Cannabis L. (Cannabis sativa)
Characterization of major phytocannabinoids, cannabidiol and cannabinol, as isoform-selective and potent inhibitors of human CYP1 enzymes CSV JSON

Inhibitory effects of Delta(9)-tetrahydrocannabinol (Delta(9)-THC), cannabidiol (CBD), and cannabinol (CBN), the three major constituents in marijuana, on catalytic activities of human cytochrome P450 (CYP) 1 enzymes were investigated. These cannabinoids inhibited 7-ethoxyresorufin O-deethylase activity of recombinant CYP1A1, CYP1A2, and CYP1B1 in a competitive manner. CBD most potently inhibited the CYP1A1 activity; the apparent K(i) value (0.155microM) was at least one-seventeenth of the values for other CYP1 isoforms. On the other hand, CBN more effectively decreased the activity of CYP1A2 and CYP1B1 (K(i)=0.0790 and 0.148microM, respectively) compared with CYP1A1 (K(i)=0.541microM). Delta(9)-THC less potently inhibited the CYP1 activity than CBD and CBN, and showed low selectivity against the CYP1 inhibition (K(i)=2.47-7.54microM). The preincubation of CBD resulted in a time- and concentration-dependent decrease in catalytic activity of all the recombinant CYP1 enzymes and human liver microsomes. Similarly, the preincubation of Delta(9)-THC or CBN caused a time- and concentration-dependent inhibition of recombinant CYP1A1. The inactivation of CYP1A1 by CBD indicated the highest k(inact)/K(I) value (540l/mmol/min) among the CYP1 enzyme sources tested. The inactivation of recombinant CYP1A1 and human liver microsomes by CBD required NADPH, was not influenced by dialysis and by glutathione, N-acetylcysteine, and superoxide dismutase as trapping agents. These results indicated that CBD and CBN showed CYP1 isoform-selective direct inhibition and that CBD was characterized as a potent mechanism-based inhibitor of human CYP1 enzymes, especially CYP1A1.

PMID: 20117100

20117100

1 . HLMs: CBD (id=NPDI-bxWjqg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

cannabidiol (cbd)

resorufin -7999853

  • CYP1A1 4173297

Cell fraction Pooled human liver microsomes -7999662

Results

Tables 2 and 3.
IC50 at 20 min

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

5 μg

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM

2 . 1A1: CBD (id=NPDI-jYDUsw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

cannabidiol (cbd)

resorufin -7999853

  • CYP1A1 4173297

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Tables 2, 3, and 4. 
IC50 at 20 min.
Fig 4. % inhibition estimated with 0.625 μM
Fig 5. With NADPH at 9 min

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

10 fmol

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM

3 . 1A2: CBD (id=NPDI-FompNA)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

cannabidiol (cbd)

resorufin -7999853

  • CYP1A2 4312402

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Tables 2, 3, and 4
IC50 at 20 min

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

60 fmol

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM

4 . HLMs: CBN (id=NPDI-XKoD2A)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

cannabinol (cbn)

resorufin -7999853

  • CYP1A1 4173297

Cell fraction Pooled human liver microsomes -7999662

Results

Tables 2 and 3.
IC50 at 20 min

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

5 μg

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM

5 . 1A2: CBN (id=NPDI-RC8Kxw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

cannabinol (cbn)

resorufin -7999853

  • CYP1A2 4312402

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Tables 2 and 3
IC50 at 20 min

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

60 fmol

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM

6 . 1A1: CBN (id=NPDI-v65nxg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

cannabinol (cbn)

resorufin -7999853

  • CYP1A1 4173297

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Tables 2, 3, and 4
IC50 at 20 min

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

10 fmol

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM

7 . HLMs: THC (id=NPDI-DQGnJw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

resorufin -7999853

  • CYP1A1 4173297

Cell fraction Pooled human liver microsomes -7999662

Results

Tables 2 and 3.
IC50 at 20 min

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

5 μg

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM

8 . 1A2: THC (id=NPDI-F-0XWg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

resorufin -7999853

  • CYP1A2 4312402

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Tables 2 and 3
IC50 at 20 min
Fig 4. %inhibition estimated for 8 μM

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

60 fmol

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM

9 . 1A1: THC (id=NPDI-4tAywg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

resorufin -7999853

  • CYP1A1 4173297

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Tables 2, 3, and 4
IC50 at 20 min

Sample Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

96-well

10 fmol

Commercially available

200 μL

30 min

NADPH

150 nM

5 min

No NADPH with precipitant

0.025-25 μM