Cannabis L. (Cannabis sativa)
Structural requirements for potent direct inhibition of human cytochrome P450 1A1 by cannabidiol: role of pentylresorcinol moiety. CSV JSON

Our recent work has shown that cannabidiol (CBD) exhibits the most potent direct inhibition of human cytochrome P450 1A1 (CYP1A1) among the CYP enzymes examined. However, the mechanism underlying this CBD inhibition remains to be clarified. Thus, to elucidate the structural requirements for the potent inhibition by CBD, the effects of CBD and its structurally related compounds on CYP1A1 activity were investigated with recombinant human CYP1A1. Olivetol, which corresponds to the pentylresorcinol moiety of CBD, inhibited the 7-ethoxyresorufin O-deethylase activity of CYP1A1; its inhibitory effect (IC50=13.8 µM) was less potent than that of CBD (IC50=0.355 µM). In contrast, d-limonene, which corresponds to the terpene moiety of CBD, only slightly inhibited CYP1A1 activity. CBD-2'-monomethyl ether (CBDM) and CBD-2',6'-dimethyl ether inhibited CYP1A1 activity with IC50 values of 4.07 and 23.0 µM, respectively, indicating that their inhibitory effects attenuated depending on the level of methylation on the free phenolic hydroxyl groups in the pentylresorcinol moiety of CBD. Cannabidivarin inhibited CYP1A1 activity, although its inhibitory potency (IC50=1.85 µM) was lower than that of CBD. The inhibitory effects of Δ(9)-tetrahydrocannabinol and cannabielsoin (IC50s ≈10 µM), which contain a free phenolic hydroxyl group and are structurally constrained, were less potent than that of CBDM, which contains a free phenolic hydroxyl group and is rotatable between pentylresorcinol and terpene moieties. These results suggest that the pentylresorcinol structure in CBD may have structurally important roles in direct CYP1A1 inhibition, although the whole structure of CBD is required for overall inhibition.

1 . Cannabidiol (id=NPDI-BfJ7dA)

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

Estimated from Fig 4a. CBD 1 μM.
Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

200 μL

NADPH

5 min

2 . Cannabidiol-2'-monomethyl ether (id=NPDI-E6xHTA)

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

%inhibition estimated from Fig 3
Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

200 μL

NADPH

5 min

3 . Cannabidiol-2',6'-dimethyl ether (id=NPDI-9ju4Lw)

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

%inhibition estimated from Fig 3 at 25 μM.
Table 1.

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

200 μL

NADPH

5 min

4 . Cannabidvarin (id=NPDI-ZmjyHw)

In Vitro Enzyme Inhibition Experiment

Inhibition was detected.  Cutoff used — Not specified

7-ethoxyresorufin -7999995

cannabidivarin

resorufin -7999853

  • CYP1A1 4173297

Recombinant expression system Baculovirus-insect cells
Cytochrome B5 No

Results

%inhibition estimated from Fig 4a.
Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

200 μL

NADPH

5 min

5 . THC (id=NPDI-iJRQWg)

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 Not available

Results

Fig 5
Table 1

Compound measured Measurement Value Study sequence Additional information N replicates

Experimental Conditions

Commercially available

200 μL

NADPH

5 min