Table 1.

Calculated binding affinities (in kcal/mol), 2D chemical structures and binding features for darunavir and the top five most promising cembranoid diterpenes against SARS-CoV-2 main protease (M^pro) ^a.

Compound Name (Number)	Genus	2D Chemical Structure	Docking Score (kcal/mol)	Binding Features b
Darunavir	---		−8.2	LEU167 (1.96 Å), GLU166 (1.94, 2.88 Å)
Sarelengan B (363)	S. elegans		−9.8	GLY143 (2.39 Å), GLU166 (1.94 Å), GLN189 (2.58 Å), THR190 (2.33 Å)
Bislatumlide A (340)	S. latum		−9.6	GLY143 (1.88 Å), GLU166 (2.68 Å)
Dioxanyalolide (347)	S. elegans		−9.5	GLU166 (2.07 Å)
Desacetylnyalolide (345)	S. elegans		−9.1	GLU166 (1.66, 2.12 Å), THR190 (2.42 Å)
Lobophytone W (357)	S. elegans		−8.7	HIS41 (2.01 Å), CYS145 (2.34 Å), GLU166 (2.35, 2.86 Å)

^a The potent Sarcophyton cembranoid diterpenes metabolites were selected based on latter MM-GBSA binding energy calculations. ^b Only hydrogen bonds (in Å) were displayed.