Chemical composition of Scutellaria baicalensis Georgi. (Huangqin) extracts, their effects on ACE2 binding of SARS-CoV-2 spike protein, ACE2 activity, and free radicals

Authors: GAO, BOYAN - Shanghai Jiaotong University; ZHU, HANSHU - Shanghai Jiaotong University; LIU, ZHIHAO - University Of Maryland; He, Xiaohua; Sun, Jianghao; LI, YANFANG - University Of Maryland; Wu, Xianli; Pehrsson, Pamela; ZHANG, YAQIONG - Shanghai Jiaotong University; YU, LIANGLI - University Of Maryland

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/1/2024
Publication Date: 2/7/2024
Citation: Gao, B., Zhu, H., Liu, Z., He, X., Sun, J., Li, Y., Wu, X., Pehrsson, P.R., Zhang, Y., Yu, L. 2024. Chemical composition of Scutellaria baicalensis Georgi. (Huangqin) extracts, their effects on ACE2 binding of SARS-CoV-2 spike protein, ACE2 activity, and free radicals. International Journal of Molecular Sciences. 25(4). Article 2045. https://doi.org/10.3390/ijms25042045.
DOI: https://doi.org/10.3390/ijms25042045

Interpretive Summary: The root of Scutellaria baicalensis was named Huangqin, and has been used for centuries in traditional Chinese medicine for its biological properties. Huangqin has been shown to have antitumor, antibacterial and anti-viral activities in clinical studies. The flavonoids are considered as its primary active components. Flavonoids have been shown to be a promising therapeutic intervention for several health problems in in silico, in vitro, in vivo, and clinical studies, as they act on different targets while producing less toxicity. Scutellarein, baicalein and oroxylin A are the flavonoid compounds detected in Huangqin, and have been tested and verified by molecular docking and in vitro studies with preventive effects against SARS-CoV-2 infection via inhibiting chymotrypsin-like protease (3CLpro) activity, which is responsible for the maturation of nonstructural proteins in virus. Therefore, this study was conducted to investigate the chemical compositions of Huangqin water and ethanol extracts, their inhibitory effects on SARS-CoV-2 to ACE2 binding and ACE2 activity, and their free radical scavenging capacities. The results give information on potential ability of Huangqin to intervene in ACE2-mediated SARS-CoV-2 infection, and provide a scientific foundation for the development of preventive and therapeutic agents from Huangqin against COVID-19.

Technical Abstract: The water and ethanol extracts of Huangqin, the roots of Scutellaria baicalensis Georgi. with potential antiviral properties and antioxidant activities, were investigated for their chemical profiles and their abilities in interfering the interaction between SARS-CoV-2 spike protein and ACE2, inhibiting ACE2 activity and scavenging free radicals. A total of 76 compounds were tentatively identified from the extracts. The water extract showed a greater inhibition on the interaction between SARS-CoV-2 spike protein and ACE2, but less inhibition on ACE2 activity than that of the ethanol extract on a per botanical weight concentration basis. The total phenolic content was 65.27 mg gal-lic acid equivalent (GAE)/g dry botanical and the scavenging capacity against HO', DPPH' and ABTS'+ were 1369.39, 334.37 and 533.66 µmol trolox equivalent (TE)/g dry botanical for the water extract, respectively. These values were greater than those of the ethanol extract with a TPC of 20.34 mg GAE/g, and 217.17, 10.93, 50.21 µmol TE/g against HO', DPPH' and ABTS'+, respectively. The results suggested the potential use of Huangqin as a functional food ingredient in preventing COVID-19.