Discovery of the covalent SARS‐CoV‐2 M^pro inhibitors from antiviral herbs via integrating target‐based high‐throughput screening and chemoproteomic approaches

Abstract

The main proteases (Mpro) are highly conserved cysteine‐rich proteins that can be covalently modified by numerous natural and synthetic compounds. Herein, we constructed an integrative approach to efficiently discover covalent inhibitors of Mpro from complex herbal matrices. This work begins with biological screening of 60 clinically used antiviral herbal medicines, among which Lonicera japonica Flos (LJF) demonstrated the strongest anti‐Mpro effect (IC50 = 37.82 μg/mL). Mass spectrometry (MS)‐based chemical analysis and chemoproteomic profiling revealed that LJF extract contains at least 50 constituents, of which 22 exhibited the capability to covalently modify Mpro. We subsequently verified the anti‐Mpro effects of these covalent binders. Gallic acid and quercetin were found to potently inhibit severe acute respiratory syndrome coronavirus 2 Mpro in dose‐ and time‐ dependent manners, with the IC50 values below 10 µM. The inactivation kinetics, binding affinity and binding mode of gallic acid and quercetin were further characterized by fluorescence resonance energy transfer, surface plasmon resonance, and covalent docking simulations. Overall, this study established a practical approach for efficiently discovering the covalent inhibitors of Mpro from herbal medicines by integrating target‐based high‐throughput screening and MS‐based assays, which would greatly facilitate the discovery of key antiviral constituents from medicinal plants.

Reduction of flavonoid content in honeysuckle via Erysiphe lonicerae-mediated inhibition of three essential genes in flavonoid biosynthesis pathways

“…Recent scientific studies have highlighted its extensive potential clinical benefits, encompassing antibacterial, antiviral, antifungal, anti-inflammatory, antioxidative, antipyretic, antitumor, and anti-chronic disease effects ( Chang and Hsu, 1992 ; Yu et al., 2008 ; Chen et al., 2013 ; Jiang et al., 2014 ; Kwon et al., 2015 ; Li et al., 2015 ; Zhou et al., 2015 ; Li et al., 2018 ; Wang et al., 2019 ; Li et al., 2024 ). Its notable antiviral properties have gained significant attention, particularly for its inhibitory effects on various animal viruses and human influenza, leading to increased research and development during the Covid-19 pandemic ( Huang et al., 2023 ; Shi et al., 2024 ; Zhang et al., 2023a ). Honeysuckle is predominantly found in East Asia, especially in China, Japan, and Korea, with a notable concentration in southern China ( Li et al., 2024 ).…”