Bioisosterism is one of the most common strategies in drug structure optimization. With the development of medicinal and organic chemistry, more and more classic and non-classical bioisosteres are used in the design of novel drugs. In recent years, fluorinated groups as a bioisostere have been paid more and more attention by pharmaceutical chemists. This paper briefly reviews the physicochemical properties, chemical preparation methods of difluoromethyl (CF₂H) group, and its application in drug design to provide references for drug discovery researchers.

Zanthoxyli Radix is a traditional Chinese medicine. It can be used for the treatment of wind-colddampness arthralgia, muscle and bone pain, fall fracture, hernia, sore throat, toothache and other diseases. Due to possessing many excellent and mild pharmacological properties, there are lots of reports about Zanthoxyli Radix worldwide. At present, more than 100 bioactive components have been extracted and purified from Zanthoxyli Radix. Nitidine chloride (NC), one of the most important alkaloids in Zanthoxyli Radix, has the activities of antitumor, anti-inflammation, anti-bacteria, etc. In this review, we summarize the chemical components of Zanthoxyli Radix, pharmacological activity and mechanism of action of NC to provide references for further research and utilization of Zanthoxyli Radix.

This paper reviews modern science and technology with regard to traditional Chinese medicine (TCM) research methods, quality control, and discusses the establishment and improvement of the evaluation system for TCM, focusing on the following issues: 1) How to incorporate the efficacy of TCM in the overall evaluation of TCM quality; 2) how to quantify the efficacy and properties of TCM; 3) how to understand the correlation between the efficacy and properties of TCM and its application; 4) how to reflect the specificity of the effective components in the overall evaluation of TCM quality; and 5) how to reflect the quality value transfer of effective components in the whole process of production and metabolism in vivo to the overall evaluation of TCM quality. The overall quality evaluation of TCM needs to better reflect its clinically safety and effectiveness. It is suggested to establish a clinical quality assessment method based on the content of the chemical components of TCM to explore and establish an overall evaluation method of TCM quality that reflects the efficacy of TCM and conforms with clinical practice.

UDP glucosyltransferase (UDPGT) catalyzes the synthesis of secondary metabolites and plant hormones to regulate plant growth and development, pathogen defense and environmental adaptability. In this study 18 members of the RcUDPGT gene family were cloned from Tibetan Rhodiola crenulata and analyzed using bioinformatics. The tissue-specific expression, abiotic stresses and plant hormones (abscisic acid, auxin, methyl jasmonate) induced expression patterns were identified by real-time quantitative PCR. The bait vector of RcUDPGT (JX228125.1) was constructed to select interacting proteins from an Arabidopsis yeast library. The results of the bioinformatics analysis revealed that RcUDPGT nucleotide sequences were about 1 400 bp and encoded 452-498 amino acids. In the primary protein sequences, C-terminal sequences were more conserved compared with N-terminal regions, which held a PSPG (plant secondary product glycosyltransferase) domain. In the tertiary structures, RcUDPGTs contained a UDP sugar donor recognition binding site. In addition, all genes had multiple phosphorylation sites. The results of qRT-PCR showed that RcUDPGTs genes were expressed in root, stem and leaf. The expression levels were regulated by low temperature/ultraviolet light and various plant hormones (ABA, IAA, MeJA), but the expression patterns were quite different among them. For example, RcUDPGT6, RcUDPGT11, and RcUDPGT17 had the highest expression in leaves and were induced by all three hormones, suggesting that the functions of these genes might be to respond to environmental changes. RcUDPGT9, RcUDPGT10, RcUDPGT14 were most abundantly expressed in roots and were significantly induced by ABA and MeJA hormones, indicating that these genes may be involved in the synthesis and accumulation of salidroside. Yeast two-hybrid results showed that RcUDPGT did not exhibit autoactivation and cell toxicity, and two significant interactional genes were identified, AtKCR1 (AT1G67730.1) and AtSNL4 (AT1G70060). The AtKCR1 gene encodes a β-ketoacyl reductase (KCR) involved in synthesis of very long chain fatty acids. The AtSNL4 gene encodes a homolog of the transcriptional repressor SIN3, which could participate in the ABA hormone signaling pathway and enhance the transcriptional repression of AP2/EREBP class factors in Arabidopsis. These results suggest that the accumulation of the secondary metabolite salidroside in Rhodiola crenulata might be affected by several regulatory mechanisms. The above results may lay the foundation for understanding the adaptive mechanism of Rhodiola crenulata in a high altitude environment and stimulate an in-depth study of the synthesis and accumulation of secondary metabolites in this species.

Gentiana crassicaulis Duthie ex Burk. in Gentiana (Sect. Cruciata), Gentianaceae, is one of the original plants of both Gentianae Macrophyllae Radix and Tibetan herb Jie-Ji Na-Bao, which contain such bioactive iridoids as gentiopicroside, loganic acid and others. In this study, based on previous work, the transcriptome of G. crassicaulis was sequenced and analyzed to construct transcriptome databases of roots, stems, leaves and flowers. qRT-PCR verification was conducted for parts of unigenes that may be key enzymes in the pathway of iridoid biosynthesis. The results are as follows: ① a total of 159 534 unigenes were obtained, with an average length of 679 bp. According to the functional classification of GO, unigenes can be divided into 3 categories with 67 branches. The unigenes were aligned in the KOG database and were classified into 25 categories according to function. ② In the KEGG database, 215 unigenes were implicated in 20 standard secondary metabolism pathways. The analysis shows that 305 unigenes encoded 28 key enzymes in the pathway of iridoid biosynthesis, and their expression in different organs is different; and ③ qRT-PCR was approximately consistent with RNA-Seq results. The 7 annotated unigenes identified in this study, HMGS, DXS, MCS, GPPS, G10H, 7-DLNGT and STR, all had higher relative expression levels in the above-ground parts (stem, leaf and flower) than in the underground part (root). Iridoids are common active and index components of such traditional Chinese medicines as Qinjiao, Longdan, Dangyao, and Qingyedan, among others. Therefore, this work provides basic scientific data for further development including obtaining active components or intermediates through biotechnology, exploring the accumulation of effective components, evaluating the quality of different ecotype varieties, and identifying authentic biosynthesis pathways of medicinal materials.

This research explored the synergistic effects and the potential mechanisms of RCE-4 and various nonsteroidal anti-inflammatory drugs (NSAIDs) on the proliferation of cervical cancer Ca Ski cells. The MTT assay and CalcuSyn V2.0 software were used to detect cell proliferation and calculate the combination index (CI); the expression levels of various proteins were analyzed using Western blot assay; mitochondrial membrane potential (MMP) was assessed using JC-1 staining; acridine orange/ethidium bromide (AO/EB) double-fluorescence staining was used to detect the apoptosis of Ca Ski cells; a co-immunoprecipitation (Co-IP) assay was used to analyze the relative content of Bcl-2-Beclin 1 complex in Ca Ski cells. The results demonstrate that the combination of RCE-4 and NSAIDs increases the inhibition of Ca Ski cells compared to the single-RCE-4 group, and celecoxib provided the best synergistic effect among the four NSAIDs tested, with a CI of 0.32. The combination of RCE-4 and celecoxib significantly down-regulated the expression of cyclooxygenase-2 (COX-2) and nuclear transcription factor-κB (NF-κB), and promoted the expression of non-steroidal anti-inflammatory drugs activity gene-1 (NAG-1). In addition, autophagy induced by RCE-4 was markedly inhibited in combination with celecoxib, which was associated with down-regulation of the expression of microtubule-associated protein 3 (LC3)-Ⅱ, Beclin 1, p62 and autophagy-related gene (ATG) 3/4B/5/7/14. RCE-4-induced apoptosis was significantly enhanced by altering the depolarization of mitochondrial membrane potential and the expression of B cell lymphoma-2 (Bcl-2), B cell lymphoma-xl (Bcl-xl), Bcl-2 associated X protein (Bax), Bcl-2/Bcl-xl-associated death promoter (Bad) and cleaved cysteinyl aspartate specific proteinase (cleaved-caspase) 3/7/9. Furthermore, the formation of the Bcl-2-Beclin 1 complex was significantly inhibited in Ca Ski cells treated with RCE-4 in combination with celecoxib. Taken together, this research shows that the combination of RCE-4 and celecoxib has a significant synergistic effect on the proliferation of Ca Ski cells by promoting apoptosis, inhibiting autophagy and disturbing the formation of the Bcl-2-Beclin 1 complex, which may be a novel strategy to increase the sensitivity of anti-cervical cancer drugs.

1-Deoxy-D-xylulose-5-phosphate synthase (DXS) is a rate-limiting enzyme involved in the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway for terpenoid precursor biosynthesis. DXS plays an essential role in glycyrrhizic acid (GA) biosynthesis. Based on our previous transcriptome study, there was a negative correlation between DXS expression and GA content. Therefore, we explored the regulatory role of DXS in GA biosynthesis using both gene overexpression and gene knockout in a hairy root culture system. DXS was cloned from Glycyrrhiza glabra L. (GenBank Accession No. MN158121). A plant binary expression vector pCA-DXS was constructed by a gene fusion method. The sgRNA sequence was designed based on the first exon of DXS to construct the gene editing vector pHSE-DXS. Hairy roots overexpressing or knocking out DXS were generated through an Agrobacterium-mediated method with licorice hypocotyls as explants. Wild-type hairy roots and negative control hairy roots containing empty plasmids were also evaluated. UPLC was used to determine the GA content in each licorice hairy root line. Results showed that the content of GA in the hairy root group knocking out DXS was significantly higher than that in the wild-type and negative control groups, while in the hairy root group overexpressing DXS was significantly lower, suggesting that DXS plays a negative role in GA biosynthesis. This study provides a foundation for determining the function of DXS in terpenoid metabolism and for further establishment of a molecular regulatory network of GA biosynthesis.

As a key signal transduction molecule involved in the innate immune response, stimulator of interferon genes (STING) is triggered by cytosolic DNA from pathogen and host origins, and plays an important role in inducing the secretion of type Ⅰ interferons and proinflammatory cytokines, thereby defending against viral and intracellular bacterial infections and regulating the production of spontaneous antitumor immune responses in vivo. Thus, STING agonists have shown useful therapeutic effects for pathogen infection and cancer. In the past decade research on STING and its agonists has progressed rapidly. Here, we summarize recent advances in the structure and activation of STING and the mechanism of the cGAS-STING pathway. In particular, we review research advances of STING agonists, analyze the crystal structure of STING in complex with its agonists and the structure-activity relationship of STING agonists, and summarize the strong challenges of developing STING agonists.

In this paper, the effects of the blend of nanoparticles and microneedle matrix materials on the mechanical properties of dissolving microneedles were studied mainly, so as to construct microneedles with excellent mechanical properties. Different kinds of nanoparticles (calcium carbonate, hydroxyapatite, silica), particle sizes (20, 60, 100 nm) and the proportion of prescription (2%, 6%, 10%) were blended with the matrix material[polyvinyl pyrrolidone (PVP), poly(1-vinylpyrrolidone-co-vinyl acetate)(PVP/VA)] to form dissolving microneedles. The effects of nanoparticles on the elastic modulus and hardness of the microneedles were investigated using a nanoindenter. The results showed that the elastic modulus and hardness of PVP microneedles were significantly improved by nano-calcium carbonate (P < 0.001), and the elastic modulus and hardness of PVP/VA microneedles were significantly improved by nano-hydroxyapatite (P < 0.001). When the particle size of hydroxyapatite was 20 nm, the elastic modulus of PVP/VA microneedles was (10.6±1.0) GPa, and the hardness was (0.47±0.06) GPa. As the size of the nanoparticles increases, the mechanical performance of the microneedles decreases. When the mass proportion of nano-hydroxyapatite increased from 2% to 6%, the elastic modulus and hardness of the microneedles were significantly improved (P < 0.001), but the effect of continue increasing the proportion of nanoparticles on the microneedles was not significant. The nano-enhanced PVP/VA dissolving microneedles has no irritant effect on intact skin and has a slight irritation to damaged skin, but they disappear completely after 72 h. Animal experiments have been approved by the Laboratory Animal Welfare and Ethics Committee of Zhejiang University of Technology. Therefore, the nano-enhanced dissolving microneedles has good biological safety. To sum up, it is necessary to select the appropriate kind of nanoparticle, particle size, and prescription ratio when microneedles constructing with a given matrix material, so as to effectively improve its mechanical performance.

Gemcitabine (GEM) is a commonly used drug in the clinical treatment of non-small cell lung cancer. Due to the accumulation of cells mediating immune escape and T cell depletion after chemotherapy, tumor microenvironment (TME) tends to be immunosuppressive status, which ultimately leads to tumor metastasis. The experimental protocol was approved by the Medical Laboratory Animal Ethics Committee of Jiangsu Provincial Academy of Chinese Medicine. Therefore, we observed the immunomodulatory effects of micro-particulate Ganoderma lucidum spore β-glucan (PGSG) on macrophages in vitro experiments. Next, mice subcutaneous Lewis lung cancer models were established to observe the anti-tumor effects of PGSG through oral administration of PGSG combined with GEM. Flow cytometry analysis was used to analyze the ratio of anti-tumor T cells in tumors and spleen, as well as the proportion of myeloid-derived suppressor cells (MDSC), tumor-associated macrophages (TAM) and regulatory cells (Tregs). The results showed that PGSG can up-regulate the expression of major histocompatibility antigens (MHC-Ⅱ), CD40, CD86 and CD80 on the surface of macrophages, enhance the ability to phagocytosis of neutral red and further mediate the release of interleukin-6 (IL-6), tumor necrosis factor-α(TNF-α), interleukin-4 (IL-4) and interleukin-10 (IL-10). In vivo experiments, combined administration can significantly decrease the volume and weight of tumors, reduce the ratio of MDSC (CD11b⁺Gr-1⁺), M-MDSC (CD11b⁺Ly6G^-Ly6C^high) and Treg (CD4⁺Foxp3⁺). At the same time, PGSG promoted the conversion of M₂ (F4/80⁺CD206⁺) to M1 (F4/80⁺MHC-Ⅱ⁺) and enhanced the response of helper T cell-1 (Th1) (CD4⁺IFN-γ⁺) and cytotoxic T lymphocyte (CTL) (CD8⁺IFN-γ⁺), which is of great significance for killing tumors. These results suggest that PGSG can regulate innate and adaptive antitumor immune responses, reshape the immunosuppressive microenvironment and enhance the anti-lung cancer effect of GEM.