Table 1.
List of test ingredients used for the in vitro screening.
Fig 1.
Screening of toothpaste and mouthwash ingredients exhibited inhibitory effects on the interaction between the spike protein RBD of SARS-CoV-2 and ACE2.
Eighteen toothpaste and mouthwash ingredients at 1% (w/w) exhibited inhibitory effects interaction between the spike protein of SARS-CoV-2 and ACE2 in vitro. The interaction between the spike protein RBD of SARS-CoV-2 and ACE2 was evaluated by measuring AV at 450 nm using a microplate reader. Data are expressed as the mean ± SD (n = 3).
Fig 2.
Effect of ingredient concentration on inhibitory effects of the interaction between the spike protein of SARS-CoV-2 and ACE2.
The dose-response inhibitory effects of interaction between spike protein of SARS-CoV-2 and ACE2 for (A) Sodium tetradecene sulfonate, (B) Sodium N-lauroyl-N-methyltaurate, (C) Sodium N-lauroylsarcosinate, (D) Copper gluconate, and (E) Sodium dodecyl sulfate are shown. The data were plotted and modeled by a four-parameter Log-logistic fit (A–D) and a four-parameter Brain–Cousens fit (E) to determine the 50% inhibitory concentration (IC50) value. All data points were expressed as the mean ± SD (n = 3).
Fig 3.
Screening of toothpaste and mouthwash ingredients exhibited inhibitory effects on the serine protease activity of TMPRSS2.
Eighteen toothpaste and mouthwash ingredients at 1% (w/w) exhibited inhibitory effects on the TMPRSS2 serine protease activity. TMPRSS2 cleaved Boc-Gln-Ala-Arg-MCA as the substrate and produced the potent fluorophore, AMC (7-amino-4-methylcoumarin). Values were normalized against the intensity of the absence of test ingredients. Data are expressed as the mean ± SD (n = 3).
Fig 4.
Effect of ingredient concentration on inhibitory effects of serine protease activity of TMPRSS2.
The dose-response inhibitory effects of TMPRSS2 serine protease activity by (A) Sodium dodecyl sulfate, (B) Sodium tetradecene sulfonate, (C) Copper gluconate, (D) Tranexamic acid, (E) Sodium N-lauroyl-N-methyltaurate, (F) Sodium N-lauroylsarcosinate, and (G) 6-aminohexanoic acid are shown. The data were plotted and modeled by a four-parameter Log-logistic fit to determine the 50% inhibitory concentration (IC50) value. All data points expressed as the mean ± SD (n = 3).
Fig 5.
Re-docking studies for human ACE2 and human TMPRSS2 model with their crystal inhibitors.
(A, B) Human ACE2. (C, D) Human TMPRSS2 model. The most stable docking mode of crystal inhibitor shows in CPK color using tubes. The original crystal structure of the inhibitor is represented by black tubes. A magenta sphere shows Zn2+ ion and a green sphere shows the Cl− ion. The inhibitor-binding site located at 3 Å from all heavy atoms of the crystal inhibitor is shown in cyan color. Amino acid residues located at 3 Å from the inhibitor are shown using thin tubes with label. Hydrogen atoms are neglected.
Fig 6.
Stable docking mode of the selected ingredients obtained from AutoDock Vina docking simulations.
(A) Human ACE2. (B) Human TMPRSS2 model. Stable docking mode of test compounds is shown as CPK-colored tubes. The original crystal structure of the inhibitor is shown in black lines. A magenta sphere shows Zn2+ ion. Inhibitor-binding site located at 3 Å from all heavy atoms of the crystal inhibitor is shown in cyan color. Amino acid residues located at 3 Å from the inhibitor are shown using thin tubes with label. Hydrogen atoms are neglected.
Table 2.
Test ingredients subjected to docking simulations.
Table 3.
Vina score of test ingredients for human ACE2.
Table 4.
Vina score of test ingredients for human TMPRSS2 model.