Table 2.

IC₅₀ values of honokiol thioethers against the entry of SARS-CoV-2 spike pseudovirus into HEK-293 T-ACE2^h cells.

Compound	Substituent R	CC0 (µM) for 4 h	IC50 (µM) against pseudovirus entry
7a	–Ph	>100	>100
7b	–(2-F)Ph	>100	>100
7c	–(3-F)Ph	>100	>100
7d	–(4-F)Ph	>100	>100
7e	–(2-Cl)Ph	>100	84.35 ± 5.58
7f	–(3-Cl)Ph	>100	>100
7g	–(4-Cl)Ph	>100	>100
7h	–(2-Br)Ph	>100	>100
7i	–(3-Br)Ph	>100	>100
7j	–(4-Br)Ph	>100	>100
7k	–(2-CH3)Ph	>100	>100
7l	–(3-CH3)Ph	>100	>100
7m	–(4-CH3)Ph	>100	>100
7n	–(2-OCH3)Ph	>100	>100
7o	–(3-OCH3)Ph	>100	>100
7p	–(4-OCH3)Ph	>100	>100
9a	-Ph	>100	16.96 ± 2.45
9b	–(2-F)Ph	>100	>100
9e	–(2-Cl)Ph	>100	85.18 ± 12.76
9k	–(2-CH3)Ph	>100	>100
9r	3-pyridyl	>100	45.61 ± 4.66
honokiol	/	50.00	>50
Evans blue	/	>100	21.98 ± 1.98