Search

Cell membrane chromatography is an effective method for screening bioactive components acting on specific receptors in complex systems, which maintains the biological activity of the membrane receptors and improves screening efficiency. However, traditional cell membrane chromatography suffers from poor stability, resulting in a limited life span and low reproducibility, greatly limiting the application of this method. To address this problem, cyanuric chloride‐decorated silica gel was used for the covalent immobilization of the cell membranes. Cyanuric chloride reacts with amino groups on the cell membranes and membrane receptors to form covalent bonds. In this way, the cell membranes are not easy to fall off. The column life of the cyanuric chloride‐decorated epidermal growth factor receptor/cell membrane chromatography column was extended to more than 8 days, whereas the column life of the normal cell membrane chromatography column dropped sharply in the first 3 days. A cyanuric chloride‐decorated epidermal growth factor receptor/cell membrane chromatography online HPLC‐IT‐TOF‐MSn system was applied for screening drug leads from Trifolium pratense L. One potential drug lead, formononetin, which acts on the epidermal growth factor receptor, was screened. Our strategy of covalently immobilizing cell membrane receptors also improved the stability of cell membrane chromatography. [ABSTRACT FROM AUTHOR]

Chloroquine and hydroxychloroquine have been studied since the early clinical treatment of SARS‐CoV‐2 outbreak. Considering these two chiral drugs are currently in use as the racemate, high‐expression angiotensin‐converting enzyme 2 cell membrane chromatography was established for investigating the differences of two paired enantiomers binding to angiotensin‐converting enzyme 2 receptor. Molecular docking assay and detection of SARS‐CoV‐2 spike pseudotyped virus entry into angiotensin‐converting enzyme 2‐HEK293T cells were also conducted for further investigation. Results showed that each single enantiomer could bind well to angiotensin‐converting enzyme 2, but there were differences between the paired enantiomers and corresponding racemate in frontal analysis. R‐Chloroquine showed better angiotensin‐converting enzyme 2 receptor binding ability compared to S‐chloroquine/chloroquine (racemate). S‐Hydroxychloroquine showed better angiotensin‐converting enzyme 2 receptor binding ability than R‐hydroxychloroquine/hydroxychloroquine. Moreover, each single enantiomer was proved effective compared with the control group; compared with S‐chloroquine or the racemate, R‐chloroquine showed better inhibitory effects at the same concentration. As for hydroxychloroquine, R‐hydroxychloroquine showed better inhibitory effects than S‐hydroxychloroquine, but it slightly worse than the racemate. In conclusion, R‐chloroquine showed better angiotensin‐converting enzyme 2 receptor binding ability and inhibitory effects compared to S‐chloroquine/chloroquine (racemate). S‐Hydroxychloroquine showed better angiotensin‐converting enzyme 2 receptor binding ability than R‐hydroxychloroquine/hydroxychloroquine (racemate), while the effect of preventing SARS‐CoV‐2 pseudovirus from entering cells was weaker than R‐hydroxychloroquine/hydroxychloroquine (racemate). [ABSTRACT FROM AUTHOR]

The current worldwide outbreak of the coronavirus disease 2019 (COVID‐19) has been declared a public health emergency. The angiotensin‐converting enzyme II (ACE2) has been reported as the primary host‐cell receptor for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), the causative virus of COVID‐19. In this study, we screened ACE2 ligands from Radix Scutellariae and investigated its suppressive effect on SARS‐CoV‐2 spiked pseudotyped virus in vitro. HEK293T cells stably expressing ACE2 receptors (ACE2 cells) were used to provide the receptor for the ACE2/cell membrane chromatography (CMC) method used for analysis. The SARS‐CoV‐2‐spiked pseudotyped virus was used to examine the anti‐viropexis effect of the screened compounds in ACE2 cells. Molecular docking and the surface plasmon resonance (SPR) assay were used to determine the binding properties. Oroxylin A exhibited an appreciable suppressive effect against the entrance of the SARS‐CoV‐2‐spiked pseudotyped virus into ACE2 cells, which showed good binding to ACE2 as determined using SPR and CMC. Oroxylin A was shown to be a potential candidate in the treatment for COVID‐19 by virtue of its blocking the entrance of SARS‐CoV‐2 into ACE2 cells by specifically binding to the ACE2 receptor. [ABSTRACT FROM AUTHOR]

Adverse drug reactions of traditional Chinese medicine injection mainly manifested as pseudo‐allergic reactions. In the present study, ginsenoside Rd, Ro, and Rg3 were identified as pseudo‐allergic components in Shengmai injection by a high‐expression Mas‐related G protein‐coupled receptor X2 cell membrane chromatography coupled online with high‐performance liquid chromatography and mass spectrometry. Their pseudo‐allergic activities were evaluated by in vitro and in vivo assay. The three compounds were further found to induce pseudo‐allergic reaction through Mas‐related G protein‐coupled receptor X2. Therefore, we concluded that ginsenoside Rd, Ro and Rg3 may be potential allergens that cause pseudo‐allergic reactions. This study might be helpful for the safe use of Shengmai injection. [ABSTRACT FROM AUTHOR]