Table 1.
Virtual screening and anti-proteolytic evaluation results for the biflavones.
| Compound | Docking analysis |
Anti-proteolytic activity |
||||
|---|---|---|---|---|---|---|
| CDOCKER scorea | Binding energyb | Hydrogen bondc | Interacting residues | IC50/μMd | Ki/μMe | |
| Biflavones | ||||||
| 1 | 58.1 | −129.6 | 6 | Lys157, Leu162, Arg166, Glu167, Asn267, Thr301 | 13.0 ± 1.2 | 9.1 ± 0.7 |
| 2 | 50.3 | −66.2 | 4 | Lys157, Leu162, Glu167, Thr301 | 43.2 ± 2.9 | 36.5 ± 4.2 |
| 3 | 55.6 | −117.2 | 5 | Lys157, Leu162, Asp164, Arg166, Gly266 | 29.8 ± 1.5 | 17.7 ± 1.1 |
| 4 | 57.6 | −123.5 | 4 | Lys157, Leu162, Asp164, Arg166 | 31.2 ± 3.4 | 26.5 ± 2.8 |
| 5 | 55.7 | −113.4 | 2 | Lys157, Leu162 | 34.8 ± 3.7 | 23.6 ± 1.3 |
| 6 | 43.1 | −81.6 | 1 | Arg166 | 36.4 ± 4.8 | 30.7 ± 2.9 |
| 7 | 50.9 | −119.1 | 5 | Lys157, Glu161, Asp164, Arg166, Gly266 | 9.5 ± 1.2 | 7.8 ± 0.5 |
| 8 | 47.8 | −87.9 | 3 | Lys157, Glu161, Arg166 | 26.3 ± 3.2 | 14.3 ± 1.0 |
| 9 | 48.1 | −105.2 | 4 | Lys157, Leu162, Arg166, Glu167 | 22.8 ± 0.9 | 19.7 ± 1.6 |
| Flavone monomers | ||||||
| Apigenin | 29.4 | −48.2 | 2 | Ala246, Tyr264 | 75.7 ± 6.4 | n.d.f |
| Acacetin | 28.3 | −38.7 | 1 | Tyr264 | 91.2 ± 11.3 | n.d. |
| Positive control | ||||||
| Psoralidin | 38.7 | −55.8 | 1 | Tyr264 | 27.8 ± 2.2 | n.d. |
a
Indicated as negative value of CDOCKER interaction energy.
b
presented in Kcal/mol.
c
Number of hydrogen bonds formed between inhibitor and PLpro.
d
Concentrations of 50% inhibition of PLpro anti-proteolytic activity, represented as mean ± SD.
e
Inhibition constant, determined by Dixon plots.
f
Not determined.