Synthesis and biological evaluation of new ligustrazine derivatives as anti-tumor agents

Natural Products-Pyrazine Hybrids: A Review of Developments in Medicinal Chemistry

Pyrazine is a six-membered heterocyclic ring containing nitrogen, and many of its derivatives are biologically active compounds. References have been downloaded through Web of Science, PubMed, Science Direct, and SciFinder Scholar. The structure, biological activity, and mechanism of natural product derivatives containing pyrazine fragments reported from 2000 to September 2023 were reviewed. Publications reporting only the chemistry of pyrazine derivatives are beyond the scope of this review and have not been included. The results of research work show that pyrazine-modified natural product derivatives have a wide range of biological activities, including anti-inflammatory, anticancer, antibacterial, antiparasitic, and antioxidant activities. Many of these derivatives exhibit stronger pharmacodynamic activity and less toxicity than their parent compounds. This review has a certain reference value for the development of heterocyclic compounds, especially pyrazine natural product derivatives.

[A Novel Chinese Medicine Formula Inhibits Non-small Cell Lung Cancer by Triggering Oxidative Stress Dependent on Pentose Phosphate Pathway]

BACKGROUND

Non-small cell lung cancer (NSCLC) is one of the most lethal malignancies worldwide. A novel Chinese medicine formula-01 (NCHF-01) has shown significant clinical efficacy in the treatment of NSCLC, but the mechanism of this formula in the treatment of NSCLC is not fully understood. The aim of this study is to investigate the molecular mechanism of NCHF-01 in inhibiting NSCLC.

METHODS

Lewis lung cells (LLC) tumor bearing mice were established to detect the tumor inhibitory effect of NCHF-01. The morphological changes of tissues and organs in LLC tumor-bearing mice were detected by hematoxylin-eosin (HE) staining. NSCLC cells were treated by NCHF-01. The effects of cell viability and proliferation were detected by MTT and crystal violet staining experiment. Flow cytometry was used to detect cell cycle, apoptosis and reactive oxygen species (ROS). Network pharmacology was used to predict the mechanism of its inhibitory effect of NSCLC. Western blot and immunohistochemistry (IHC) were used to detect the expression of related proteins.

RESULTS

NCHF-01 can inhibit tumor growth in LLC tumor-bearing mice, and has no obvious side effects on other tissues and organs. NCHF-01 could inhibit cell viability and proliferation, induce G2/M phase arrest and apoptosis, and promote the increase of ROS level. Network pharmacological analysis showed that NCHF-01 exerts anti-NSCLC effects through various biological processes such as oxidative stress and central carbon metabolism. NCHF-01 can reduce the protein expression and enzyme activity of the key enzymes 6-phosphate glucose dehydrogenase (G6PD) and 6-phosphogluconate dehydrogenase (6PGD) in the pentose phosphate pathway (PPP).

CONCLUSIONS

NCHF-01 can inhibit NSCLC through oxidative stress dependent on the PPP.

Synthesis and bioactivity evaluation of pachymic acid derivatives as potential cytotoxic agents

Pachymic acid, a well-known natural lanostane-type triterpenoid, exhibits various pharmacological properties. In this study, 18 derivatives of pachymic acid were synthesized by modifying their molecular structures and evaluated for their anticancer activity against two human cancer cell lines using the CCK-8 assay. Structure-activity relationship studies according to the in vitro cytotoxicity unexpectedly found one promising derivative A17 (namely tumulosic acid, also found in Poria cocos), which had stronger anti-proliferative activity than the positive drug cisplatin against HepG2 and HSC-2 cell lines with IC₅₀ values of 7.36 ± 0.98 and 2.50 ± 0.15 μM, respectively. Further pharmacological analysis demonstrated that A17 induced HSC-2 cell cycle arrest at the S phase, cell apoptosis, and autophagy. Western blotting confirmed the regulatory effects of A17 on cell cycle arrest-, apoptosis-, and autophagy-related proteins expression. In addition, A17 regulated the AKT and AMPK pathways in HSC-2 cells. These results demonstrated that A17 possesses great potential as an anticancer agent.

Graphical Abstract

Pharmacological profiles and therapeutic applications of pachymic acid (Review)

Poria cocos is a saprophytic fungus that grows in diverse species of Pinus. Its sclerotium, called fu-ling or hoelen, has been used in various traditional Chinese medicines and health foods for thousands of years, and in several modern proprietary traditional Chinese medicinal products. It has extensive clinical indications, including sedative, diuretic, and tonic effects. Pachymic acid (PA) is the main lanostane-type triterpenoid in Poria cocos. Evidence suggests that PA has various biological properties such as cytotoxic, anti-inflammatory, antihyperglycemic, antiviral, antibacterial, sedative-hypnotic, and anti-ischemia/reperfusion activities. Although considerable advancements have been made, some fundamental and intricate issues remain unclear, such as the underlying mechanisms of PA. The present study aimed to summarize the biological properties and therapeutic potential of PA. The biosynthetic, pharmacokinetic, and metabolic pathways of PA, and its underlying mechanisms were also comprehensively summarized.

Natural inspired ligustrazine-based SLC-0111 analogues as novel carbonic anhydrase inhibitors

Ligustrazine is the principle bioactive alkaloid in the widely-used Chinese herb Chuan Xiong rhizome. Herein, a series of novel derivatives has been designed as human carbonic anhydrases inhibitors (hCAIs) starting from the natural product Ligustrazine inserted as a tail instead of the 4-fluorophenyl tail of SLC-0111, a front-runner selective hCA IX inhibitor currently in clinical trials as antitumor/antimetastatic agent. Other derivatives were designed via incorporation of different linkers, of amide and ester type, or incorporation of different zinc anchoring groups such as secondary sulfamoyl and carboxylic acid functionalities. The newly designed molecules were prepared following different synthetic pathways, and were assessed for their inhibitory actions against four isoforms: the widespread cytosolic (hCA I and II), and the transmembrane tumor-related (hCA IX and XII). The primary sulfonamides efficiently inhibited the target hCA IX and hCA XII in the nanomolar range (K_Is: 6.2-951.5 nM and 3.3-869.3 nM, respectively). The most selective hCA IX inhibitors 6c and 18 were assessed for their potential anticancer effects, and displayed anti-proliferative activity against MCF-7 cancer cell line with IC₅₀s of 11.9 and 36.7 μM, respectively. Molecular modelling studies unveiled the relationship between structural features and inhibitory profiles against the off-target hCA II and the target, tumor-related isoforms hCA IX and XII.

Tetramethylpyrazine: A Review of Its Antitumor Potential and Mechanisms

Cancer remains a major public health threat. The mitigation of the associated morbidity and mortality remains a major research focus. From a molecular biological perspective, cancer is defined as uncontrolled cell division and abnormal cell growth caused by various gene mutations. Therefore, there remains an urgent need to develop safe and effective antitumor drugs. The antitumor effect of plant extracts, which are characterized by relatively low toxicity and adverse effect, has attracted significant attention. For example, increasing attention has been paid to the antitumor effects of tetramethylpyrazine (TMP), the active component of the Chinese medicine Chuanqiong, which can affect tumor cell proliferation, apoptosis, invasion, metastasis, and angiogenesis, as well as reverse chemotherapeutic resistance in neoplasms, thereby triggering antitumor effects. Moreover, TMP can be used in combination with chemotherapeutic agents to enhance their effects and reduce the side effect associated with chemotherapy. Herein, we review the antitumor effects of TMP to provide a theoretical basis and foundation for the further exploration of its underlying antitumor mechanisms and promoting its clinical application.

Synthesis and biological evaluation of novel ligustrazine-chalcone derivatives as potential anti-triple negative breast cancer agents

A series of novel ligustrazine-chalcone hybrids were synthesized and evaluated for their in vitro and in vivo antitumor activities. The results showed that most of these compounds exhibited significant in vitro cytotoxicity against MDA-MB-231, MCF-7, A549 and HepG2 cell lines with IC₅₀ values as low as sub-micromole. Among them, compounds 6c and 6f possessed better comprehensive characteristics for the antiproliferation effects on both MDA-MB-231 (IC₅₀: 6c, 1.60 ± 0.21 μM; 6f, 1.67 ± 1.25 μM) and MCF-7 (IC₅₀: 6c, 1.41 ± 0.23 μM; 6f, 1.54 ± 0.30 μM). They also exhibited the potent colony-formation inhibitory abilities on above two cell lines in both concentration and time dependent manners, as well as the significantly suppression capabilities against the migration of such cell lines in a concentration dependent manner by wound-healing assay. Of note, compound 6c could significantly induce the apoptosis of MDA-MB-231 cells in a concentration dependent manner and inhibited the transformation of the growth cycle of MDA-MB-231 cells and blocked the cell growth cycle in G0/G1 phase. Moreover, the in vivo antiproliferation assay of compound 6c on TNBC model indicated such compound had a remarkable potency against tumor growth with a widely safety window. Further immunohistochemistry analysis illustrated that compound 6c was provided with a potent capacity to significantly reduce the Ki-67 positive rate in a dose dependent manner. All the results suggested that these hybrids presented both in vitro and in vivo proliferation inhibition potency against breast cancer and further development with good therapeutic potential should be of great interest.

Design, Synthesis and Biological Evaluation of New HDAC1 and HDAC2 Inhibitors Endowed with Ligustrazine as a Novel Cap Moiety

Introduction

Histone deacetylases (HDACs) represent one of the most validated cancer targets. The inhibition of HDACs has been proven to be a successful strategy for the development of novel anticancer candidates.

Methods

This work describes design and synthesis of a new set of HDAC inhibitors (7a-c and 8a, b) utilizing ligustrazine as a novel cap moiety, and achieving the pharmacophoric features required to induce the desired inhibition.

Results

The newly synthesized derivatives were evaluated for their potential inhibitory activity toward two class I histone deacetylases, namely HDAC1 and HDAC2. The tested ligustrazine-based compounds were more potent toward HDAC2 (IC₅₀ range: 53.7–205.4 nM) than HDAC1 (IC₅₀ range: 114.3–2434.7 nM). Furthermore, the antiproliferative activities against two HDAC-expressing cancer cell lines; HT-29 and SH-SY5Y were examined by the MTT assay. Moreover, a molecular docking study of the designed HDAC inhibitors (7a-c and 8a,b) was carried out to investigate their binding pattern within their prospective targets; HDAC1 (PDB-ID: 4BKX) and HDAC2 (PDB-ID: 6G3O).

Discussion

Compound 7a was found to be the most potent analog in this study toward HDAC1 and HDAC2 with IC₅₀ values equal 114.3 and 53.7 nM, respectively. Moreover, it was the most effective counterpart (IC₅₀ = 1.60 µM), with 4.7-fold enhanced efficiency than reference drug Gefitinib (IC₅₀ = 7.63 µM) against SH-SY5Y cells. Whereas, compound 8a (IC₅₀ = 1.96 µM) was the most active member toward HT-29 cells, being 2.5-times more potent than Gefitinib (IC₅₀ = 4.99 µM). Collectively, these results suggest that 7a merits further optimization and development as an effective new HDACI lead compound.

Novel Homo-Bivalent and Polyvalent Compounds Based on Ligustrazine and Heterocyclic Ring as Anticancer Agents

Bivalent and polyvalent inhibitors can be used as antitumor agents. In this experiment, eight ligustrazine dimers and seven ligustrazine tetramers linked by alkane diamine with different lengths of carbon chain lengths were synthesized. After screening their antiproliferation activities against five cancer cell lines, most ligustrazine derivatives showed better cytotoxicity than the ligustrazine monomer. In particular, ligustrazine dimer 8e linked with decane-1,10-diamine exhibited the highest cytotoxicity in FaDu cells with an IC50 (50% inhibiting concentration) value of 1.36 nM. Further mechanism studies suggested that 8e could induce apoptosis of FaDu cells through the depolarization of mitochondrial membrane potential and S-phase cell cycle arrest. Inspired by these results, twenty-seven additional small molecule heterocyclic dimers linked with decane-1,10-diamine and nine cinnamic acid dimers bearing ether chain were synthesized and screened. Most monocyclic and bicyclic aromatic systems showed highly selective anti-proliferation activity to FaDu cells and low toxicity to normal MCF 10A cells. The structure-activity relationship revealed that the two terminal amide bonds and the alkyl linker with a chain length of 8-12 carbon were two important factors to maintain its antitumor activity. In addition, the ADMET calculation predicted that most of the potent compounds had good oral bioavailability.

Design, Synthesis and Biological Evaluation of Diosgenin-Amino Acid Derivatives with Dual Functions of Neuroprotection and Angiogenesis

Diosgenin, a natural product with steroidal structure, has a wide range of clinical applications in China. It also shows great potential in the treatment of blood clots and nerve damage. To enhance the bioavailability as well as efficacy of diosgenin, eighteen diosgenin-amino acid derivatives were designed and synthesized. The neuroprotective effects of these compounds were evaluated by SH-SY5Y cell line and the biosafety was evaluated by H9c2 cell line. The results displayed that part of the derivatives' activities (EC₅₀ < 20 μM) were higher than positive control edaravone (EC₅₀ = 21.60 ± 3.04 μM), among which, DG-15 (EC₅₀ = 6.86 ± 0.69 μM) exhibited the best neuroprotection. Meanwhile, biosafety evaluation showed that DG-15 had no cytotoxicity on H9c2 cell lines. Interestingly, combined neuroprotective and cytotoxic results, part of the derivatives without their protecting group were superior to compounds with protecting group. Subsequently, Giemsa staining and DAPI (4',6-diamidino-2-phenylindole) staining indicated that DG-15 had a protective effect on damaged SH-SY5Y cells by reducing apoptosis. Moreover, DG-15 showed a higher role in promoting angiogenesis at high concentrations (4 mg/mL) on the chorioallantoic membrane model. This finding displayed that DG-15 had dual functions of neuroprotection and angiogenesis, which provided further insight into designing agent for the application in treatment of ischemic stroke.

Synthesis of Novel Baicalein Amino Acid Derivatives and Biological Evaluation as Neuroprotective Agents

Baicalein, a famously effective component of the traditional Chinese medicine Rhizoma Huang Qin (Scutellaria altissima L.), has been proved to have potent neuroprotection and anti-platelet aggregation effects with few side effects. Meanwhile, recent studies have revealed that the introduction of amino acid to baicalein could improve its neuroprotective activity. In the present study, a series of novel baicalein amino acid derivatives were designed, synthesized, and screened for their neuroprotective effect against tert-butyl, hydroperoxide-induced, SH-SY5Y neurotoxicity cells and toxicity on the normal H9C2 cell line by standard methylthiazol tetrazolium (MTT) assay. In addition, all of the newly synthesized compounds were characterized by ¹H-NMR, ¹³C-NMR, and high resolution mass spectrometry (HR-MS). The results showed that most of the compounds provided more potent neuroprotection than baicalein, and were equivalent to the positive drug edaravin. They showed no obvious cytotoxicity on normal H9C2 cells. Notably, the most active compound 8 displayed the highest protective effect (50% effective concentration (EC₅₀) = 4.31 μM) against tert-butyl, hydroperoxide-induced, SH-SY5Y neurotoxicity cells, which was much better than the baicalein (EC₅₀ = 24.77 μM) and edaravin (EC₅₀ = 5.62 μM). Further research on the chick chorioallantoic membrane (CAM) model indicated that compound 8 could significantly increase angiogenesis, which might promote neurovascular proliferation. The detection of apoptosis analysis showed that compound 8 could dramatically alleviate morphological manifestations of cell damage. Moreover, the benzyloxycarbonyl (cbz)-protected baicalein amino acid derivatives showed better neuroprotective activity than the t-Butyloxy carbonyl (boc)-protected derivatives.

Sichong formula inhibits the proliferation and migration of human gastric cancer cells

Purpose

Traditional Chinese medicine (TCM) has gained increasing attention for the treatment of multiple chronic diseases, such as cancer. Here we aim to identify the antitumor activity of Sichong formula, a novel TCM, in human gastric cancer cells and investigate the underlying mechanisms.

Methods

The AGS and MKN45 gastric cancer cells were treated with Sichong formula at different concentrations. The proliferation rates were tested by CCK-8 and colony formation assays. Cell migration and invasion were tested by scratch and transwell assays. Gelatin zymography was used to detect the matrix metalloproteinase 9 (MMP9) activity in cell suspendents. Cell apoptosis was analyzed by Annexin V/PI staining and flow cytometry. The expression of interest proteins was tested by Western blot.

Results

Cell proliferation analysis indicated that Sichong formula inhibited cell viability of AGS and MKN45 cells in a dose- and time-dependent manner. The IC50 values were 240 μg/mL and 200 μg/mL for AGS and MKN45 cells, respectively. Furthermore, we found that Sichong formula could inhibit the invasion and migration of gastric cancer cells, which might be mediated by the downregulation of MMP9 activity. Flow cytometry results indicated that Sichong formula induced apoptosis in gastric cancer cells through upregulation of Bax/Bcl2 ratio and activation of caspase cascade. The results from Western blot indicated that Sichong formula resulted in cell autophagy and inactivation of AKT signaling pathway.

Conclusion

Our data suggest that Sichong formula inhibits the proliferation and migration and induces apoptosis in human gastric cancer cells. The inhibitory effect of Sichong formula was, at least partly, mediated by cell autophagy and AKT pathway.

In Vitro and In Vivo Inhibitory Effect of Gujin Xiaoliu Tang in Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a serious threat to people's health. This study aims to determine the possible effect of Gujin Xiaoliu Tang (GJXLT) on NSCLC, which is an empirical formula from Professor Dai-Han Zhou. In this study, chromatographic fingerprinting of GJXLT and A549 cell model in vitro and in vivo was established. We cultured A549 cells in vitro and found that GJXLT inhibited A549 cell growth and induced apoptosis. Compared with the control group, the expression of p-STAT3 and VEGF proteins in the GJXLT groups was decreased. Similar findings were also observed in vivo. First, GJXLT inhibited the growth of transplanted tumor and did not reduce the weight of the tumor-bearing mice in comparison with that of the control group. Then, the Ki-67 expression of transplanted tumor in the GJXLT groups was decreased. In addition, the apoptosis rate of transplanted tumor in the GJXLT groups was increased. Overall, our data showed that GJXLT inhibited A549 cell proliferation and induced apoptosis in vivo and in vitro. Furthermore, GJXLT inhibited the growth of lung cancer xenograft in nude mice model with no obvious side effects. The anti-tumor effect of GJXLT might also be related to the inhibition of p-STATS and VEGF expression in the JAK2/STAT3 pathway. Our results demonstrated the potential of GJXLT as a novel treatment for NSCLC.

Design, Synthesis, and Cytotoxic Analysis of Novel Hederagenin⁻Pyrazine Derivatives Based on Partial Least Squares Discriminant Analysis

Hederagenin (He) is a novel triterpene template for the development of new antitumor compounds. In this study, 26 new He–pyrazine derivatives were synthetized in an attempt to develop potent antitumor agents; they were screened for in vitro cytotoxicity against tumor and non-tumor cell lines. The majority of these derivatives showed much stronger cytotoxic activity than He. Remarkably, the most potent was compound 9 (half maximal inhibitory concentration (IC₅₀) was 3.45 ± 0.59 μM), which exhibited similar antitumor activities against A549 (human non-small-cell lung cancer) as the positive drug cisplatin (DDP; IC₅₀ was 3.85 ± 0.63 μM), while it showed lower cytotoxicity on H9c2 (murine heart myoblast; IC₅₀ was 16.69 ± 0.12 μM) cell lines. Compound 9 could induce the early apoptosis and evoke cell-cycle arrest at the synthesis (S) phase of A549 cells. Impressively, we innovatively introduced the method of cluster analysis modeled as partial least squares discriminant analysis (PLS-DA) into the structure–activity relationship (SAR) evaluation, and SAR confirmed that pyrazine had a profound effect on the antitumor activity of He. The present studies highlight the importance of pyrazine derivatives of He in the discovery and development of novel antitumor agents.

1H NMR based metabolite profiling for optimizing the ethanol extraction of Wolfiporia cocos

Metabolite profiling of Wolfiporia cocos (family: Polyporaceae) had been much advancement in recent days, and its analysis by nuclear magnetic resonance (NMR) spectroscopy has become well established. However, the highly important trait of W. cocos still needs advanced protocols despite some standardization. Partial least squares discriminant analysis (PLS-DA) was used as the multivariate statistical analysis of the ¹H NMR data set. The PLS-DA model was validated, and the key metabolites contributing to the separation in the score plots of different ethanol W. cocos extract. ¹H NMR spectroscopy of W. cocos identified 33 chemically diverse metabolites in D₂O, consisting of 13 amino acids, 11 organic acids 2 sugars, 3 sugar alcohols, 1 nucleoside, and 3 others. Among these metabolites, the levels of tyrosine, proline, methionine, sarcosine, choline, acetoacetate, citrate, 4-aminobutyrate, aspartate, maltose, malate, lysine, xylitol, lactate threonine, leucine, valine, isoleucine, uridine, guanidoacetate, arabitol, mannitol, glucose, and betaine were increased in the 95% ethanol extraction sample compared with the levels in other samples, whereas level of acetate, phenylalanine, alanine, succinate, and fumarate were significantly increased in the 0% ethanol extraction sample. A biological triterpenoid, namely pachymic acid, was detected from different ethanol P. cocos extract using ¹H-NMR spectra were found in CDCl₃. This is the first report to perform the metabolomics profiling of different ethanol W. cocos extract. These researches suggest that W. cocos can be used to obtain substantial amounts of bioactive ingredients for use as potential pharmacological and nutraceuticals agents.

Recent progress in the structural modification and pharmacological activities of ligustrazine derivatives

Ligustrazine is a main active fraction of the traditional medicine known as Ligusticum chuanxiong hort, which has been used as clinical medication for cerebral thrombosis, coronary heart disease and stenocardia recently. The rapid metabolism and short half-life of ligustrazine seriously limits its application in clinical practice. Therefore, derivatives of ligustrazine are designed and synthesized in our and other labs, including piperazine, cinnamic acid, styrene, acylguanidine, amides, curcumin and triterpenes derivatives of ligustrazine. Most of these compounds present better pharmacodynamics activities and more favorable pharmacokinetic properties compared to the parent compound. Besides, some new biological activities of these compounds are discovered. Hence, this review continues the previous review of our group as well as aims to highlight recent prominent advances in this field in the past ten years.

Oleanolic Acid-amino Acids Derivatives: Design, Synthesis, and Hepatoprotective Evaluation In Vitro and In Vivo

Activated hepatic stellate cells (HSCs) are the main extracellular matrix (ECM)-producing cells in the injured liver and the key mediators of liver fibrosis; they also promote the progression of hepatocellular carcinoma (HCC). In the acidic extracellular microenvironment of HCC, HSCs are activated to promote the migration of HCC cells. It is worth attempting to alter the weak acidic microenvironment to promote activated HSC apoptosis to treat liver fibrosis and liver cancer. In the present study, a series of novel OA-amino acids analogues were designed and synthesized to introduce different amino acids in the 3-hydroxyl of OA using the ester condensation reaction to enhance hydrophilicity, alkalinity, and biological activity. We found that OA-lysine derivative (3g) could improve the hydrophilic of OA and induce HSCs apoptosis via inducing MMP depolarization and increasing intracellular Ca2+ levels. Additionally, 3g displayed a better hepatoprotective effect than OA (20 mg/kg, intragastric administration) against the acute liver injury induced by carbon tetrachloride (CCl₄) in mice. The results suggested that basic amino acids (lysine) could effectively enhance OA's hydrophilicity, alkalinity, and hepatoprotective activity in vitro and in vivo, which might be likely associated with increasing bioavailability and altering an extracellular weak acidic microenvironment with further verification. Therefore, the OA-lysine derivative (3g) has the potential to be developed as an agent with hepatoprotective activity.

Neuroprotection by new ligustrazine-cinnamon acid derivatives on CoCl2-induced apoptosis in differentiated PC12 cells

A new series of ligustrazine-cinnamon acid derivatives had been designed and synthesized as potential neuro-protective agents. Among the derivatives, 3a exhibited the promising neuroprotective activity (EC₅₀ = 3.68 μM). Moreover, with the deep research of the drug pathway, it (the further mechanism researches) suggested compound 3a could inhibit the apoptosis of injured PC12 cells via blocking the mitochondria apoptosis pathway including up-regulation the ratio of Bcl-2/Bax, down-regulation the expression of cytochrome-c (Cyt-c) and inhibition of the activity of caspase-9 and -3. In addition, the structure-activity relationships (SARs) of novel compounds were also discussed.

Synthesis and evaluation of antitumor, anti-inflammatory and analgesic activity of novel deoxycholic acid derivatives bearing aryl- or hetarylsulfanyl moieties at the C-3 position

Novel deoxycholic acid (DCA) derivatives were stereoselectively synthesised with -OH and -CH₂SR moieties at the C-3 position, where R was a substituted aryl [2-aminophenyl (8) or 4-chlorophenyl (9)] or hetaryl [1-methylimidazolyl (5), 1,2,4-triazolyl (6), 5-amino-1,3,4-thiadiazolyl (7), pyridinyl (10) or pyrimidinyl (11)]. These compounds were prepared in good yields from the C-3β-epoxy derivative 2 in the epoxide ring-opening reaction by S-nucleophiles. These derivatives were evaluated for their in vitro anti-proliferation activity in a panel of tumor cell lines. Data showed that: (i) heterocycle-containing derivatives displayed higher cytotoxicity profiles than the parent molecule; (ii) heterocyclic substituents were more preferable than aryl moieties for enhancing anti-proliferation activity; (iii) the sensitivity of tumor cell lines to analysed compounds decreased in the following order: HuTu-80 (duodenal carcinoma)>KB-3-1 (cervical carcinoma)>HepG2 (hepatocellular carcinoma)>MH-22a (hepatoma); (iv) compounds 5, 6 and 11 exhibited a high cytotoxic selectivity index (HuTu-80: SI>7.7, 38.5 and 12.0, respectively). Compounds 2 and 6-8 markedly inhibited NO synthesis by interferon γ-induced macrophages. Screening for anti-inflammatory activity of these derivatives in vivo showed their high potency on histamine- (5, 10) and formalin- (2, 10, 11) induced paw edema models.

Origin and Formation Mechanism Investigation of Compound Precipitation from the Traditional Chinese Prescription Huang-Lian-Jie-Du-Tang by Isothermal Titration Calorimetry

Previous studies have shown that compounds in the form of precipitate (CFP) from Huang-Lian-Jie-Du-Tang (HLJDT) were stable, and the CFP content reached 2.63% of the whole decoction and had good neuroprotective effects. However, there has been no research on their specific source. In this study, it was found that HLJDT CFP mainly came from the reaction of Scutellaria baicalensis and Coptis chinensis by studying the separated prescription components (accounting for 81.33% of HLJDT CFP). Unlike previous studies on HLJDT CFP, in this research the chemical composition of Scutellaria baicalensis–Coptis chinensis (SB–CC) CFP was identified by high performance liquid chromatography coupled with mass spectrometry (HPLC-MSⁿ), which further proved that the main source of HLJDT CFP was Scutellaria baicalensis–Coptis chinensis CFP compared with previous HLJDT CFP studies. To explain the reaction mechanism between the decoctions of Scutellaria baicalensis and Coptis chinensis, isothermal titration calorimetry (ITC) was used to analyze their binding heat and the thermodynamic parameters (ΔH, ΔS, ΔG, n, Ka) of the reaction between baicalin and berberine, which are the main components of Scutellaria baicalensis and Coptis chinensis, respectively. The results showed that the reaction between decoctions of Scutellaria baicalensis and Coptis chinensis was exothermic and the reaction between baicalin and berberine was a spontaneous and enthalpy-driven chemical reaction, the binding ratio being 1:1. In addition, HLJDT CFP (EC₅₀ = 14.71 ± 0.91 µg/mL) and SB-CC CFP (EC₅₀ = 6.11 ± 0.12 µg/mL) showed similar protective activities on PC12 cells injured by cobalt chloride (CoCl₂). This study provided a new angle to research on the main chemical components and therapeutic values of CFP in Traditional Chinese Medicine compounds.

Herbal formula YYJD inhibits tumor growth by inducing cell cycle arrest and senescence in lung cancer

Lung cancer represents a major cause of cancer-related death worldwide. Although various tactics and anti-tumor drugs have been used to improve curative effects, five-year survival rate of lung cancer patients remains poor. In this study, we investigated the action and underlying mechanisms of our recently optimized Chinese herbal formula Yangyinjiedu (YYJD) against lung cancer. YYJD significantly inhibits the proliferation of lung cancer cell lines (95-D, A549, H460 and H1975) by inducing cell cycle arrest and senescence in a dose-dependent manner. In particular, YYJD induces significant G2/M phase arrest and inhibits the colony formation of lung cancer cells. Moreover, we found that administration of YYJD could inhibit the growth of xenografted lung cancer cells in nude mice without loss in body weight. Our findings suggest that the herbal formula YYJD is a potential anti-tumor agent against lung cancer.

A New Oleanolic Acid Derivative against CCl₄-Induced Hepatic Fibrosis in Rats

A novel hepatoprotective oleanolic acid derivative, 3-oxours-oleana-9(11), 12-dien-28-oic acid (Oxy-Di-OA), has been reported. In previous studies, we found that Oxy-Di-OA presented the anti-HBV (Hepatitis B Virus) activity (IC₅₀ = 3.13 µg/mL). Remarkably, it is superior to lamivudine in the inhibition of the rebound of the viral replication rate. Furthermore, Oxy-Di-OA showed good performance of anti-HBV activity in vivo. Some studies showed that liver fibrosis may affiliate with HBV gene mutations. In addition, the anti-hepatic fibrosis activity of Oxy-Di-OA has not been studied. Therefore, we evaluated the protective effect of Oxy-Di-OA against carbon tetrachloride (CCl₄)-induced liver injury in rats. Daily intraperitoneally administration of Oxy-Di-OA prevented the development of CCl₄-induced liver fibrosis, which was evidenced by histological study and immunohistochemical analysis. The entire experimental protocol lasted nine weeks. Oxy-Di-OA significantly suppressed the increases of plasma aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels (p < 0.05). Furthermore, Oxy-Di-OA could prevent expression of transforming growth factor β1 (TGF-β1). It is worth noting that the high-dose group Oxy-Di-OA is superior to bifendate in elevating hepatic function. Compared to the model group, Oxy-Di-OA in the high-dose group and low-dose group can significantly reduce the liver and spleen indices (p < 0.05). The acute toxicity test showed that LD₅₀ and a 95% confidence interval (CIs) value of Oxy-Di-OA were 714.83 mg/kg and 639.73–798.73 mg/kg via intraperitoneal injection in mice, respectively. The LD₅₀ value of Oxy-Di-OA exceeded 2000 mg/kg via gavage in mice. In addition, a simple and rapid high performance liquid chromatography-ultraviolet (HPLC-UV) method was developed and validated to study the pharmacokinetic characteristics of the compound. After single-dose oral administration, time to reach peak concentration of Oxy-Di-OA (C_max = 8.18 ± 0.66 μg/mL) was 10 ± 2.19 h; the elimination half-life and area under the concentration-time curve from t = 0 to the last time of Oxy-Di-OA was 2.19 h and 90.21 μg·h/mL, respectively.

Combination of amino acid/dipeptide with ligustrazine-betulinic acid as antitumor agents

The lead compound TBA, 3β-Hydroxy-lup-20(29)-ene-28-oic acid-3, 5, 6-trimethylpyrazin-2-methyl ester, which exhibited promising antitumor activity and induced tumor cell apoptosis in various cancer cell lines, had previously been reported. Moreover, reports have revealed that the introduction of amino acid to betulinic acid could improve selective cytotoxicity as well as water solubility. Thus, a series of novel TBA amino acid and dipeptide derivatives were designed, synthesized and screened for selective cytotoxic activity against five cancer cell lines (HepG2, HT-29, Hela, BCG-823 and A549) and the not malignant cell line MDCK by standard MTT assay. Most of the tested TBA-amino acid and dipeptide analogues showed stronger anti-proliferative activity against all tested tumor cell lines than TBA. Among them, BA-25 exhibited the greatest cytotoxic activity on tumor cell lines (mean IC₅₀ = 2.31 ± 0.78 μM), that was twofold than the positive drug cisplatin (DDP), while it showed lower cytotoxicity on MDCK cell line than DDP. Further cell apoptosis analyses indicated BA-25-induced apoptosis was associated with loss of mitochondrial membrane potential and increase of intracellular free Ca²⁺ concentration.

Design, synthesis, and biological evaluation of the novel glycyrrhetinic acid-cinnamoyl hybrids as anti-tumor agents

Background

Glycyrrhetinic acid (GA) derivatives had shown not only cytotoxicity but also could trigger apoptosis in various human cancer cell lines. Moreover, cinnamic acid (CA) and its phenolic analogues as potent antitumor agents were employed in the design of anti-tumor drugs. To further improve the anti-tumor activity of GA and CA derivatives, a series of novel compounds were designed and synthesized using GA and CA derivatives fragments.

Results

The result showed that all the novel glycyrrhetinic acid-cinnamoyl (GA–CA) hybrids presented higher antitumor activity on the tumor cell lines of HepG2, HT-29, Hela and lower cytotoxicity on three non-tumor cells lines MDCK, HY926, H9C2 than the parent compounds (IC₅₀ > 50 μM). It was worth noting that 8a had a superior cytotoxicity effect on Hela cells (IC₅₀ = 8.54 μM) than on other cancer cell lines (IC₅₀ > 15 μM). And it also indicated that 8a showed lower cytotoxicity (IC₅₀ > 27 μM) towards MDCK, HY926 and H9C2 cells than cisplatin (DDP, IC₅₀ < 10 μM). Moreover, according to the acute toxicity, it could be indicated that the LD₅₀ of 8a exceeded 3.0 g/kg by oral administration in mice. The further research using Giemsa, H33342 staining, flow cytometric analysis and caspase-3 assay showed that 8a could cause Hela cell damage, nuclei lysis and apoptosis. In addition, the structure–activity relationships of these hybrids were briefly discussed.

Conclusions

Compared with GA, target compounds demonstrated better anti-tumor activity, among which 8a was the most active one. What’s more, structure–activity relationship analysis also revealed that hybrids with trans olefinic bond group show higher antitumor activity than those without olefinic bond, such as 1a > 1b, 6a > 2b, 8a > 3b, 9a > 4b. In addition, it was found that the methoxy substituent might enhance selectivity of GA–CA hybrids towards regular non-cancerous cells MDCK, HY926 and H9C2, such as 4a, 6a, 7a, 8a. However, there might be less relationship between the cytotoxicity and the quantity, position of methoxy moiety. Hence, it is urgent need to synthesize efficient, low toxicity and multi-target anti-tumor compounds based on the structure combination principle.

Ligustrazine-Oleanolic Acid Glycine Derivative, G-TOA, Selectively Inhibited the Proliferation and Induced Apoptosis of Activated HSC-T6 Cells

Hepatic fibrosis is a naturally occurring wound-healing reaction, with an imbalance of extracellular matrix (ECM) during tissue repair response, which can further deteriorate to hepatocellular carcinoma without timely treatment. Inhibiting activated hepatic stellate cell (HSC) proliferation and inducing apoptosis are the main methods for the treatment of liver fibrosis. In our previous study, we found that the TOA-glycine derivative (G-TOA) had exhibited more significant inhibitory activity against HepG2 cells and better hydrophilicity than TOA, ligustrazine (TMP), and oleanolic acid (OA). However, inhibiting activated HSC proliferation and inducing apoptosis by G-TOA had not been reported. In this paper, the selective cytotoxicity of G-TOA was evaluated on HSC-T6 cells and L02 cells, and apoptosis mechanisms were explored. It was found that G-TOA could selectively inhibit the proliferation of activated HSC-T6 cells, induce morphological changes, early apoptosis, and mitochondrial membrane potential depolarization, increase intracellular free calcium levels, downregulate the expression of NF-κB/p65 and COX-2 protein, and decrease the ratio of Bcl-2/Bax, thereby inducing HSC-T6 cell apoptosis. Thence, G-TOA might be a potential antifibrosis agent for the therapy of hepatic fibrosis, provided that it exerts anti-fibrosis effects on activated HSC-T6 cells.

Cardiovascular Actions and Therapeutic Potential of Tetramethylpyrazine (Active Component Isolated from Rhizoma Chuanxiong): Roles and Mechanisms

Tetramethylpyrazine (TMP), a pharmacologically active component isolated from the rhizome of the Chinese herb Rhizoma Chuanxiong (Chuanxiong), has been clinically used in China and Southeast Asian countries for the prevention and treatment of cardiovascular diseases (CVDs) for about fifty years. The pharmacological effects of TMP on the cardiovascular system have attracted great interest. Emerging experimental studies and clinical trials have demonstrated that TMP prevents atherosclerosis as well as ischemia-reperfusion injury. The cardioprotective effects of TMP are mainly related to its antioxidant, anti-inflammatory, or calcium-homeostasis effects. This review focuses on the roles and mechanisms of action of TMP in the cardiovascular system and provides a novel perspective on TMP's clinical use.

Potent Anti-Inflammatory Activity of Tetramethylpyrazine Is Mediated through Suppression of NF-k

The purpose of the current study was to evaluate the anti-inflammatory activity of tetramethlpyrazine on oxazolone-induced colitis mice. Spleen mononuclear cells (SMC), lamina propria mononuclear cells (LPMC) and peripheral blood mononuclear cells (PBMC) were isolated from oxazolone-induced colitis and normal mice. The colitis cells treated by oxazolone were randomly divided into model, low dose, middle dose and high dose groups treated with 0, 0.5, 1.0 and 2.0 g/L tetramethlpyrazine, respectively. The apoptotic rate of SMC and LPMC in the oxazolone-induced group was lower than that in the normal group. Compared with model group, apoptotic rate of SMC was significantly increased in the high dose group, while the apoptotic rate of LPMC in the middle dose group was increased. Compared with SMC, LPMC and PBMC of normal group, the mRNA level of nuclear factor kappa B (NF-kB), transcription factor-activated protein-1 (AP-1) and nuclear factor of activated T cells (NF-AT) were higher in model group. Tetramethylpyrazine inhibited the increase of NF-kB, AP-1 and NF-AT mRNA induced by oxazolone. For SMC, LPMC and PBMC there was significant difference in the mRNA level of AP-1 among the three different doses of tetramethylpyrazine treated groups. However, no significant difference was observed in the mRNA levels of NF-AT and NF-κB between normal and middle groups. Tetramethylpyrazine promoted the apoptotic rate of SMC and LPMC in-vitro, and suppressed the expression of transcription factors in SMC, LPMC and PBMC isolated from oxazolone-induced colitis mice. The study provides a novel insight into the mechanism behind the effect of etramethylpyrazine on colitis.

Inhibition of acid sensing ion channel by ligustrazine on angina model in rat

Ligustrazine, a compound extracted from roots of Ligusticum chuanxiong, is widely used in Chinese traditional medicine to treat cardiac and cerebrovascular diseases and pain, including angina. The mechanism(s) of ligustrazine's effect to reduce angina is not clear. Angina is mediated by cardiac afferent sensory neurons. These neurons display a large acid-evoked depolarizing sodium current that can initiate action potentials in response to acidification that accompanies myocardial ischemia. Acid-sensing ion channels (ASICs) mediate this current. Here we tested the hypothesis that ligustrazine reduces ischemia-induced cardiac dysfunction and acid-evoked pain by an action to inhibit ASIC-mediated current. The effects of ligustrazine to attenuate ischemia-induced ST-segment depression, T wave changes, and myocardial infarct size in hearts of anesthetized rats were determined. Effects of ligustrazine on currents mediated by ASICs expressed in cultured Chinese hamster ovary cells, and effects of the drug on acid-induced nociceptive behavior and acid-induced currents in isolated dorsal root ganglions cells were measured. Ligustrazine significantly attenuated acid-induced ASIC currents, reduced cardiac ischemia-induced electrical dysfunction and infarct size, and decreased the nociceptive response to injection of acid into the paw of the rat hindlimb. The ASIC channel inhibitor A-317567 similarly reduced electrical dysfunction, infarct size, and nociceptive behavior in the rat. Inhibition of ASICs by ligustrazine may explain at least in part the beneficial effects of the drug that are observed in patients with ischemic heart disease and angina.

A Series of New Ligustrazine-Triterpenes Derivatives as Anti-Tumor Agents: Design, Synthesis, and Biological Evaluation

A series of novel ligustrazine-triterpenes derivatives was designed, synthesized and screened for their cytotoxicity against five cancer cell lines (Bel-7402, HepG2, HT-29, Hela, and MCF-7) and Madin-Darby canine kidney (MDCK). Current study suggested that most of the ligustrazine-triterpenes conjunctions showed better cytotoxicity than the starting materials. In particular, compound 4a exhibited better cytotoxic activity (IC₅₀ < 5.23 μM) against Bel-7402, HT-29, MCF-7, Hela, and HepG2 than the standard anticancer drug cisplatin (DDP). The cytotoxicity selectivity detection revealed that 4a exhibited low cytotoxicity (IC₅₀ > 20 μM) towards MDCK cells. A combination of fluorescence staining observation and flow cytometric analysis indicated that 4a could induce HepG2 cell apoptosis. Further studies suggested that 4a-induced apoptosis is mediated through depolarization of the mitochondrial membrane potential and increase of intracellular free Ca²⁺ concentration. In addition, the structure-activity relationships of these derivatives were briefly discussed.

A New Ligustrazine Derivative-Selective Cytotoxicity by Suppression of NF-κB/p65 and COX-2 Expression on Human Hepatoma Cells. Part 3

A new anticancer ligustrazine derivative, 3β-hydroxyolea-12-en-28-oic acid-3,5,6-trimethylpyrazin-2-methylester (T-OA, C₃₈H₅₈O₃N₂), was previously reported. It was synthesized via conjugating hepatoprotective and anticancer ingredients of traditional Chinese medicine. We found that T-OA exerted its anticancer activity by preventing the expression of nuclear transcription factor NF-κB/p65 and COX-2 in S180 mice. However, the selective cytotoxicity of T-OA on various kinds of cell lines has not been studied sufficiently. In the present study, compared with Cisplatin, T-OA was more toxic to human hepatoma cell line Bel-7402 (IC₅₀ = 6.36 ± 1.56 µM) than other three cancer cell lines (HeLa, HT-29, BGC-823), and no toxicity was observed toward Madin–Darby canine kidney cell line MDCK (IC₅₀ > 150 µM). The morphological changes of Bel-7402 cells demonstrated that T-OA had an apoptosis-inducing effect which had been substantiated using 4ʹ,6-diamidino-2-phenylindole (DAPI) staining, acridine orange (AO)/ethidium bromide (EB) staining, flow cytometry and mitochondrial membrane potential assay. Combining the immumohistochemical staining, we found T-OA could prevent the expression of NF-κB/p65 and COX-2 in Bel-7402 cells. Both of the proteins have been known to play roles in apoptosis and are mainly located in the nuclei. Moreover subcellular localization was performed to reveal that T-OA exerts in nuclei of Bel-7402 cells. The result was in accordance with the effects of down-regulating the expression of NF-κB/p65 and COX-2.

New synthesis method for sultone derivatives: synthesis, crystal structure and biological evaluation of S-CA

There has been no remarkable progress in the synthesis of sultones in recent years. To facilitate more detailed studies of this functional group, we found a new method to synthesize the sulfonic acid lactone derivatives and finish its ring-closing reaction. A new sultone derivative, (E)-ethyl 4-oxo-6-styryl-3,4-dihydro-1,2-oxathiine-5-carboxylate 2,2-dioxide (S-CA), was synthesized and structurally identified by ¹H-NMR, ¹³C-NMR, HMQC and X-ray single crystal diffraction analysis. The new rapid synthesis extended the method of ring-closing reaction of sulfonic acid lactone derivatives. The angiogenesis activities of S-CA were evaluated by the chick chorioallantoic membrane (CAM) model. It could selectively suppress small angiogenesis in CAM, without influencing either middle and large angiogenesis. In addition, anticancer efficacy of S-CA was evaluated in vivo using a murine sarcoma S180 model. Reduction of the tumor weight and tumor HE staining regions demonstrated that S-CA (10 mg/kg, intraperitoneal injection) had potent inhibition effects and a 44.71% inhibitory rate in S180 mice. Moreover, an acute toxicity test showed that the LD₅₀ value of S-CA via intraperitoneal injection was 25.624 mg/kg.

Ligustrazinyl amides: a novel class of ligustrazine-phenolic acid derivatives with neuroprotective effects

Background

Ligustrazine has potent effects of thrombolysis, neuroprotection and vascular protection, which were important for effectively protecting the nervous system. Previous study in our laboratory reported that ligustrazine-benzoic acid derivatives have been shown to exhibit beneficial effect against CoCl₂-induced neurotoxicity in differentiated PC12 cells. To further improve ligustrazine’s neuroprotection, we integrated the ligustrazine and phenolic acid fragments into one molecule via an amide bond based on structural combination.

Results

In this study, 12 novel ligustrazine-phenolic acid derivatives were synthesized and nine others were prepared by improved methods. Furthermore, these compounds were evaluated for their protective effects against CoCl₂-induced neurotoxicity in differentiated PC12 cells. The amides conjunctional derivatives exhibited promising neuroprotective activities in comparison with ligustrazine. In addition, the most active congener (E)-3-(2,3,4-trimethoxyphenyl)-N-((3,5,6-trimethylpyrazin-2-yl)methyl)acrylamide (L10, EC₅₀ = 25 μM), which is 2 times higher than that of ligustrazine, may be a potential candidate for intervention in neurological diseases. Structure-activity relationship was discussed briefly.

Conclusions

Results of series of ligustrazinyl amides enrich the study of ligustrazine derivatives with neuroprotective effects. Our completed work supports that the attempt to apply structure combination to discover more efficient neuroprotection lead compounds is viable.

Graphical Abstract

Synthesis and protective effect of new ligustrazine derivatives against CoCl2-induced neurotoxicity in differentiated PC12 cells. Part 2

The novel ligustrazine derivatives were synthesized and displayed the remarkable protective effect (highest EC₅₀ = 0.719 μM) on PC12 cells damaged by CoCl₂.

Amino acid derivatives of ligustrazine-oleanolic acid as new cytotoxic agents

A series of novel ligustrazine-oleanolic acid (TOA) derivatives were designed, and synthesized by conjugating amino acids to the 3-hydroxy group of TOA by ester bonds. Their cytotoxicity was evaluated on four cancer cell lines (HepG2, HT-29, Hela and BGC-823) by standard MTT assays. The ClogP values were calculated by means of computer simulation, and logP values of both 3β-glycine ester olean-12-en-28-oic acid-3,5,6-trimethylpyrazin-2-methyl ester (6a) and TOA were determined using a shake flask-ultraviolet spectrophotometry method. It was found that 6a and the 3β-L-lysine ester-6g not only displayed good cytotoxicity (IC50<3.5 μM) but also possessed better hydrophilicity than TOA. Moreover, 6a (IC50=4.884 μM) had lower nephrotoxicity than both 6g (IC50=2.310 μM) and cisplatin (CDDP, IC50=3.691 μM) on MDCK cells. Combining Giemsa and DAPI staining, it was further verified that 6a could induce HepG2 apoptosis via nuclei fragmentation and had lower nephrotoxicity. In addition, the structure-activity relationships of these derivatives are briefly discussed.

Protection of a new heptapeptide from Carapax trionycis against carbon tetrachloride-induced acute liver injury in mice

A new heptapeptide GAGPHGG (OC1) was isolated from Carapax trionycis which was a traditional Chinese medicine (TCM) used for treatment of hepatic diseases. The structure of OC1 was characterized by MS, NMR techniques, together with amino acid sequence analysis. The hepatoprotective activity of OC1 was evaluated in vivo using the CCl4-induced acute liver injury model. Combining the pathological examination and the biochemical assays, OC1 (0.34 mg/kg, hypodermic injection) displayed better hepatoprotective effect than bifendate (100 mg/kg, intragastric administration) against the acute liver injury induced by carbon tetrachloride (CCl4) in mice. Compared with the model group, OC1 could significantly suppress the increase of serum level of aminotransferase (alanine transaminase (ALT) and aspartate aminotransferase (AST)), decrease the formation of malondialdehyde (MDA) and elevate the activity of glutathione peroxidase (GSH-Px) in liver (p<0.01). And the acute toxic test showed that median lethal dose (LD50) of OC1 exceeded 6.8 mg/kg, via hypodermic injection in mice.

In-vitro and in-vivo comparison of T-OA microemulsions and solid dispersions based on EPDC

The goal of this study was to enhance the absorption of a new water-insoluble antitumor lead compound, T-OA (3β-hydroxyolea-12-en-28-oic acid-3, 5, 6-trimethylpyrazin-2-methyl ester). Early-stage preparation discovery concept (EPDC) was employed in this study. Based on this concept, a microemulsion system was chosen as the method of improving bioavailability. The solubility of T-OA was checked in different oils, surfactants and cosurfactants. Ternary phase diagrams were constructed to evaluate the microemulsion domain. Developed high-performance liquid chromatography method was used to determine drug content. The transparent o/w microemulsion formulation composed of oleic acid (oil), Tween 80 (surfactant), ethanol (co-surfactant) and water enhanced the solubility of T-OA up to 20 mg/mL. It was characterized in terms of appearance, content, viscosity, zeta potential, conductivity, morphology and particle size. The particle size distribution, viscosity, conductivity and zeta potential were found to be 70 nm, 15.57 MPa s, 44.1 μS cm(-1) and -0.174, respectively. Oral bioavailability of T-OA microemulsion and oleic acid solution were checked by using rat model. Contrast to the solid dispersion and proto drug, the area-under-the-curve (AUC) of T-OA microemulsion and oleic acid solution were significantly enhanced. The relative bioavailability of T-OA microemulsion was found to be 5654.7%, which is 57-fold higher than the pure drug. Improved T-OA solubility in microemulsion was found sustained 48 h in dilution study. While the solid dispersion may precipitate under the gastrointestinal circumstance based on dilution results. The in-vivo and in-vitro results indicated that, compare to improve the solubility, it is more important to maintain and prolong the T-OA dissolved status, for improvement of the in-vivo absorption.

Synthesis and protective effect of new ligustrazine-benzoic acid derivatives against CoCl2-induced neurotoxicity in differentiated PC12 cells

A series of novel ligustrazine-benzoic acid derivatives were synthesized and evaluated for their protective effect against cobalt chloride-induced neurotoxicity in differentiated PC12 cells. Combining hematoxylin and eosin staining, we found compound that (3,5,6-trimethylpyrazin-2-yl)methyl 3-methoxy-4-[(3,5,6-trimethylpyrazin-2-yl)methoxy]benzoate (4a) displayed promising protective effect on the proliferation of the injured PC12 cells (EC₅₀ = 4.249 µM). Structure-activity relationships are briefly discussed.

A novel herbal formula induces cell cycle arrest and apoptosis in association with suppressing the PI3K/AKT pathway in human lung cancer A549 cells

AIM OF THE STUDY

In recent years, the incidence of lung cancer, as well as the mortality rate from this disease, has increased. Moreover, because of acquired drug resistance and adverse side effects, the effectiveness of current therapeutics used for the treatment of lung cancer has decreased significantly. Chinese medicine has been shown to have significant antitumor effects and is increasingly being used for the treatment of cancer. However, as the mechanisms of action for many Chinese medicines are undefined, the application of Chinese medicine for the treatment of cancer is limited. The formula tested has been used clinically by the China National Traditional Chinese Medicine Master, Professor Zhonging Zhou for treatment of cancer. In this article, we examine the efficacy of Ke formula in the treatment of non-small cell lung cancer and elucidate its mechanism of action.

METHODS

A Balb/c nude mouse xenograft model using A549 cells was previously established. The mice were randomly divided into normal, mock, Ke, cisplatin (DDP), and co-formulated (Ke + DDP) groups. After 15 days of drug administration, the animals were sacrificed, body weight and tumor volume were recorded, and the tumor-inhibiting rate was calculated. A cancer pathway finder polymerase chain reaction array was used to monitor the expression of 88 genes in tumor tissue samples. The potential antiproliferation mechanism was also investigated by Western blot analysis.

RESULTS

Ke formula minimized chemotherapy-related weight loss in tumor-bearing mice without exhibiting distinct toxicity. Ke formula also inhibited tumor growth, which was associated with the downregulation of genes in the PI3K/AKT, MAPK, and WNT/β-catenin pathways. The results from Western blot analyses further indicated that Ke blocked the cell cycle progression at the G1/S phase and induced apoptosis mainly via the PI3K/AKT pathway.

CONCLUSION

Ke formula inhibits tumor growth in an A549 xenograft mouse model with no obvious side effects. Moreover, Ke exhibits synergistic antitumor effects when combined with DDP. The mechanism of action of Ke is to induce cell cycle arrest and apoptosis by suppressing the PI3K/AKT pathway. Further research will be required to determine the mechanism of action behind the synergistic effect of Ke and DDP.

Role of the ROS/AMPK signaling pathway in tetramethylpyrazine-induced apoptosis in gastric cancer cells

Tetramethylpyrazine (TMPZ) is one of the active compounds extracted from the traditional Chinese medicinal herb Chuanxiong and several studies have shown it to possess anticancer properties. However, its effectiveness in gastric cancer and its cellular mechanisms are relatively unknown. The present study aimed to investigate the effect of TMPZ on SGC7901 cells, and it was demonstrated that a high dose of TMPZ inhibited cell viability and induced apoptosis by stimulating AMP-activated protein kinase (AMPK) through the generation of reactive oxygen species (ROS). Furthermore, TMPZ-induced apoptosis resulted in the sequential events beginning with the translocation of Bax, the collapse of mitochondrial membrane potential (ΔΨm), the release of cytochrome c and the activation of caspase-9 and -3. Each of these events was inhibited by compound C, a pharmacological inhibitor of AMPK. To the best of our knowledge, these results demonstrate for the first time that the induction of apoptosis by TMPZ in gastric cancer cells is associated with the activation of the ROS/AMPK pathway. AMPK activation induces apoptosis through the mitochondrial apoptotic pathway. In addition, these results raise the possibility that TMPZ may have a future therapeutic role in gastric cancer.

Preparation and evaluation of solid dispersions of a new antitumor compound based on early-stage preparation discovery concept

Ensuring sufficient drug solubility is a crucial problem in pharmaceutical-related research. For water-insoluble drugs, various formulation approaches are employed to enhance the solubility and bioavailability of lead compounds. The goal of this study was to enhance the dissolution and absorption of a new antitumor lead compound, T-OA. Early-stage preparation discovery concept was employed in this study. Based on this concept, a solid dispersion system was chosen as the method of improving drug solubility and bioavailability. Solid dispersions of T-OA in polyvinylpyrrolidone (PVP) K30 were prepared by the solvent evaporation method. Dissolution testing determined that the ideal drug-to-PVP ratio was 1:5. X-ray diffraction, Fourier transform infrared spectroscopy, and differential scanning calorimetry were employed to confirm the formation of solid dispersions. Scanning electron microscopy demonstrated that T-OA was converted into an amorphous form. Both in vitro dissolution testing and the in vivo studies demonstrated that the solubility and bioavailability of T-OA were significantly improved when formulated in a solid dispersion with PVP. The dissolution rate of the T-OA/PVP solid dispersion was greatly enhanced relative to the pure drug, and the relative bioavailability of T-OA solid dispersions was found to be 392.0%, which is 4-fold higher than the pure drug.