3-O-β-chacotriosyl glycyrrhetinic acid derivatives as potential small-molecule SARS-CoV-2 fusion inhibitors against SARS-CoV-2 entry into host cells
WAN Xin
HONG Chongjun
WANG Jinshen
SONG Gaopeng
LIU Shuwen
Abstract：Objective To study the inhibitory activities of 3-O-β-chacotriosyl glycyrrhetinic acid derivatives against the entry of SARS-CoV-2 into host cells.Methods With pentacyclic triterpene saponin glycyrrhizic acid(a natural SARS-CoV-2 entry inhibitor)as the lead compound,a series of 3-O-β-chacotriosyl glycyrrhetinic acid derivatives were designed and synthesized based on hypridization principle,and their inhibitory activities against virus entry were tested in SARS-CoV-2 pseudovirus-infected cells.The antiviral targets of the lead compound 1b was identified by pseudotyped SARS-CoV-2 infection assay and surface plasmon resonance(SPR)assay,and the S protein-mediated cell-cell fusion assay was used to evaluate the effect of 1b on virus-cell membrane fusion.Molecular docking and single amino acid mutagenesis were carried out to analyze the effect of 1b on binding activitiy of S protein.Results The lead compound 1b showed significant inhibitory effect against Omicron pseudovirus with an EC50 value of 3.28µmol/L(P<0.05),and had broad-spectrum antiviral activity against other SARS-CoV-2 pseudovirus.Spike-dependent cell-cell fusion assay demonstrated an inhibitory effect of 1b against SARS-CoV-2 S protein-mediated cell-cell fusion.Molecular docking analysis predicted that the lead compound 1b could be well fitted into a cavity between the attachment(S1)and fusion(S2)subunits at the 3-fold axis,where it formed multiple hydrophobic interactions with Glu309,Ser305,Arg765 and Lys964 residues with a KD value of-8.6 kcal/mol.The compound 1b at 10,5,2.5 and 1.25 µmol/L showed a significantly reduced inhibitory activity against the pseudovirus with mutated Arg765,Lys964,Glu309 and Leu303(P<0.01).Conclusion 3-O-β-chacotriosyl glycyrrhetinic acid derivatives are capable of stabilizing spike protein in the pre-fusion step to interfere with the fusion of SARS-CoV-2 with host cell membrane,and can thus serve as potential novel small-molecule SARS-CoV-2 fusion inhibitors.
Keywords：SARS-CoV-2small-molecule SARS-CoV-2 fusion inhibitorsspike proteinglycyrrhetinic acid derivatives
Publication Date：2024-03-20
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：10( 474-483 )