Chemical Compositions of Clove (Syzygium aromaticum (L.) Merr. & L.) Extracts and Their Potentials in Suppressing SARS-CoV‑2 Spike Protein–ACE2 Binding, Inhibiting ACE2, and Scavenging Free Radicals

• Published in: Journal of agricultural and food chemistry 2022-11, Vol.70 (45), p.14403-14413
• Main Authors: Li, Yanfang, Liu, Zhihao, Zeng, Melody, El Kadiri, Alem, Huang, Jhongyan, Kim, Ashley, He, Xiaohua, Sun, Jianghao, Chen, Pei, Wang, Thomas T. Y., Zhang, Yaqiong, Gao, Boyan, Xie, Zhuohong, Yu, Liangli Lucy
• Format: Article
• Language: English
• Subjects: Bioactive Constituents, Metabolites, and Functions
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.2c06300

COVID-19 is initiated by binding the SARS-CoV-2 spike protein to angiotensin-converting enzyme 2 (ACE2) on host cells. Food factors capable of suppressing the binding between the SARS-CoV-2 spike protein and ACE2 or reducing the ACE2 availability through ACE2 inhibitions may potentially reduce the risk of SARS-CoV-2 infection and COVID-19. In this study, the chemical compositions of clove water and ethanol extracts were investigated, along with their potentials in suppressing SARS-CoV-2 spike protein–ACE2 binding, reducing ACE2 availability, and scavenging free radicals. Thirty-four compounds were tentatively identified in the clove water and ethanol extracts, with six reported in clove for the first time. Clove water and ethanol extracts dose-dependently suppressed SARS-CoV-2 spike protein binding to ACE2 and inhibited ACE2 activity. The water extract had stronger inhibitory effects than the ethanol extract on a dry weight basis. The clove water extract also had more potent free radical scavenging activities against DPPH• and ABTS•+ (536.9 and 3525.06 μmol TE/g, respectively) than the ethanol extract (58.44 and 2298.01 μmol TE/g, respectively). In contrast, the ethanol extract had greater total phenolic content (TPC) and relative HO• scavenging capacity (HOSC) values (180.03 mg GAE/g and 2181.08 μmol TE/g, respectively) than the water extract (120.12 mg GAE/g and 1483.02 μmol TE/g, respectively). The present study demonstrated the potential of clove in reducing the risk of SARS-CoV-2 infection and COVID-19 development.