Flavokawain A inhibits Cytochrome P450 in in vitro metabolic and inhibitory investigations.
BACKGROUND
Flavokawain A, the major chalcone in kava extracts, was served as beverages for informal social occasions and traditional ceremonials in most South Pacific islands. It exhibited strong antiproliferative and apoptotic effects against human prostate and urinary bladder cancer cells.


OBJECTIVE
The current study was purposed to investigate the interaction between Flavokawain A and Cytochrome P450, including the inhibitory effects of Flavokawain A on predominant CYP450 isotypes and further clarified the inhibitory mechanism of FKA on CYP450 enzymes. Besides, study about identifying the key CYP450 isotypes responsible for the metabolism of FKA was also performed.


METHODS
In this study, probe-based assays with rat liver microsome system were used to characterize the inhibitory effects of FKA. Molecular docking study was performed to further explore the binding site of FKA on CYP450 isoforms. In addition, chemical inhibition experiments using specific inhibitors (a-naphthoflavone, quinidine, sulfamethoxazde, ketoconazole, omeprazole) were performed to clarify the individual CYP450 isoform that are responsible for the metabolism of FKA.


RESULTS
FKA showed significant inhibition on CYP1A2, CYP2D1, CYP2C6 and CYP3A2 activities with IC50 values of 102.23, 20.39, 69.95, 60.22μmol/L, respectively. The inhibition model was competitive, mixed-inhibition, uncompetitive, and noncompetitive for CYP1A2, CYP2D1, CYP2C6 and CYP3A2 enzymes. Molecular docking study indicated the ligand-binding conformation of FKA in the active site of CYP450 isoforms. The chemical inhibition experiments showed that the metabolic clearance rate of Flavokawain A decreased to 19.84%, 50.38%, and 67.02% of the control in the presence of ketoconazole, sulfamethoxazde and a-naphthoflavone.


CONCLUSIONS
The study showed that Flavokawain A has varying inhibitory effect on CYP450 enzymes and CYP3A2 was the principal CYP isoform contributing to the metabolism of Flavokawain A. Besides, CYP2C6 and CYP1A2 isoforms also play important roles in the metabolism of FKA. Our results provided a basis for better understanding the biotransformation of FKA and prediction of drug-drug interaction of FKA.
College of Pharmacy, Zhengzhou University, Ke Xue Road, Zhengzhou, China.
Lifeng
L
Niu
College of Pharmacy, Zhengzhou University, Ke Xue Road, Zhengzhou, China.
Lina
L
Ding
College of Pharmacy, Zhengzhou University, Ke Xue Road, Zhengzhou, China.
Chunyun
C
Lu
College of Pharmacy, Zhengzhou University, Ke Xue Road, Zhengzhou, China.
Feifei
F
Zuo
College of Pharmacy, Zhengzhou University, Ke Xue Road, Zhengzhou, China.
Ke
K
Yao
College of Pharmacy, Zhengzhou University, Ke Xue Road, Zhengzhou, China.
Shaobo
S
Xu
College of Pharmacy, Zhengzhou University, Ke Xue Road, Zhengzhou, China.
Wen
W
Li
Department of Pharmaceutical Sciences,College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Queens, New York, NY 11439, USA.
Donghua
D
Yang
College of Pharmacy, Zhengzhou University, Ke Xue Road, Zhengzhou, China. Electronic address: xuxia@zzu.edu.cn.
Xia
X
Xu
D000818:Animals; D001665:Binding Sites; D001711:Biotransformation; D002599:Chalcone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology / Q000633:toxicity; D019388:Cytochrome P-450 CYP1A2 / Q000378:metabolism; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D065607:Cytochrome P-450 Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology* / Q000633:toxicity; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D000072467:Cytochrome P450 Family 2 / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D007527:Isoenzymes; D007700:Kinetics; D008099:Liver / Q000187:drug effects* / Q000201:enzymology; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology; D062105:Molecular Docking Simulation; D011485:Protein Binding; D011487:Protein Conformation; D017207:Rats, Sprague-Dawley
D065607:Cytochrome P-450 Enzyme Inhibitors; D007527:Isoenzymes; C500809:flavokawain A; D002599:Chalcone; D003577:Cytochrome P-450 Enzyme System; C017170:Cyp1a2 protein, rat; C089877:Cyp2c6v1 protein, rat; C465260:Cyp3a2 protein, rat; D019388:Cytochrome P-450 CYP1A2; D051544:Cytochrome P-450 CYP3A; D000072467:Cytochrome P450 Family 2
Cytochrome P450; Flavokawain A; Metabolism; Molecular docking; Rat liver microsome