Table 3 shows the binding free energies of 3 small molecules including ivermectin. AFAIK higher energy implies a greater likelihood of binding.

Therefore, it can be suggested that the binding pocket of SARS-CoV-2 to ACE2 might be a potential target for drug discovery to disrupt the viral S protein/ACE2 interface.

I read this as "Ivermectin (etc.) can bind with the covid19 spike to prevent the virus from penetrating the cell via ACE2 receptors."

This figure (which I don't understand but nonetheless think is really cool) shows how ivermectin interacts with the ACE2 binding pocket.

Conclusion
In this study, based on structure-based virtual screening of clinically approved drugs and the crystallographic structure of SARS-CoV-2-RBD, several lead drugs were identified. The results obtained from docking pose analysis and molecular interactions between SARS-CoV-2-RBD and the lead drugs demonstrated that Diammonium Glycyrrhizinate, Digitoxin, Ivermectin, Rapamycin, Rifaximin, and Amphotericin B drugs had better binding affinities and conformation than other drugs, subsequently, among the selected lead drugs, MD simulation and binding free energy calculation were accomplished for three complexes with highest binding affinity: Diammonium Glycyrrhizinate and Digitoxin and Ivermectin. All three drugs were formed stable complexes with SARS-CoV-2-RBD during simulation periods. Additionally, binding free energy analysis showed that Diammonium Glycyrrhizinate had the lowest free energy of binding in SARS-CoV-2-RBD complex. The results of this study can be utilized for selecting candidate drugs for in vitro and in vivo surveys, and also can provide information for next studies.

Binding with covid19's RBD (the receptor-binding domain of the spike protein) prevents use of ACE2 for cell entry.

There's quite a lot of covid-19 research into Diammonium Glycyrrhizinate. For the molecule itself, there are 2136 entries in PubMed; 18 of those are covid-19 specific.

This one verifies the results of the posted study:

Glycyrrhizic acid exerts inhibitory activity against the spike protein of SARS-CoV-2

Abstract
Coronavirus causes a disease with high infectivity and pathogenicity, especially SARS in 2003, MERS in 2012, and COVID-2019 currently. The spike proteins of these coronaviruses are critical for host cell entry by receptors. Thus, searching for broad-spectrum anti-coronavirus candidates, such as spike protein inhibitors, is vital and desirable due to the mutations in the spike protein. In this study, a combination of computer-aided drug design and biological verification was used to discover active monomers from traditional Chinese medicine. Surface plasmon resonance (SPR) assays and NanoBit assays were used to verify the predicated compounds with their binding activities to spike proteins and inhibitory activities on the SARS-CoV-2 RBD/ACE2 interaction, respectively. Furthermore, an MTT assay was used to evaluate the cell toxicities of active compounds. As a result, glycyrrhizic acid (ZZY-44) was found to be the most efficient and nontoxic broad-spectrum anti-coronavirus molecule in vitro, especially, the significant effect on SARS-CoV-2, which provided a theoretical basis for the study of the pharmacodynamic material basis of traditional Chinese medicine against SARS-CoV-2 and offered a lead compound for further structural modification in order to obtain more effective candidate drugs against SARS-CoV-2.

This one suggests a tasty prophylaxis potential (I love licorice):

Symptomatic Protective Action of Glycyrrhizin (Licorice) in COVID-19 Infection?

Abstract The role of the ACE2 enzyme in the COVID-19 infection is 2-fold, with opposing implications for the disease development. 1. The membrane bound angiotensin converting enzyme 2 (ACE2) serves as the entry point of COVID-19 2. Conversely, it supports an anti-inflammatory pathway. This led to the controversy of the impact of medications, which influence its expression. ACE2 is part of the wider renin-angiotensin-aldosterone system (RAAS) and is upregulated via compounds, which inhibits the classical ACE, thereby plasma aldosterone and aldosterone receptor (MR) activation. MR activation may therefore protect organs from binding the COVID-19 by reducing ACE2 expression. Glycyrrhizin (GL) is a frequent component in traditional Chinese medicines, which have been used to control COVID-19 infections. Its systemically active metabolite glycyrrhetinic acid (GA) inhibits 11beta hydroxysteroid dehydrogenase(11betaHSD2) and activates MR in organs, which express this enzyme, including the lungs.

Does this affect the protective effect of ACE2? Importantly, GL has anti-inflammatory properties by itself via toll like receptor 4 (TLR4) antagonism and therefore compensates for the reduced protection of the downregulated ACE2. Finally, a direct effect of GL or GA to reduce virus transmission exists, which may involve reduced expression of type 2 transmembrane serine protease (TMPRSS2), which is required for virus uptake. Glycyrrhizin may reduce the severity of an infection with COVID-19 at the two stages of the COVID-19 induced disease process, 1. To block the number of entry points and 2. provide an ACE2 independent anti-inflammatory mechanism.

1. sounds like prophylaxis to me!

Looking at Amazon, glycyrrhizin is contraindicated for people with high blood pressure. Dammit.

Edit: I looked into glycyrrhizic-containing licorice a little and posted about it here.

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Would someone please post this study to /r/covid19? I'm banned there for a while because I stupidly posted about my vitamin D regimen (10000IU/day) which is strictly forbidden there. If you want my post with the links exposed so you can post them over there, let me know. I don't think my summary of the study is particularly good, though. I was just looking at ivermectin bits.

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Did somebody post it already?

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