A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to determine the plasma concentration of progesterone in Beagle dogs, and apply it to the study of the pharmacokinetics of progesterone sustained-release formulation in Beagle dogs. The plasma samples were processed by protein precipitation method and megestrol acetate was used as an internal standard (IS). The quantitation analysis was performed using multiple-reaction monitoring (MRM) mode at the specific ion transitions of m/z 315.2→97.0 for progesterone and m/z 385.2→267.1 for megestrol acetate (IS) under the positive ion condition. Male Beagle dogs were injected intramuscularly with progesterone sustained-release microspheres and the plasma samples were collected at different time points after administration. The relevant pharmacokinetic parameters were calculated by WinNonlin 8.1 software. A good linearity over the range of 0.1-500.0 ng·mL^-1 was yielded by this method. The intra- and inter-day precision (RSD) were all less than 13.25% and the accuracy (RE) was within 8.92%. Stability test showed that progesterone in dog plasma was stable at room temperature for 12 h, up to 60 days at -20 ℃ and after three cycles of freeze-thaw. The recovery of it ranged from 71.43%-77.97%. After intramuscular injection of progesterone sustained-release microspheres in Beagle dogs, t_max was 19.00 ± 25.36 h, C_max was 137.72 ± 11.59 ng·mL^-1, t_1/2 was 83.83 ± 26.43 h. The drug was released continuously in vivo and in a continuous absorption process for many times with good sustained-release effect. The method developed in this study is sensitive, rapid and stable. It is suitable for the determination of progesterone plasma concentration in Beagle dogs, and can be applied to the preclinical pharmacokinetic study of progesterone-related formulations. The animal experiment scheme of this study was approved by the Animal Ethics Committee of the Academy of Military Medical Sciences.

Cirsium souliei (Asteraceae) is a perennial medicinal herb of Cirsium with important medicinal and ecological values. Here, we sequenced the complete chloroplast (cp) genome of C. souliei based on high-throughput sequencing technology, then assembled and annotated it, and analysed the structure and characteristics of the cp genome. The result indicated that the cp genome of C. souliei was a typical quadripartite circular structure of 152 470 bp in length, and GC content was 37.7%. The cp genome of C. souliei encoded 134 genes, including 89 protein-coding genes, 37 tRNA genes and 8 rRNA genes. Meanwhile, we detected 188 simple sequence repeats (SSR) loci in the cp genome, which were mainly composed of mononucleotide repeats. Codon bias analysis showed that leucine (Leu) was the highest amino acids with frequency (10.51%), and there were 30 codons with the value of relative synonymous codon usage (RSCU) above one, of which mostly ended with A/U. Additionally, the result from phylogenetic analysis based on 46 cp genomes of Carduoideae showed that C. souliei and C. vulgare were sister species, and had the closest relationship with 100% bootstrap within Cirsium. This study provides theoretical basis for future studying genetic diversity, population genetic structure, systematics and evolution, and speciation mechanism.

Alzheimer's disease (AD) and other aging-related diseases have become an important public health issue in China. However, current clinical drugs have failed to reverse the pathological process of AD. The holistic approach of traditional Chinese medicine offers advantages in improving cognitive function in AD through multiple molecular pathways, and may have potential for preventing AD. This paper summarizes the effects of classical traditional Chinese medicine and its active components in the improvement of AD-related cognitive dysfunction and describes the functional targets and related molecular mechanisms. This may have significance for the prevention and treatment of AD through multi-target intervention.

With the acceleration of the aging process of our country's population, the impact of aging-related diseases - Alzheimer's disease (AD) on society and families has become increasingly prominent. AD is caused by multiple mechanisms, and the pathogenesis has not been fully elucidated. Most of the clinical treatments are single therapy, which mainly focuses on improving symptoms and are difficult to reverse the disease process. Therefore, the development of drugs that can both improve symptoms and reverse the disease process is extremely urgent in clinical. Increasing number of studies has shown that traditional Chinese medicine plays an important role in the prevention and treatment of AD. The natural products have many advantages, such as novel structures, multiple targets and diverse activities, which can be used as an important source of leading compounds for the treatment of AD. The review summarizes the main clinical treatment methods and the research progress of natural ingredients in traditional Chinese medicine, and provides a reference for the follow-up clinical treatment of AD combined with the advantages of traditional Chinese medicine treatment.

As one of the major sources of infection, viruses could infect all organisms including bacteria, plants, animals, and humans. Infectious diseases caused by viruses pose a great threat and damage to human health and economic activities all over the world. Adaptor-associated protein kinase 1 (AAK1) is a member of the Ark1/Prk1 family of serine/threonine kinases and a specific key kinase regulating the phosphorylation of AP-2 protein μ2 subunit T156. In the past, AAK1 has been regarded as a feasible biological target for the treatment of nerve pain. Recently, scientists have found that inhibiting AAK1 can regulate endocytosis and inhibit virus invasion into cells. Therefore, AAK1 could be the potential target of anti-virus therapy. This paper reviews the research progress of small molecule AAK1 inhibitors in the field of antiviral, analyzes the future research directions and challenges, and provides new ideas for the development of antiviral drugs targeting AAK1.

Cell senescence is characterized by permanent cell cycle arrest, accompanied by the changes in cell metabolism and epigenetic regulation. Alzheimer's disease (AD) is a common neurodegenerative disease, with the main symptoms of memory loss and cognitive impairment. A large number of studies have shown that the senescence of central nervous system cells such as astrocytes and microglia is closely related to the occurrence of AD. Inhibition of brain cell senescence is expected to provide new ideas and therapeutic strategies for the prevention and treatment of AD. This paper reviews the potential roles and mechanisms of senescence of brain cells in AD, and interaction effects among brain cells. This review will provide a new direction for the study of pathological mechanism of AD and the development of anti-AD drugs.

Based on the idea of multi-target drug design, taking p-aminosalicylic acid (PAS) as the parent nucleus, the unreported target molecules TM1 and TM2 were designed with PAS, isonicotinic acid and fluoroquinolone as three structural units conjugated by different linkers. Sixteen target molecules were synthesized by multi-step reaction, and their activities against Mycobacterium tuberculosis and human pathogenic bacteria were evaluated. The results showed that the anti-tuberculosis activity of TM2a was stronger than those of the assayed fluoroquinolones, while TM1a was comparable to that of clinafloxacin, the most active compound of the positive control fluoroquinolones; TM1a showed the strongest inhibitory activity to all almost tested strains, TM1b and TM2a showed very strong inhibitory activity to most strains, and TM1h/2h had strong inhibitory activity to some strains; The inhibitory activities of TM1a/1h on Staphylococcus aureus ATCC14125 are much stronger than those of fluoroquinolones, which eminently deserves further study. The hemolysis test results showed that the highly active molecules TM1a and TM2a exhibited relative safety below the concentrations of 8 and 32 μg·mL^-1, respectively. In this study, a new hybrid molecule of three molecular pharmacophores with PAS as the parent nucleus was synthesized for the first time, and some of which have highly strong antibacterial activity, which provides a new idea for the research and development of antibiotics.

Asiatic acid (AA) is a ursane pentacyclic triterpenoids, which possesses a wide range of pharmacological activities, such as anti-tumor, hypoglycemic, anti-inflammatory, anti-bacterial. Due to poor solubility and low bioavailability, clinical application of asiatic acid is limited. To address these defects, the structural modifications of AA have been carried out, and large numbers of AA-based derivatives with novel structure and eximious biological activity have been developed. In this paper, the research progress of structural modifications, biological activity, structure-activity relationship and mechanism studies in recent twenty years are reviewed, which provides reference for development of AA-related drugs.

For quantitative analysis of related substances in TSD-1 active pharmaceutical ingredient, structures of prepared impurities were confirmed by NMR and UHPLC-MS, and a high performance liquid chromatographic method was established to determine the related substances in TSD-1. The analytical column was an Agilent ZORBAX Eclipe XDB-C8 (250 mm × 4.6 mm, 5 µm). The mobile phase A was 50 mmol·L^-1 ammonium acetate solution (adjusted pH to 5.8 with acetic acid) and the mobile phase B was acetonitrile. The whole run was carried out by gradient elution at a flow rate of 1.0 mL·min^-1. The detection wavelength was set at 240 nm and the column temperature was 30 ℃. The resolutions among peaks of TSD-1, impurity A, impurity B, TSD-D, and TSD-F were good. The calibration curves (n = 7) of TSD-1, impurity A, impurity B, TSD-D and TSD-F were linear in their respective weight ranges of 0.242-48.4 µg·mL^-1 (r = 1.000 0), 0.244-9.75 µg·mL^-1 (r = 0.999 9), 0.244-4.80 µg·mL^-1 (r = 0.999 9), 0.254-1.02 µg·mL^-1 (r = 0.999 9), and 0.247-0.987 µg·mL^-1 (r = 0.999 9). The lower limits of quantitation were 0.244, 0.244, 0.254, and 0.247 µg·mL^-1 for impurity A, impurity B, TSD-D, and TSD-F, respectively, and the average recovery of each impurity ranged from 99.08% to 103.00% with high accuracy. TSD-D and TSD-F were not detected in the three batches of TSD-1 active pharmaceutical ingredients, and impurity A and impurity B were not detected beyond the limit. The established HPLC method is simple, accurate, and suitable for determination of related substances of TSD-1, which can provide a valuable reference for the subsequent development of TSD-1.

Immune checkpoints (ICs) are immunosuppressive molecules expressed on immune cells, which can regulate immune cells' activation. Immune checkpoint inhibitors (ICIs) which can block the interaction of immune checkpoints and their ligands, improve the cytotoxic effect of the immune system on tumor cells. Immunotherapy such as employing ICIs has gradually become a conventional therapeutic strategy for cancer treatment. However, the low response rate and the emergence of drug resistance have seriously affected the clinical efficacy of ICIs. Reactive oxygen species (ROS) are electronic reduction products of active oxygen, as well as natural by-products of cell metabolism, which can be used as regulators of intercellular signals. Tumor microenvironment (TME) is often in the state of oxidative stress (OS), which is the imbalance between oxidative system and antioxidant system. ROS can affect the interaction with its ligands by regulating the expression and activity of immune checkpoints in TME, thus affecting the anti-tumor effect of immune cells. Accumulating studies have shown that ROS could regulate tumor immune checkpoints through several pathways. Due to different types and stages of tumor, it would be clinical beneficial to understand the mechanistic link of ROS on tumor immune checkpoint, and choose appropriate ROS regulators combined with immune checkpoint inhibitors to maximize anti-tumor effects. This article reviews the common metabolic sources and characteristics of ROS, the regulatory effect and mechanism of ROS on tumor immune checkpoints and its therapeutic application.