Table 4 Physicochemical properties of the top binding terpenoids from African plants to ACE2, TMPRSS2, and S protein of SARS-Cov-2

 Lipinski filters

T1

T3

T5

T6

 Molecular weight (g/mol)

454.77

450.52

402.48

558.70

 Num. heavy atoms

33

33

30

40

 Num. rotatable bonds

5

4

4

6

 Num. H-bond acceptors

1

6

4

8

 Hydrogen bond donor

1

3

0

3

 MLogP

7.30

2.96

3.79

1.76

 Molar refractivity

144.50

126.11

116.15

150.94

 Lipinski violation

1

0

0

1

  Blood-brain barrier

BBB+ (0.96)

BBB+ (0.60)

BBB+ (0.61)

BBB+ (0.81)

  Human intestinal absorption

HIA+ (0.99)

HIA+ (0.92)

HIA+ (0.92)

HIA+ (0.97)

  Bioavailability score

0.55

0.55

0.55

0.55

  Caco-2 permeability

Caco2+ (0.79)

Caco2+ (0.59)

Caco2+ (0.59)

Caco2+ (0.61)

  P-glycoprotein substrate

Substrate (0.73)

Substrate (0.78)

Non-inhibitor (0.58)

Substrate (0.79)

  P-glycoprotein inhibitor

Non-inhibitor (0.65)

Non-inhibitor (0.74)

Non-inhibitor (0.74)

Non-inhibitor (0.61)

  Renal organic cation transporter

Inhibitor (0.75)

Inhibitor (0.90)

Non-inhibitor (0.90)

Non-inhibitor (0.87)

  Subcellular localization

Lysosome (0.55)

Mitochondria (0.86)

Mitochondria (0.86)

Mitochondria (0.77)

  CYP450 substrate

Substrate (0.77)

Non-inhibitor (0.78)

Substrate

Non-inhibitor (0.83)

Non-substrate (0.65)

inhibitor (0.80)

Inhibitor (0.79)

Non-substrate (0.83)

  AMES toxicity

Non-AMES toxic (0.71)

AMES toxic (0.87)

Non-AMES toxic (0.87)

Non-AMES toxic (0.84)

  Carcinogens

Non-carcinogens (0.92)

Non-carcinogens (0.90)

Non-carcinogens (0.90)

Non-carcinogens (0.92)

  Acute oral toxicity

III (0.77)

III (0.59)

III (0.57)

I (0.78)

  Rat acute toxicity LD₅₀, mol/kg

3.2804

2.5370

2.5370

3.8742

  Aqueous solubility (LogS)

− 4.76258

− 4.5550

− 4.7201

− 4.5035

  Lower GI absorption

Low

High

High

Low

  Log K_p (skin permeation) cm/s

− 1.48

− 5.58

− 5.33

− 7.83