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1.
J Pharm Biomed Anal ; 209: 114538, 2022 Feb 05.
Article in English | MEDLINE | ID: covidwho-1670797

ABSTRACT

The 3C-like protease (3CLpro) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential to the virus life cycle and is supposed to be a potential target for the treatment of coronaviral infection. Traditional Chinese medicines (TCMs) have played an impressive role in the treatment of COVID-19 in China. The effectiveness of TCM formulations prompts scientists to take continuous effort on searching for bioactive small molecules from the ancient resources. Herein, we developed a native mass spectrometry-based affinity-selection method for rapid screening of active small molecules from crude herbal extracts applied for COVID-19 therapy. Six common herbs named Lonicera japonica, Scutellaria baicalensis, Forsythia suspensa, Glycyrrhiza uralensis, Cirsium japonicum, and Andrographis paniculata were investigated. After preliminary separation of the crude extracts, the fractions were incubated with 3CLpro. A native MS-based affinity screening assay was then conducted to search for the protein-ligand complexes. A UHPLC-Q/TOF-MS with UNIFI data acquisition and data processing software was applied to identify the hit compounds. Standard compounds were used to verify the outcomes. Among the 16 hits, three flavonoids, baicalein, scutellarein and ganhuangenin, were identified as potential noncovalent inhibitors against 3CLpro with IC50 values of 0.94, 3.02, and 0.84 µM, respectively. Their binding affinities were further characterized by native MS, with Kd values being 1.43, 3.85, and 1.09 µM, respectively. Overall, we established an efficient native MS-based strategy for discovering 3CLpro ligands from crude mixtures, which supplies a potential strategy of small molecule lead discovery from TCMs.


Subject(s)
COVID-19 , SARS-CoV-2 , Antiviral Agents/pharmacology , Humans , Molecular Docking Simulation , Peptide Hydrolases , Protease Inhibitors/pharmacology
2.
Nat Commun ; 12(1): 3623, 2021 06 15.
Article in English | MEDLINE | ID: covidwho-1270656

ABSTRACT

The ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) urgently needs an effective cure. 3CL protease (3CLpro) is a highly conserved cysteine proteinase that is indispensable for coronavirus replication, providing an attractive target for developing broad-spectrum antiviral drugs. Here we describe the discovery of myricetin, a flavonoid found in many food sources, as a non-peptidomimetic and covalent inhibitor of the SARS-CoV-2 3CLpro. Crystal structures of the protease bound with myricetin and its derivatives unexpectedly revealed that the pyrogallol group worked as an electrophile to covalently modify the catalytic cysteine. Kinetic and selectivity characterization together with theoretical calculations comprehensively illustrated the covalent binding mechanism of myricetin with the protease and demonstrated that the pyrogallol can serve as an electrophile warhead. Structure-based optimization of myricetin led to the discovery of derivatives with good antiviral activity and the potential of oral administration. These results provide detailed mechanistic insights into the covalent mode of action by pyrogallol-containing natural products and a template for design of non-peptidomimetic covalent inhibitors against 3CLpros, highlighting the potential of pyrogallol as an alternative warhead in design of targeted covalent ligands.


Subject(s)
Coronavirus 3C Proteases/drug effects , Pyrogallol/chemistry , Pyrogallol/isolation & purification , Pyrogallol/pharmacology , SARS-CoV-2/drug effects , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , COVID-19/drug therapy , Coronavirus Papain-Like Proteases , Drug Design , Flavonoids , HEK293 Cells , Humans , Kinetics , Ligands , Molecular Dynamics Simulation , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Viral Nonstructural Proteins/chemistry
3.
J Pharm Biomed Anal ; 194: 113806, 2021 Feb 05.
Article in English | MEDLINE | ID: covidwho-1065380

ABSTRACT

Remdesivir is a prodrug of the nucleotide analogue and used for COVID-19 treatment. However, the bioanalysis of the active metabolites remdesivir nucleotide triphosphate (RTP) and its precursor remdesivir nucleotide monophosphate (RMP) is very challenging. Herein, we established a novel method to separate RTP and RMP on a BioBasic AX column and quantified them by high-performance liquid chromatography-tandem mass spectrometry in positive electrospray ionization mode. Stepwise, we optimized chromatographic retention on an anion exchange column, improved stability in matrix through the addition of 5,5'-dithiobis-(2nitrobenzoic acid) and PhosSTOP EASYpack, and increased recovery by dissociation of tight protein binding with 2 % formic acid aqueous solution. The method allowed lower limit of quantification of 20 nM for RMP and 10 nM for RTP. Method validation demonstrated acceptable accuracy (93.6%-103% for RMP, 94.5%-107% for RTP) and precision (RSD < 11.9 % for RMP, RSD < 11.4 % for RTP), suggesting that it was sensitive and robust for simultaneous quantification of RMP and RTP. The method was successfully applied to analyze RMP and RTP in mouse tissues. In general, the developed method is suitable to monitor RMP and RTP, and provides a useful approach for exploring more detailed effects of remdesivir in treating diseases.


Subject(s)
Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , Prodrugs/analysis , Prodrugs/metabolism , Tandem Mass Spectrometry/methods , Adenosine Monophosphate/analysis , Adenosine Monophosphate/metabolism , Adenosine Monophosphate/pharmacology , Alanine/analysis , Alanine/metabolism , Alanine/pharmacology , Animals , Antiviral Agents/analysis , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , COVID-19/drug therapy , COVID-19/metabolism , Chromatography, Liquid/methods , Humans , Liver/chemistry , Liver/drug effects , Liver/metabolism , Male , Mice , Prodrugs/pharmacology
4.
Acta Pharmacol Sin ; 41(9): 1167-1177, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-691161

ABSTRACT

Human infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19) and there is no cure currently. The 3CL protease (3CLpro) is a highly conserved protease which is indispensable for CoVs replication, and is a promising target for development of broad-spectrum antiviral drugs. In this study we investigated the anti-SARS-CoV-2 potential of Shuanghuanglian preparation, a Chinese traditional patent medicine with a long history for treating respiratory tract infection in China. We showed that either the oral liquid of Shuanghuanglian, the lyophilized powder of Shuanghuanglian for injection or their bioactive components dose-dependently inhibited SARS-CoV-2 3CLpro as well as the replication of SARS-CoV-2 in Vero E6 cells. Baicalin and baicalein, two ingredients of Shuanghuanglian, were characterized as the first noncovalent, nonpeptidomimetic inhibitors of SARS-CoV-2 3CLpro and exhibited potent antiviral activities in a cell-based system. Remarkably, the binding mode of baicalein with SARS-CoV-2 3CLpro determined by X-ray protein crystallography was distinctly different from those of known 3CLpro inhibitors. Baicalein was productively ensconced in the core of the substrate-binding pocket by interacting with two catalytic residues, the crucial S1/S2 subsites and the oxyanion loop, acting as a "shield" in front of the catalytic dyad to effectively prevent substrate access to the catalytic dyad within the active site. Overall, this study provides an example for exploring the in vitro potency of Chinese traditional patent medicines and effectively identifying bioactive ingredients toward a specific target, and gains evidence supporting the in vivo studies of Shuanghuanglian oral liquid as well as two natural products for COVID-19 treatment.


Subject(s)
Betacoronavirus/drug effects , Coronavirus Infections , Drugs, Chinese Herbal , Flavanones , Flavonoids , Pandemics , Pneumonia, Viral , Virus Replication/drug effects , Administration, Oral , Animals , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , Betacoronavirus/physiology , COVID-19 , Chlorocebus aethiops , Coronavirus Infections/drug therapy , Coronavirus Infections/virology , Drugs, Chinese Herbal/chemistry , Drugs, Chinese Herbal/pharmacology , Enzyme Assays , Flavanones/chemistry , Flavanones/pharmacokinetics , Flavonoids/chemistry , Flavonoids/pharmacokinetics , Humans , Pneumonia, Viral/drug therapy , Pneumonia, Viral/virology , SARS-CoV-2 , Vero Cells , Virus Replication/physiology
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