Identification of cytochrome P450 enzymes responsible for metabolism of cannabidiol by human liver microsomes
Identification of cytochrome P450 enzymes responsible for metabolism of cannabidiol by human liver microsomes
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DOI：
10.1016/j.lfs.2011.05.018
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发表时间：
2011-08-01
期刊：
影响因子：
6.1
通讯作者：
Watanabe, Kazuhito
中科院分区：
文献类型：
--
作者：
Jiang, Rongrong;Yamaori, Satoshi;Watanabe, Kazuhito
大麻二酚（CBD）是大麻中的主要成分之一，已被实验动物和人类广泛代谢。然而，负责CBD代谢的人类肝酶仍有待阐明。在这项研究中，我们研究了CBD与人肝微粒体（HLM）的体外代谢，以澄清参与CBD氧化的细胞色素P450（CYP）亚型。主要方法：通过气相色谱/质谱分析HLM和重组人CYP酶中CBD的氧化。CBD被合并的HLM代谢为8种单羟基化代谢产物（6 α-OH-、6 β-OH-、7-OH-、1“-OH-、2”-OH-、3“-OH-、4”-OH-和5“-OH-CBD）。在这些代谢产物中，6 α-OH-、6 β-OH-、7-OH-。根据m/z 478的相对丰度估计，4“-OH-CBD是主要的代谢产物，m/z 478是代谢产物三甲基硅基衍生物的主要碎片离子。14种重组人CBD酶中有7种（CYP 1A 1、CYP 1A 2、CYP 2C 9、CYP 2C 19、CYP 2D 6、CYP 3A 4和CYP 3A 5）能够代谢CBD。在16个HLM中，β-羟色胺异构体特异性活性与CBD氧化活性之间的相关性表明，6个β-OH-和4“-OH-CBD主要由CYP 3A 4形成，这得到了使用酮康唑和抗CYP 3A 4抗体进行的抑制研究的支持。相关性和抑制性研究还表明，CBD 6 α-羟基化主要由CYP 3A 4和CYP 2C 19催化，而CBD 7-羟基化主要由CYP 2C 19催化。这些结果表明，CYP 3A 4和CYP 2C 19可能是负责HLM中CBD的6 α-、6 β-、7-和/或4“-羟基化的主要同种型。(C)2011 Elsevier Inc. All rights reserved.
Aims: Cannabidiol (CBD), one of the major constituents in marijuana, has been shown to be extensively metabolized by experimental animals and humans. However, human hepatic enzymes responsible for the CBD metabolism remain to be elucidated. In this study, we examined in vitro metabolism of CBD with human liver microsomes (HLMs) to clarify cytochrome P450 (CYP) isoforms involved in the CBD oxidations.Main methods: Oxidations of CBD in HLMs and recombinant human CYP enzymes were analyzed by gas chromatography/mass spectrometry.Key findings: CBD was metabolized by pooled HLMs to eight monohydroxylated metabolites (6 alpha-OH-, 6 beta-OH-, 7-OH-, 1 ''-OH-, 2 ''-OH-, 3 ''-OH-, 4 ''-OH-, and 5 ''-OH-CBDs). Among these metabolites, 6 alpha-OH-, 6 beta-OH-, 7-OH-. and 4 ''-OH-CBDs were the major ones as estimated from the relative abundance of m/z 478, which was a predominant fragment ion of trimethylsilyl derivatives of the metabolites. Seven of 14 recombinant human CYP enzymes examined (CYP1A1, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A5) were capable of metabolizing CBD. The correlations between CYP isoform-specific activities and CBD oxidative activities in 16 individual HLMs indicated that 6 beta-OH- and 4 ''-OH-CBDs were mainly formed by CYP3A4, which was supported by inhibition studies using ketoconazole and an anti-CYP3A4 antibody. The correlation and inhibition studies also showed that CBD 6 alpha-hydroxylation was mainly catalyzed by CYP3A4 and CYP2C19, whereas CBD 7-hydroxylation was predominantly catalyzed by CYP2C19.Significance: This study indicated that CBD was extensively metabolized by HLMs. These results suggest that CYP3A4 and CYP2C19 may be major isoforms responsible for 6 alpha-, 6 beta-, 7-, and/or 4 ''-hydroxylations of CBD in HLMs. (C) 2011 Elsevier Inc. All rights reserved.