Structural Requirements for Potent Direct Inhibition of Human Cytochrome P450 1A1 by Cannabidiol: Role of Pentylresorcinol Moiety

Abstract

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 (IC 50 =13.8 µm)was less potent than that of CBD (IC 50 =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 IC 50 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 (IC 50 =1.85 µm) was lower than that of CBD. The inhibitory effects of Δ 9 -tetrahydrocannabinol and cannabielsoin (IC 50 s ≈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.Key words cannabidiol; cytochrome P450 1A1; direct inhibition; structural requirement; pentylresorcinol Cannabidiol (CBD), one of the major constituents in marijuana, 1) is not psychoactive but has several pharmacological effects such as prolonging drug-induced sleep, antiepileptic, anxiolytic, and antiemetic actions.2) CBD is also known to inhibit hepatic microsomal drug metabolism in mammals. [3][4][5] A previous clinical study has shown that the administration of CBD reduces the systemic clearance of hexobarbital, which is metabolized by cytochrome P450 2C9 (CYP2C9), in human subjects.6) In vitro studies by Jaeger et al. 7) and us 8-13) demonstrated that CBD inhibits catalytic activities of CYP1A1, CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5 in human liver microsomes and/or recombinant CYP enzymes. Interestingly, we have recently reported that the CBD-mediated direct inhibition of human CYP1A1 activity is the strongest among those of CYP activities reported so far.8) In addition, CYP1A1 was more potently inhibited by CBD than by the other major phytocannabinoids examined. 8) CYP1A1 is expressed in various tissues including the liver and lung, [14][15][16] although the constitutive expression level is very low. In general, hepatic and pulmonary CYP1A1 is induced by exposure to tobacco smoke. 17,18) C...

A New Data Repository for Pharmacokinetic Natural Product-Drug Interactions: From Chemical Characterization to Clinical Studies

“…Data from a total of 22 published in vitro reports focusing on cannabis-drug interactions were entered into the repository (Holland et al, 2006(Holland et al, , 2007(Holland et al, , 2008Zhu et al, 2006;Watanabe et al, 2007;Mazur et al, 2009;Alhamoruni et al, 2010;Tournier et al, 2010;Yamaori et al, 2010Yamaori et al, , 2011aYamaori et al, ,b, 2012Yamaori et al, , 2013Yamaori et al, , 2014Yamaori et al, , 2015Jiang et al, 2011Jiang et al, , 2013Arnold et al, 2012;Al Saabi et al, 2013;Feinshtein et al, 2013a,b;Qian et al, 2019). As Figure 4 shows, experiments using either human liver microsomes or recombinant baculovirus-transfected insect cells expressing specific P450/UGT isoforms reported that cannabinoids inhibit CYP1A1, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4/5, and UGT (Mazur et al, 2009;Yamaori et al, 2010Yamaori et al, , 2011aYamaori et al, ,b, 2012Yamaori et al, , 2013Al Saabi et al, 2013;Jiang et al, 2013;Qian et al, 2019). Yamaori et al reported that CBD mechanistically inhibited CYP1A1 in vitro in recombinant baculovirus transfected insect cells.…”

To CBD or not to CBD?: What pharmacists need to know

“…12 It is important to note that while all these changes in hemp classifi cation have occurred, marijuana and other cannabinoids are still currently considered a Schedule I substance. Therefore, marijuana and cannabinoid products 1 F Fi ig gu ur re e 3 3 C CY YP P4 45 50 0 E En nz zy ym me e I In nt te er ra ac ct ti io on ns s 48,49,50 . CYP450 Enzyme Interactions 47,48,49 are still under strict regulation of CSA and DEA and are not for legal production.…”

“…Therefore, marijuana and cannabinoid products 1 F Fi ig gu ur re e 3 3 C CY YP P4 45 50 0 E En nz zy ym me e I In nt te er ra ac ct ti io on ns s 48,49,50 . CYP450 Enzyme Interactions 47,48,49 are still under strict regulation of CSA and DEA and are not for legal production. In comparison to hemp, THC levels for these products can average anywhere between 10% to 30%.…”

Characterization of the structural determinants required for potent mechanism-based inhibition of human cytochrome P450 1A1 by cannabidiol

“…We previously elucidated the structural requirements for the inhibition of cyclooxygenase, lipoxygenase, and CYP by CBD and its derivatives [6][7][8][10][11][12]. Our direct inhibition study with CBD derivatives and molecular modeling revealed that the pentylresorcinol structure in CBD had structurally important roles in direct CYP1A1 inhibition; however, the whole structure of CBD is known to be required for overall inhibition [13]. These studies on structure-inhibition relationships may provide an insight into the mechanism(s) underlying the potent inhibition of human CYP1A1 by CBD.…”