Biosensor‐based active ingredient recognition system for screening potential small molecular Severe acute respiratory syndrome coronavirus 2 entry blockers targeting the spike protein from Rugosa rose

Abstract The traditional formulation Hanchuan zupa granules (HCZPs) have been widely used for controlling coronavirus disease 2019 (COVID‐19). However, its active components remain unknown. Here, HCZP components targeting the spike receptor‐binding domain (S‐RBD) of SARS‐CoV‐2 were investigated using a surface plasmon resonance (SPR) biosensor‐based active ingredient recognition system (SPR‐AIRS). Recombinant S‐RBD proteins were immobilized on the SPR chip by amine coupling for the prescreening of nine HCZP medicinal herbs. Ultra‐performance liquid chromatography‐tandem mass spectrometry (UPLC‐MS/MS) identified gallic acid (GA) and methyl gallate (MG) from Rosa rugosa as S‐RBD ligands, with K D values of 2.69 and 0.95 μM, respectively, as shown by SPR. Molecular dynamics indicated that GA formed hydrogen bonds with G496, N501, and Y505 of S‐RBD, and MG with G496 and Y505, inhibiting S‐RBD binding to angiotensin‐converting enzyme 2 (ACE2). SPR‐based competition analysis verified that both compounds blocked S‐RBD and ACE2 binding, and SPR demonstrated that GA and MG bound to ACE2 ( K D = 5.10 and 4.05 μM, respectively), suggesting that they blocked the receptor and neutralized SARS‐CoV‐2. Infection with SARS‐CoV‐2 pseudovirus showed that GA and MG suppressed viral entry into 293T‐ACE2 cells. These S‐RBD inhibitors have potential for drug design, while the findings provide a reference on HCZP composition and its use for treating COVID‐19.