TABLE 2.

Natural compounds targeting host proteins: ACE2 (VII), TMPRSS2 (VIII), and CatL (IX).

No	Compound	IC50	Target	References
20	Apigenin	280.00 μM	ACE2	Loizzo et al. (2007)
21	Luteolin	290.00 μM	ACE2	Loizzo et al. (2007)
129	Kaempferol-3-O-α-arabinopyranoside	320.00 μM	ACE2	Loizzo et al. (2007)
130	Kaempferol-3-O-β-galactopyranoside	260.00 μM	ACE2	Loizzo et al. (2007)
131	Quercetin-3-O-α-arabinopyranoside	310.00 μM	ACE2	Loizzo et al. (2007)
132	Luteolin-7-O-β-glucopyranoside	280.00 μM	ACE2	Loizzo et al. (2007)
133	Nicotianamine	84.00 nM	ACE2	Takahashi et al. (2015)
134	Aprotinin	No data	TMPRSS2	Shen et al. (2017)
25	Tannic acid	2.31 μM	TMPRSS2	Wang et al. (2020)
32	Celastrol	No data	TMPRSS2	(Fernandez-Quintela et al., 2020; Habtemariam et al., 2020)
135	Leupeptin	No data	Cathepsin L	(Salminen and Gottesman, 1990; Nishimura et al., 1995)
136	Gallinamide A	5.00 nM	Cathepsin L	Miller et al. (2014)
137	Panduratin A	1.50 μM	Cathepsin L	Deb Majumdar et al. (2011)
138	Nicolaidesin C	1.00 μM	Cathepsin L	Deb Majumdar et al. (2011)
139	Grassypeptolide A	14.00 μM	Cathepsin L	Kwan et al. (2014)
140	Grassypeptolide B	21.30 μM	Cathepsin L	Kwan et al. (2014)
141	Grassypeptolide C	20.40 μM	Cathepsin L	Kwan et al. (2014)