Table 7.

Detailed analysis of selected drugs with spike glycoprotein RBD model involving significant interactions.

Sr.No.	Drug	Significant spike RBD model interacting residues	Bond Type	Bond Length (in Å)	Interacting residues of Actual spike Glycoprotein		Precise Loop Interactions	Contact residues of the SARS-CoV-2 RBD–ACE2	Cysteine residue interactions
					RBD (319–541)	RBM (437–508)
1	Tenofovir	W436	Conventional Hydrogen bond	2.62	Yes	No	No	No	No
		F342	Carbon Hydrogen bond	3.30	Yes	No	No	No	No
		W436	Electrostatic (pi-anion)	3.48	Yes	No	No	No	No
		L441*	Hydrophobic (pi-sigma)	3.58	Yes	Yes	2 g	No	No
		W436	Hydrophobic (pi-sigma)	3.80	Yes	No	No	No	No
2	Eugenol	E471	Carbon Hydrogen bond	3.30	Yes	Yes	3a	No	No
		E471	Carbon Hydrogen bond	3.29	Yes	Yes	3a	No	No
		D467	Electrostatic (pi-anion)	3.74	Yes	Yes	No	No	No
		K458	Hydrophobic (pi-sigma)	3.81	Yes	Yes	2 g	No	No
3	Allicin	E471	Electrostatic interaction	3.78	Yes	Yes	3a	No	No
		K458	Hydrogen bond	2.70	Yes	Yes	2 g	No	No
		S469	Hydrogen bond	3.08	Yes	Yes	No	No	No
		P491	Hydrophobic interaction	3.98	Yes	Yes	3 b	No	No
4	Stavudine	Y453	Conventional Hydrogen bond	2.35	Yes	Yes	2 g	Yes	No
		N501*	Conventional Hydrogen bond	3.05	Yes	Yes	3f	Yes	No
		R403*	Carbon Hydrogen bond	3.30	Yes	Yes	1e	No	No
		Y495	Carbon Hydrogen bond	3.23	Yes	Yes	3f	No	No
		S494	Carbon Hydrogen bond	3.30	Yes	Yes	3 b	No	No
5	Raltegravir	S349	Conventional Hydrogen bond	2.59	Yes	No	No	No	No
		S399	Conventional Hydrogen bond	2.98	Yes	No	No	No	No
		S349	Conventional Hydrogen bond	2.96	Yes	No	No	No	No
		F347	Conventional Hydrogen bond	2.90	Yes	No	No	No	No
		L441*	Halogen (Fluorine)	3.65	Yes	Yes	2 g	Yes	No
		N354	Pi-Donor Hydrogen bond	2.44	Yes	No	No	No	No
		A348	Hydrophobic (alkyl)	3.54	Yes	No	No	No	No
6	Zalcitabine	R403*	Carbon Hydrogen bond	3.30	Yes	No	1e	No	No
7	Favipiravir	R403*	Conventional Hydrogen bond	3.05	Yes	No	1e	No	No
		Y505	Conventional Hydrogen bond	3.30	Yes	Yes	3f	Yes	No
		R403*	Carbon Hydrogen bond	3.40	Yes	No	1e	No	No
8	Camostat	L441*	Conventional Hydrogen bond	2.91	Yes	Yes	2 g	No	No
		N354	Carbon Hydrogen bond	3.30	Yes	No	No	No	No
9	Doxycycline	Y449	Conventional Hydrogen bond	1.87	Yes	Yes	2 g	Yes	No
		N501*	Conventional Hydrogen bond	2.35	Yes	Yes	3f	Yes	No
		S494	Conventional Hydrogen bond	3.22	Yes	Yes	3 b	No	No
		Y505	Hydrophobic (pi-sigma)	3.63	Yes	Yes	3f	Yes	No
10	Ivermectin	G381	Conventional Hydrogen bond	2.32	Yes	No	No	No	No
		F377	Carbon Hydrogen bond	2.99	Yes	No	No	No	No
		Y380	Carbon Hydrogen bond	3.74	Yes	No	No	No	No
		C379	Sulfur-X	2.99	Yes	No	No	No	Yes
		Y369	Pi-Donor Hydrogen bond	3.28	Yes	No	No	No	No

RBD = Receptor Binding Domain; RBM = Receptor Binding Motif; ACE-2 = Angiotensin Converting Enzyme type II; * = Possible mutated amino acids in SARS-CoV-2.