New candidate targets, biological mechanisms as well as small-molecules are significant factors in the research and development of first-in-class drugs, which is a challenging process with a large amount of time and money devoted as well as high risks. A successful first-in-class drug can not only become a new strategy for disease treatment but can also offer innovative research ideas for the design of drugs. The Food and Drug Administration (FDA) approved 48 new drugs to the market in 2019, among which small-molecule drugs still predominated, containing several first-in-class drugs. Brexanolone, for example, is the first positive modulator of GABA_A receptor for the treatment of postpartum depression; Selinexor is the first small-molecule drug to treat recurrent refractory multiple myeloma by inhibiting exportin (XPO1); Tenapanor is the first sodium/proton exchanger type 3 (NHE3) inhibitor that can treat irritable bowel syndrome; Lasmiditan is the first approved agonist with selectivity for 5-HT_1F, treating migraines. The research and development processes of the first-in-class drugs mentioned above are distinctive from each other with uniqueness and innovation. In this review, we briefly analyze the background and process of the research and development of three typical cases as well as their therapeutic applications in an attempt to offer some help for the future development of first-in-class drugs.

Angiogenesis is the formation of new capillaries from pre-existing vasculature, which plays a critical role in several diseases. Under the normal physiological conditions, only about 0.5% of endothelial cells (ECs) undergo mitosis, while the most ECs are in a resting state. Angiogenesis is a dynamic process in which ECs shift from resting to activated state, including three basic steps:① excessive vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF), platelet-derived endothelial growth factor (PDGF) and other pro-angiogenic factors secreted by ECs can promote the germination of ECs in the original blood vessels; ② the sprouts are continuously elongated through the proliferation of ECs and the degradation and migration of basement membrane. At this time, the ECs present two phenotypes with filamentous feet and strong proliferation ability; ③ the buds are continuously elongated to form a tubular structure and connect with adjacent blood vessels, and the junction is wrapped by wall cells and basement membrane to form new blood vessels. Nowadays, angiogenesis has become a target for clinical treatment of multifarious diseases. On one hand, anti-angiogenesis is used to treat various diseases with excessive angiogenesis, such as cancer, atherosclerosis, and diabetic retinopathy, etc. On the other hand, the diseases caused by insufficient angiogenesis, including myocardial infarction, myocardial ischemia/reperfusion injury, stroke, wound long-term healing and other ischemic diseases can be improved by pro-angiogenesis therapy. Large numbers of researches have shown that many active ingredients of traditional Chinese medicine can effectively treat the previously mentioned diseases by regulating angiogenesis in different ways. Therefore, the anti-and pro-angiogenesis effects of some active ingredients derived from traditional Chinese medicine and their mechanism were summarized in this manuscript, arming to provide theoretical basis for the development of new drugs for the treatment of angiogenesis-related diseases.

Gut microbiota dysbiosis is closely related to a variety of host diseases. Recently, targeting the metabolic pathways of gut microbiota for the prevention and treatment of host diseases has become a frontier strategy and research hotspot. Inflammatory bowel disease (IBD) is a group of chronic progressive intestinal inflammatory diseases of unknown etiology. The relationship between IBD and gut microbiota disorders and bacterial respiratory/energy metabolism has been confirmed in recent research. This article will introduce the relationship among them, and propose a new treatment strategy to alleviate host gut inflammation by regulating gut microbiota respiration and energy metabolism based on the latest research progress. In the progression of IBD, the gut microbiota homeostasis is disturbed. The main reasons include two aspects:on the one hand, when the intestinal inflammation of the host occurs, with increasing of oxygen concentration in the intestinal cavity, facultative anaerobic bacteria, especially Enterobacteriaceae bacteria would proliferate abnormally; while the growth of absolute anaerobic bacteria such as Firmicutes is inhibited. On the other hand, intestinal inflammation by-products also support the expansion of facultative anaerobic bacteria, which ultimately exacerbates the imbalance of gut microbiota. Dysregulated intestinal flora will further disturb intestinal immune homeostasis and exacerbate intestinal inflammation. The latest research proposed the possibility that IBD can be alleviated by interfering with the respiration of bacteria, inhibiting the abnormal proliferation of bacteria, or increasing the level of "beneficial" metabolites of gut microbiota. The above studies suggest that alleviating host intestinal inflammation can be explored by focusing on the metabolic pathways of gut microbiota and regulating the intestinal bacterial respiration and energy metabolism, which is of great significance for the clinical treatment of IBD and the research of innovative drugs.

Snake bite is a common acute and severe disease in tropical and subtropical regions, and its public health importance has been largely neglected. Snake venom is a complex mixture of active proteins, polypeptides, and other toxins. Many of these components can target multiple ion channels, cell receptors, and membrane transporters. Compared with traditional small molecule drugs, the proteins and polypeptides from snake venom have stronger specificity and affinity to targets and are especially suitable for novel drug design. The current studies show that snake venom and its components have great potential for development as leading compounds of new drugs. In this paper, the recent advances in main components, toxic effects, and detoxification strategies of snake venom, as well as its pharmacological activities and medical application are reviewed. The aim is to provide reference for clinical diagnosis and treatment of snake bite and development of new drugs based on snake venom.

Rheumatoid arthritis (RA) is an autoimmune disease characterized by synovial inflammation and cartilage destruction. An imbalance in macrophage polarization is closely related to the occurrence and development of RA, including a central role for M1 macrophages in promoting inflammation and bone destruction in the cytokine network environment of RA. It is a remarkable fact that the abnormal immune-microenvironment in RA patients promotes the metabolic reprogramming of macrophages, which disrupts the dynamic balance of M1/M2 by regulating the polarization of macrophages, leading to a persistent tissue inflammation. Using drugs to inhibit M1 macrophage polarization or induce M2 macrophage polarization is expected to be an ideal strategy for drug development for RA treatment. This review summarizes the effects of metabolic reprogramming of macrophages on polarization phenotype and the metabolism-related signaling pathways in the RA microenvironment, and provides references for the development of RA drugs that can target macrophage metabolism.

In scientific research, it is often needed to knock in, knock out, knock down, or overexpress a specific gene in model organisms or specific types of cells to achieve precise regulation of experimental independent variables. In this case, various transgenic mice are required. The cyclization recombinase (Cre) can directly interact with different loxP (locus X over P1) DNA sequences without any cofactors to perform specific gene knock-in or knock-out at specific targets. Because of its advantages of simple action principles, high spatial specificity, and high reorganization efficiency, the Cre-loxP system is widely used in scientific research. Furthermore, the CreERT2 system (mutant of the fusion protein of Cre and estrogen receptor ligand binding domain) and the tetracycline (Tet)-on/off system, derived from the Cre-loxP system, have made the recombination of the target gene occur in temporal-specificity on the basis of spatial-specificity. This dual specificity of time and space is indispensable for research in specific directions such as fear memory and engram cells on the basis of reducing the impacts on experimental animals. Therefore, these derived systems have broad application prospects.

Cisplatin is one of the most commonly used chemotherapeutic drugs in clinic and has good therapeutic effect on various cancers, but the development of drug resistance limits its clinical treatment. The development of cisplatin resistance is caused by many factors, including the decrease of intracellular cisplatin accumulation, the inactivation of cisplatin by mercaptan proteins, the increase of DNA damage repair, apoptosis inhibition, tumor microenvironment and cancer stem cells. In recent years, traditional Chinese medicine (TCM) has been favored for its remarkable effect of reversing cisplatin resistance. This review will explore the mechanisms of cisplatin resistance and the combined modality treatment strategy of TCM to reverse cisplatin resistance, hoping to provide reference for clinical and scientific research.

Breast cancer is the most common malignant tumor in women worldwide. In breast cancer tumor tissues, a variety of targets related to the occurrence and development of breast cancer have been observed, and many drugs have been used in clinical applications for these targets. However, most of these drugs are small molecule inhibitors. With the long-term use of these drugs, acquired drug resistance often occurs in breast cancer patients. To overcome the drug resistance, the development of more efficient drugs is highly desirable in the treatment of breast cancer. Proteolysis targeting chimera (PROTAC) technology is a new kind of targeted protein degradation technology, which has shown broad prospect of applications in the field of drug development. The use of PROTAC technology to target the degradation of relevant targets in breast cancer has become a feasible strategy for breast cancer treatment.

In recent years the role of sphingosine kinase 2 (SphK2), a key enzyme in the sphingolipid pathway, in the process of tumorigenesis has gradually been elucidated. Recent research has shown that SphK2 inhibitors can be used as anticancer drugs alone or in combination with existing drugs to increase the therapeutic sensitivity of drug-resistant tumors. Among them, one selective SphK2 inhibitor, ABC294640, shows excellent oral bioavailability and biodistribution in vivo and has now entered Phase Ⅱ clinical research. Therefore, developing innovative drugs based on SphK2 is of great interest. Herein, we discuss progress in understanding the role of SphK2 in tumorigenesis and review the recent development of inhibitors of SphK2.

Ursodeoxycholic acid (UDCA) is an essential drug for the treatment of cholestatic liver diseases. As the most important representative of endogenous drugs, the metabolism and disposition of UDCA in human is characterized by both host-gut microbial co-metabolism and hepato-billilary-intestinal circulation. These distinct metabolic and pharmacokinetic features have brought great challenges into the bioequivalence (BE) evaluation of UDCA generic formulations. These challenges include not only biopharmaceutical problems derived from the unique physiochemical properties of amphiphilic molecules and the large single dose, but also the drug metabolism and pharmacokinetic problems associated with endogenous metabolism, long terminal half-life, high inter-and intra-individual variations, as well as accurate determination of UDCA and its metabolites. This review summarized academic and industrial literatures about the clinical pharmacokinetics and endogenous metabolism of UDCA. Current guidelines and technical challenges of UDCA BE studies were extensively discussed. Knowledge summarized in this review is expected to provide valuable reference for the development of UDCA generic formulations.

In order to achieve rapid proliferation and adapt to the complex microenvironment, tumor cells have dominant characteristics such as unique metabolic patterns and the ability to escape from immunoregulation. Tumor cells reprogram multiple metabolic pathways to promote immune escape, which impacts tumor diagnosis, treatment and prognosis. Based on the effect of metabolic changes on tumor immune escape and its molecular mechanism, metabolic regulation provides new approaches to enhance immunotherapy. We review recent advances in tumor immuno-escape and immunotherapy based on metabolic regulation. Cutting-edge analytical techniques and methods for tumor metabolism research such as metabolomics, mass spectrometry imaging-based spatially-resolved metabolomics and metabolic flow analysis are also discussed.

In recent years therapeutic proteins products including therapeutic antibodies have become a major driving force for the modern biopharmaceutical industry. However, they have complex product quality attributes (PQAs) which limit product development and quality control (QC). Recent advances in high resolution mass spectrometry (MS) have led to the use of an MS-based multi-attribute method (MAM) for quality control testing of therapeutic proteins, which allows for direct measurement of multiple PQAs and identification of impurities. MAM helps to promote the improvement of product quality and QC and a reduction in manufacturing cost. To explore the application of MAM in QC, we discuss generic MAM workflow, the current state of MAM application in product development and QC, identify points to consider for use of MAM as a QC test, and summarize MAM's advantages and challenges in this article. The future application of MAM for therapeutic antibodies and the opportunities for its further development, use, and substitution for conventional methods is presented.

Ferroptosis is a cell death path for the abnormal accumulation of iron dependent reactive oxygen species, which leads to the dysregulation of redox homeostasis. As a new type of cancer treatments, ferroptosis has attracted extensive attention of researchers. With the development of nanoscience, various functional nanomaterials can produce H₂O₂, exhaust glutathione, and gather Fenton reaction catalysts in tumor site. Therefore, these nanomaterials can play a stronger role in tumor inhibition in coordination with the ferroptosis-inducing agents. Firstly, this paper introduced the mechanism of ferroptosis and the feasibility of ferroptosis-inducing strategy in cancer therapy. Secondly, we summarized the construction strategies of the ferroptosis-inducing nanomedicines for cancer therapy, including accelerating intracellular Fenton reaction, inhibiting the activity of glutathione peroxidase 4, and increasing the exogenous delivery of lipid peroxides. In addition, we also discussed the combination therapy based on ferroptosis, including the combination of ferroptosis with traditional therapy strategies (combined with apoptosis-inducing drugs, immunotherapy and gene therapy) and external energy (including ultrasound therapy and photodynamic therapy). Finally, the expectations and challenges of ferroptosis-inducing nanomedicines for cancer therapy in the future were discussed.

Tanshinones and salvianolic acids are important materials in the treatment of coronary heart disease, myocardial infarction, hypertension, hyperlipidemia, stroke and others illnesses. In recent years, with the development of genomics, transcriptome, metabolomics and bioinformatics, many advances have been made in the biosynthesis and transcriptional regulation of tanshinones and salvianolic acids. This paper summarizes these advances and suggests further study on the downstream synthesis pathways and transcriptional regulatory mechanisms to reveal new molecular mechanism of synthesis, transport, regulation and modification. Additionally, we discuss the design and construction of new biological pathways to increase the expression of biosynthesis genes and the production of secondary components, is a newly developing research field.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the pathogen that caused the global COVID-19 outbreak. The 3C-like protease (3CL^pro) of SARS-CoV-2 plays a key role in virus replication and has become an ideal target for antiviral drug design. In this paper, we report the validation and use of bioluminescence resonance energy transfer (BRET) technology to establish a cell-based assay for screening for SARS-CoV-2 virus 3CL protease inhibitors. The results show that the method is able to monitor the cleavage efficiency of 3CL protease with good reproducibility (Z' factor is 0.59), and is consistent with antiviral activity analysis in cell culture. This work demonstrates that this method can be applied to the screening and evaluation of 3CL protease inhibitors, providing a powerful tool for the development of new drugs.

This study was designed to investigate the effect of dihydromyricetin (DHM) on inducing apoptosis of ovarian cancer cells A2780 through endoplasmic reticulum stress (ERS) pathway and the mechanisms involved in vitro and in vivo. A2780 cells were treated with different concentrations of DHM, and the protein expression levels of glucose-regulated protein 78 (GRP78) which is related to ERS increased, apoptotic proteins C/EBP-homologous protein (CHOP), and cysteinyl aspartate specific proteinase-12 (caspase-12) elevated. After pretreatment with ERS inhibitor, 4-phenyl butyric acid (4-PBA), following the intervention with DHM, the A2780 cell viability decreased and apoptotic rate increased. All animal welfare and experimental procedures were approved by the Animal Ethics Committee of Chongqing Medical University. Intraperitoneal injection of DHM suspension into nude mice with ovarian cancer could significantly inhibit the growth of transplanted tumor in vivo, increase the protein expression levels of GRP78, CHOP, and caspase-3. Moreover, swollen and broken endoplasmic reticulum could be observed in tumor tissues, suggesting that DHM intervention induces apoptosis mediated by ERS. The results indicated that DHM could induce apoptosis of ovarian cancer cells and inhibit the growth of transplanted tumors in nude mice, which might be related to the activation of ERS pathway.

The pharmacodynamic material basis and mechanisms of Ju-Hong Tan-Ke liquid (JHTKL) for its anti-tussive, anti-asthmatic and expectorant effects were investigated by using network pharmacology. We collected, screened, and predicted potential targets and signaling pathways for 24 compounds in the 8 herbs of JHTKL and grouped them according to their efficacy. Combined with the evidence analysis in the literature database, we explored molecular mechanisms of the components of this formula in different diseases and analyzed their compatibility laws. To verify the network analysis results, we used software to perform molecular docking of a part of the pivotal targets with their corresponding compounds. The results show that the main active ingredients in JHTKL may be naringin, L-ephedrine, glaucogenin C, amygdalin, deoxyschizandrin, neotuberostemonine, pachymic acid and glycyrrhizic acid. Moreover, efficacy groups of JHTKL may play a role by acting on pivotal gene targets such as the muscarinic acetylcholine receptor M1, acetylcholinesterase, beta-2 adrenergic receptor, prostaglandin G/H synthase 2, tumor necrosis factor, epidermal growth factor receptor and biological pathways such as the neuroactive ligand-receptor interaction, cholinergic synapses, calcium signaling pathway, NF-kappa B signaling pathway, MAPK signaling pathway, and PI3K-Akt signaling pathway. In this study, we have confirmed the pharmacodynamic material basis and mechanisms of JHTKL by using network pharmacology, laying a foundation for improving the quality standards of JHTKL and providing a reference basis for its potential expansion in clinical applications.

Glucagon-like peptide-1 (GLP-1) could increase the level of cyclic adenosine monophosphate (cAMP) in cells to stimulate insulin secretion in β cells of pancreas. So GLP-1 analogues, such as liraglutide, have become new anti-hyperglycemia drugs for type 2 diabetes. In this study, a set of in vitro activity detection method suitable for GLP-1 analogues was established using GLP-1R-GFP (green fluorescent protein, GFP)-HEK293A cells which stably expressing GLP-1 receptor (GLP-1R). After optimizing the detection parameters such as assay sensitivity, cell density, and the incubation condition, the cAMP content level of GLP-1R-GFP-HEK293A cells stimulated by four GLP-1 analogues, such as liraglutide, were detected by homogeneous time-resolved fluorescence (HTRF). The values of concentration for 50% of maximal effect (EC₅₀) of GLP-1 analogues were calculated by cAMP dose-response curve to evaluate the in vitro activity of those drugs. In addition, enzyme-linked immunosorbent assay and quantitative polymerase chain reaction were applied to determine the content of host cell protein and host residual DNA, respectively. This study provides a stable, reliable, and sensitive in vitro activity analysis and host impurity detection method for high-throughput screening of GLP-1 analogues.

This research explored the synergistic effects and the mechanism of parthenolide (PTL) and vorinostat (suberoylanilide hydroxamic acid, SAHA) on the proliferation of A549 non-small cell lung cancer cells. The combination effect of PTL and SAHA was detected by cell counting kit-8 (CCK-8) and colony formation assays. Scratch test was performed to detect cell migration. Annexin V-fluorescein isothiocyanate isomer/propidium iodide (FITC/PI) flow cytometry and Western blot analyses were used to determine cell apoptosis and its mechanism. The results showed that combination of PTL and SAHA inhibited the proliferation and migration of A549 with a synergistic effect compared to the single-drug groups. The combination of PTL and SAHA had synergistic effect to induce cell apoptosis by regulating p53 and c-myc pathways, and affected the expression levels of poly ADP-ribose polymerase (PARP), cysteinyl aspartate specific proteinase (caspase)-9, and caspase-3. Taken together, this study shows that combination of PTL and SAHA has synergistic effect, induces cell apoptosis and inhibits A549 proliferation, which is likely to be a novel strategy for the treatment of non-small cell lung cancer.

Eighteen dihydroartemisinin-fluoroquinolone molecules conjugated with L-homoserine were designed and synthesized using fragmented drug splicing approaches. The in vitro activities of the synthesized conjugates against Mycobacterium tuberculosis (MTB) and the lipid-lowering target PCSK9 were evaluated. The bioassay test results showed that most of the synthesized molecules had anti-tuberculosis (anti-TB) activity. Five compounds showed greater than 80% inhibitory activity against MTB in the replication state and three compounds exhibited more than 50% inhibitory activity against H₃₇Rv in the non-replication state. A structure-activity relationship analysis demonstrated that TM2 series compounds (Boc protection) have better anti-TB activity than TM1 series compounds (Cbz protection). There were 13 compounds with strong inhibitory activity toward PCSK9 (>73%) and TM1-3 compounds reached 92%. The determination of physical parameters showed that all the molecules are largely nontoxic. The structure-toxicity relationship analysis showed that the safety of TM2 is higher than that of TM1 in all parameters, perhaps related to the protecting group of the amino acid in the target molecule, and provides new ideas for the design and structural modification of subsequent molecules. This study sets a precedent for L-homoserine as a linking structural unit in multi-target drug molecules.

To identify an effective structural modification strategy for improving the antitumor activity of fluoroquinolones, sixteen new 1-cyclopropyl-6-fluoro-7-(4-methyl-piperazin-1-yl)-3-arylidene-2, 3-dihydroquinolin-4(1H)-ones compounds (4a-4p), were designed and synthesized by a condensation reaction of dihydroquinolin-4-one (3) and aromatic aldehydes, based on the structure of ciprofloxacin (1). Their structures were characterized by elemental analysis and spectral data, and anti-cell proliferative activities against Hep-3B, Capan-1 and HL60 cell lines were measured by an MTT assay. Preliminary pharmacological results indicated that the synthesized target compounds had greater potency than ciprofloxacin (1). SAR revealed that the halophenyl compounds such as fluorophenyl (4h, 4i), chlorophenyl (4j, 4k) or bromophenyl compounds (4l, 4m) and aromatic heterocyclic compounds such as furanly (4n) or pyridyl compounds (4o, 4p) demonstrated better activity than the control compounds, and the IC₅₀ values of the chlorophenyl compounds 4j and 4k against Capan-1 cell growth were comparable to that of doxorubicin. Thus, a 3-arylidene as an isostere of the C-3 carboxylic acid group appears to be beneficial in improving the antitumor activity of fluoroquinolone. Furthermore, an α, β-unsaturated ketone fragment used as a potential bioisostere of C-3 carboxylic acid group may warrant further study.

The chemical structures of new components of Epimedium were deduced and verified by combining the secondary metabolism of Epimedium flavonoids with high resolution mass spectrometry. Based on the literature of Epimedium chemistry, the biosynthesis pathway of Yinyanghuo was constructed, and the possible metabolites were deduced. This metabolite information was entered into the PeakView software program and the ions meeting the quality error of less than 5 ppm with correct isotope distribution and containing secondary fragments were taken as the target compounds. Through the use of the software Formula Finder, Mass Calculators, online database (ChemSpider, Metlin, HMDB, etc.) and the fragmentation law of secondary fragments, the chemical structures of 22 metabolites were determined. One new component and eight new compounds were identified in 54 batches of Epimedium samples from 15 varieties by high resolution mass spectrometry. This study avoids the long time and tedious steps of phytochemical separation, saves experimental costs, and provides a new method for the analysis and identification of secondary metabolites with pharmacodynamic activity.

Metabonomics techniques were used to investigate the mechanism and metabolic pathways of total extract of Amygdalus mongolicus against renal fibrosis in rats. Rats were randomly divided into a model group (MOD), a sham surgery group (SDG), a benazepril hydrochloride-treated group (BHT) and three groups treated with the total extract of Amygdalus mongolicus:low-dose group (TOT-L), middle-dose group (TOT-M) and high-dose group (TOT-H), with 10 rats in each group. The rats were given intragastric administration for 3 weeks and kidney and blood samples were taken. Pharmacodynamic studies and ultra performance liquid chromatography-quadrupole time of flight-mass spectrometry (UPLC-Q-TOF/MS) analysis were used to show that the total extract of Amygdalus mongolicus has an anti-fibrotic effect in rats. Compared with the MOD group, rats in the TOT-L, TOT-M and TOT-H groups showed a reversal in 67, 69, and 70 biomarkers, respectively, and shared 62 biomarkers. Reversal was observed for 7 key biomarkers related to renal fibrosis, including S-adenosy-L-methioninamine, ornithine, diketogulonic acid, and others, and changes in 5 metabolic pathways, including arginine and proline metabolism, pentose and glucuronate interconversions. These results give evidence of the metabolic pathways and the mechanism of action of Amygdalus mongolicus to prevent renal fibrosis in rats. The animal experiments were approved by the Medical Ethics Committee of Baotou Medical College (No. 20190314).

Drug metabolites in the systemic circulation can be closely related to the safety or efficacy of drugs, so it is necessary to evaluate the pharmacokinetics of both the parent drug and its major metabolites in plasma. Bisthianostat, a novel histone deacetylase (HDAC) inhibitor, is currently under development. An LC-MS/MS method was developed and validated for the simultaneous determination of bisthianostat and its hydrolyzed N-hydroxyamide metabolite M351 in human plasma to evaluate their pharmacokinetic characteristics in humans. After extraction from the plasma by acetonitrile-induced protein precipitation, the analytes and endogenous substances were separated on a Waters BEH C₁₈ column (2.1 mm×50 mm, 1.7 μm). The mobile phase consisted of acetonitrile and 5 mmol·L^-1 ammonium acetate (containing 0.2% formic acid, v/v) for gradient elution. Positive electrospray ionization was performed using multiple reaction monitoring (MRM) with transitions of m/z 367.1→235.0 for bisthianostat, m/z 352.1→207.0 for M351, m/z 371.1→235.0 for d₄-bisthianostat, and m/z 357.1→208.0 for d₅-M351. The method was linear over a concentration range of 2.00-2000 ng·mL^-1 for bisthianostat and 4.00-4 000 ng·mL^-1 for M351. The results of quality control samples showed that the intra-and inter-day precision were no more than 6.2% for bisthianostat and 6.8% for M351. The accuracy ranged from -1.1% to 4.3% for bisthianostat and -0.5% to 4.9% for M351. The pharmacokinetic results show that after a single oral administration of 100 mg bisthianostat, the time to peak (t_max) of M351 in the plasma of three patients with tumors was significantly longer than that of the parent drug (t_max was 4.00 h and 0.67 h, respectively), and the C_max and plasma exposure of M351 were about 1.7 times and 11 times higher, respectively, than that of the parent drug. This clinical trial was approved by the society of ethics and conducted in Renji Hospital, Shanghai Jiaotong University School of Medicine.

The treatment plan for chronic pain often proceeds from a single drug to drug combination therapy. Sinomenine and ligustrazine, natural alkaline substances derived from traditional Chinese medicines, are expected to provide a new choice for combination analgesic therapy strategies. Here we establish a microdialysis sampling and HPLC-MS/MS quantification method for sinomenine, ligustrazine, gabapentin, paracetamol, pregabalin and amitriptyline in rat blood and brain extracellular fluid. Blood and brain microdialysis probes were implanted in the jugular vein toward the right atrium and left corpus striatum zone (AP +0.2 mm, ML 3.0 mm, DV 3.5 mm) in rats. The blood and brain microdialysis probes were perfused with citric acid buffer solution and Ringer's solution, respectively. Blood and brain extracellular fluid microdialysate were collected at intervals of 20 min at a perfusion rate of 1.5 μL·min^-1, and continuously collected for 24 h after administration. The liquid chromatographic separation used a C18-reversed phase chromatographic column (HSS T3 2.5 μm, 2.1 mm×50 mm), the mobile phase was methanol/water (containing 0.05‰ formic acid), and gradient elution was carried out at a flow rate of 0.3 mL·min^-1. Mass spectrometric detection used an electrospray ion source, positive ion mode and multi-reaction monitoring method. The selected quantitative ions for sinomenine, ligustrazine, gabapentin, paracetamol, pregabalin, amitriptyline and internal standard naloxone were 330/181, 137/80, 172/154, 152/110, 160/142, 278/233 and 328/310 respectively. The specificity, linear range, matrix effect, accuracy, precision, stability and probe recovery were investigated and confirmed to be suitable for the determination of the above drugs in rat blood and brain extracellular fluid microdialysate. The calculated in vivo recovery of microdialysis probes ranged from 19.38% to 25.88%. After intravenous administration of sinomenine (50 mg·kg^-1), ligustrazine (50 mg·kg^-1), gabapentin (50 mg·kg^-1), paracetamol (50 mg·kg^-1), pregabalin (50 mg·kg^-1) and amitriptyline (40 mg·kg^-1) to rats, the peak concentration in the blood microdialysate was in the range of 0.2-10 μg·mL^-1. Drug concentrations could also be detected in brain extracellular fluid microdialysate, however with lower levels (peak concentration:0.1-6 μg·mL^-1) than those of blood microdialysates at each time point. In conclusion, this method can be applied to microdialysis sampling and quantification of sinomenine, ligustrazine, gabapentin, paracetamol, pregabalin and amitriptyline in rats. The method will promote research in identifying herb-drug pharmacokinetic interactions, as well as safety concerns in combination-therapy strategies.

Chalcone synthase (CHS) is the rate-limiting enzyme involved in the biosynthetic pathway of flavonoids in Glycyrrhiza uralensis. It plays an important role in the regulation and control of flavonoids biosynthesis. In this study, X-ray irradiated G. uralensis samples with high or low content of flavonoids were studied. The CHS gene polymorphism in these samples were analyzed, the specific haplotypes were identified, and CHS function was parsed. 109 CHS cDNA sequences with a length of 1 170 bp were cloned, 220 variable sites (116 missense mutation sites) were found and 85 haplotypes were identified, which encoded 65 amino acid sequences with 96 variable sites. aa-20 and aa-45 were the most common amino acid sequences in samples with high flavonoid content, while aa-11 was the most sequence in samples with low flavonoid content. Molecular docking results showed that the mutation sites at 383 in aa-20 and 229 in aa-45 were related to substrate binding, while the mutation sites at 383 and 229 in aa-11 were not involved. Therefore, we speculate that the two mutation sites have significant influence on the function of CHS. We analyzed a large number of CHS cDNA sequences and identified the important functional sites, which will provide a basis for further functional studies. This paper will provide ideas for further research of the molecular regulation of the flavonoid biosynthetic pathway in G. uralensis.

Glucose-6-phosphate dehydrogenase, a key enzyme in the pentose phosphate pathway, plays an important role in plant resistance. In this study, three full length cDNAs of G6PDH genes, namely AsG6PDH1, AsG6PDH2 and AsG6PDH3 were cloned from Aquilaria sinensis for the first time. The open reading frames (ORF) of AsG6PDH1, AsG6PDH2 and AsG6PDH3 were 1 809, 1 767 and 1 548 bp, respectively, encoding proteins of 602, 588 and 516 amino acid residues, respectively, with predicted molecular masses of 68.02, 67.02, 59.35 kDa, respectively. The three AsG6PDHs proteins shared high sequence identity with the G6PDH proteins of various plants, and possessed three conserved sequences found in G6PDH proteins. The phylogenic analysis showed that AsG6PDH1 and AsG6PDH2 were grouped in the plastidic cluster, while AsG6PDH3 was classified into the cytosolic cluster. Expression analysis indicated that AsG6PDH1 and AsG6PDH2 were primarily observed in root, while AsG6PDH3 was primarily observed in stem. The expression of AsG6PDH1, AsG6PDH2 and AsG6PDH3 was induced by salt, drought, low temperature and CdCl₂ treatments, while the content of AsG6PDH1 and AsG6PDH2 was most significantly increased by drought stress, and the transcript level of AsG6PDH3 was most significantly induced by metal stress. Furthermore, G6PDH activity was stimulated under salt, drought, low temperature and CdCl₂ treatments, and G6PDH activity was remarkably increased under drought stress. These results provide valuable insights into the role of AsG6PDHs in plant defense and the mechanism of agarwood formation.

The 2-oxoglutarate-dependent dioxygenase (2-ODD) gene is regarded as the key enzyme gene involved with aryl naphthalene lignan-podophyllotoxin synthesis. To study the expression pattern and function of the Sc2-ODD gene, a full-length cDNA of the gene was cloned. Bioinformatic analysis, the expression pattern, and prokaryotic expression and purification were implemented. The open reading frame of Sc2-ODD gene was 1 077 bp and encoded 358 amino acids with a molecular weight of 40.16 kD. The Sc2-ODD protein contained the conserved 2OG-FeII-oxy sequence of the 2-ODD protein. The results of phylogenetic analysis revealed that Sc2-ODD is most closely related to Corchorus olitorius 2-ODD. qRT-PCR results showed that Sc2-ODD expression displayed obvious up-regulation at the fruit-swelling stage, then down-regulation in the fruit-coloring period. The Sc2-ODD gene was cloned into the bacterial expression vector pGS21T, the recombinant Sc2-ODD protein was expressed in Escherichia coli Rosetta (DE3) cells and the fusion protein was obtained and purified by GST fusion protein purification technology. This study will lay a foundation for further research on the function and expressional regulation of the Sc2-ODD gene in the aryl naphthalene lignans biosynthesis pathway, and also provides a scientific basis for improving the lignan content and the medicinal quality of Schisandra chinensis using plant genetic engineering.