SARS-CoV-2 Mpro inhibitors with antiviral activity in a transgenic mouse model.

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continually poses serious threats to global public health. The main protease (Mpro) of SARS-CoV-2 plays a central role in viral replication. We designed and synthesized 32 new bicycloproline-containing Mpro inhibitors derived from either boceprevir or telaprevir, both of which are approved antivirals. All compounds inhibited SARS-CoV-2 Mpro activity in vitro, with 50% inhibitory concentration values ranging from 7.6 to 748.5 nM. The cocrystal structure of Mpro in complex with MI-23, one of the most potent compounds, revealed its interaction mode. Two compounds (MI-09 and MI-30) showed excellent antiviral activity in cell-based assays. In a transgenic mouse model of SARS-CoV-2 infection, oral or intraperitoneal treatment with MI-09 or MI-30 significantly reduced lung viral loads and lung lesions. Both also displayed good pharmacokinetic properties and safety in rats.

Discovery of thieno[2,3-d]pyrimidin-4(3H)-one derivatives as a new class of ROCK inhibitors.

Herein, we report the discovery of a series of thieno[2,3-d]pyrimidin-4(3H)-one derivatives as a new class of ROCK inhibitors. Structure-activity relationship studies of these compounds led to the identification of the most potent compound, 3-(3-methoxybenzyl)-6-(1H-pyrrolo[2,3-b]pyridin-4-yl)thieno[2,3-d]pyrimidin-4(3H)-one (8k), which showed IC50 values of 0.004 µM and 0.001 µM against ROCK Ⅰ and ROCK Ⅱ, respectively. In vitro, 8k significantly reduced the phosphorylation level of ROCK downstream signaling protein and induce changes in cell morphology and migration. Overall, this study provides a promising lead compound for drug discovery targeting ROCKs.

Structural optimization and structure-activity relationship studies of N-phenyl-7,8-dihydro-6H-pyrimido[5,4-b][1,4]oxazin-4-amine derivatives as a new class of inhibitors of RET and its drug resistance mutants.

The RET tyrosine kinase is an important therapeutic target for medullary thyroid cancer (MTC), and drug resistance mutations of RET, particularly V804M and V804L, are a main challenge for the current targeted therapy of MTC based on RET inhibitors. In this investigation, we report the structural optimization and structure-activity relationship studies of N-phenyl-7,8-dihydro-6H-pyrimido[5,4-b][1,4]oxazin-4-amine derivatives as a new class of RET inhibitors. Among all the obtained kinase inhibitors, 1-(5-(tert-butyl)isoxazol-3-yl)-3-(4-((6,7,8,9-tetrahydropyrimido[5,4-b][1,4]oxazepin-4-yl)amino)phenyl)urea (17d) is a multi-kinase inhibitor and potently inhibits RET and its drug resistance mutants. It showed IC50 (half maximal inhibitory concentration) values of 0.010 µM, 0.015 µM, and 0.009 µM against RET-wild-type, RET-V804M, and RET-V804L, respectively. 17d displayed significant anti-viability potencies against various RET-driving tumor cell lines. In a xenograft mouse model of NIH3T3-RET-C634Y, 17d exhibited potent in vivo anti-tumor activity, and no obvious toxicity was observed. Mechanisms of action were also investigated by Western blot and immunohistochemical assays. Collectively, 17d could be a promising agent for the treatment of MTC, hence deserving a further investigation.

[Folic acid modified polyrotaxanes effectively transfer si RNA-CD47 to inhibit the proliferation of melanoma].

To investigate the effect that folic acid-modified polyrotaxanes(FPP) transfered siRNA CD47 to inhibit melanoma proliferation, the expression of CD47 in clinical melanoma patients was tested by Western blot and RT-PCR, respectively. Physical performance of FPP(siRNA-CD47: CD47) nanoparticles was tested by Malvern particle size instrument and scanning electron microscope. The clone formation experiment demonstrated that FPP(CD47) nanoparticles inhibited the growth of clones. Invasion assay revealed that FPP(CD47) inhibited migration of B16F10 cells. Tumor bearing mice were used in the experiment to test the efficacy of FPP(CD47) treatment. Compared with the control group, high expression of CD47 was observed in the clinical melanoma patients. FPP(CD47) nanoparticle size at 80 nm exhibited a potential of 10 m V; compared with FPP(Con), fluorescence intensity was significantly reduced to 4.2% and B16F10 cell clone formation was decreased by 91% in the FPP(CD47) treatment. Tumor volume of tumor-burdened mice was decreased by 90% with FPP(CD47) treatment. FPP(CD47) lowered CD47 protein and m RNA expression in the tumor. This study suggests that FPP may transfer siRNA CD47 into the cancer cells to inhibit melanoma growth effectively.

Rapid resolution liquid chromatography-electrospray ionisation tandem mass spectrometry method for identification of chemical constituents in Citri Reticulatae Pericarpium.

Citri Reticulatae Pericarpium (CRP) is one of the most commonly used traditional Chinese medicines with great medicinal and dietary values. In this work, we developed an approach utilising rapid resolution liquid chromatography/electrospray ionisation tandem mass spectrometry (RRLC-ESI-MS/MS) for the identification and profiling of chemical composition in CRP. On the basis of RRLC retention times, cochromatography with available authentic standards, mass spectral fragmentation patterns and literature information, a total of 41 chemical compounds, including 4 flavone-C-glycosides, 7 flavonoid-O-glycosides and 19 polymethoxyflavones were unambiguously identified or tentatively characterised in CRP. The occurrence of 1 flavone-C-glycoside and 3 cyclic peptides in particular has not yet been described. The results indicated that the developed method could serve as a rapid, effective tool for structural characterisation of chemical constituents in CRP.

Paeoniflorin inhibits growth of human colorectal carcinoma HT 29 cells in vitro and in vivo.

The aim of the therapy of human malignancies is the inhibition of cell proliferation and/or induction of apoptosis. In present experiment, we investigated the in vitro and in vivo anticancer effects and associated mechanisms of paeoniflorin (PF), isolated from the paeony root, against colorectal cancer. In vitro, cell growth assay obviously showed the inhibition of tumor cell growth in a dose-dependent manner. Flow cytometry analysis showed that PF could mainly have the cell cycle arrest at G1, which is associated with DNA damage and activation of p53/14-3-3 zeta (ζ). The pro-apoptotic effect of PF was demonstrated by Annexin V-PI staining, and activation of caspase-3 and caspase-9 by Western immunoblotting. In vivo, the results showed that positive cells of PCNA in PF and docetaxel-treated group was decreased to 30% and 15% compared with control group of tumors, respectively. But apoptosis cells in PF- and docetaxel treated groups studied by TUNEL is increased to 40 ± 1.2% and 30 ± 1.5% compared with 24 ± 2.3% in negative control, respectively. Furthermore, the efficiency of tumor-bearing mice treated by PF was superior to docetaxel in vivo. Overall, PF may be an effective chemopreventive agent against colorectal cancer HT29, and the mechanism could be mediated via an regulation of p53/14-3-3ζ.

Fast profiling of chemical constituents in Yiqing Capsule by ultra-performance liquid chromatography coupled to electrospray ionization tandem mass spectrometry.

An ultra-performance liquid chromatography/electrospray ionization tandem mass spectrometry (UPLC-ESI-MS(n)) has been developed for structural characterization and identification of multi-constituents in Yiqing Capsule, a well-known combined herbal remedy prepared from the extract mixtures of Rhizoma Coptidis, Radix et Rhizoma Rhei and Radix Scutellariae. The UPLC analysis was performed on an Agilent ZorBax SB-C(18) column (4.6 mm×50 mm, 1.8 µm) and gradient elution of 0.1% formic acid solution and acetonitrile in 16 min. Based on their retention times and mass spectra in comparison with the data from standards or references, a total of 29 compounds including 3 phenolic acids and 4 anthraquinones from Radix et Rhizoma Rhei, 8 alkaloids from Rhizoma Coptidis and 14 flavonoids from Radix Scutellariae were unambiguously identified or tentatively characterized in the complex system. The MS data and fragmentation information of two isomers of feruloylquinic acid were first reported in Radix et Rhizoma Rhei and in Yiqing Capsules. This study is expected to be accepted as an effective and reliable pattern for comprehensive and systematic characterization of this commonly used Chinese herbal preparation.

[Paeoniflorin increases beta-defensin expression and attenuates lesion in the colonic mucosa from mice with oxazolone-induced colitis].

Previous studies have demonstrated that the Chinese medicine paeoniflorin, derived from the Ranunculaceae plant peony, peony, purple peony root, was able to have anti-inflammatory, anti-ulcer, anti-hypersusceptibility and anti-oxidation activity. In order to elucidate the pesticide effect and the mechanisms by which paeoniflorin exerts its effect of anti-inflammation and immunoregulation on oxazolone-induced colitic mice, disease activity index (DAI) and histological grading of colitis (HGC) were evaluated in animal model. Moreover, the expressions of HBD-2, IL-6 and IL-10 of mice with experimental colitis were observed with immunohistochemistry and RT-PCR in this study. Results showed that DAI and HGC of oxazolone control group was significantly higher than that of normal control group, and that paeoniflorin groups and 5-ASA group, compared with oxazolone control group, could alleviate the symptoms and histological damages of colitic mice (P < 0.05, P < 0.01). The expression of HBD-2 and IL-6 cytokine on the colon of colitic mice was higher than that of normal control, paeoniflorin and 5-ASA groups (P < 0.05, P < 0.01), but the expression of IL-10 is lower than that of normal control, paeoniflorin and 5-ASA groups (P < 0.05, P < 0.01). The positive correlations were demonstrated between the expression of (HBD-2 and IL-6) and DAI (Pearson r = 0.728, Pearson r = 0.758, P < 0.01, respectively), (HBD-2 and IL-6) and HGC (Pearson r = 0.819, Pearson r = 0.825, P < 0.01, respectively), whereas, the negative correlations were demonstrated between the expression of IL-10 and DAI (Pearson r = -0.789, P < 0.01), IL-10 and HGC (Pearson r = -0.725, P < 0.01). It can be concluded that to some extent paeoniflorin effectively alleviate the symptoms of oxazolone-induced colitis through regulating the expression of HBD-2, IL-6 and IL-10.

[Study on effects of Astragalus, Angelica and their combination on vascular endothelial cell proliferation in vitro].

OBJECTIVE: To study the effects of Astragalus membranaceus (AM), Angelica sinensis (AS) and their combination on human umbilical vein endothelial cell (HUVEC) proliferation and cells cycle. METHODS: The effects were observed and studied by means of taking the cultured HUVECs as model to determine the cell proliferation with MTT method, cell cycle was analyzed with cytometry, and vascular endothelial growth factor (VEGF) expression with SABC method. The regulatory effects of AM, AS and their combination on the HUVEC proliferation promoting were observed and studied. RESULTS: AM and AS, used singly or in combination, could promote the growth of endothelial cells, increase the cell population in S phase, the effects showed more significant when used in combination (P < 0.05 or P < 0.001). Meanwhile, VEGF expression in all the medicated group was up-regulated, but in the PBS control group, it showed only weak expression (P < 0.05 or P < 0.01). CONCLUSION: AM and AS have effect in promoting vascular endothelial cell proliferation and DNA synthesis, and showed synergistic effect when they were used in combination, suggesting that these two Chinese herbs could have certain effect on the genesis and development of neogenetic vascularization in ischemic myocardium.