[Metabolic detoxification of bakuchiol is mediated by cytochrome P450 enzymes in human liver microsomes].
OBJECTIVE
To analyze cytochrome P450 (CYP) phenotyping for bakuchiol metabolism and study the mechanism of detoxification of bakuchiol by  human liver microsomes (HLM) in vitro.


METHODS
The CYP phenotyping for bakuchiol metabolism was determined using HLM combined with CYP  specific inhibitors and recombinant human CYP isoforms. The relative activities of CYP isoforms were determined by analyzing the formation of the  substrate metabolites using HPLC-MS/MS, in presence or absence of 1-aminobenzotriazole (ABT) which was CYP enzymes' broad spectrum inhibitor.  The residual concentrations of bakuchiol in microsomal incubates were determined using HPLC to investigate ABT's effect on the metabolism of  bakuchiol. The effects of CYP enzymes on the nephrotoxicity of bakuchiol were investigated using human kidney-2(HK-2) by MTT assay, in presence or  absence of ABT.


RESULTS
CYP1A2, CYP2C9, CYP2C19 and CYP3A4 in HLM were involved in bakuchiol metabolism, among which CYP2C19 showed  the highest metabolic rate. Co-incubation with ABT (2.5 mmol/L) could inhibit more than 90% of the enzyme activities for CYP1A2, CYP2C9, CYP2C19 and  CYP3A4. ABT (2.5 mmol/L) could inhibit the HLM metabolism of bakuchiol with inhibition ratio 83.24%±2.13%. When preincubated with ABT, the metabolic  detoxification of bakuchiol by HLM was significantly reduced (P<0.05).


CONCLUSIONS
The mechanism of metabolic detoxification of bakuchiol by HLM is  associated with bakuchiol metabolism by CYP enzymes to form non toxic or lower toxic metabolites. The broad spectrum inhibitor of CYP could inverse the  detoxification of HLM.
Department of Toxicology, Peking University School of Public Health, Beijing, China.
Ai-fang
AF
Li
Guo-lin
GL
Shen
Shi-yong
SY
Jiao
Hua
H
Li
Qi
Q
Wang
D002460:Cell Line; D065607:Cytochrome P-450 Enzyme Inhibitors; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D006801:Humans; D008658:Inactivation, Metabolic / Q000502:physiology; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000187:drug effects; D008862:Microsomes, Liver / Q000201:enzymology*; D010636:Phenols / Q000493:pharmacokinetics*; D014230:Triazoles / Q000494:pharmacology
D065607:Cytochrome P-450 Enzyme Inhibitors; D010636:Phenols; D014230:Triazoles; C033020:1-aminobenzotriazole; D003577:Cytochrome P-450 Enzyme System; C012765:bakuchiol