tetano
Editor, Senior Moderator
Bioorg Med Chem
. 2025 May 23:128:118258.
doi: 10.1016/j.bmc.2025.118258. Online ahead of print. Synthesis and multitarget inhibitory effect of indole-based ethyl cinnamate derivatives against SARS-CoV-2 M[SUP]pro[/SUP] and cathepsins for broad-spectrum anti-coronavirus activity
Andrea Citarella[SUP] 1 [/SUP], Giulia Sibille[SUP] 2 [/SUP], Davide Moi[SUP] 3 [/SUP], Alessandro Dimasi[SUP] 4 [/SUP], Tommaso Braga[SUP] 4 [/SUP], Lorenzo Dal Col[SUP] 4 [/SUP], Lorenzo Ruberto[SUP] 4 [/SUP], Stefano Pieraccini[SUP] 4 [/SUP], Maurizio Sironi[SUP] 4 [/SUP], Nicola Micale[SUP] 5 [/SUP], Tanja Schirmeister[SUP] 6 [/SUP], Valerio Fasano[SUP] 4 [/SUP], Alessandra Silvani[SUP] 4 [/SUP], Clelia Giannini[SUP] 4 [/SUP], Giorgio Gribaudo[SUP] 2 [/SUP], Daniele Passarella[SUP] 4 [/SUP]
Affiliations
The experience of the SARS-CoV-2 pandemic has highlighted the urgent need to develop broad-spectrum antivirals (BSA) agents capable of targeting viral and/or host factors essential for infection as undeniable weapons against future coronavirus threats with potential pandemic perspectives. In this study, we report the synthesis and biological evaluation of a novel series of indole-based ethyl cinnamate derivatives designed as multitarget inhibitors of both SARS-CoV-2 Main Protease (M[SUP]pro[/SUP]) and human cathepsin, namely CatL and CatS, key enzymes involved in viral replication and entry. Enzymatic assays showed that several compounds exert significant inhibition on multiple targets. Structure-activity relationship (SAR) studies highlighted the critical role of the tert-leucine (Tle) residue at P2 position of these (pseudo)dipeptides, which proved to be essential for multitarged enzyme inhibition and antiviral activity. In antiviral assays against representative α- (hCoV-229E) and β-coronavirus (hCoV-OC43), 12 (EC[SUB]50[/SUB] = 4.09 µM for hCoV-OC43, 0.77 µM for hCoV-229E), 20 (EC[SUB]50[/SUB] = 6.68 µM for hCoV-OC43, 0.62 µM for hCoV-229E), and 3 (EC[SUB]50[/SUB] = 2.96 µM for hCoV-OC43, 0.64 µM for hCoV-229E) restricted viral replication with high selectivity values (SI = 98, 56, and 101, respectively). Time-of-drug-addition experiments then revealed that 12 primarily inhibited viral entry by targeting CatL, whereas 20 affected both entry and post-entry stages of hCoV replication cycle likely thanks to its dual-inhibitory activity against both CatL and M[SUP]pro[/SUP]. These findings support the development of multitarget inhibitors as promising antivirals able to inhibit both α- and β-coronavirus, so as to reduce the risk of resistance associated with single-target agents. Furthermore, the demonstrated effectiveness of Tle-containing indole-based cinnamates as BSA highlights their potential in the context of the strategic framework for pandemic preparedness.
Keywords: Broad-spectrum antivirals; Cathepsins; Coronaviruses; Enzyme inhibitors; Ethyl cinnamate; M(pro); Medicinal chemistry; Multitarget; Organic chemistry; SARS-CoV-2.
. 2025 May 23:128:118258.
doi: 10.1016/j.bmc.2025.118258. Online ahead of print. Synthesis and multitarget inhibitory effect of indole-based ethyl cinnamate derivatives against SARS-CoV-2 M[SUP]pro[/SUP] and cathepsins for broad-spectrum anti-coronavirus activity
Andrea Citarella[SUP] 1 [/SUP], Giulia Sibille[SUP] 2 [/SUP], Davide Moi[SUP] 3 [/SUP], Alessandro Dimasi[SUP] 4 [/SUP], Tommaso Braga[SUP] 4 [/SUP], Lorenzo Dal Col[SUP] 4 [/SUP], Lorenzo Ruberto[SUP] 4 [/SUP], Stefano Pieraccini[SUP] 4 [/SUP], Maurizio Sironi[SUP] 4 [/SUP], Nicola Micale[SUP] 5 [/SUP], Tanja Schirmeister[SUP] 6 [/SUP], Valerio Fasano[SUP] 4 [/SUP], Alessandra Silvani[SUP] 4 [/SUP], Clelia Giannini[SUP] 4 [/SUP], Giorgio Gribaudo[SUP] 2 [/SUP], Daniele Passarella[SUP] 4 [/SUP]
Affiliations
- PMID: 40435714
- DOI: 10.1016/j.bmc.2025.118258
The experience of the SARS-CoV-2 pandemic has highlighted the urgent need to develop broad-spectrum antivirals (BSA) agents capable of targeting viral and/or host factors essential for infection as undeniable weapons against future coronavirus threats with potential pandemic perspectives. In this study, we report the synthesis and biological evaluation of a novel series of indole-based ethyl cinnamate derivatives designed as multitarget inhibitors of both SARS-CoV-2 Main Protease (M[SUP]pro[/SUP]) and human cathepsin, namely CatL and CatS, key enzymes involved in viral replication and entry. Enzymatic assays showed that several compounds exert significant inhibition on multiple targets. Structure-activity relationship (SAR) studies highlighted the critical role of the tert-leucine (Tle) residue at P2 position of these (pseudo)dipeptides, which proved to be essential for multitarged enzyme inhibition and antiviral activity. In antiviral assays against representative α- (hCoV-229E) and β-coronavirus (hCoV-OC43), 12 (EC[SUB]50[/SUB] = 4.09 µM for hCoV-OC43, 0.77 µM for hCoV-229E), 20 (EC[SUB]50[/SUB] = 6.68 µM for hCoV-OC43, 0.62 µM for hCoV-229E), and 3 (EC[SUB]50[/SUB] = 2.96 µM for hCoV-OC43, 0.64 µM for hCoV-229E) restricted viral replication with high selectivity values (SI = 98, 56, and 101, respectively). Time-of-drug-addition experiments then revealed that 12 primarily inhibited viral entry by targeting CatL, whereas 20 affected both entry and post-entry stages of hCoV replication cycle likely thanks to its dual-inhibitory activity against both CatL and M[SUP]pro[/SUP]. These findings support the development of multitarget inhibitors as promising antivirals able to inhibit both α- and β-coronavirus, so as to reduce the risk of resistance associated with single-target agents. Furthermore, the demonstrated effectiveness of Tle-containing indole-based cinnamates as BSA highlights their potential in the context of the strategic framework for pandemic preparedness.
Keywords: Broad-spectrum antivirals; Cathepsins; Coronaviruses; Enzyme inhibitors; Ethyl cinnamate; M(pro); Medicinal chemistry; Multitarget; Organic chemistry; SARS-CoV-2.