Cannabis L. (Cannabis sativa)
Cannabidiol, a major phytocannabinoid, as a potent atypical inhibitor for CYP2D6. CSV JSON

Δ(9)-Tetrahydrocannabinol, cannabidiol (CBD), and cannabinol are the three major cannabinoids contained in marijuana, which are devoid of nitrogen atoms in their structures. In this study, we investigated the inhibitory effects of the major phytocannabinoids on the catalytic activity of human CYP2D6. These major cannabinoids inhibited the 3-[2-(N,N-diethyl-N-methylammonium)ethyl]-7-methoxy-4-methylcoumarin (AMMC) and dextromethorphan O-demethylase activities of recombinant CYP2D6 and pooled human liver microsomes in a concentration-dependent manner (IC(50) = 4.01-24.9 μM), indicating the strongest inhibitory potency of CBD. However, these cannabinoids showed no or weak metabolism-dependent inhibition. CBD competitively inhibited the CYP2D6 activities with the apparent K(i) values of 1.16 to 2.69 μM. To clarify the structural requirement for CBD-mediated CYP2D6 inhibition, effects of CBD-related compounds on the AMMC O-demethylase activity of recombinant CYP2D6 were examined. Olivetol (IC(50) = 7.21 μM) inhibited CYP2D6 activity as potently as CBD did (IC(50) = 6.52 μM), whereas d-limonene did not show any inhibitory effect. Pentylbenzene failed to inhibit CYP2D6 activity. Furthermore, neither monomethyl nor dimethyl ethers of CBD inhibited the activity. Cannabidivarin having a propyl side chain inhibited CYP2D6 activity; its inhibitory effect (IC(50) = 10.2 μM) was less potent than that of CBD. On the other hand, orcinol and resorcinol showed lack of inhibition. The inhibitory effect of CBD on CYP2D6 activity was more potent than those of 16 compounds without nitrogen atoms tested, such as progesterone. These results indicated that CBD caused potent direct CYP2D6 inhibition, in which two phenolic hydroxyl groups and the pentyl side chain of CBD may play important roles.

1 . Recombinant: CBD-AMMC (id=NPDI-8jlF2g)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

  • CYP2D6 4173631

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Table 1
Figure 3

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

2pmol

Commercially available

200 μL

30 min

MgCl2
NADPH regenerating system

0.24-15 μM

5 min

NADPH with precipitant

2 . Recombinant: CBDV-AMMC (id=NPDI-iDzluw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

  • CYP2D6 4173631

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Figure 5
Figure 4E

  • Ki at log(-4.4) (concentration estimated)

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

2pmol

Commercially available

200 μL

30 min

MgCl2
NADPH regenerating system

0.24-15 μM

5 min

NADPH with precipitant

3 . Recombinant: CBN-AMMC (id=NPDI-b-kubA)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

  • CYP2D6 4173631

Cell fraction Pooled human liver microsomes -7999662

Results

Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

2pmol

Commercially available

200 μL

30 min

MgCl2
NADPH regenerating system

0.24-15 μM

5 min

NADPH with precipitant

4 . Recombinant: THC-AMMC (id=NPDI-XBXjow)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

  • CYP2D6 4173631

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Table 1 (AMMC)
Table 3 (20 min)

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

2pmol

Commercially available

200 μL

30 min

MgCl2
NADPH regenerating system

0.24-15 μM

5 min

NADPH with precipitant

5 . Recombinant: CBD-dextromethorphan (id=NPDI-THQe_g)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

dextromethorphan 1119510

cannabidiol

dextrorphan 4349487

  • CYP2D6 4173631

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Table 1
Figure 3

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.25 pmol

Commercially available

200 μL

10 min

MgCl2
NADPH regenerating system

0.15-24 μM

5 min

NADPH with precipitant

6 . pHLM: CBD-dextromethorphan (id=NPDI-ckGWRw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

dextromethorphan 1119510

cannabidiol

dextrorphan 4349487

  • CYP2D6 4173631

Cell fraction Pooled human liver microsomes -7999662

Results

Table 1
Figure 3

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.25 pmol

Commercially available

200 μL

10 min

MgCl2
NADPH regenerating system

0.15-24 μM

5 min

NADPH with precipitant

7 . pHLM: CBN-dextromethorphan (id=NPDI-p2jqFw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

dextromethorphan 1119510

cannabinol

dextrorphan 4349487

  • CYP2D6 4173631

Cell fraction Pooled human liver microsomes -7999662

Results

Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.25 pmol

Commercially available

200 μL

10 min

MgCl2
NADPH regenerating system

0.15-24 μM

5 min

NADPH with precipitant

8 . Recombinant: CBN-dextromethorphan (id=NPDI-0g58zw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

dextromethorphan 1119510

cannabinol

dextrorphan 4349487

  • CYP2D6 4173631

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.25 pmol

Commercially available

200 μL

10 min

MgCl2
NADPH regenerating system

0.15-24 μM

5 min

NADPH with precipitant

9 . Recombinant: THC-dextramethorphan (id=NPDI-Hsp-vg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

dextromethorphan 1119510

dextrorphan 4349487

  • CYP2D6 4173631

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.25 pmol

Commercially available

200 μL

10 min

MgCl2
NADPH regenerating system

0.15-24 μM

5 min

NADPH with precipitant

10 . HLMs: THC-dextromethorphan (id=NPDI-KQoVKg)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

dextromethorphan 1119510

dextrorphan 4349487

  • CYP2D6 4173631

Cell fraction Pooled human liver microsomes -7999662

Results

Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

0.25 pmol

Commercially available

200 μL

10 min

MgCl2
NADPH regenerating system

0.15-24 μM

5 min

NADPH with precipitant

11 . Recombinant: CBDD-AMMC (id=NPDI-F3DjaQ)

In Vitro Enzyme Inhibition Experiment

Negligible Inhibition was detected.  Cutoff used — Not specified

  • CYP2D6 4173631

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Figure 4E

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

2pmol

Commercially available

200 μL

30 min

MgCl2
NADPH regenerating system

0.24-15 μM

5 min

NADPH with precipitant

12 . Recombinant: CBDM-AMMC (id=NPDI-y29wsw)

In Vitro Enzyme Inhibition Experiment

Negligible Inhibition was detected.  Cutoff used — Not specified

  • CYP2D6 4173631

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

Figure 4C

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

2pmol

Commercially available

200 μL

30 min

MgCl2
NADPH regenerating system

0.24-15 μM

5 min

NADPH with precipitant