Drug-drug complexes play important roles in improving the physicochemical properties of drugs including the solubility, dissolution rate and stability of the active pharmaceutical ingredients (APIs). In this paper, the design, synthesis, characterization, changes in physicochemical and pharmacologic properties, structural polymorphisms and the research and development pipelines of a variety of drug-drug cocrystals/salts synthesized based on the crystal engineering design are reviewed. This may provide theoretical support for the development of the new solid-state combinational drugs.

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.

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.

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.

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.

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.

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.

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.

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.