A group from Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan, etc. has reported that an extract from coffee leaf (Coffea Arabica) effectively inhibited five Variants of SARS-CoV-2 (Alpha, Beta, Gamma, Delta, and Omicron strain) from entering host cells.
https://www.ijbs.com/v18p4677.htm
At 100 μg/ml, coffee leaf extract had a significant inhibitory effect on the infection of five VOC (Alpha, Beta, Gamma, Delta, and Omicron strain) pseudoviral SARS-CoV-2 as shown below.
In the coffee extract, four main compounds, including caffeine, CGA, quinic acid, and mangiferin, were identified. ACE2 TR-FRET Assay was used to evaluate inhibitory effect of Spike-ACE2 interactions. Due to the nature of the compounds, mangiferin and CGA were soluble in DMSO, and caffeine and quinic acid were soluble in water. It was demonstrated that treatment with four main compounds could inhibit the activity of Spike-ACE2.