Blocking Effect of Demethylzeylasteral on the Interaction between Human ACE2 Protein and SARS-CoV-2 RBD Protein Discovered Using SPR Technology.

The novel coronavirus disease (2019-nCoV) has been affecting global health since the end of 2019, and there is no sign that the epidemic is abating. Targeting the interaction between the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein and the human angiotensin-converting enzyme 2 (ACE2) receptor is a promising therapeutic strategy. In this study, surface plasmon resonance (SPR) was used as the primary method to screen a library of 960 compounds. A compound 02B05 (demethylzeylasteral, CAS number: 107316-88-1) that had high affinities for S-RBD and ACE2 was discovered, and binding affinities (KD, µM) of 02B05-ACE2 and 02B05-S-RBD were 1.736 and 1.039 µM, respectively. The results of a competition experiment showed that 02B05 could effectively block the binding of S-RBD to ACE2 protein. Furthermore, pseudovirus infection assay revealed that 02B05 could inhibit entry of SARS-CoV-2 pseudovirus into 293T cells to a certain extent at nontoxic concentration. The compoundobtained in this study serve as references for the design of drugs which have potential in the treatment of COVID-19 and can thus accelerate the process of developing effective drugs to treat SARS-CoV-2 infections.

Synthesis and antiviral activity of a novel class of (5-oxazolyl)phenyl amines.

A series of novel (5-oxazolyl)phenyl amine derivatives were synthesized and their antiviral activities against the hepatitis C virus (HCV) and the coxsackie virus B3 (CVB3) and B6 (CVB6) were evaluated in vitro. Bioassays showed that the synthesized compounds 17a1, 17a4, 17a6, 17b1, 17d1, 17e2 and 17g3 exhibited potent antiviral activity against HCV (IC50 = 0.28-0.92 µM) and most synthesized compounds exhibited low cytotoxicity in Huh7.5 cells, compared to telaprevir. The compounds 17a1, 17a4, 17a5, 17a6, 17b1, 17b2, 17g1 and 17g3 showed strong activity against the CVB3 and/or CVB6 at low concentrations (IC50 < 2.0 µM). The (5-oxazolyl)phenyl amines 17a1, 17a4, 17a8, 17b1, 17d1, 17e2, 17f3 and 17g3 were identified as the most active on the biological assays, and will be studied further.

LC-MS/MS method for determination of geldanamycin derivative GM-AMPL in rat plasma to support preclinical development.

A LC-MS/MS method for determining the concentration of the small molecule Hsp90 inhibitor, GM-AMPL, has been developed and validated in rat plasma to support preclinical development. 17-[2-(morpholine-4-yl)ethyl]amino-17-demethoxygeldanamycin (GM-AMPL) and the internal standard 17-allylamino-17-demethoxygeldanamycin (17-AAG) were sufficiently separated on a Venusil MP C18 column that was eluted with 80% methanol in water at 40°C. Quantification studies were performed with a multiple reaction monitoring (MRM) transition of m/z 657.3→614.3 and 584.3→541.3 for GM-AMPL and IS, respectively, in the negative ion mode. The present method exhibited good linearity (R>0.999) over the concentration range of 2-600ng/mL for GM-AMPL in rat plasma with a lower limit of quantification (LLOQ) of 2ng/mL. The intra-batch and inter-batch assay coefficients of variation (CV) were in range of 1.56-6.84% and 1.62-6.98%, respectively. The plasma samples were extracted with methanol to precipitate protein with extraction recovery in range of 84.09-95.25%. The matrix effect was determined as internal substance (IS) normalized matrix factor of 1.09, 1.18 and 1.05 for samples with three concentration levels of 4, 40 and 400ng/mL, respectively. This validated method was further applied to successfully determine the pharmacokinetic parameters and oral availability of GM-AMPL in Sprague-Dawley rats following intravenous injection and oral administration.

Synthesis and antiviral activity of substituted bisaryl amide compounds as novel influenza virus inhibitors.

The influenza virus is a persistent cause of mortality and morbidity on an annual basis and thus presents itself as an important target for pharmaceutical investigation. In this work, substituted bisaryl amide compounds were found to be a new class of potential anti-influenza agents, and a series of substituted bisaryl amide compounds were synthesised and evaluated for their anti-influenza virus activities. The analysis of the results produced a preliminary structure-activity relationship study (SAR). Compounds 1a, 1g, 1h, 1j, 1l and 1n exhibited clear antiviral activities against the influenza A (A/Guangdong Luohu/219/2006, H1N1) virus with 50% inhibitory concentrations (IC(50)) for virus growth ranging from 12.5 to 59.0 µM. Specifically, compound 1j also possessed antiviral activity against both oseltamivir-resistant influenza (A/Jinnan/15/2009) virus and influenza B (B/Jifang/13/97) virus with IC(50) values of 9.2 µM and 21.4 µM, respectively. Compound 1j is thus worth further investigation as an anti-influenza virus candidate.

[Synthesis and antiviral activities of geldanamycin analog TC-GM in vitro].

In order to find antiviral compounds with novel structures, geldanamycin and lamivudine with different antiviral mechanisms were conjunctively synthesized to acquire a new compound TC-GM, and the antiviral activity of TC-GM was measured. The antiviral activity against HIV-1 was examined by p24 antigen ELISA kit. The activity against HBV was examined by dotblot. The activity against HSV and CoxB virus was examined by CPE. TC-GM exhibited broad-spectrum antiviral activities similarly like geldanamycin. TC-GM inhibited the replication of different viruses, including HIV-1, HBV, HSV 1 and 2, CoxB6. TC-GM showed more potent inhibitory activity against HIV-1 and HBV than other detected virus.

A novel class of geldanamycin derivatives as HCV replication inhibitors targeting on Hsp90: synthesis, structure-activity relationships and anti-HCV activity in GS4.3 replicon cells.

A novel class of geldanamycin (GA) derivatives as hepatitis C virus (HCV) replication inhibitors has been synthesized and their anti-HCV activities were evaluated in GS4.3 HCV replicon cells. Most of the synthesized compounds demonstrated potential activities against HCV in vitro. Substitution with an aliphatic cyclic group (2b) and polar phosphate group (2f) at the 17 position of GA resulted in more potent inhibitory activity. The configurations of the tetrahydrofurfurylamino (THFM) substituents obviously affected their antiviral activities. The 2b with a 2'-(R)-THFM group at the 17 position showed much potent activity and higher selectivity than its 2'-(S) and 2'-(R, S) epimers. In the tested GA derivatives, 2b and 2f show the most potential leading compounds for development of novel anti-HCV agents.

Synthesis and biological evaluation of heat-shock protein 90 inhibitors: geldanamycin derivatives with broad antiviral activities.

BACKGROUND: Previous studies have suggested that geldanamycin (GA) inhibits the replication of several viruses in vitro. Here, we aimed to synthesize and evaluate the antiviral activity of 17-amino-17-demethoxygeldanamycin derivatives. METHODS: A series of 17-substituted and 17-,19-disubstituted GA derivatives were screened for antiviral activities against eight different viral strains, including herpesvirus, hepatitis virus, retrovirus and picornavirus. RESULTS: Most of the tested compounds showed inhibitory activity against the viruses and showed reduced cytotoxicity in vitro as compared with the parent compound GA. In vivo efficacy evaluation results showed that compound 6 noticeably inhibited duckling hepatitis B virus DNA replication in duckling serum after oral administration. Viral rebound did not occur after termination of the treatment. The modified GA derivatives also showed median lethal dose values that were higher than that of the parent GA in mice intraperitoneally treated with the study compounds. CONCLUSIONS: Targeting heat-shock protein 90 could be a new antiviral approach that is not prone to the development of drug resistance. The 17-amino-17-demethoxygeldanamycin derivatives could be novel agents with potential antiviral activity.