Title:Phytochemicals: Promising Inhibitors of Human Rhinovirus Type 14 3C
Protease as a Strategy to Fight the Common Cold
Volume: 24
Issue: 15
Author(s): Nefeli Theodora Tsilimingkra and Christos Papaneophytou*
Affiliation:
- Department of Life Sciences, School of Life and Health Sciences, University of Nicosia, 2417, Nicosia, Cyprus
Keywords:
Common cold, 3C protease, Phytochemicals, Molecular docking, Inhibition, Colorimetric assay.
Abstract:
Background: Human rhinovirus 3C protease (HRV-3Cpro) plays a crucial role in viral
proliferation, establishing it as a prime target for antiviral therapy. However, research on identifying
HRV-3Cpro inhibitors is still limited.
Objective: This study had two primary objectives: first, to validate the efficacy of an end-point colorimetric
assay, previously developed by our team, for identifying potential inhibitors of
HRV-3Cpro; and second, to discover phytochemicals in medicinal plants that inhibit the enzyme's
activity.
Methods: Rupintrivir, a well-known inhibitor of HRV-3Cpro, was used to validate the colorimetric
assay. Following this, we conducted a two-step in silico screening of 2532 phytochemicals, which
led to the identification of eight active compounds: apigenin, carnosol, chlorogenic acid, kaempferol,
luteolin, quercetin, rosmarinic acid, and rutin. We subsequently evaluated these candidates in
vitro. To further investigate the inhibitory potential of the most promising candidates, namely,
carnosol and rosmarinic acid, molecular docking studies were performed to analyze their binding
interactions with HRV-3Cpro.
Results: The colorimetric assay we previously developed is effective in identifying compounds
that selectively inhibit HRV-3Cpro. Carnosol and rosmarinic acid emerged as potent inhibitors, inhibiting
HRV-3Cpro activity in vitro by over 55%. Our analysis indicated that carnosol and rosmarinic
acid exert their inhibitory effects through a competitive mechanism. Molecular docking
confirmed their competitive binding to the enzyme's active site.
Conclusion: Carnosol and rosmarinic acid warrant additional investigation for their potential in
the development of common cold treatment. By highlighting these compounds as effective
HRV-3Cpro inhibitors, our study presents a promising approach for discovering phytochemical inhibitors
against proteases from similar pathogens.