TP-induced hepatotoxicity.

Diterpenes and Their Derivatives as Potential Anticancer Agents

As therapeutic tools, diterpenes and their derivatives have gained much attention of the medicinal scientists nowadays. It is due to their pledging and important biological activities. This review congregates the anticancer diterpenes. For this, a search was made with selected keywords in PubMed, Science Direct, Web of Science, Scopus, The American Chemical Society and miscellaneous databases from January 2012 to January 2017 for the published articles. A total 28, 789 published articles were seen. Among them, 240 were included in this study. More than 250 important anticancer diterpenes and their derivatives were seen in the databases, acting in the different pathways. Some of them are already under clinical trials, while others are in the nonclinical and/or pre-clinical trials. In conclusion, diterpenes may be one of the lead molecules in the treatment of cancer. Copyright © 2017 John Wiley & Sons, Ltd.

Rapid screening the potential mechanism-based inhibitors of CYP3A4 from Tripterygium wilfordi based on computer approaches combined with in vitro bioassay

CYP3A4 is the main human metabolizing enzyme, and many clinically relevant drug/herb-drug interactions (DDIs/HDIs) involving CYP3A4 are due to mechanism-based inhibition. In this study, pharmacophore model together with molecular docking (MD) are used to rapidly screen the potential CYP3A4 mechanism-based inhibitors from Tripterygium wilfordii, and in vitro experiments are conducted to validate the computational data. The results showed that the rate of computational prediction could be improved based on a combination of pharmacophore model and MD, and a combination of computational approaches might be a useful tool to identify potential mechanism-based inhibitor of CYP3A4 from herbal medicines.

Bigelovin triggered apoptosis in colorectal cancer in vitro and in vivo via upregulating death receptor 5 and reactive oxidative species

Colorectal cancer (CRC) is the third most prevalent cancer and the third highest cancer-related mortality in the United States. Bigelovin, a sesquiterpene lactone isolated from Inula helianthus aquatica, has been proven to induce apoptosis and exhibit anti-inflammatory and anti-angiogenic activities. However, the effects of bigelovin on CRC and underlying mechanisms have not been explored. The present study demonstrated that bigelovin exhibited potent anti-tumor activities against CRC in vitro and in vivo. Bigelovin suppressed cell proliferation and colony formation and induced apoptosis in human colorectal cancer HT-29 and HCT 116 cells in vitro. Results also revealed that bigelovin activated caspases, caused the G2/M cell cycle arrest and induced DNA damage through up-regulation of death receptor (DR) 5 and increase of ROS. In HCT 116 xenograft model, bigelovin treatment resulted in suppression of tumor growth. Bigelovin at 20 mg/kg showed more significant tumor suppression and less side effects than conventional FOLFOX (containing folinic acid, 5-fluorouracil and oxaliplatin) treatment. In addition, in vivo data confirmed that anti-tumor activity of bigelovin in CRC was through induction of apoptosis by up-regulating DR5 and increasing ROS. In conclusion, these results strongly suggested that bigelovin has potential to be developed as therapeutic agent for CRC patients.

The terpene synthase gene family in Tripterygium wilfordii harbors a labdane-type diterpene synthase among the monoterpene synthase TPS-b subfamily

Tripterygium wilfordii (Celastraceae) is a medicinal plant with anti-inflammatory and immunosuppressive properties. Identification of a vast array of unusual sesquiterpenoids, diterpenoids and triterpenoids in T. wilfordii has spurred investigations of their pharmacological properties. The tri-epoxide lactone triptolide was the first of many diterpenoids identified, attracting interest due to the spectrum of bioactivities. To probe the genetic underpinning of diterpenoid diversity, an expansion of the class II diterpene synthase (diTPS) family was recently identified in a leaf transcriptome. Following detection of triptolide and simple diterpene scaffolds in the root, we sequenced and mined the root transcriptome. This allowed identification of the root-specific complement of TPSs and an expansion in the class I diTPS family. Functional characterization of the class II diTPSs established their activities in the formation of four C-20 diphosphate intermediates, precursors of both generalized and specialized metabolism and a novel scaffold for Celastraceae. Functional pairs of the class I and II enzymes resulted in formation of three scaffolds, accounting for some of the terpenoid diversity found in T. wilfordii. The absence of activity-forming abietane-type diterpenes encouraged further testing of TPSs outside the canonical class I diTPS family. TwTPS27, close relative of mono-TPSs, was found to couple with TwTPS9, converting normal-copalyl diphosphate to miltiradiene. The phylogenetic distance to established diTPSs indicates neo-functionalization of TwTPS27 into a diTPS, a function not previously observed in the TPS-b subfamily. This example of evolutionary convergence expands the functionality of TPSs in the TPS-b family and may contribute miltiradiene to the diterpenoids of T. wilfordii.

Natural Compounds As Modulators of Non-apoptotic Cell Death in Cancer Cells

Cell death is an innate capability of cells to be removed from microenvironment, if and when they are damaged by multiple stresses. Cell death is often regulated by multiple molecular pathways and mechanism, including apoptosis, autophagy, and necroptosis. The molecular network underlying these processes is often intertwined and one pathway can dynamically shift to another one acquiring certain protein components, in particular upon treatment with various drugs. The strategy to treat human cancer ultimately relies on the ability of anticancer therapeutics to induce tumor-specific cell death, while leaving normal adjacent cells undamaged. However, tumor cells often develop the resistance to the drug-induced cell death, thus representing a great challenge for the anticancer approaches. Numerous compounds originated from the natural sources and biopharmaceutical industries are applied today in clinics showing advantageous results. However, some exhibit serious toxic side effects. Thus, novel effective therapeutic approaches in treating cancers are continued to be developed. Natural compounds with anticancer activity have gained a great interest among researchers and clinicians alike since they have shown more favorable safety and efficacy then the synthetic marketed drugs. Numerous studies in vitro and in vivo have found that several natural compounds display promising anticancer potentials. This review underlines certain information regarding the role of natural compounds from plants, microorganisms and sea life forms, which are able to induce non-apoptotic cell death in tumor cells, namely autophagy and necroptosis.

Molecular Analysis of Chinese Celastrus and Tripterygium and Implications in Medicinal and Pharmacological Studies

Celastrus and Tripterygium species, which are used in traditional Chinese medicine, have attracted much attention due to their anti-tumor promoting and neuroprotective activities, in addition to their applications in autoimmune disorders. However, systematic relationships between them and among species are unclear, and it may disturb their further medicinal utilization. In the present study, the molecular analysis of combined chloroplast and nuclear markers of all Chinese Celastrus and Tripterygium was performed, and clear inter- and intra-genus relationships were presented. The result suggests that Tripterygium constitute a natural monophyletic clade within Celastrus with strong support value. Fruit and seed type are better than inflorescence in subgeneric classification. Chinese Celastrus are classified for three sections: Sect. Sempervirentes (Maxim.) CY Cheng & TC Kao, Sect. Lunatus XY Mu & ZX Zhang, sect. nov., and Sect. Ellipticus XY Mu & ZX Zhang, sect. nov. The phylogenetic data was consistent with their chemical components reported previously. Owing to the close relationship, several evergreen Celastrus species are recommended for chemical and pharmacological studies. Our results also provide reference for molecular identification of Chinese Celastrus and Tripterygium.

Triptolide Induces hepatotoxicity via inhibition of CYP450s in Rat liver microsomes

Background

Triptolide (TP), an active constituent of Tripterygium wilfordii, possesses numerous pharmacological activities. However, its effects on cytochrome P450 enzymes (CYP450s) in rats remain unexplored.

Methods

In this study, the effects of triptolide on the six main CYP450 isoforms (1A2, 2C9, 2C19, 2D6, 2E1, and 3A) were investigated both in vivo and in vitro. We monitored the body weight, survival proportions, liver index, changes in pathology, and biochemical index upon TP administration, in vivo. Using a cocktail probe of CYP450 isoform-specific substrates and their metabolites, we then carried out in vitro enzymatic studies in liver microsomal incubation systems via ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Finally, we verified our results at the messenger ribonucleic acid (mRNA) and protein level through quantitative real-time polymerase chain reaction (RT-qPCR), western blotting, and immunohistochemical detection.

Results

The in vivo toxicity study confirmed that Sprague-Dawley (SD) rats exhibited dose-dependent hepatotoxicity after intragastric administration of TP [200, 400, and 600 μg/(kg.day)] for 28 days. In case of the CYP450 isoforms 3A, 2C9, 2C19, and 2E1, the in vitro metabolic study demonstrated a decrease in the substrate metabolic rate, metabolite production rate, and Vmax, with an increase in the Km value, compared with that observed in the control group. Additionally, a TP dose-dependent decrease in the mRNA levels was observed in the four major isoforms of CYP3A subfamily (3A1/3A23, 3A2, 3A9, and 3A62) and CYP2C9. A similar effect was also observed with respect to the protein levels of CYP2C19 and CYP2E1.

Conclusions

This study suggests that TP can cause hepatotoxicity by reducing the substrate affinity, activity, and expression at the transcriptional and protein levels of the CYP450 isoforms 3A, 2C9, 2C19, and 2E1. TP also has the potential to cause pharmacokinetic drug interactions when co-administered with drugs metabolized by these four isoforms. However, further clinical studies are needed to evaluate the significance of this interaction.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-016-1504-3) contains supplementary material, which is available to authorized users.

Triptolide Combined with Radiotherapy for the Treatment of Nasopharyngeal Carcinoma via NF-κB-Related Mechanism

Advanced nasopharyngeal carcinoma (NPC) has a poor prognosis because of the lack of an effective treatment. Here we explored the efficiency and the molecular mechanisms of combined treatment with triptolide and ionizing radiation for treating NPC. Human nasopharyngeal carcinoma (CNE) cells were treated with triptolide, ionizing radiation, or triptolide plus ionizing radiation in vitro. Tumor potency was examined in an in vivo CNE cell xenograft mouse model, which was treated as above. Our results demonstrated that triptolide caused a significant reduction in cell growth and colony number, and induced a marked apoptosis that was further enhanced with increasing doses of ionizing radiation. Combination treatment synergistically reduced tumor weight and volume without obvious toxicity. Western blot analysis in vitro and in vivo showed that triptolide induced apoptotic protein Bax expression and inhibited phosph-NF-κB p65, Bcl-2 and VEGF proteins without affecting other NF-κB related protein expression. In conclusion, our findings revealed that triptolide plus ionizing radiation had synergistic anti-tumor and anti-angiogenesis effects in NPC via down-regulating NF-κB p65 phosphorylation. The combination therapy may provide novel mechanism insights into inhibit NPC.

EFFECT OF TRIPTOLIDE ON PROLIFERATION AND APOPTOSIS OF ANGIOTENSIN II-INDUCED CARDIAC FIBROBLASTS IN VITRO: A PRELIMINARY STUDY

BACKGROUND

The effect of triptolide (TPL) on cardiac fibroblasts (CFbs) and cardiac fibrosis remain unknown till now. This study was conducted to explore the effects of TPL on proliferation and apoptosis of angiotensin II (Ang II)-induced CFbs.

MATERIALS AND METHODS

Ang II was used to promote proliferation of CFbs. Two dosages of TPL (10ng/ml and 100ng/ml) were chosen. MTT assay was used to detect cell survival rate in vitro. Flow cytometer was performed to analyze apoptosis of CFbs. Hydroxyproline concentration was detected with hydroxyproline assay kit. Quantitative real-time PCR was used to detect the expression of TGF-β1 and Smad3 mRNA.

RESULTS

Ang II promoted CFbs proliferation significantly. Compared to Ang II group, TPL markedly reduced the viability of CFbs and its Hydroxyproline concentration (P<0.05). Besides, TPL can significantly promote apoptosis of CFbs (P<0.05). Furthermore, TPL reduced the expressions of TGF-βΙ and Smad3 mRNA in Ang II-induced CFbs (P<0.05).

CONCLUSION

TPL can inhibit the proliferation of CFbs in rats by down-regulating TGF-β1/Smad3 signaling pathway. TPL might be a promising therapeutic drug for myocardial fibrosis.

Renal-targeting triptolide-glucosamine conjugate exhibits lower toxicity and superior efficacy in attenuation of ischemia/reperfusion renal injury in rats

AIM

We previously reported a novel triptolide (TP)-glucosamine conjugate (TPG) that specifically accumulated in kidneys and protected renal function from acute ischemia/reperfusion (I/R) injury in rats. In this study we further examined the molecular mechanisms underlying the renoprotective action of TPG.

METHODS

The renal-targeting of TPG was investigated in a human proximal renal tubular epithelial cell line (HK-2) by measuring cell uptake of TP or TPG. The effects of TP or TPG on cell cycle distribution and apoptosis rate of HK-2 cells were assessed, and the activities of caspase-3 and caspase-9 were also measured. SD rats were subjected to bilateral renal ischemia by temporarily clamping both renal pedicles. The rats were administered TP (4.17 μmol·kg-1·d-1, iv) or TPG (4.17 μmol·kg-1·d-1, iv) for 3 d before the renal surgery. The kidneys were harvested after 24 h of recovery from the surgery. The levels of oxidative stress, proinflammatory cytokines, chemotactic cytokines and intracellular adhesion molecules in kidneys were examined.

RESULTS

The uptake of TPG in HK-2 cells was 2-3 times higher than that of TP at the concentrations tested. Furthermore, TPG targeting the proximal tubules was mediated through interactions with megalin receptors. TP (40-160 nmol/L) concentration-dependently increased G2/M arrest, apoptosis and caspase-3/caspase-9 activity in HK-2 cells, whereas the same concentrations of TPG did not show those features when compared with the control group. In I/R-treated rats, TPG administration caused more robust down-regulation of proinflammatory cytokines (TNF-α, IL-6, IL-1, TGF-β) and chemotactic cytokines (MCP-1) in the kidneys compared with TP administration, suggesting the inhibition of the proliferation and accumulation of lymphocytes. And TPG administration also caused more prominent inhibition on the levels of oxidative stress and intracellular adhesion molecules in the kidneys, compared with TP administration.

CONCLUSION

The renal-targeting TPG is more effective and less toxic than TP, in amelioration of I/R-induced rat renal injury, which may provide a new avenue for the treatment of acute kidney injury.